We search for an extent entry with .offset = -1, which shouldn't be a
thing, but corruption happens. Add an ASSERT() for the developers,
return -EUCLEAN for mortals.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We define __TRANS_DUMMY always, so this extra ifdef stuff is not needed.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This comment was much closer to the related code when it was originally
added, but has slowly migrated north far from its ancestral lands. Move
it back down with its people.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We pass in the path, but use btrfs_next_item() using the root we
searched with. Pass the root down to add_keyed_refs() instead of the
fs_info so we can continue to use the same root we searched with.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Nobody is using this anymore, remove it.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The root on the trans->root can be anything, and generally we're
committing from the transaction kthread so it's usually the tree_root.
Change this to just take an fs_info, and to maintain compatibility
simply put the ROOT_TREE_OBJECTID as the root objectid for the
tracepoint. This will allow use to remove trans->root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we do this awful thing where we get another ref on a trans
handle, async off that handle and commit the transaction from that work.
Because we do this we have to mess with current->journal_info and the
freeze counting stuff.
We already have an async thing to kick for the transaction commit, the
transaction kthread. Replace this work struct with a flag on the
fs_info to tell the kthread to go ahead and commit even if it's before
our timeout. Then we can drastically simplify the async transaction
commit path.
Note: this can be simplified and functionality based on the pending
operation COMMIT.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add note ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is no longer used, the -o nobarrier is handled by
BTRFS_MOUNT_NOBARRIER. Remove the flag.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reshuffle the code inside the first loop of tree_search_offset so that
one if() is eliminated and the becomes more linear.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When debugging calc_bio_boundaries(), I found that even for RAID1
metadata, we're following stripe length to calculate stripe boundary.
# mkfs.btrfs -m raid1 -d raid1 /dev/test/scratch[12]
# mount /dev/test/scratch /mnt/btrfs
# xfs_io -f -c "pwrite 0 64K" /mnt/btrfs/file
# umount
Above very basic operations will make calc_bio_boundaries() to report
the following result:
submit_extent_page: r/i=1/1 file_offset=22036480 len_to_stripe_boundary=49152
submit_extent_page: r/i=1/1 file_offset=30474240 len_to_stripe_boundary=65536
...
submit_extent_page: r/i=1/1 file_offset=30523392 len_to_stripe_boundary=16384
submit_extent_page: r/i=1/1 file_offset=30457856 len_to_stripe_boundary=16384
submit_extent_page: r/i=5/257 file_offset=0 len_to_stripe_boundary=65536
submit_extent_page: r/i=5/257 file_offset=65536 len_to_stripe_boundary=65536
submit_extent_page: r/i=1/1 file_offset=30490624 len_to_stripe_boundary=49152
submit_extent_page: r/i=1/1 file_offset=30507008 len_to_stripe_boundary=32768
Where "r/i" is the rootid and inode, 1/1 means they metadata.
The remaining names match the member used in kernel.
Even all data/metadata are using RAID1, we're still following stripe
length.
[CAUSE]
This behavior is caused by a wrong condition in btrfs_get_io_geometry():
if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
/* Fill using stripe_len */
len = min_t(u64, em->len - offset, max_len);
} else {
len = em->len - offset;
}
This means, only for SINGLE we will not follow stripe_len.
However for profiles like RAID1*, DUP, they don't need to bother
stripe_len.
This can lead to unnecessary bio split for RAID1*/DUP profiles, and can
even be a blockage for future zoned RAID support.
[FIX]
Introduce one single-use macro, BTRFS_BLOCK_GROUP_STRIPE_MASK, and
change the condition to only calculate the length using stripe length
for stripe based profiles.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is a small optimisation since the currently 'entry' is already
checked in the if () {} else if {} construct above the loop. In essence
the first iteration of the final while loop is redundant. To eliminate
this extra check simply get the next entry at the beginning of the loop.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I noticed a few corner cases when looking at my bytes_index patch for
obvious bugs, so add a bunch of tests to validate proper behavior of the
bytes_index tree. A couple of basic tests to make sure it puts things
in the correct order, and then more complicated tests to make sure it
re-arranges bitmap entries properly and does the right thing when we try
to make allocations.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we index free space on offset only, because usually we have a
hint from the allocator that we want to honor for locality reasons.
However if we fail to use this hint we have to go back to a brute force
search through the free space entries to find a large enough extent.
With sufficiently fragmented free space this becomes quite expensive, as
we have to linearly search all of the free space entries to find if we
have a part that's long enough.
To fix this add a cached rb tree to index based on free space entry
bytes. This will allow us to quickly look up the largest chunk in the
free space tree for this block group, and stop searching once we've
found an entry that is too small to satisfy our allocation. We simply
choose to use this tree if we're searching from the beginning of the
block group, as we know we do not care about locality at that point.
I wrote an allocator test that creates a 10TiB ram backed null block
device and then fallocates random files until the file system is full.
I think go through and delete all of the odd files. Then I spawn 8
threads that fallocate 64MiB files (1/2 our extent size cap) until the
file system is full again. I use bcc's funclatency to measure the
latency of find_free_extent. The baseline results are
nsecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 10356 |**** |
512 -> 1023 : 58242 |************************* |
1024 -> 2047 : 74418 |******************************** |
2048 -> 4095 : 90393 |****************************************|
4096 -> 8191 : 79119 |*********************************** |
8192 -> 16383 : 35614 |*************** |
16384 -> 32767 : 13418 |***** |
32768 -> 65535 : 12811 |***** |
65536 -> 131071 : 17090 |******* |
131072 -> 262143 : 26465 |*********** |
262144 -> 524287 : 40179 |***************** |
524288 -> 1048575 : 55469 |************************ |
1048576 -> 2097151 : 48807 |********************* |
2097152 -> 4194303 : 26744 |*********** |
4194304 -> 8388607 : 35351 |*************** |
8388608 -> 16777215 : 13918 |****** |
16777216 -> 33554431 : 21 | |
avg = 908079 nsecs, total: 580889071441 nsecs, count: 639690
And the patch results are
nsecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 6883 |** |
512 -> 1023 : 54346 |********************* |
1024 -> 2047 : 79170 |******************************** |
2048 -> 4095 : 98890 |****************************************|
4096 -> 8191 : 81911 |********************************* |
8192 -> 16383 : 27075 |********** |
16384 -> 32767 : 14668 |***** |
32768 -> 65535 : 13251 |***** |
65536 -> 131071 : 15340 |****** |
131072 -> 262143 : 26715 |********** |
262144 -> 524287 : 43274 |***************** |
524288 -> 1048575 : 53870 |********************* |
1048576 -> 2097151 : 55368 |********************** |
2097152 -> 4194303 : 41036 |**************** |
4194304 -> 8388607 : 24927 |********** |
8388608 -> 16777215 : 33 | |
16777216 -> 33554431 : 9 | |
avg = 623599 nsecs, total: 397259314759 nsecs, count: 637042
There's a little variation in the amount of calls done because of timing
of the threads with metadata requirements, but the avg, total, and
count's are relatively consistent between runs (usually within 2-5% of
each other). As you can see here we have around a 30% decrease in
average latency with a 30% decrease in overall time spent in
find_free_extent.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While adding self tests for my space index change I was hitting a
problem where the space indexed tree wasn't returning the expected
->max_extent_size. This is because we will skip searching any entry
that doesn't have ->bytes >= the amount of bytes we want. However we'll
still set the max_extent_size based on that entry. The problem is if we
don't search the bitmap we won't have ->max_extent_size set properly, so
we can't really trust it.
This doesn't really result in a problem per-se, it can just result in us
not finding contiguous area that may exist. Fix the max_extent_size
helper to return ->bytes if ->max_extent_size isn't set, and add a big
comment explaining why we're doing this.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We use @nr_written to record how many pages have been started by
btrfs_run_delalloc_range().
Currently there are only two cases that would populate @nr_written:
- Inline extent creation
- Compressed write
But both cases will also set @page_started to one.
In fact, in writepage_delalloc() we have the following code, showing
that @nr_written is really only utilized for above two cases:
/* did the fill delalloc function already unlock and start
* the IO?
*/
if (page_started) {
/*
* we've unlocked the page, so we can't update
* the mapping's writeback index, just update
* nr_to_write.
*/
wbc->nr_to_write -= nr_written;
return 1;
}
But for such cases, writepage_delalloc() will return 1, and exit
__extent_writepage() without going through __extent_writepage_io().
Thus this means, inside __extent_writepage_io(), we always get
@nr_written as 0.
So this patch is going to remove the unnecessary parameter from the
following functions:
- writepage_delalloc()
As @nr_written passed in is always the initial value 0.
Although inside that function, we still need a local @nr_written
to update wbc->nr_to_write.
- __extent_writepage_io()
As explained above, @nr_written passed in can only be 0.
This also means we can remove one update_nr_written() call.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We used to need the root for btrfs_reserve_metadata_bytes to check the
orphan cleanup state, but we no longer need that, we simply need the
fs_info. Change btrfs_reserve_metadata_bytes() to use the fs_info, and
change both btrfs_block_rsv_refill() and btrfs_block_rsv_add() to do the
same as they simply call btrfs_reserve_metadata_bytes() and then
manipulate the block_rsv that is being used.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we don't care about the stage of the orphan_cleanup_state,
simply replace it with a bit on ->state to make sure we don't call the
orphan cleanup every time we wander into this root.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is very old code before we were stealing from the global reserve
during evict. We have proper ways to steal from the global reserve
while we're evicting, so rip out this code as it's no longer necessary.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I forgot to convert this over when I introduced the global reserve
stealing code to the space flushing code. Evict was simply trying to
make its reservation and then if it failed it would steal from the
global rsv, which is racey because it's outside of the normal ticketing
code.
Fix this by setting ticket->steal if we are BTRFS_RESERVE_FLUSH_EVICT,
and then make the priority flushing path do the steal for us.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're going to use this helper in the priority flushing loop, move this
check into the helper to simplify the logic.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we're dropping locks before we enter the priority flushing loops
we could have had our ticket granted before we got the space_info->lock.
So add this check to avoid doing some extra flushing in the priority
flushing cases.
The case in priority_reclaim_metadata_space is an optimization. Think
we came in to reserve, we didn't have the space, we added our ticket to
the list. But at the same time somebody was waiting on the space_info
lock to add space and do btrfs_try_granting_ticket(), so we drop the
lock, get satisfied, come in to do our loop, and we have been
satisfied.
This is the priority reclaim path, so to_reclaim could be !0 still
because we may have only satisfied the priority tickets and still left
non priority tickets on the list. We would then have to_reclaim but
->bytes == 0.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add note about the optimization ]
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the error case for the priority tickets is handled where we
deal with all of the tickets, priority and non-priority. This is OK in
general, but it makes for some awkward locking. We take and drop the
space_info->lock back to back because of these different types of
tickets.
Rework the code to handle priority ticket failures in their respective
helpers. This allows us to be less wonky with our space_info->lock
usage, and means that the main handler simply has to check
ticket->error, as the ticket is guaranteed to be off any list and
completely handled by the time it exits one of the handlers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When mounting a device, we are reporting the zones twice: once for
checking the zone attributes in btrfs_get_dev_zone_info and once for
loading block groups' zone info in
btrfs_load_block_group_zone_info(). With a lot of block groups, that
leads to a lot of REPORT ZONE commands and slows down the mount
process.
This patch introduces a zone info cache in struct
btrfs_zoned_device_info. The cache is populated while in
btrfs_get_dev_zone_info() and used for
btrfs_load_block_group_zone_info() to reduce the number of REPORT ZONE
commands. The zone cache is then released after loading the block
groups, as it will not be much effective during the run time.
Benchmark: Mount an HDD with 57,007 block groups
Before patch: 171.368 seconds
After patch: 64.064 seconds
While it still takes a minute due to the slowness of loading all the
block groups, the patch reduces the mount time by 1/3.
Link: https://lore.kernel.org/linux-btrfs/CAHQ7scUiLtcTqZOMMY5kbWUBOhGRwKo6J6wYPT5WY+C=cD49nQ@mail.gmail.com/
Fixes: 5b31646898 ("btrfs: get zone information of zoned block devices")
CC: stable@vger.kernel.org
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit ba8a9d0795 ("Btrfs: delete the entire async bio submission
framework") removed submit workqueues, the parameter fs_devices is not used
anymore.
Remove it, no functional changes.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the transaction commit path we are acquiring the tree log mutex too
early and we have a stale comment because:
1) It mentions a function named btrfs_commit_tree_roots(), which does not
exists anymore, it was the old name of commit_cowonly_roots(), renamed
a very long time ago by commit 5d4f98a28c ("Btrfs: Mixed back
reference (FORWARD ROLLING FORMAT CHANGE)"));
2) It mentions that we need to acquire the tree log mutex at that point
to ensure we have no running log writers. That is not correct anymore,
for many years at least, since we are guaranteed that we do not have
any log writers at that point simply because we have set the state of
the transaction to TRANS_STATE_COMMIT_DOING and have waited for all
writers to complete - meaning no one can log until we change the state
of the transaction to TRANS_STATE_UNBLOCKED. Any attempts to join the
transaction or start a new one will block until we do that state
transition;
3) The comment mentions a "trans mutex" which doesn't exists since 2011,
commit a4abeea41a ("Btrfs: kill trans_mutex") removed it;
4) The current use of the tree log mutex is to ensure proper serialization
of super block writes - if someone started a new transaction and uses it
for logging, it will wait for the previous transaction to write its
super block before writing the super block when attempting to sync the
log.
So acquire the tree log mutex only when it's absolutely needed, before
setting the transaction state to TRANS_STATE_UNBLOCKED, fix and move the
stale comment, add some assertions and new comments where appropriate.
Also, this has no effect on concurrency or performance, since the new
start of the critical section is still when the transaction is in the
state TRANS_STATE_COMMIT_DOING.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_prepare_sprout() splices seed devices into its own struct fs_devices,
so that its parent function btrfs_init_new_device() can add the new sprout
device to fs_info->fs_devices.
Both btrfs_prepare_sprout() and btrfs_init_new_device() need
device_list_mutex. But they are holding it separately, thus create a
small race window. Close it and hold device_list_mutex across both
functions btrfs_init_new_device() and btrfs_prepare_sprout().
Split btrfs_prepare_sprout() into btrfs_init_sprout() and
btrfs_setup_sprout(). This split is essential because device_list_mutex
must not be held for allocations in btrfs_init_sprout() but must be held
for btrfs_setup_sprout(). So now a common device_list_mutex can be used
between btrfs_init_new_device() and btrfs_setup_sprout().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Declare int seeding_dev as a bool. Also, move its declaration a line
below to adjust packing.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Again, I don't think this was ever used since iterate_dir_item() is only
used for xattrs. No functional change.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
As far as I can tell, this was never used. No functional change.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The name btrfs_item_end_nr() is a bit of a misnomer, as it's actually
the offset of the end of the data the item points to. In fact all of
the helpers that we use btrfs_item_end_nr() use data in their name, like
BTRFS_LEAF_DATA_SIZE() and leaf_data(). Rename to btrfs_item_data_end()
to make it clear what this helper is giving us.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're only using btrfs_item_end() from btrfs_item_end_nr(), so this can
be collapsed.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all call sites are using the slot number to modify item values,
rename the SETGET helpers to raw_item_*(), and then rework the _nr()
helpers to be the btrfs_item_*() btrfs_set_item_*() helpers, and then
rename all of the callers to the new helpers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The last remaining place where we have the pattern of
item = btrfs_item_nr(slot)
<do something with the item>
are the token helpers. Handle this by introducing token helpers that
will do the btrfs_item_nr() work inside of the helper itself, and then
convert all users of the btrfs_item token helpers to the new _nr()
variants.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of getting the btrfs_item for this, simply pass in the slot of
the item and then use the btrfs_item_size_nr() helper inside of
btrfs_file_extent_inline_item_len().
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have the pattern of
item = btrfs_item_nr(slot);
btrfs_set_item_*(leaf, item);
in a bunch of places in our code. Fix this by adding
btrfs_set_item_*_nr() helpers which will do the appropriate work, and
replace those calls with
btrfs_set_item_*_nr(leaf, slot);
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have this pattern in a lot of places
item = btrfs_item_nr(slot);
btrfs_item_size(leaf, item);
when we could simply use
btrfs_item_size(leaf, slot);
Fix all callers of btrfs_item_size() and btrfs_item_offset() to use the
_nr variation of the helpers.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we log only dir index keys when logging a directory, we no longer
need to deal with dir item keys in the log replay code for replaying
directory deletes. This is also true for the case when we replay a log
tree created by a kernel that still logs dir items.
So remove the remaining code of the replay of directory deletes algorithm
that deals with dir item keys.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, when logging a directory, we copy both dir items and dir index
items from the fs/subvolume tree to the log tree. Both items have exactly
the same data (same struct btrfs_dir_item), the difference lies in the key
values, where a dir index key contains the index number of a directory
entry while the dir item key does not, as it's used for doing fast lookups
of an entry by name, while the former is used for sorting entries when
listing a directory.
We can exploit that and log only the dir index items, since they contain
all the information needed to correctly add, replace and delete directory
entries when replaying a log tree. Logging only the dir index items is
also backward and forward compatible: an unpatched kernel (without this
change) can correctly replay a log tree generated by a patched kernel
(with this patch), and a patched kernel can correctly replay a log tree
generated by an unpatched kernel.
The backward compatibility is ensured because:
1) For inserting a new dentry: a dentry is only inserted when we find a
new dir index key - we can only insert if we know the dir index offset,
which is encoded in the dir index key's offset;
2) For deleting dentries: during log replay, before adding or replacing
dentries, we first replay dentry deletions. Whenever we find a dir item
key or a dir index key in the subvolume/fs tree that is not logged in
a range for which the log tree is authoritative, we do the unlink of
the dentry, which removes both the existing dir item key and the dir
index key. Therefore logging just dir index keys is enough to ensure
dentry deletions are correctly replayed;
3) For dentry replacements: they work when we log only dir index keys
and this is mostly due to a combination of 1) and 2). If we replace a
dentry with name "foobar" to point from inode A to inode B, then we
know the dir index key for the new dentry is different from the old
one, as it has an index number (key offset) larger than the old one.
This results in replaying a deletion, through replay_dir_deletes(),
that causes the old dentry to be removed, both the dir item key and
the dir index key, as mentioned at 2). Then when processing the new
dir index key, we add the new dentry, adding both a new dir item key
and a new index key pointing to inode B, as stated in 1).
The forward compatibility, the ability for a patched kernel to replay a
log created by an older, unpatched kernel, comes from the changes required
for making sure we are able to replay a log that only contains dir index
keys - we simply ignore every dir item key we find.
So modify directory logging to log only dir index items, and modify the
log replay process to ignore dir item keys, from log trees created by an
unpatched kernel, and process only with dir index keys. This reduces the
amount of logged metadata by about half, and therefore the time spent
logging or fsyncing large directories (less CPU time and less IO).
The following test script was used to measure this change:
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
NUM_NEW_FILES=1000000
NUM_FILE_DELETES=10000
mkfs.btrfs -f $DEV
mount -o ssd $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_NEW_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after adding $NUM_NEW_FILES files"
# sync to force transaction commit and wipeout the log.
sync
del_inc=$(( $NUM_NEW_FILES / $NUM_FILE_DELETES ))
for ((i = 1; i <= $NUM_NEW_FILES; i += $del_inc)); do
rm -f $MNT/testdir/file_$i
done
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after deleting $NUM_FILE_DELETES files"
echo
umount $MNT
The tests were run on a physical machine, with a non-debug kernel (Debian's
default kernel config), for different values of $NUM_NEW_FILES and
$NUM_FILE_DELETES, and the results were the following:
** Before patch, NUM_NEW_FILES = 1 000 000, NUM_DELETE_FILES = 10 000 **
dir fsync took 8412 ms after adding 1000000 files
dir fsync took 500 ms after deleting 10000 files
** After patch, NUM_NEW_FILES = 1 000 000, NUM_DELETE_FILES = 10 000 **
dir fsync took 4252 ms after adding 1000000 files (-49.5%)
dir fsync took 269 ms after deleting 10000 files (-46.2%)
** Before patch, NUM_NEW_FILES = 100 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 745 ms after adding 100000 files
dir fsync took 59 ms after deleting 1000 files
** After patch, NUM_NEW_FILES = 100 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 404 ms after adding 100000 files (-45.8%)
dir fsync took 31 ms after deleting 1000 files (-47.5%)
** Before patch, NUM_NEW_FILES = 10 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 67 ms after adding 10000 files
dir fsync took 9 ms after deleting 1000 files
** After patch, NUM_NEW_FILES = 10 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 36 ms after adding 10000 files (-46.3%)
dir fsync took 5 ms after deleting 1000 files (-44.4%)
** Before patch, NUM_NEW_FILES = 1 000, NUM_DELETE_FILES = 100 **
dir fsync took 9 ms after adding 1000 files
dir fsync took 4 ms after deleting 100 files
** After patch, NUM_NEW_FILES = 1 000, NUM_DELETE_FILES = 100 **
dir fsync took 7 ms after adding 1000 files (-22.2%)
dir fsync took 3 ms after deleting 100 files (-25.0%)
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since both unused block groups and reclaim bgs lists are protected by
unused_bgs_lock then free them in the same critical section without
doing an extra unlock/lock pair.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When enabling quotas, we attempt to commit a transaction while holding the
mutex fs_info->qgroup_ioctl_lock. This can result on a deadlock with other
quota operations such as:
- qgroup creation and deletion, ioctl BTRFS_IOC_QGROUP_CREATE;
- adding and removing qgroup relations, ioctl BTRFS_IOC_QGROUP_ASSIGN.
This is because these operations join a transaction and after that they
attempt to lock the mutex fs_info->qgroup_ioctl_lock. Acquiring that mutex
after joining or starting a transaction is a pattern followed everywhere
in qgroups, so the quota enablement operation is the one at fault here,
and should not commit a transaction while holding that mutex.
Fix this by making the transaction commit while not holding the mutex.
We are safe from two concurrent tasks trying to enable quotas because
we are serialized by the rw semaphore fs_info->subvol_sem at
btrfs_ioctl_quota_ctl(), which is the only call site for enabling
quotas.
When this deadlock happens, it produces a trace like the following:
INFO: task syz-executor:25604 blocked for more than 143 seconds.
Not tainted 5.15.0-rc6 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:24800 pid:25604 ppid: 24873 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
btrfs_commit_transaction+0x994/0x2e90 fs/btrfs/transaction.c:2201
btrfs_quota_enable+0x95c/0x1790 fs/btrfs/qgroup.c:1120
btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:4229 [inline]
btrfs_ioctl+0x637e/0x7b70 fs/btrfs/ioctl.c:5010
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f86920b2c4d
RSP: 002b:00007f868f61ac58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f86921d90a0 RCX: 00007f86920b2c4d
RDX: 0000000020005e40 RSI: 00000000c0109428 RDI: 0000000000000008
RBP: 00007f869212bd80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f86921d90a0
R13: 00007fff6d233e4f R14: 00007fff6d233ff0 R15: 00007f868f61adc0
INFO: task syz-executor:25628 blocked for more than 143 seconds.
Not tainted 5.15.0-rc6 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:29080 pid:25628 ppid: 24873 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
__mutex_lock_common kernel/locking/mutex.c:669 [inline]
__mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729
btrfs_remove_qgroup+0xb7/0x7d0 fs/btrfs/qgroup.c:1548
btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:4333 [inline]
btrfs_ioctl+0x683c/0x7b70 fs/btrfs/ioctl.c:5014
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Reported-by: Hao Sun <sunhao.th@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CACkBjsZQF19bQ1C6=yetF3BvL10OSORpFUcWXTP6HErshDB4dQ@mail.gmail.com/
Fixes: 340f1aa27f ("btrfs: qgroups: Move transaction management inside btrfs_quota_enable/disable")
CC: stable@vger.kernel.org # 4.19
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing a direct IO write against a file range that either has
preallocated extents in that range or has regular extents and the file
has the NOCOW attribute set, the write fails with -ENOSPC when all of
the following conditions are met:
1) There are no data blocks groups with enough free space matching
the size of the write;
2) There's not enough unallocated space for allocating a new data block
group;
3) The extents in the target file range are not shared, neither through
snapshots nor through reflinks.
This is wrong because a NOCOW write can be done in such case, and in fact
it's possible to do it using a buffered IO write, since when failing to
allocate data space, the buffered IO path checks if a NOCOW write is
possible.
The failure in direct IO write path comes from the fact that early on,
at btrfs_dio_iomap_begin(), we try to allocate data space for the write
and if it that fails we return the error and stop - we never check if we
can do NOCOW. But later, at btrfs_get_blocks_direct_write(), we check
if we can do a NOCOW write into the range, or a subset of the range, and
then release the previously reserved data space.
Fix this by doing the data reservation only if needed, when we must COW,
at btrfs_get_blocks_direct_write() instead of doing it at
btrfs_dio_iomap_begin(). This also simplifies a bit the logic and removes
the inneficiency of doing unnecessary data reservations.
The following example test script reproduces the problem:
$ cat dio-nocow-enospc.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
# Use a small fixed size (1G) filesystem so that it's quick to fill
# it up.
# Make sure the mixed block groups feature is not enabled because we
# later want to not have more space available for allocating data
# extents but still have enough metadata space free for the file writes.
mkfs.btrfs -f -b $((1024 * 1024 * 1024)) -O ^mixed-bg $DEV
mount $DEV $MNT
# Create our test file with the NOCOW attribute set.
touch $MNT/foobar
chattr +C $MNT/foobar
# Now fill in all unallocated space with data for our test file.
# This will allocate a data block group that will be full and leave
# no (or a very small amount of) unallocated space in the device, so
# that it will not be possible to allocate a new block group later.
echo
echo "Creating test file with initial data..."
xfs_io -c "pwrite -S 0xab -b 1M 0 900M" $MNT/foobar
# Now try a direct IO write against file range [0, 10M[.
# This should succeed since this is a NOCOW file and an extent for the
# range was previously allocated.
echo
echo "Trying direct IO write over allocated space..."
xfs_io -d -c "pwrite -S 0xcd -b 10M 0 10M" $MNT/foobar
umount $MNT
When running the test:
$ ./dio-nocow-enospc.sh
(...)
Creating test file with initial data...
wrote 943718400/943718400 bytes at offset 0
900 MiB, 900 ops; 0:00:01.43 (625.526 MiB/sec and 625.5265 ops/sec)
Trying direct IO write over allocated space...
pwrite: No space left on device
A test case for fstests will follow, testing both this direct IO write
scenario as well as the buffered IO write scenario to make it less likely
to get future regressions on the buffered IO case.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.16-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more fixes, almost all error handling one-liners and for stable.
- regression fix in directory logging items
- regression fix of extent buffer status bits handling after an error
- fix memory leak in error handling path in tree-log
- fix freeing invalid anon device number when handling errors during
subvolume creation
- fix warning when freeing leaf after subvolume creation failure
- fix missing blkdev put in device scan error handling
- fix invalid delayed ref after subvolume creation failure"
* tag 'for-5.16-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix missing blkdev_put() call in btrfs_scan_one_device()
btrfs: fix warning when freeing leaf after subvolume creation failure
btrfs: fix invalid delayed ref after subvolume creation failure
btrfs: check WRITE_ERR when trying to read an extent buffer
btrfs: fix missing last dir item offset update when logging directory
btrfs: fix double free of anon_dev after failure to create subvolume
btrfs: fix memory leak in __add_inode_ref()
The function btrfs_scan_one_device() calls blkdev_get_by_path() and
blkdev_put() to get and release its target block device. However, when
btrfs_sb_log_location_bdev() fails, blkdev_put() is not called and the
block device is left without clean up. This triggered failure of fstests
generic/085. Fix the failure path of btrfs_sb_log_location_bdev() to
call blkdev_put().
Fixes: 12659251ca ("btrfs: implement log-structured superblock for ZONED mode")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When creating a subvolume, at ioctl.c:create_subvol(), if we fail to
insert the new root's root item into the root tree, we are freeing the
metadata extent we reserved for the new root to prevent a metadata
extent leak, as we don't abort the transaction at that point (since
there is nothing at that point that is irreversible).
However we allocated the metadata extent for the new root which we are
creating for the new subvolume, so its delayed reference refers to the
ID of this new root. But when we free the metadata extent we pass the
root of the subvolume where the new subvolume is located to
btrfs_free_tree_block() - this is incorrect because this will generate
a delayed reference that refers to the ID of the parent subvolume's root,
and not to ID of the new root.
This results in a failure when running delayed references that leads to
a transaction abort and a trace like the following:
[3868.738042] RIP: 0010:__btrfs_free_extent+0x709/0x950 [btrfs]
[3868.739857] Code: 68 0f 85 e6 fb ff (...)
[3868.742963] RSP: 0018:ffffb0e9045cf910 EFLAGS: 00010246
[3868.743908] RAX: 00000000fffffffe RBX: 00000000fffffffe RCX: 0000000000000002
[3868.745312] RDX: 00000000fffffffe RSI: 0000000000000002 RDI: ffff90b0cd793b88
[3868.746643] RBP: 000000000e5d8000 R08: 0000000000000000 R09: ffff90b0cd793b88
[3868.747979] R10: 0000000000000002 R11: 00014ded97944d68 R12: 0000000000000000
[3868.749373] R13: ffff90b09afe4a28 R14: 0000000000000000 R15: ffff90b0cd793b88
[3868.750725] FS: 00007f281c4a8b80(0000) GS:ffff90b3ada00000(0000) knlGS:0000000000000000
[3868.752275] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[3868.753515] CR2: 00007f281c6a5000 CR3: 0000000108a42006 CR4: 0000000000370ee0
[3868.754869] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[3868.756228] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[3868.757803] Call Trace:
[3868.758281] <TASK>
[3868.758655] ? btrfs_merge_delayed_refs+0x178/0x1c0 [btrfs]
[3868.759827] __btrfs_run_delayed_refs+0x2b1/0x1250 [btrfs]
[3868.761047] btrfs_run_delayed_refs+0x86/0x210 [btrfs]
[3868.762069] ? lock_acquired+0x19f/0x420
[3868.762829] btrfs_commit_transaction+0x69/0xb20 [btrfs]
[3868.763860] ? _raw_spin_unlock+0x29/0x40
[3868.764614] ? btrfs_block_rsv_release+0x1c2/0x1e0 [btrfs]
[3868.765870] create_subvol+0x1d8/0x9a0 [btrfs]
[3868.766766] btrfs_mksubvol+0x447/0x4c0 [btrfs]
[3868.767669] ? preempt_count_add+0x49/0xa0
[3868.768444] __btrfs_ioctl_snap_create+0x123/0x190 [btrfs]
[3868.769639] ? _copy_from_user+0x66/0xa0
[3868.770391] btrfs_ioctl_snap_create_v2+0xbb/0x140 [btrfs]
[3868.771495] btrfs_ioctl+0xd1e/0x35c0 [btrfs]
[3868.772364] ? __slab_free+0x10a/0x360
[3868.773198] ? rcu_read_lock_sched_held+0x12/0x60
[3868.774121] ? lock_release+0x223/0x4a0
[3868.774863] ? lock_acquired+0x19f/0x420
[3868.775634] ? rcu_read_lock_sched_held+0x12/0x60
[3868.776530] ? trace_hardirqs_on+0x1b/0xe0
[3868.777373] ? _raw_spin_unlock_irqrestore+0x3e/0x60
[3868.778280] ? kmem_cache_free+0x321/0x3c0
[3868.779011] ? __x64_sys_ioctl+0x83/0xb0
[3868.779718] __x64_sys_ioctl+0x83/0xb0
[3868.780387] do_syscall_64+0x3b/0xc0
[3868.781059] entry_SYSCALL_64_after_hwframe+0x44/0xae
[3868.781953] RIP: 0033:0x7f281c59e957
[3868.782585] Code: 3c 1c 48 f7 d8 4c (...)
[3868.785867] RSP: 002b:00007ffe1f83e2b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[3868.787198] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281c59e957
[3868.788450] RDX: 00007ffe1f83e2c0 RSI: 0000000050009418 RDI: 0000000000000003
[3868.789748] RBP: 00007ffe1f83f300 R08: 0000000000000000 R09: 00007ffe1f83fe36
[3868.791214] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
[3868.792468] R13: 0000000000000003 R14: 00007ffe1f83e2c0 R15: 00000000000003cc
[3868.793765] </TASK>
[3868.794037] irq event stamp: 0
[3868.794548] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[3868.795670] hardirqs last disabled at (0): [<ffffffff98294214>] copy_process+0x934/0x2040
[3868.797086] softirqs last enabled at (0): [<ffffffff98294214>] copy_process+0x934/0x2040
[3868.798309] softirqs last disabled at (0): [<0000000000000000>] 0x0
[3868.799284] ---[ end trace be24c7002fe27747 ]---
[3868.799928] BTRFS info (device dm-0): leaf 241188864 gen 1268 total ptrs 214 free space 469 owner 2
[3868.801133] BTRFS info (device dm-0): refs 2 lock_owner 225627 current 225627
[3868.802056] item 0 key (237436928 169 0) itemoff 16250 itemsize 33
[3868.802863] extent refs 1 gen 1265 flags 2
[3868.803447] ref#0: tree block backref root 1610
(...)
[3869.064354] item 114 key (241008640 169 0) itemoff 12488 itemsize 33
[3869.065421] extent refs 1 gen 1268 flags 2
[3869.066115] ref#0: tree block backref root 1689
(...)
[3869.403834] BTRFS error (device dm-0): unable to find ref byte nr 241008640 parent 0 root 1622 owner 0 offset 0
[3869.405641] BTRFS: error (device dm-0) in __btrfs_free_extent:3076: errno=-2 No such entry
[3869.407138] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2159: errno=-2 No such entry
Fix this by passing the new subvolume's root ID to btrfs_free_tree_block().
This requires changing the root argument of btrfs_free_tree_block() from
struct btrfs_root * to a u64, since at this point during the subvolume
creation we have not yet created the struct btrfs_root for the new
subvolume, and btrfs_free_tree_block() only needs a root ID and nothing
else from a struct btrfs_root.
This was triggered by test case generic/475 from fstests.
Fixes: 67addf2900 ("btrfs: fix metadata extent leak after failure to create subvolume")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Filipe reported a hang when we have errors on btrfs. This turned out to
be a side-effect of my fix c2e3930529 ("btrfs: clear extent buffer
uptodate when we fail to write it") which made it so we clear
EXTENT_BUFFER_UPTODATE on an eb when we fail to write it out.
Below is a paste of Filipe's analysis he got from using drgn to debug
the hang
"""
btree readahead code calls read_extent_buffer_pages(), sets ->io_pages to
a value while writeback of all pages has not yet completed:
--> writeback for the first 3 pages finishes, we clear
EXTENT_BUFFER_UPTODATE from eb on the first page when we get an
error.
--> at this point eb->io_pages is 1 and we cleared Uptodate bit from the
first 3 pages
--> read_extent_buffer_pages() does not see EXTENT_BUFFER_UPTODATE() so
it continues, it's able to lock the pages since we obviously don't
hold the pages locked during writeback
--> read_extent_buffer_pages() then computes 'num_reads' as 3, and sets
eb->io_pages to 3, since only the first page does not have Uptodate
bit set at this point
--> writeback for the remaining page completes, we ended decrementing
eb->io_pages by 1, resulting in eb->io_pages == 2, and therefore
never calling end_extent_buffer_writeback(), so
EXTENT_BUFFER_WRITEBACK remains in the eb's flags
--> of course, when the read bio completes, it doesn't and shouldn't
call end_extent_buffer_writeback()
--> we should clear EXTENT_BUFFER_UPTODATE only after all pages of
the eb finished writeback? or maybe make the read pages code
wait for writeback of all pages of the eb to complete before
checking which pages need to be read, touch ->io_pages, submit
read bio, etc
writeback bit never cleared means we can hang when aborting a
transaction, at:
btrfs_cleanup_one_transaction()
btrfs_destroy_marked_extents()
wait_on_extent_buffer_writeback()
"""
This is a problem because our writes are not synchronized with reads in
any way. We clear the UPTODATE flag and then we can easily come in and
try to read the EB while we're still waiting on other bio's to
complete.
We have two options here, we could lock all the pages, and then check to
see if eb->io_pages != 0 to know if we've already got an outstanding
write on the eb.
Or we can simply check to see if we have WRITE_ERR set on this extent
buffer. We set this bit _before_ we clear UPTODATE, so if the read gets
triggered because we aren't UPTODATE because of a write error we're
guaranteed to have WRITE_ERR set, and in this case we can simply return
-EIO. This will fix the reported hang.
Reported-by: Filipe Manana <fdmanana@suse.com>
Fixes: c2e3930529 ("btrfs: clear extent buffer uptodate when we fail to write it")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When logging a directory, once we finish processing a leaf that is full
of dir items, if we find the next leaf was not modified in the current
transaction, we grab the first key of that next leaf and log it as to
mark the end of a key range boundary.
However we did not update the value of ctx->last_dir_item_offset, which
tracks the offset of the last logged key. This can result in subsequent
logging of the same directory in the current transaction to not realize
that key was already logged, and then add it to the middle of a batch
that starts with a lower key, resulting later in a leaf with one key
that is duplicated and at non-consecutive slots. When that happens we get
an error later when writing out the leaf, reporting that there is a pair
of keys in wrong order. The report is something like the following:
Dec 13 21:44:50 kernel: BTRFS critical (device dm-0): corrupt leaf:
root=18446744073709551610 block=118444032 slot=21, bad key order, prev
(704687 84 4146773349) current (704687 84 1063561078)
Dec 13 21:44:50 kernel: BTRFS info (device dm-0): leaf 118444032 gen
91449 total ptrs 39 free space 546 owner 18446744073709551610
Dec 13 21:44:50 kernel: item 0 key (704687 1 0) itemoff 3835
itemsize 160
Dec 13 21:44:50 kernel: inode generation 35532 size
1026 mode 40755
Dec 13 21:44:50 kernel: item 1 key (704687 12 704685) itemoff
3822 itemsize 13
Dec 13 21:44:50 kernel: item 2 key (704687 24 3817753667)
itemoff 3736 itemsize 86
Dec 13 21:44:50 kernel: item 3 key (704687 60 0) itemoff 3728 itemsize 8
Dec 13 21:44:50 kernel: item 4 key (704687 72 0) itemoff 3720 itemsize 8
Dec 13 21:44:50 kernel: item 5 key (704687 84 140445108)
itemoff 3666 itemsize 54
Dec 13 21:44:50 kernel: dir oid 704793 type 1
Dec 13 21:44:50 kernel: item 6 key (704687 84 298800632)
itemoff 3599 itemsize 67
Dec 13 21:44:50 kernel: dir oid 707849 type 2
Dec 13 21:44:50 kernel: item 7 key (704687 84 476147658)
itemoff 3532 itemsize 67
Dec 13 21:44:50 kernel: dir oid 707901 type 2
Dec 13 21:44:50 kernel: item 8 key (704687 84 633818382)
itemoff 3471 itemsize 61
Dec 13 21:44:50 kernel: dir oid 704694 type 2
Dec 13 21:44:50 kernel: item 9 key (704687 84 654256665)
itemoff 3403 itemsize 68
Dec 13 21:44:50 kernel: dir oid 707841 type 1
Dec 13 21:44:50 kernel: item 10 key (704687 84 995843418)
itemoff 3331 itemsize 72
Dec 13 21:44:50 kernel: dir oid 2167736 type 1
Dec 13 21:44:50 kernel: item 11 key (704687 84 1063561078)
itemoff 3278 itemsize 53
Dec 13 21:44:50 kernel: dir oid 704799 type 2
Dec 13 21:44:50 kernel: item 12 key (704687 84 1101156010)
itemoff 3225 itemsize 53
Dec 13 21:44:50 kernel: dir oid 704696 type 1
Dec 13 21:44:50 kernel: item 13 key (704687 84 2521936574)
itemoff 3173 itemsize 52
Dec 13 21:44:50 kernel: dir oid 704704 type 2
Dec 13 21:44:50 kernel: item 14 key (704687 84 2618368432)
itemoff 3112 itemsize 61
Dec 13 21:44:50 kernel: dir oid 704738 type 1
Dec 13 21:44:50 kernel: item 15 key (704687 84 2676316190)
itemoff 3046 itemsize 66
Dec 13 21:44:50 kernel: dir oid 2167729 type 1
Dec 13 21:44:50 kernel: item 16 key (704687 84 3319104192)
itemoff 2986 itemsize 60
Dec 13 21:44:50 kernel: dir oid 704745 type 2
Dec 13 21:44:50 kernel: item 17 key (704687 84 3908046265)
itemoff 2929 itemsize 57
Dec 13 21:44:50 kernel: dir oid 2167734 type 1
Dec 13 21:44:50 kernel: item 18 key (704687 84 3945713089)
itemoff 2857 itemsize 72
Dec 13 21:44:50 kernel: dir oid 2167730 type 1
Dec 13 21:44:50 kernel: item 19 key (704687 84 4077169308)
itemoff 2795 itemsize 62
Dec 13 21:44:50 kernel: dir oid 704688 type 1
Dec 13 21:44:50 kernel: item 20 key (704687 84 4146773349)
itemoff 2727 itemsize 68
Dec 13 21:44:50 kernel: dir oid 707892 type 1
Dec 13 21:44:50 kernel: item 21 key (704687 84 1063561078)
itemoff 2674 itemsize 53
Dec 13 21:44:50 kernel: dir oid 704799 type 2
Dec 13 21:44:50 kernel: item 22 key (704687 96 2) itemoff 2612
itemsize 62
Dec 13 21:44:50 kernel: item 23 key (704687 96 6) itemoff 2551
itemsize 61
Dec 13 21:44:50 kernel: item 24 key (704687 96 7) itemoff 2498
itemsize 53
Dec 13 21:44:50 kernel: item 25 key (704687 96 12) itemoff
2446 itemsize 52
Dec 13 21:44:50 kernel: item 26 key (704687 96 14) itemoff
2385 itemsize 61
Dec 13 21:44:50 kernel: item 27 key (704687 96 18) itemoff
2325 itemsize 60
Dec 13 21:44:50 kernel: item 28 key (704687 96 24) itemoff
2271 itemsize 54
Dec 13 21:44:50 kernel: item 29 key (704687 96 28) itemoff
2218 itemsize 53
Dec 13 21:44:50 kernel: item 30 key (704687 96 62) itemoff
2150 itemsize 68
Dec 13 21:44:50 kernel: item 31 key (704687 96 66) itemoff
2083 itemsize 67
Dec 13 21:44:50 kernel: item 32 key (704687 96 75) itemoff
2015 itemsize 68
Dec 13 21:44:50 kernel: item 33 key (704687 96 79) itemoff
1948 itemsize 67
Dec 13 21:44:50 kernel: item 34 key (704687 96 82) itemoff
1882 itemsize 66
Dec 13 21:44:50 kernel: item 35 key (704687 96 83) itemoff
1810 itemsize 72
Dec 13 21:44:50 kernel: item 36 key (704687 96 85) itemoff
1753 itemsize 57
Dec 13 21:44:50 kernel: item 37 key (704687 96 87) itemoff
1681 itemsize 72
Dec 13 21:44:50 kernel: item 38 key (704694 1 0) itemoff 1521
itemsize 160
Dec 13 21:44:50 kernel: inode generation 35534 size 30
mode 40755
Dec 13 21:44:50 kernel: BTRFS error (device dm-0): block=118444032
write time tree block corruption detected
So fix that by adding the missing update of ctx->last_dir_item_offset with
the offset of the boundary key.
Reported-by: Chris Murphy <lists@colorremedies.com>
Link: https://lore.kernel.org/linux-btrfs/CAJCQCtT+RSzpUjbMq+UfzNUMe1X5+1G+DnAGbHC=OZ=iRS24jg@mail.gmail.com/
Fixes: dc2872247e ("btrfs: keep track of the last logged keys when logging a directory")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When creating a subvolume, at create_subvol(), we allocate an anonymous
device and later call btrfs_get_new_fs_root(), which in turn just calls
btrfs_get_root_ref(). There we call btrfs_init_fs_root() which assigns
the anonymous device to the root, but if after that call there's an error,
when we jump to 'fail' label, we call btrfs_put_root(), which frees the
anonymous device and then returns an error that is propagated back to
create_subvol(). Than create_subvol() frees the anonymous device again.
When this happens, if the anonymous device was not reallocated after
the first time it was freed with btrfs_put_root(), we get a kernel
message like the following:
(...)
[13950.282466] BTRFS: error (device dm-0) in create_subvol:663: errno=-5 IO failure
[13950.283027] ida_free called for id=65 which is not allocated.
[13950.285974] BTRFS info (device dm-0): forced readonly
(...)
If the anonymous device gets reallocated by another btrfs filesystem
or any other kernel subsystem, then bad things can happen.
So fix this by setting the root's anonymous device to 0 at
btrfs_get_root_ref(), before we call btrfs_put_root(), if an error
happened.
Fixes: 2dfb1e43f5 ("btrfs: preallocate anon block device at first phase of snapshot creation")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Line 1169 (#3) allocates a memory chunk for victim_name by kmalloc(),
but when the function returns in line 1184 (#4) victim_name allocated
by line 1169 (#3) is not freed, which will lead to a memory leak.
There is a similar snippet of code in this function as allocating a memory
chunk for victim_name in line 1104 (#1) as well as releasing the memory
in line 1116 (#2).
We should kfree() victim_name when the return value of backref_in_log()
is less than zero and before the function returns in line 1184 (#4).
1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
1058 struct btrfs_root *root,
1059 struct btrfs_path *path,
1060 struct btrfs_root *log_root,
1061 struct btrfs_inode *dir,
1062 struct btrfs_inode *inode,
1063 u64 inode_objectid, u64 parent_objectid,
1064 u64 ref_index, char *name, int namelen,
1065 int *search_done)
1066 {
1104 victim_name = kmalloc(victim_name_len, GFP_NOFS);
// #1: kmalloc (victim_name-1)
1105 if (!victim_name)
1106 return -ENOMEM;
1112 ret = backref_in_log(log_root, &search_key,
1113 parent_objectid, victim_name,
1114 victim_name_len);
1115 if (ret < 0) {
1116 kfree(victim_name); // #2: kfree (victim_name-1)
1117 return ret;
1118 } else if (!ret) {
1169 victim_name = kmalloc(victim_name_len, GFP_NOFS);
// #3: kmalloc (victim_name-2)
1170 if (!victim_name)
1171 return -ENOMEM;
1180 ret = backref_in_log(log_root, &search_key,
1181 parent_objectid, victim_name,
1182 victim_name_len);
1183 if (ret < 0) {
1184 return ret; // #4: missing kfree (victim_name-2)
1185 } else if (!ret) {
1241 return 0;
1242 }
Fixes: d3316c8233 ("btrfs: Properly handle backref_in_log retval")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.16-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more regression fixes and stable patches, mostly one-liners.
Regression fixes:
- fix pointer/ERR_PTR mismatch returned from memdup_user
- reset dedicated zoned mode relocation block group to avoid using it
and filling it without any recourse
Fixes:
- handle a case to FITRIM range (also to make fstests/generic/260
work)
- fix warning when extent buffer state and pages get out of sync
after an IO error
- fix transaction abort when syncing due to missing mapping error set
on metadata inode after inlining a compressed file
- fix transaction abort due to tree-log and zoned mode interacting in
an unexpected way
- fix memory leak of additional extent data when qgroup reservation
fails
- do proper handling of slot search call when deleting root refs"
* tag 'for-5.16-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: replace the BUG_ON in btrfs_del_root_ref with proper error handling
btrfs: zoned: clear data relocation bg on zone finish
btrfs: free exchange changeset on failures
btrfs: fix re-dirty process of tree-log nodes
btrfs: call mapping_set_error() on btree inode with a write error
btrfs: clear extent buffer uptodate when we fail to write it
btrfs: fail if fstrim_range->start == U64_MAX
btrfs: fix error pointer dereference in btrfs_ioctl_rm_dev_v2()
I hit the BUG_ON() with generic/475 test case, and to my surprise, all
callers of btrfs_del_root_ref() are already aborting transaction, thus
there is not need for such BUG_ON(), just go to @out label and caller
will properly handle the error.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When finishing a zone that is used by a dedicated data relocation
block group, also remove its reference from fs_info, so we're not trying
to use a full block group for allocations during data relocation, which
will always fail.
The result is we're not making any forward progress and end up in a
deadlock situation.
Fixes: c2707a2556 ("btrfs: zoned: add a dedicated data relocation block group")
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fstests runs on my VMs have show several kmemleak reports like the following.
unreferenced object 0xffff88811ae59080 (size 64):
comm "xfs_io", pid 12124, jiffies 4294987392 (age 6.368s)
hex dump (first 32 bytes):
00 c0 1c 00 00 00 00 00 ff cf 1c 00 00 00 00 00 ................
90 97 e5 1a 81 88 ff ff 90 97 e5 1a 81 88 ff ff ................
backtrace:
[<00000000ac0176d2>] ulist_add_merge+0x60/0x150 [btrfs]
[<0000000076e9f312>] set_state_bits+0x86/0xc0 [btrfs]
[<0000000014fe73d6>] set_extent_bit+0x270/0x690 [btrfs]
[<000000004f675208>] set_record_extent_bits+0x19/0x20 [btrfs]
[<00000000b96137b1>] qgroup_reserve_data+0x274/0x310 [btrfs]
[<0000000057e9dcbb>] btrfs_check_data_free_space+0x5c/0xa0 [btrfs]
[<0000000019c4511d>] btrfs_delalloc_reserve_space+0x1b/0xa0 [btrfs]
[<000000006d37e007>] btrfs_dio_iomap_begin+0x415/0x970 [btrfs]
[<00000000fb8a74b8>] iomap_iter+0x161/0x1e0
[<0000000071dff6ff>] __iomap_dio_rw+0x1df/0x700
[<000000002567ba53>] iomap_dio_rw+0x5/0x20
[<0000000072e555f8>] btrfs_file_write_iter+0x290/0x530 [btrfs]
[<000000005eb3d845>] new_sync_write+0x106/0x180
[<000000003fb505bf>] vfs_write+0x24d/0x2f0
[<000000009bb57d37>] __x64_sys_pwrite64+0x69/0xa0
[<000000003eba3fdf>] do_syscall_64+0x43/0x90
In case brtfs_qgroup_reserve_data() or btrfs_delalloc_reserve_metadata()
fail the allocated extent_changeset will not be freed.
So in btrfs_check_data_free_space() and btrfs_delalloc_reserve_space()
free the allocated extent_changeset to get rid of the allocated memory.
The issue currently only happens in the direct IO write path, but only
after 65b3c08606e5 ("btrfs: fix ENOSPC failure when attempting direct IO
write into NOCOW range"), and also at defrag_one_locked_target(). Every
other place is always calling extent_changeset_free() even if its call
to btrfs_delalloc_reserve_space() or btrfs_check_data_free_space() has
failed.
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a report of a transaction abort of -EAGAIN with the following
script.
#!/bin/sh
for d in sda sdb; do
mkfs.btrfs -d single -m single -f /dev/\${d}
done
mount /dev/sda /mnt/test
mount /dev/sdb /mnt/scratch
for dir in test scratch; do
echo 3 >/proc/sys/vm/drop_caches
fio --directory=/mnt/\${dir} --name=fio.\${dir} --rw=read --size=50G --bs=64m \
--numjobs=$(nproc) --time_based --ramp_time=5 --runtime=480 \
--group_reporting |& tee /dev/shm/fio.\${dir}
echo 3 >/proc/sys/vm/drop_caches
done
for d in sda sdb; do
umount /dev/\${d}
done
The stack trace is shown in below.
[3310.967991] BTRFS: error (device sda) in btrfs_commit_transaction:2341: errno=-11 unknown (Error while writing out transaction)
[3310.968060] BTRFS info (device sda): forced readonly
[3310.968064] BTRFS warning (device sda): Skipping commit of aborted transaction.
[3310.968065] ------------[ cut here ]------------
[3310.968066] BTRFS: Transaction aborted (error -11)
[3310.968074] WARNING: CPU: 14 PID: 1684 at fs/btrfs/transaction.c:1946 btrfs_commit_transaction.cold+0x209/0x2c8
[3310.968131] CPU: 14 PID: 1684 Comm: fio Not tainted 5.14.10-300.fc35.x86_64 #1
[3310.968135] Hardware name: DIAWAY Tartu/Tartu, BIOS V2.01.B10 04/08/2021
[3310.968137] RIP: 0010:btrfs_commit_transaction.cold+0x209/0x2c8
[3310.968144] RSP: 0018:ffffb284ce393e10 EFLAGS: 00010282
[3310.968147] RAX: 0000000000000026 RBX: ffff973f147b0f60 RCX: 0000000000000027
[3310.968149] RDX: ffff974ecf098a08 RSI: 0000000000000001 RDI: ffff974ecf098a00
[3310.968150] RBP: ffff973f147b0f08 R08: 0000000000000000 R09: ffffb284ce393c48
[3310.968151] R10: ffffb284ce393c40 R11: ffffffff84f47468 R12: ffff973f101bfc00
[3310.968153] R13: ffff971f20cf2000 R14: 00000000fffffff5 R15: ffff973f147b0e58
[3310.968154] FS: 00007efe65468740(0000) GS:ffff974ecf080000(0000) knlGS:0000000000000000
[3310.968157] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[3310.968158] CR2: 000055691bcbe260 CR3: 000000105cfa4001 CR4: 0000000000770ee0
[3310.968160] PKRU: 55555554
[3310.968161] Call Trace:
[3310.968167] ? dput+0xd4/0x300
[3310.968174] btrfs_sync_file+0x3f1/0x490
[3310.968180] __x64_sys_fsync+0x33/0x60
[3310.968185] do_syscall_64+0x3b/0x90
[3310.968190] entry_SYSCALL_64_after_hwframe+0x44/0xae
[3310.968194] RIP: 0033:0x7efe6557329b
[3310.968200] RSP: 002b:00007ffe0236ebc0 EFLAGS: 00000293 ORIG_RAX: 000000000000004a
[3310.968203] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007efe6557329b
[3310.968204] RDX: 0000000000000000 RSI: 00007efe58d77010 RDI: 0000000000000006
[3310.968205] RBP: 0000000004000000 R08: 0000000000000000 R09: 00007efe58d77010
[3310.968207] R10: 0000000016cacc0c R11: 0000000000000293 R12: 00007efe5ce95980
[3310.968208] R13: 0000000000000000 R14: 00007efe6447c790 R15: 0000000c80000000
[3310.968212] ---[ end trace 1a346f4d3c0d96ba ]---
[3310.968214] BTRFS: error (device sda) in cleanup_transaction:1946: errno=-11 unknown
The abort occurs because of a write hole while writing out freeing tree
nodes of a tree-log tree. For zoned btrfs, we re-dirty a freed tree
node to ensure btrfs can write the region and does not leave a hole on
write on a zoned device. The current code fails to re-dirty a node
when the tree-log tree's depth is greater or equal to 2. That leads to
a transaction abort with -EAGAIN.
Fix the issue by properly re-dirtying a node on walking up the tree.
Fixes: d3575156f6 ("btrfs: zoned: redirty released extent buffers")
CC: stable@vger.kernel.org # 5.12+
Link: https://github.com/kdave/btrfs-progs/issues/415
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
generic/484 fails sometimes with compression on because the write ends
up small enough that it goes into the btree. This means that we never
call mapping_set_error() on the inode itself, because the page gets
marked as fine when we inline it into the metadata. When the metadata
writeback happens we see it and abort the transaction properly and mark
the fs as readonly, however we don't do the mapping_set_error() on
anything. In syncfs() we will simply return 0 if the sb is marked
read-only, so we can't check for this in our syncfs callback. The only
way the error gets returned if we called mapping_set_error() on
something. Fix this by calling mapping_set_error() on the btree inode
mapping. This allows us to properly return an error on syncfs and pass
generic/484 with compression on.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I got dmesg errors on generic/281 on our overnight fstests. Looking at
the history this happens occasionally, with errors like this
WARNING: CPU: 0 PID: 673217 at fs/btrfs/extent_io.c:6848 assert_eb_page_uptodate+0x3f/0x50
CPU: 0 PID: 673217 Comm: kworker/u4:13 Tainted: G W 5.16.0-rc2+ #469
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Workqueue: btrfs-cache btrfs_work_helper
RIP: 0010:assert_eb_page_uptodate+0x3f/0x50
RSP: 0018:ffffae598230bc60 EFLAGS: 00010246
RAX: 0017ffffc0002112 RBX: ffffebaec4100900 RCX: 0000000000001000
RDX: ffffebaec45733c7 RSI: ffffebaec4100900 RDI: ffff9fd98919f340
RBP: 0000000000000d56 R08: ffff9fd98e300000 R09: 0000000000000000
R10: 0001207370a91c50 R11: 0000000000000000 R12: 00000000000007b0
R13: ffff9fd98919f340 R14: 0000000001500000 R15: 0000000001cb0000
FS: 0000000000000000(0000) GS:ffff9fd9fbc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f549fcf8940 CR3: 0000000114908004 CR4: 0000000000370ef0
Call Trace:
extent_buffer_test_bit+0x3f/0x70
free_space_test_bit+0xa6/0xc0
load_free_space_tree+0x1d6/0x430
caching_thread+0x454/0x630
? rcu_read_lock_sched_held+0x12/0x60
? rcu_read_lock_sched_held+0x12/0x60
? rcu_read_lock_sched_held+0x12/0x60
? lock_release+0x1f0/0x2d0
btrfs_work_helper+0xf2/0x3e0
? lock_release+0x1f0/0x2d0
? finish_task_switch.isra.0+0xf9/0x3a0
process_one_work+0x270/0x5a0
worker_thread+0x55/0x3c0
? process_one_work+0x5a0/0x5a0
kthread+0x174/0x1a0
? set_kthread_struct+0x40/0x40
ret_from_fork+0x1f/0x30
This happens because we're trying to read from a extent buffer page that
is !PageUptodate. This happens because we will clear the page uptodate
when we have an IO error, but we don't clear the extent buffer uptodate.
If we do a read later and find this extent buffer we'll think its valid
and not return an error, and then trip over this warning.
Fix this by also clearing uptodate on the extent buffer when this
happens, so that we get an error when we do a btrfs_search_slot() and
find this block later.
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We've always been failing generic/260 because it's testing things we
actually don't care about and thus won't fail for. However we probably
should fail for fstrim_range->start == U64_MAX since we clearly can't
trim anything past that. This in combination with an update to
generic/260 will allow us to pass this test properly.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If memdup_user() fails the error handing will crash when it tries
to kfree() an error pointer. Just return directly because there is
no cleanup required.
Fixes: 1a15eb724a ("btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.16-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fix from David Sterba:
"One more fix to the lzo code, a missing put_page causing memory leaks
when some error branches are taken"
* tag 'for-5.16-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix the memory leak caused in lzo_compress_pages()
[BUG]
Fstests generic/027 is pretty easy to trigger a slow but steady memory
leak if run with "-o compress=lzo" mount option.
Normally one single run of generic/027 is enough to eat up at least 4G ram.
[CAUSE]
In commit d4088803f5 ("btrfs: subpage: make lzo_compress_pages()
compatible") we changed how @page_in is released.
But that refactoring makes @page_in only released after all pages being
compressed.
This leaves error path not releasing @page_in. And by "error path"
things like incompressible data will also be treated as an error
(-E2BIG).
Thus it can cause a memory leak if even nothing wrong happened.
[FIX]
Add check under @out label to release @page_in when needed, so when we
hit any error, the input page is properly released.
Reported-by: Josef Bacik <josef@toxicpanda.com>
Fixes: d4088803f5 ("btrfs: subpage: make lzo_compress_pages() compatible")
Reviewed-and-tested-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Several xes and one old ioctl deprecation. Namely there's fix for
crashes/warnings with lzo compression that was suspected to be caused
by first pull merge resolution, but it was a different bug.
Summary:
- regression fix for a crash in lzo due to missing boundary checks of
the page array
- fix crashes on ARM64 due to missing barriers when synchronizing
status bits between work queues
- silence lockdep when reading chunk tree during mount
- fix false positive warning in integrity checker on devices with
disabled write caching
- fix signedness of bitfields in scrub
- start deprecation of balance v1 ioctl"
* tag 'for-5.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: deprecate BTRFS_IOC_BALANCE ioctl
btrfs: make 1-bit bit-fields of scrub_page unsigned int
btrfs: check-integrity: fix a warning on write caching disabled disk
btrfs: silence lockdep when reading chunk tree during mount
btrfs: fix memory ordering between normal and ordered work functions
btrfs: fix a out-of-bound access in copy_compressed_data_to_page()
The v2 balance ioctl has been introduced more than 9 years ago. Users of
the old v1 ioctl should have long been migrated to it. It's time we
deprecate it and eventually remove it.
The only known user is in btrfs-progs that tries v1 as a fallback in
case v2 is not supported. This is not necessary anymore.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The bitfields have_csum and io_error are currently signed which is not
recommended as the representation is an implementation defined
behaviour. Fix this by making the bit-fields unsigned ints.
Fixes: 2c36395430 ("btrfs: scrub: remove the anonymous structure from scrub_page")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When a disk has write caching disabled, we skip submission of a bio with
flush and sync requests before writing the superblock, since it's not
needed. However when the integrity checker is enabled, this results in
reports that there are metadata blocks referred by a superblock that
were not properly flushed. So don't skip the bio submission only when
the integrity checker is enabled for the sake of simplicity, since this
is a debug tool and not meant for use in non-debug builds.
fstests/btrfs/220 trigger a check-integrity warning like the following
when CONFIG_BTRFS_FS_CHECK_INTEGRITY=y and the disk with WCE=0.
btrfs: attempt to write superblock which references block M @5242880 (sdb2/5242880/0) which is not flushed out of disk's write cache (block flush_gen=1, dev->flush_gen=0)!
------------[ cut here ]------------
WARNING: CPU: 28 PID: 843680 at fs/btrfs/check-integrity.c:2196 btrfsic_process_written_superblock+0x22a/0x2a0 [btrfs]
CPU: 28 PID: 843680 Comm: umount Not tainted 5.15.0-0.rc5.39.el8.x86_64 #1
Hardware name: Dell Inc. Precision T7610/0NK70N, BIOS A18 09/11/2019
RIP: 0010:btrfsic_process_written_superblock+0x22a/0x2a0 [btrfs]
RSP: 0018:ffffb642afb47940 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 00000000ffffffff RSI: ffff8b722fc97d00 RDI: ffff8b722fc97d00
RBP: ffff8b5601c00000 R08: 0000000000000000 R09: c0000000ffff7fff
R10: 0000000000000001 R11: ffffb642afb476f8 R12: ffffffffffffffff
R13: ffffb642afb47974 R14: ffff8b5499254c00 R15: 0000000000000003
FS: 00007f00a06d4080(0000) GS:ffff8b722fc80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff5cff5ff0 CR3: 00000001c0c2a006 CR4: 00000000001706e0
Call Trace:
btrfsic_process_written_block+0x2f7/0x850 [btrfs]
__btrfsic_submit_bio.part.19+0x310/0x330 [btrfs]
? bio_associate_blkg_from_css+0xa4/0x2c0
btrfsic_submit_bio+0x18/0x30 [btrfs]
write_dev_supers+0x81/0x2a0 [btrfs]
? find_get_pages_range_tag+0x219/0x280
? pagevec_lookup_range_tag+0x24/0x30
? __filemap_fdatawait_range+0x6d/0xf0
? __raw_callee_save___native_queued_spin_unlock+0x11/0x1e
? find_first_extent_bit+0x9b/0x160 [btrfs]
? __raw_callee_save___native_queued_spin_unlock+0x11/0x1e
write_all_supers+0x1b3/0xa70 [btrfs]
? __raw_callee_save___native_queued_spin_unlock+0x11/0x1e
btrfs_commit_transaction+0x59d/0xac0 [btrfs]
close_ctree+0x11d/0x339 [btrfs]
generic_shutdown_super+0x71/0x110
kill_anon_super+0x14/0x30
btrfs_kill_super+0x12/0x20 [btrfs]
deactivate_locked_super+0x31/0x70
cleanup_mnt+0xb8/0x140
task_work_run+0x6d/0xb0
exit_to_user_mode_prepare+0x1f0/0x200
syscall_exit_to_user_mode+0x12/0x30
do_syscall_64+0x46/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f009f711dfb
RSP: 002b:00007fff5cff7928 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 000055b68c6c9970 RCX: 00007f009f711dfb
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000055b68c6c9b50
RBP: 0000000000000000 R08: 000055b68c6ca900 R09: 00007f009f795580
R10: 0000000000000000 R11: 0000000000000246 R12: 000055b68c6c9b50
R13: 00007f00a04bf184 R14: 0000000000000000 R15: 00000000ffffffff
---[ end trace 2c4b82abcef9eec4 ]---
S-65536(sdb2/65536/1)
-->
M-1064960(sdb2/1064960/1)
Reviewed-by: Filipe Manana <fdmanana@gmail.com>
Signed-off-by: Wang Yugui <wangyugui@e16-tech.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Ordered work functions aren't guaranteed to be handled by the same thread
which executed the normal work functions. The only way execution between
normal/ordered functions is synchronized is via the WORK_DONE_BIT,
unfortunately the used bitops don't guarantee any ordering whatsoever.
This manifested as seemingly inexplicable crashes on ARM64, where
async_chunk::inode is seen as non-null in async_cow_submit which causes
submit_compressed_extents to be called and crash occurs because
async_chunk::inode suddenly became NULL. The call trace was similar to:
pc : submit_compressed_extents+0x38/0x3d0
lr : async_cow_submit+0x50/0xd0
sp : ffff800015d4bc20
<registers omitted for brevity>
Call trace:
submit_compressed_extents+0x38/0x3d0
async_cow_submit+0x50/0xd0
run_ordered_work+0xc8/0x280
btrfs_work_helper+0x98/0x250
process_one_work+0x1f0/0x4ac
worker_thread+0x188/0x504
kthread+0x110/0x114
ret_from_fork+0x10/0x18
Fix this by adding respective barrier calls which ensure that all
accesses preceding setting of WORK_DONE_BIT are strictly ordered before
setting the flag. At the same time add a read barrier after reading of
WORK_DONE_BIT in run_ordered_work which ensures all subsequent loads
would be strictly ordered after reading the bit. This in turn ensures
are all accesses before WORK_DONE_BIT are going to be strictly ordered
before any access that can occur in ordered_func.
Reported-by: Chris Murphy <lists@colorremedies.com>
Fixes: 08a9ff3264 ("btrfs: Added btrfs_workqueue_struct implemented ordered execution based on kernel workqueue")
CC: stable@vger.kernel.org # 4.4+
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2011928
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Chris Murphy <chris@colorremedies.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
The following script can cause btrfs to crash:
$ mount -o compress-force=lzo $DEV /mnt
$ dd if=/dev/urandom of=/mnt/foo bs=4k count=1
$ sync
The call trace looks like this:
general protection fault, probably for non-canonical address 0xe04b37fccce3b000: 0000 [#1] PREEMPT SMP NOPTI
CPU: 5 PID: 164 Comm: kworker/u20:3 Not tainted 5.15.0-rc7-custom+ #4
Workqueue: btrfs-delalloc btrfs_work_helper [btrfs]
RIP: 0010:__memcpy+0x12/0x20
Call Trace:
lzo_compress_pages+0x236/0x540 [btrfs]
btrfs_compress_pages+0xaa/0xf0 [btrfs]
compress_file_range+0x431/0x8e0 [btrfs]
async_cow_start+0x12/0x30 [btrfs]
btrfs_work_helper+0xf6/0x3e0 [btrfs]
process_one_work+0x294/0x5d0
worker_thread+0x55/0x3c0
kthread+0x140/0x170
ret_from_fork+0x22/0x30
---[ end trace 63c3c0f131e61982 ]---
[CAUSE]
In lzo_compress_pages(), parameter @out_pages is not only an output
parameter (for the number of compressed pages), but also an input
parameter, as the upper limit of compressed pages we can utilize.
In commit d4088803f5 ("btrfs: subpage: make lzo_compress_pages()
compatible"), the refactoring doesn't take @out_pages as an input, thus
completely ignoring the limit.
And for compress-force case, we could hit incompressible data that
compressed size would go beyond the page limit, and cause the above
crash.
[FIX]
Save @out_pages as @max_nr_page, and pass it to lzo_compress_pages(),
and check if we're beyond the limit before accessing the pages.
Note: this also fixes crash on 32bit architectures that was suspected to
be caused by merge of btrfs patches to 5.16-rc1. Reported in
https://lore.kernel.org/all/20211104115001.GU20319@twin.jikos.cz/ .
Reported-by: Omar Sandoval <osandov@fb.com>
Fixes: d4088803f5 ("btrfs: subpage: make lzo_compress_pages() compatible")
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note ]
Signed-off-by: David Sterba <dsterba@suse.com>
This PR includes 5 commits that update the zstd library version:
1. Adds a new kernel-style wrapper around zstd. This wrapper API
is functionally equivalent to the subset of the current zstd API that is
currently used. The wrapper API changes to be kernel style so that the symbols
don't collide with zstd's symbols. The update to zstd-1.4.10 maintains the same
API and preserves the semantics, so that none of the callers need to be
updated. All callers are updated in the commit, because there are zero
functional changes.
2. Adds an indirection for `lib/decompress_unzstd.c` so it
doesn't depend on the layout of `lib/zstd/` to include every source file.
This allows the next patch to be automatically generated.
3. Imports the zstd-1.4.10 source code. This commit is automatically generated
from upstream zstd (https://github.com/facebook/zstd).
4. Adds me (terrelln@fb.com) as the maintainer of `lib/zstd`.
5. Fixes a newly added build warning for clang.
The discussion around this patchset has been pretty long, so I've included a
FAQ-style summary of the history of the patchset, and why we are taking this
approach.
Why do we need to update?
-------------------------
The zstd version in the kernel is based off of zstd-1.3.1, which is was released
August 20, 2017. Since then zstd has seen many bug fixes and performance
improvements. And, importantly, upstream zstd is continuously fuzzed by OSS-Fuzz,
and bug fixes aren't backported to older versions. So the only way to sanely get
these fixes is to keep up to date with upstream zstd. There are no known security
issues that affect the kernel, but we need to be able to update in case there
are. And while there are no known security issues, there are relevant bug fixes.
For example the problem with large kernel decompression has been fixed upstream
for over 2 years https://lkml.org/lkml/2020/9/29/27.
Additionally the performance improvements for kernel use cases are significant.
Measured for x86_64 on my Intel i9-9900k @ 3.6 GHz:
- BtrFS zstd compression at levels 1 and 3 is 5% faster
- BtrFS zstd decompression+read is 15% faster
- SquashFS zstd decompression+read is 15% faster
- F2FS zstd compression+write at level 3 is 8% faster
- F2FS zstd decompression+read is 20% faster
- ZRAM decompression+read is 30% faster
- Kernel zstd decompression is 35% faster
- Initramfs zstd decompression+build is 5% faster
On top of this, there are significant performance improvements coming down the
line in the next zstd release, and the new automated update patch generation
will allow us to pull them easily.
How is the update patch generated?
----------------------------------
The first two patches are preparation for updating the zstd version. Then the
3rd patch in the series imports upstream zstd into the kernel. This patch is
automatically generated from upstream. A script makes the necessary changes and
imports it into the kernel. The changes are:
- Replace all libc dependencies with kernel replacements and rewrite includes.
- Remove unncessary portability macros like: #if defined(_MSC_VER).
- Use the kernel xxhash instead of bundling it.
This automation gets tested every commit by upstream's continuous integration.
When we cut a new zstd release, we will submit a patch to the kernel to update
the zstd version in the kernel.
The automated process makes it easy to keep the kernel version of zstd up to
date. The current zstd in the kernel shares the guts of the code, but has a lot
of API and minor changes to work in the kernel. This is because at the time
upstream zstd was not ready to be used in the kernel envrionment as-is. But,
since then upstream zstd has evolved to support being used in the kernel as-is.
Why are we updating in one big patch?
-------------------------------------
The 3rd patch in the series is very large. This is because it is restructuring
the code, so it both deletes the existing zstd, and re-adds the new structure.
Future updates will be directly proportional to the changes in upstream zstd
since the last import. They will admittidly be large, as zstd is an actively
developed project, and has hundreds of commits between every release. However,
there is no other great alternative.
One option ruled out is to replay every upstream zstd commit. This is not feasible
for several reasons:
- There are over 3500 upstream commits since the zstd version in the kernel.
- The automation to automatically generate the kernel update was only added recently,
so older commits cannot easily be imported.
- Not every upstream zstd commit builds.
- Only zstd releases are "supported", and individual commits may have bugs that were
fixed before a release.
Another option to reduce the patch size would be to first reorganize to the new
file structure, and then apply the patch. However, the current kernel zstd is formatted
with clang-format to be more "kernel-like". But, the new method imports zstd as-is,
without additional formatting, to allow for closer correlation with upstream, and
easier debugging. So the patch wouldn't be any smaller.
It also doesn't make sense to import upstream zstd commit by commit going
forward. Upstream zstd doesn't support production use cases running of the
development branch. We have a lot of post-commit fuzzing that catches many bugs,
so indiviudal commits may be buggy, but fixed before a release. So going forward,
I intend to import every (important) zstd release into the Kernel.
So, while it isn't ideal, updating in one big patch is the only patch I see forward.
Who is responsible for this code?
---------------------------------
I am. This patchset adds me as the maintainer for zstd. Previously, there was no tree
for zstd patches. Because of that, there were several patches that either got ignored,
or took a long time to merge, since it wasn't clear which tree should pick them up.
I'm officially stepping up as maintainer, and setting up my tree as the path through
which zstd patches get merged. I'll make sure that patches to the kernel zstd get
ported upstream, so they aren't erased when the next version update happens.
How is this code tested?
------------------------
I tested every caller of zstd on x86_64 (BtrFS, ZRAM, SquashFS, F2FS, Kernel,
InitRAMFS). I also tested Kernel & InitRAMFS on i386 and aarch64. I checked both
performance and correctness.
Also, thanks to many people in the community who have tested these patches locally.
If you have tested the patches, please reply with a Tested-By so I can collect them
for the PR I will send to Linus.
Lastly, this code will bake in linux-next before being merged into v5.16.
Why update to zstd-1.4.10 when zstd-1.5.0 has been released?
------------------------------------------------------------
This patchset has been outstanding since 2020, and zstd-1.4.10 was the latest
release when it was created. Since the update patch is automatically generated
from upstream, I could generate it from zstd-1.5.0. However, there were some
large stack usage regressions in zstd-1.5.0, and are only fixed in the latest
development branch. And the latest development branch contains some new code that
needs to bake in the fuzzer before I would feel comfortable releasing to the
kernel.
Once this patchset has been merged, and we've released zstd-1.5.1, we can update
the kernel to zstd-1.5.1, and exercise the update process.
You may notice that zstd-1.4.10 doesn't exist upstream. This release is an
artifical release based off of zstd-1.4.9, with some fixes for the kernel
backported from the development branch. I will tag the zstd-1.4.10 release after
this patchset is merged, so the Linux Kernel is running a known version of zstd
that can be debugged upstream.
Why was a wrapper API added?
----------------------------
The first versions of this patchset migrated the kernel to the upstream zstd
API. It first added a shim API that supported the new upstream API with the old
code, then updated callers to use the new shim API, then transitioned to the
new code and deleted the shim API. However, Cristoph Hellwig suggested that we
transition to a kernel style API, and hide zstd's upstream API behind that.
This is because zstd's upstream API is supports many other use cases, and does
not follow the kernel style guide, while the kernel API is focused on the
kernel's use cases, and follows the kernel style guide.
Where is the previous discussion?
---------------------------------
Links for the discussions of the previous versions of the patch set.
The largest changes in the design of the patchset are driven by the discussions
in V11, V5, and V1. Sorry for the mix of links, I couldn't find most of the the
threads on lkml.org.
V12: https://www.spinics.net/lists/linux-crypto/msg58189.html
V11: https://lore.kernel.org/linux-btrfs/20210430013157.747152-1-nickrterrell@gmail.com/
V10: https://lore.kernel.org/lkml/20210426234621.870684-2-nickrterrell@gmail.com/
V9: https://lore.kernel.org/linux-btrfs/20210330225112.496213-1-nickrterrell@gmail.com/
V8: https://lore.kernel.org/linux-f2fs-devel/20210326191859.1542272-1-nickrterrell@gmail.com/
V7: https://lkml.org/lkml/2020/12/3/1195
V6: https://lkml.org/lkml/2020/12/2/1245
V5: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/
V4: https://www.spinics.net/lists/linux-btrfs/msg105783.html
V3: https://lkml.org/lkml/2020/9/23/1074
V2: https://www.spinics.net/lists/linux-btrfs/msg105505.html
V1: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/
Signed-off-by: Nick Terrell <terrelln@fb.com>
Tested By: Paul Jones <paul@pauljones.id.au>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
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Merge tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux
Pull zstd update from Nick Terrell:
"Update to zstd-1.4.10.
Add myself as the maintainer of zstd and update the zstd version in
the kernel, which is now 4 years out of date, to a much more recent
zstd release. This includes bug fixes, much more extensive fuzzing,
and performance improvements. And generates the kernel zstd
automatically from upstream zstd, so it is easier to keep the zstd
verison up to date, and we don't fall so far out of date again.
This includes 5 commits that update the zstd library version:
- Adds a new kernel-style wrapper around zstd.
This wrapper API is functionally equivalent to the subset of the
current zstd API that is currently used. The wrapper API changes to
be kernel style so that the symbols don't collide with zstd's
symbols. The update to zstd-1.4.10 maintains the same API and
preserves the semantics, so that none of the callers need to be
updated. All callers are updated in the commit, because there are
zero functional changes.
- Adds an indirection for `lib/decompress_unzstd.c` so it doesn't
depend on the layout of `lib/zstd/` to include every source file.
This allows the next patch to be automatically generated.
- Imports the zstd-1.4.10 source code. This commit is automatically
generated from upstream zstd (https://github.com/facebook/zstd).
- Adds me (terrelln@fb.com) as the maintainer of `lib/zstd`.
- Fixes a newly added build warning for clang.
The discussion around this patchset has been pretty long, so I've
included a FAQ-style summary of the history of the patchset, and why
we are taking this approach.
Why do we need to update?
-------------------------
The zstd version in the kernel is based off of zstd-1.3.1, which is
was released August 20, 2017. Since then zstd has seen many bug fixes
and performance improvements. And, importantly, upstream zstd is
continuously fuzzed by OSS-Fuzz, and bug fixes aren't backported to
older versions. So the only way to sanely get these fixes is to keep
up to date with upstream zstd.
There are no known security issues that affect the kernel, but we need
to be able to update in case there are. And while there are no known
security issues, there are relevant bug fixes. For example the problem
with large kernel decompression has been fixed upstream for over 2
years [1]
Additionally the performance improvements for kernel use cases are
significant. Measured for x86_64 on my Intel i9-9900k @ 3.6 GHz:
- BtrFS zstd compression at levels 1 and 3 is 5% faster
- BtrFS zstd decompression+read is 15% faster
- SquashFS zstd decompression+read is 15% faster
- F2FS zstd compression+write at level 3 is 8% faster
- F2FS zstd decompression+read is 20% faster
- ZRAM decompression+read is 30% faster
- Kernel zstd decompression is 35% faster
- Initramfs zstd decompression+build is 5% faster
On top of this, there are significant performance improvements coming
down the line in the next zstd release, and the new automated update
patch generation will allow us to pull them easily.
How is the update patch generated?
----------------------------------
The first two patches are preparation for updating the zstd version.
Then the 3rd patch in the series imports upstream zstd into the
kernel. This patch is automatically generated from upstream. A script
makes the necessary changes and imports it into the kernel. The
changes are:
- Replace all libc dependencies with kernel replacements and rewrite
includes.
- Remove unncessary portability macros like: #if defined(_MSC_VER).
- Use the kernel xxhash instead of bundling it.
This automation gets tested every commit by upstream's continuous
integration. When we cut a new zstd release, we will submit a patch to
the kernel to update the zstd version in the kernel.
The automated process makes it easy to keep the kernel version of zstd
up to date. The current zstd in the kernel shares the guts of the
code, but has a lot of API and minor changes to work in the kernel.
This is because at the time upstream zstd was not ready to be used in
the kernel envrionment as-is. But, since then upstream zstd has
evolved to support being used in the kernel as-is.
Why are we updating in one big patch?
-------------------------------------
The 3rd patch in the series is very large. This is because it is
restructuring the code, so it both deletes the existing zstd, and
re-adds the new structure. Future updates will be directly
proportional to the changes in upstream zstd since the last import.
They will admittidly be large, as zstd is an actively developed
project, and has hundreds of commits between every release. However,
there is no other great alternative.
One option ruled out is to replay every upstream zstd commit. This is
not feasible for several reasons:
- There are over 3500 upstream commits since the zstd version in the
kernel.
- The automation to automatically generate the kernel update was only
added recently, so older commits cannot easily be imported.
- Not every upstream zstd commit builds.
- Only zstd releases are "supported", and individual commits may have
bugs that were fixed before a release.
Another option to reduce the patch size would be to first reorganize
to the new file structure, and then apply the patch. However, the
current kernel zstd is formatted with clang-format to be more
"kernel-like". But, the new method imports zstd as-is, without
additional formatting, to allow for closer correlation with upstream,
and easier debugging. So the patch wouldn't be any smaller.
It also doesn't make sense to import upstream zstd commit by commit
going forward. Upstream zstd doesn't support production use cases
running of the development branch. We have a lot of post-commit
fuzzing that catches many bugs, so indiviudal commits may be buggy,
but fixed before a release. So going forward, I intend to import every
(important) zstd release into the Kernel.
So, while it isn't ideal, updating in one big patch is the only patch
I see forward.
Who is responsible for this code?
---------------------------------
I am. This patchset adds me as the maintainer for zstd. Previously,
there was no tree for zstd patches. Because of that, there were
several patches that either got ignored, or took a long time to merge,
since it wasn't clear which tree should pick them up. I'm officially
stepping up as maintainer, and setting up my tree as the path through
which zstd patches get merged. I'll make sure that patches to the
kernel zstd get ported upstream, so they aren't erased when the next
version update happens.
How is this code tested?
------------------------
I tested every caller of zstd on x86_64 (BtrFS, ZRAM, SquashFS, F2FS,
Kernel, InitRAMFS). I also tested Kernel & InitRAMFS on i386 and
aarch64. I checked both performance and correctness.
Also, thanks to many people in the community who have tested these
patches locally.
Lastly, this code will bake in linux-next before being merged into
v5.16.
Why update to zstd-1.4.10 when zstd-1.5.0 has been released?
------------------------------------------------------------
This patchset has been outstanding since 2020, and zstd-1.4.10 was the
latest release when it was created. Since the update patch is
automatically generated from upstream, I could generate it from
zstd-1.5.0.
However, there were some large stack usage regressions in zstd-1.5.0,
and are only fixed in the latest development branch. And the latest
development branch contains some new code that needs to bake in the
fuzzer before I would feel comfortable releasing to the kernel.
Once this patchset has been merged, and we've released zstd-1.5.1, we
can update the kernel to zstd-1.5.1, and exercise the update process.
You may notice that zstd-1.4.10 doesn't exist upstream. This release
is an artifical release based off of zstd-1.4.9, with some fixes for
the kernel backported from the development branch. I will tag the
zstd-1.4.10 release after this patchset is merged, so the Linux Kernel
is running a known version of zstd that can be debugged upstream.
Why was a wrapper API added?
----------------------------
The first versions of this patchset migrated the kernel to the
upstream zstd API. It first added a shim API that supported the new
upstream API with the old code, then updated callers to use the new
shim API, then transitioned to the new code and deleted the shim API.
However, Cristoph Hellwig suggested that we transition to a kernel
style API, and hide zstd's upstream API behind that. This is because
zstd's upstream API is supports many other use cases, and does not
follow the kernel style guide, while the kernel API is focused on the
kernel's use cases, and follows the kernel style guide.
Where is the previous discussion?
---------------------------------
Links for the discussions of the previous versions of the patch set
below. The largest changes in the design of the patchset are driven by
the discussions in v11, v5, and v1. Sorry for the mix of links, I
couldn't find most of the the threads on lkml.org"
Link: https://lkml.org/lkml/2020/9/29/27 [1]
Link: https://www.spinics.net/lists/linux-crypto/msg58189.html [v12]
Link: https://lore.kernel.org/linux-btrfs/20210430013157.747152-1-nickrterrell@gmail.com/ [v11]
Link: https://lore.kernel.org/lkml/20210426234621.870684-2-nickrterrell@gmail.com/ [v10]
Link: https://lore.kernel.org/linux-btrfs/20210330225112.496213-1-nickrterrell@gmail.com/ [v9]
Link: https://lore.kernel.org/linux-f2fs-devel/20210326191859.1542272-1-nickrterrell@gmail.com/ [v8]
Link: https://lkml.org/lkml/2020/12/3/1195 [v7]
Link: https://lkml.org/lkml/2020/12/2/1245 [v6]
Link: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/ [v5]
Link: https://www.spinics.net/lists/linux-btrfs/msg105783.html [v4]
Link: https://lkml.org/lkml/2020/9/23/1074 [v3]
Link: https://www.spinics.net/lists/linux-btrfs/msg105505.html [v2]
Link: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/ [v1]
Signed-off-by: Nick Terrell <terrelln@fb.com>
Tested By: Paul Jones <paul@pauljones.id.au>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
* tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux:
lib: zstd: Add cast to silence clang's -Wbitwise-instead-of-logical
MAINTAINERS: Add maintainer entry for zstd
lib: zstd: Upgrade to latest upstream zstd version 1.4.10
lib: zstd: Add decompress_sources.h for decompress_unzstd
lib: zstd: Add kernel-specific API
If we do a direct IO read or write when the buffer given by the user is
memory mapped to the file range we are going to do IO, we end up ending
in a deadlock. This is triggered by the new test case generic/647 from
fstests.
For a direct IO read we get a trace like this:
[967.872718] INFO: task mmap-rw-fault:12176 blocked for more than 120 seconds.
[967.874161] Not tainted 5.14.0-rc7-btrfs-next-95 #1
[967.874909] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[967.875983] task:mmap-rw-fault state:D stack: 0 pid:12176 ppid: 11884 flags:0x00000000
[967.875992] Call Trace:
[967.875999] __schedule+0x3ca/0xe10
[967.876015] schedule+0x43/0xe0
[967.876020] wait_extent_bit.constprop.0+0x1eb/0x260 [btrfs]
[967.876109] ? do_wait_intr_irq+0xb0/0xb0
[967.876118] lock_extent_bits+0x37/0x90 [btrfs]
[967.876150] btrfs_lock_and_flush_ordered_range+0xa9/0x120 [btrfs]
[967.876184] ? extent_readahead+0xa7/0x530 [btrfs]
[967.876214] extent_readahead+0x32d/0x530 [btrfs]
[967.876253] ? lru_cache_add+0x104/0x220
[967.876255] ? kvm_sched_clock_read+0x14/0x40
[967.876258] ? sched_clock_cpu+0xd/0x110
[967.876263] ? lock_release+0x155/0x4a0
[967.876271] read_pages+0x86/0x270
[967.876274] ? lru_cache_add+0x125/0x220
[967.876281] page_cache_ra_unbounded+0x1a3/0x220
[967.876291] filemap_fault+0x626/0xa20
[967.876303] __do_fault+0x36/0xf0
[967.876308] __handle_mm_fault+0x83f/0x15f0
[967.876322] handle_mm_fault+0x9e/0x260
[967.876327] __get_user_pages+0x204/0x620
[967.876332] ? get_user_pages_unlocked+0x69/0x340
[967.876340] get_user_pages_unlocked+0xd3/0x340
[967.876349] internal_get_user_pages_fast+0xbca/0xdc0
[967.876366] iov_iter_get_pages+0x8d/0x3a0
[967.876374] bio_iov_iter_get_pages+0x82/0x4a0
[967.876379] ? lock_release+0x155/0x4a0
[967.876387] iomap_dio_bio_actor+0x232/0x410
[967.876396] iomap_apply+0x12a/0x4a0
[967.876398] ? iomap_dio_rw+0x30/0x30
[967.876414] __iomap_dio_rw+0x29f/0x5e0
[967.876415] ? iomap_dio_rw+0x30/0x30
[967.876420] ? lock_acquired+0xf3/0x420
[967.876429] iomap_dio_rw+0xa/0x30
[967.876431] btrfs_file_read_iter+0x10b/0x140 [btrfs]
[967.876460] new_sync_read+0x118/0x1a0
[967.876472] vfs_read+0x128/0x1b0
[967.876477] __x64_sys_pread64+0x90/0xc0
[967.876483] do_syscall_64+0x3b/0xc0
[967.876487] entry_SYSCALL_64_after_hwframe+0x44/0xae
[967.876490] RIP: 0033:0x7fb6f2c038d6
[967.876493] RSP: 002b:00007fffddf586b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
[967.876496] RAX: ffffffffffffffda RBX: 0000000000001000 RCX: 00007fb6f2c038d6
[967.876498] RDX: 0000000000001000 RSI: 00007fb6f2c17000 RDI: 0000000000000003
[967.876499] RBP: 0000000000001000 R08: 0000000000000003 R09: 0000000000000000
[967.876501] R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000003
[967.876502] R13: 0000000000000000 R14: 00007fb6f2c17000 R15: 0000000000000000
This happens because at btrfs_dio_iomap_begin() we lock the extent range
and return with it locked - we only unlock in the endio callback, at
end_bio_extent_readpage() -> endio_readpage_release_extent(). Then after
iomap called the btrfs_dio_iomap_begin() callback, it triggers the page
faults that resulting in reading the pages, through the readahead callback
btrfs_readahead(), and through there we end to attempt to lock again the
same extent range (or a subrange of what we locked before), resulting in
the deadlock.
For a direct IO write, the scenario is a bit different, and it results in
trace like this:
[1132.442520] run fstests generic/647 at 2021-08-31 18:53:35
[1330.349355] INFO: task mmap-rw-fault:184017 blocked for more than 120 seconds.
[1330.350540] Not tainted 5.14.0-rc7-btrfs-next-95 #1
[1330.351158] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[1330.351900] task:mmap-rw-fault state:D stack: 0 pid:184017 ppid:183725 flags:0x00000000
[1330.351906] Call Trace:
[1330.351913] __schedule+0x3ca/0xe10
[1330.351930] schedule+0x43/0xe0
[1330.351935] btrfs_start_ordered_extent+0x108/0x1c0 [btrfs]
[1330.352020] ? do_wait_intr_irq+0xb0/0xb0
[1330.352028] btrfs_lock_and_flush_ordered_range+0x8c/0x120 [btrfs]
[1330.352064] ? extent_readahead+0xa7/0x530 [btrfs]
[1330.352094] extent_readahead+0x32d/0x530 [btrfs]
[1330.352133] ? lru_cache_add+0x104/0x220
[1330.352135] ? kvm_sched_clock_read+0x14/0x40
[1330.352138] ? sched_clock_cpu+0xd/0x110
[1330.352143] ? lock_release+0x155/0x4a0
[1330.352151] read_pages+0x86/0x270
[1330.352155] ? lru_cache_add+0x125/0x220
[1330.352162] page_cache_ra_unbounded+0x1a3/0x220
[1330.352172] filemap_fault+0x626/0xa20
[1330.352176] ? filemap_map_pages+0x18b/0x660
[1330.352184] __do_fault+0x36/0xf0
[1330.352189] __handle_mm_fault+0x1253/0x15f0
[1330.352203] handle_mm_fault+0x9e/0x260
[1330.352208] __get_user_pages+0x204/0x620
[1330.352212] ? get_user_pages_unlocked+0x69/0x340
[1330.352220] get_user_pages_unlocked+0xd3/0x340
[1330.352229] internal_get_user_pages_fast+0xbca/0xdc0
[1330.352246] iov_iter_get_pages+0x8d/0x3a0
[1330.352254] bio_iov_iter_get_pages+0x82/0x4a0
[1330.352259] ? lock_release+0x155/0x4a0
[1330.352266] iomap_dio_bio_actor+0x232/0x410
[1330.352275] iomap_apply+0x12a/0x4a0
[1330.352278] ? iomap_dio_rw+0x30/0x30
[1330.352292] __iomap_dio_rw+0x29f/0x5e0
[1330.352294] ? iomap_dio_rw+0x30/0x30
[1330.352306] btrfs_file_write_iter+0x238/0x480 [btrfs]
[1330.352339] new_sync_write+0x11f/0x1b0
[1330.352344] ? NF_HOOK_LIST.constprop.0.cold+0x31/0x3e
[1330.352354] vfs_write+0x292/0x3c0
[1330.352359] __x64_sys_pwrite64+0x90/0xc0
[1330.352365] do_syscall_64+0x3b/0xc0
[1330.352369] entry_SYSCALL_64_after_hwframe+0x44/0xae
[1330.352372] RIP: 0033:0x7f4b0a580986
[1330.352379] RSP: 002b:00007ffd34d75418 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
[1330.352382] RAX: ffffffffffffffda RBX: 0000000000001000 RCX: 00007f4b0a580986
[1330.352383] RDX: 0000000000001000 RSI: 00007f4b0a3a4000 RDI: 0000000000000003
[1330.352385] RBP: 00007f4b0a3a4000 R08: 0000000000000003 R09: 0000000000000000
[1330.352386] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
[1330.352387] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Unlike for reads, at btrfs_dio_iomap_begin() we return with the extent
range unlocked, but later when the page faults are triggered and we try
to read the extents, we end up btrfs_lock_and_flush_ordered_range() where
we find the ordered extent for our write, created by the iomap callback
btrfs_dio_iomap_begin(), and we wait for it to complete, which makes us
deadlock since we can't complete the ordered extent without reading the
pages (the iomap code only submits the bio after the pages are faulted
in).
Fix this by setting the nofault attribute of the given iov_iter and retry
the direct IO read/write if we get an -EFAULT error returned from iomap.
For reads, also disable page faults completely, this is because when we
read from a hole or a prealloc extent, we can still trigger page faults
due to the call to iov_iter_zero() done by iomap - at the moment, it is
oblivious to the value of the ->nofault attribute of an iov_iter.
We also need to keep track of the number of bytes written or read, and
pass it to iomap_dio_rw(), as well as use the new flag IOMAP_DIO_PARTIAL.
This depends on the iov_iter and iomap changes introduced in commit
c03098d4b9 ("Merge tag 'gfs2-v5.15-rc5-mmap-fault' of
git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2").
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch:
- Moves `include/linux/zstd.h` -> `include/linux/zstd_lib.h`
- Updates modified zstd headers to yearless copyright
- Adds a new API in `include/linux/zstd.h` that is functionally
equivalent to the in-use subset of the current API. Functions are
renamed to avoid symbol collisions with zstd, to make it clear it is
not the upstream zstd API, and to follow the kernel style guide.
- Updates all callers to use the new API.
There are no functional changes in this patch. Since there are no
functional change, I felt it was okay to update all the callers in a
single patch. Once the API is approved, the callers are mechanically
changed.
This patch is preparing for the 3rd patch in this series, which updates
zstd to version 1.4.10. Since the upstream zstd API is no longer exposed
to callers, the update can happen transparently.
Signed-off-by: Nick Terrell <terrelln@fb.com>
Tested By: Paul Jones <paul@pauljones.id.au>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock. In the most basic scenario, that buffer will not be
resident and it will be mapped to the same file. Accessing the buffer
will trigger a page fault, and gfs2 will deadlock trying to take the
same inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled.
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Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
"Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock.
In the most basic deadlock scenario, that buffer will not be resident
and it will be mapped to the same file. Accessing the buffer will
trigger a page fault, and gfs2 will deadlock trying to take the same
inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled"
* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix mmap + page fault deadlocks for direct I/O
iov_iter: Introduce nofault flag to disable page faults
gup: Introduce FOLL_NOFAULT flag to disable page faults
iomap: Add done_before argument to iomap_dio_rw
iomap: Support partial direct I/O on user copy failures
iomap: Fix iomap_dio_rw return value for user copies
gfs2: Fix mmap + page fault deadlocks for buffered I/O
gfs2: Eliminate ip->i_gh
gfs2: Move the inode glock locking to gfs2_file_buffered_write
gfs2: Introduce flag for glock holder auto-demotion
gfs2: Clean up function may_grant
gfs2: Add wrapper for iomap_file_buffered_write
iov_iter: Introduce fault_in_iov_iter_writeable
iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
powerpc/kvm: Fix kvm_use_magic_page
iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
The end goal of the current buffer overflow detection work[0] is to gain
full compile-time and run-time coverage of all detectable buffer overflows
seen via array indexing or memcpy(), memmove(), and memset(). The str*()
family of functions already have full coverage.
While much of the work for these changes have been on-going for many
releases (i.e. 0-element and 1-element array replacements, as well as
avoiding false positives and fixing discovered overflows[1]), this series
contains the foundational elements of several related buffer overflow
detection improvements by providing new common helpers and FORTIFY_SOURCE
changes needed to gain the introspection required for compiler visibility
into array sizes. Also included are a handful of already Acked instances
using the helpers (or related clean-ups), with many more waiting at the
ready to be taken via subsystem-specific trees[2]. The new helpers are:
- struct_group() for gaining struct member range introspection.
- memset_after() and memset_startat() for clearing to the end of structures.
- DECLARE_FLEX_ARRAY() for using flex arrays in unions or alone in structs.
Also included is the beginning of the refactoring of FORTIFY_SOURCE to
support memcpy() introspection, fix missing and regressed coverage under
GCC, and to prepare to fix the currently broken Clang support. Finishing
this work is part of the larger series[0], but depends on all the false
positives and buffer overflow bug fixes to have landed already and those
that depend on this series to land.
As part of the FORTIFY_SOURCE refactoring, a set of both a compile-time
and run-time tests are added for FORTIFY_SOURCE and the mem*()-family
functions respectively. The compile time tests have found a legitimate
(though corner-case) bug[6] already.
Please note that the appearance of "panic" and "BUG" in the
FORTIFY_SOURCE refactoring are the result of relocating existing code,
and no new use of those code-paths are expected nor desired.
Finally, there are two tree-wide conversions for 0-element arrays and
flexible array unions to gain sane compiler introspection coverage that
result in no known object code differences.
After this series (and the changes that have now landed via netdev
and usb), we are very close to finally being able to build with
-Warray-bounds and -Wzero-length-bounds. However, due corner cases in
GCC[3] and Clang[4], I have not included the last two patches that turn
on these options, as I don't want to introduce any known warnings to
the build. Hopefully these can be solved soon.
[0] https://lore.kernel.org/lkml/20210818060533.3569517-1-keescook@chromium.org/
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=FORTIFY_SOURCE
[2] https://lore.kernel.org/lkml/202108220107.3E26FE6C9C@keescook/
[3] https://lore.kernel.org/lkml/3ab153ec-2798-da4c-f7b1-81b0ac8b0c5b@roeck-us.net/
[4] https://bugs.llvm.org/show_bug.cgi?id=51682
[5] https://lore.kernel.org/lkml/202109051257.29B29745C0@keescook/
[6] https://lore.kernel.org/lkml/20211020200039.170424-1-keescook@chromium.org/
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Merge tag 'overflow-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull overflow updates from Kees Cook:
"The end goal of the current buffer overflow detection work[0] is to
gain full compile-time and run-time coverage of all detectable buffer
overflows seen via array indexing or memcpy(), memmove(), and
memset(). The str*() family of functions already have full coverage.
While much of the work for these changes have been on-going for many
releases (i.e. 0-element and 1-element array replacements, as well as
avoiding false positives and fixing discovered overflows[1]), this
series contains the foundational elements of several related buffer
overflow detection improvements by providing new common helpers and
FORTIFY_SOURCE changes needed to gain the introspection required for
compiler visibility into array sizes. Also included are a handful of
already Acked instances using the helpers (or related clean-ups), with
many more waiting at the ready to be taken via subsystem-specific
trees[2].
The new helpers are:
- struct_group() for gaining struct member range introspection
- memset_after() and memset_startat() for clearing to the end of
structures
- DECLARE_FLEX_ARRAY() for using flex arrays in unions or alone in
structs
Also included is the beginning of the refactoring of FORTIFY_SOURCE to
support memcpy() introspection, fix missing and regressed coverage
under GCC, and to prepare to fix the currently broken Clang support.
Finishing this work is part of the larger series[0], but depends on
all the false positives and buffer overflow bug fixes to have landed
already and those that depend on this series to land.
As part of the FORTIFY_SOURCE refactoring, a set of both a
compile-time and run-time tests are added for FORTIFY_SOURCE and the
mem*()-family functions respectively. The compile time tests have
found a legitimate (though corner-case) bug[6] already.
Please note that the appearance of "panic" and "BUG" in the
FORTIFY_SOURCE refactoring are the result of relocating existing code,
and no new use of those code-paths are expected nor desired.
Finally, there are two tree-wide conversions for 0-element arrays and
flexible array unions to gain sane compiler introspection coverage
that result in no known object code differences.
After this series (and the changes that have now landed via netdev and
usb), we are very close to finally being able to build with
-Warray-bounds and -Wzero-length-bounds.
However, due corner cases in GCC[3] and Clang[4], I have not included
the last two patches that turn on these options, as I don't want to
introduce any known warnings to the build. Hopefully these can be
solved soon"
Link: https://lore.kernel.org/lkml/20210818060533.3569517-1-keescook@chromium.org/ [0]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=FORTIFY_SOURCE [1]
Link: https://lore.kernel.org/lkml/202108220107.3E26FE6C9C@keescook/ [2]
Link: https://lore.kernel.org/lkml/3ab153ec-2798-da4c-f7b1-81b0ac8b0c5b@roeck-us.net/ [3]
Link: https://bugs.llvm.org/show_bug.cgi?id=51682 [4]
Link: https://lore.kernel.org/lkml/202109051257.29B29745C0@keescook/ [5]
Link: https://lore.kernel.org/lkml/20211020200039.170424-1-keescook@chromium.org/ [6]
* tag 'overflow-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (30 commits)
fortify: strlen: Avoid shadowing previous locals
compiler-gcc.h: Define __SANITIZE_ADDRESS__ under hwaddress sanitizer
treewide: Replace 0-element memcpy() destinations with flexible arrays
treewide: Replace open-coded flex arrays in unions
stddef: Introduce DECLARE_FLEX_ARRAY() helper
btrfs: Use memset_startat() to clear end of struct
string.h: Introduce memset_startat() for wiping trailing members and padding
xfrm: Use memset_after() to clear padding
string.h: Introduce memset_after() for wiping trailing members/padding
lib: Introduce CONFIG_MEMCPY_KUNIT_TEST
fortify: Add compile-time FORTIFY_SOURCE tests
fortify: Allow strlen() and strnlen() to pass compile-time known lengths
fortify: Prepare to improve strnlen() and strlen() warnings
fortify: Fix dropped strcpy() compile-time write overflow check
fortify: Explicitly disable Clang support
fortify: Move remaining fortify helpers into fortify-string.h
lib/string: Move helper functions out of string.c
compiler_types.h: Remove __compiletime_object_size()
cm4000_cs: Use struct_group() to zero struct cm4000_dev region
can: flexcan: Use struct_group() to zero struct flexcan_regs regions
...
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Merge tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The updates this time are more under the hood and enhancing existing
features (subpage with compression and zoned namespaces).
Performance related:
- misc small inode logging improvements (+3% throughput, -11% latency
on sample dbench workload)
- more efficient directory logging: bulk item insertion, less tree
searches and locking
- speed up bulk insertion of items into a b-tree, which is used when
logging directories, when running delayed items for directories
(fsync and transaction commits) and when running the slow path
(full sync) of an fsync (bulk creation run time -4%, deletion -12%)
Core:
- continued subpage support
- make defragmentation work
- make compression write work
- zoned mode
- support ZNS (zoned namespaces), zone capacity is number of
usable blocks in each zone
- add dedicated block group (zoned) for relocation, to prevent
out of order writes in some cases
- greedy block group reclaim, pick the ones with least usable
space first
- preparatory work for send protocol updates
- error handling improvements
- cleanups and refactoring
Fixes:
- lockdep warnings
- in show_devname callback, on seeding device
- device delete on loop device due to conversions to workqueues
- fix deadlock between chunk allocation and chunk btree modifications
- fix tracking of missing device count and status"
* tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (140 commits)
btrfs: remove root argument from check_item_in_log()
btrfs: remove root argument from add_link()
btrfs: remove root argument from btrfs_unlink_inode()
btrfs: remove root argument from drop_one_dir_item()
btrfs: clear MISSING device status bit in btrfs_close_one_device
btrfs: call btrfs_check_rw_degradable only if there is a missing device
btrfs: send: prepare for v2 protocol
btrfs: fix comment about sector sizes supported in 64K systems
btrfs: update device path inode time instead of bd_inode
fs: export an inode_update_time helper
btrfs: fix deadlock when defragging transparent huge pages
btrfs: sysfs: convert scnprintf and snprintf to sysfs_emit
btrfs: make btrfs_super_block size match BTRFS_SUPER_INFO_SIZE
btrfs: update comments for chunk allocation -ENOSPC cases
btrfs: fix deadlock between chunk allocation and chunk btree modifications
btrfs: zoned: use greedy gc for auto reclaim
btrfs: check-integrity: stop storing the block device name in btrfsic_dev_state
btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls
btrfs: add a btrfs_get_dev_args_from_path helper
btrfs: handle device lookup with btrfs_dev_lookup_args
...
Commit ccaa66c8dd reinstated the kmap/kunmap that had been dropped in
commit 8c945d32e6 ("btrfs: compression: drop kmap/kunmap from lzo").
However, it seems to have done so incorrectly due to the change not
reverting cleanly, and lzo_decompress_bio() ended up not having a
matching "kunmap()" to the "kmap()" that was put back.
Also, any assert that the page pointer is not NULL should be before the
kmap() of said pointer, since otherwise you'd just oops in the kmap()
before the assert would even trigger.
I noticed this when trying to verify my btrfs merge, and things not
adding up. I'm doing this fixup before re-doing my merge, because this
commit needs to also be backported to 5.15 (after verification from the
btrfs people).
Fixes: ccaa66c8dd ("Revert 'btrfs: compression: drop kmap/kunmap from lzo'")
Cc: David Sterba <dsterba@suse.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block
Pull bdev size cleanups from Jens Axboe:
"Clean up the bdev size handling with new bdev_nr_bytes() helper"
* tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block: (34 commits)
partitions/ibm: use bdev_nr_sectors instead of open coding it
partitions/efi: use bdev_nr_bytes instead of open coding it
block/ioctl: use bdev_nr_sectors and bdev_nr_bytes
block: cache inode size in bdev
udf: use sb_bdev_nr_blocks
reiserfs: use sb_bdev_nr_blocks
ntfs: use sb_bdev_nr_blocks
jfs: use sb_bdev_nr_blocks
ext4: use sb_bdev_nr_blocks
block: add a sb_bdev_nr_blocks helper
block: use bdev_nr_bytes instead of open coding it in blkdev_fallocate
squashfs: use bdev_nr_bytes instead of open coding it
reiserfs: use bdev_nr_bytes instead of open coding it
pstore/blk: use bdev_nr_bytes instead of open coding it
ntfs3: use bdev_nr_bytes instead of open coding it
nilfs2: use bdev_nr_bytes instead of open coding it
nfs/blocklayout: use bdev_nr_bytes instead of open coding it
jfs: use bdev_nr_bytes instead of open coding it
hfsplus: use bdev_nr_sectors instead of open coding it
hfs: use bdev_nr_sectors instead of open coding it
...
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Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- mq-deadline accounting improvements (Bart)
- blk-wbt timer fix (Andrea)
- Untangle the block layer includes (Christoph)
- Rework the poll support to be bio based, which will enable adding
support for polling for bio based drivers (Christoph)
- Block layer core support for multi-actuator drives (Damien)
- blk-crypto improvements (Eric)
- Batched tag allocation support (me)
- Request completion batching support (me)
- Plugging improvements (me)
- Shared tag set improvements (John)
- Concurrent queue quiesce support (Ming)
- Cache bdev in ->private_data for block devices (Pavel)
- bdev dio improvements (Pavel)
- Block device invalidation and block size improvements (Xie)
- Various cleanups, fixes, and improvements (Christoph, Jackie,
Masahira, Tejun, Yu, Pavel, Zheng, me)
* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
blk-mq-debugfs: Show active requests per queue for shared tags
block: improve readability of blk_mq_end_request_batch()
virtio-blk: Use blk_validate_block_size() to validate block size
loop: Use blk_validate_block_size() to validate block size
nbd: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
block: re-flow blk_mq_rq_ctx_init()
block: prefetch request to be initialized
block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
block: add rq_flags to struct blk_mq_alloc_data
block: add async version of bio_set_polled
block: kill DIO_MULTI_BIO
block: kill unused polling bits in __blkdev_direct_IO()
block: avoid extra iter advance with async iocb
block: Add independent access ranges support
blk-mq: don't issue request directly in case that current is to be blocked
sbitmap: silence data race warning
blk-cgroup: synchronize blkg creation against policy deactivation
block: refactor bio_iov_bvec_set()
block: add single bio async direct IO helper
...
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Merge tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Last minute fixes for crash on 32bit architectures when compression is
in use. It's a regression introduced in 5.15-rc and I'd really like
not let this into the final release, fixes via stable trees would add
unnecessary delay.
The problem is on 32bit architectures with highmem enabled, the pages
for compression may need to be kmapped, while the patches removed that
as we don't use GFP_HIGHMEM allocations anymore. The pages that don't
come from local allocation still may be from highmem. Despite being on
32bit there's enough such ARM machines in use so it's not a marginal
issue.
I did full reverts of the patches one by one instead of a huge one.
There's one exception for the "lzo" revert as there was an
intermediate patch touching the same code to make it compatible with
subpage. I can't revert that one too, so the revert in lzo.c is
manual. Qu Wenruo has worked on that with me and verified the changes"
* tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: compression: drop kmap/kunmap from lzo"
Revert "btrfs: compression: drop kmap/kunmap from zlib"
Revert "btrfs: compression: drop kmap/kunmap from zstd"
Revert "btrfs: compression: drop kmap/kunmap from generic helpers"
This reverts commit 8c945d32e6.
The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.
The revert does not apply cleanly due to changes in a6e66e6f8c
("btrfs: rework lzo_decompress_bio() to make it subpage compatible")
that reworked the page iteration so the revert is done to be equivalent
to the original code.
Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Tested-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit bbaf9715f3.
The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.
Example stacktrace with ZSTD on a 32bit ARM machine:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c4159ed3
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 210 Comm: kworker/u2:3 Not tainted 5.14.0-rc79+ #12
Hardware name: Allwinner sun4i/sun5i Families
Workqueue: btrfs-delalloc btrfs_work_helper
PC is at mmiocpy+0x48/0x330
LR is at ZSTD_compressStream_generic+0x15c/0x28c
(mmiocpy) from [<c0629648>] (ZSTD_compressStream_generic+0x15c/0x28c)
(ZSTD_compressStream_generic) from [<c06297dc>] (ZSTD_compressStream+0x64/0xa0)
(ZSTD_compressStream) from [<c049444c>] (zstd_compress_pages+0x170/0x488)
(zstd_compress_pages) from [<c0496798>] (btrfs_compress_pages+0x124/0x12c)
(btrfs_compress_pages) from [<c043c068>] (compress_file_range+0x3c0/0x834)
(compress_file_range) from [<c043c4ec>] (async_cow_start+0x10/0x28)
(async_cow_start) from [<c0475c3c>] (btrfs_work_helper+0x100/0x230)
(btrfs_work_helper) from [<c014ef68>] (process_one_work+0x1b4/0x418)
(process_one_work) from [<c014f210>] (worker_thread+0x44/0x524)
(worker_thread) from [<c0156aa4>] (kthread+0x180/0x1b0)
(kthread) from [<c0100150>]
Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Signed-off-by: David Sterba <dsterba@suse.com>
The root argument passed to check_item_in_log() always matches the root
of the given directory, so it can be eliminated.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The root argument for tree-log.c:add_link() always matches the root of the
given directory and the given inode, so it can eliminated.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The root argument passed to btrfs_unlink_inode() and its callee,
__btrfs_unlink_inode(), always matches the root of the given directory and
the given inode. So remove the argument and make __btrfs_unlink_inode()
use the root of the directory.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The root argument for drop_one_dir_item() always matches the root of the
given directory inode, since each log tree is associated to one and only
one subvolume/root, so remove the argument.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reported bug: https://github.com/kdave/btrfs-progs/issues/389
There's a problem with scrub reporting aborted status but returning
error code 0, on a filesystem with missing and readded device.
Roughly these steps:
- mkfs -d raid1 dev1 dev2
- fill with data
- unmount
- make dev1 disappear
- mount -o degraded
- copy more data
- make dev1 appear again
Running scrub afterwards reports that the command was aborted, but the
system log message says the exit code was 0.
It seems that the cause of the error is decrementing
fs_devices->missing_devices but not clearing device->dev_state. Every
time we umount filesystem, it would call close_ctree, And it would
eventually involve btrfs_close_one_device to close the device, but it
only decrements fs_devices->missing_devices but does not clear the
device BTRFS_DEV_STATE_MISSING bit. Worse, this bug will cause Integer
Overflow, because every time umount, fs_devices->missing_devices will
decrease. If fs_devices->missing_devices value hit 0, it would overflow.
With added debugging:
loop1: detected capacity change from 0 to 20971520
BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 1 transid 21 /dev/loop1 scanned by systemd-udevd (2311)
loop2: detected capacity change from 0 to 20971520
BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 2 transid 17 /dev/loop2 scanned by systemd-udevd (2313)
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 0
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 18446744073709551615
BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 18446744073709551615
If fs_devices->missing_devices is 0, next time it would be 18446744073709551615
After apply this patch, the fs_devices->missing_devices seems to be
right:
$ truncate -s 10g test1
$ truncate -s 10g test2
$ losetup /dev/loop1 test1
$ losetup /dev/loop2 test2
$ mkfs.btrfs -draid1 -mraid1 /dev/loop1 /dev/loop2 -f
$ losetup -d /dev/loop2
$ mount -o degraded /dev/loop1 /mnt/1
$ umount /mnt/1
$ mount -o degraded /dev/loop1 /mnt/1
$ umount /mnt/1
$ mount -o degraded /dev/loop1 /mnt/1
$ umount /mnt/1
$ dmesg
loop1: detected capacity change from 0 to 20971520
loop2: detected capacity change from 0 to 20971520
BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 1 transid 5 /dev/loop1 scanned by mkfs.btrfs (1863)
BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 2 transid 5 /dev/loop2 scanned by mkfs.btrfs (1863)
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): disk space caching is enabled
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
BTRFS info (device loop1): checking UUID tree
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): disk space caching is enabled
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
BTRFS info (device loop1): flagging fs with big metadata feature
BTRFS info (device loop1): allowing degraded mounts
BTRFS info (device loop1): disk space caching is enabled
BTRFS info (device loop1): has skinny extents
BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0
BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Li Zhang <zhanglikernel@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In open_ctree() in btrfs_check_rw_degradable() [1], we check each block
group individually if at least the minimum number of devices is available
for that profile. If all the devices are available, then we don't have to
check degradable.
[1]
open_ctree()
::
3559 if (!sb_rdonly(sb) && !btrfs_check_rw_degradable(fs_info, NULL)) {
Also before calling btrfs_check_rw_degradable() in open_ctee() at the
line number shown below [2] we call btrfs_read_chunk_tree() and down to
add_missing_dev() to record number of missing devices.
[2]
open_ctree()
::
3454 ret = btrfs_read_chunk_tree(fs_info);
btrfs_read_chunk_tree()
read_one_chunk() / read_one_dev()
add_missing_dev()
So, check if there is any missing device before btrfs_check_rw_degradable()
in open_ctree().
Also, with this the mount command could save ~16ms.[3] in the most
common case, that is no device is missing.
[3]
1) * 16934.96 us | btrfs_check_rw_degradable [btrfs]();
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is preparatory work for send protocol update to version 2 and
higher.
We have many pending protocol update requests but still don't have the
basic protocol rev in place, the first thing that must happen is to do
the actual versioning support.
The protocol version is u32 and is a new member in the send ioctl
struct. Validity of the version field is backed by a new flag bit. Old
kernels would fail when a higher version is requested. Version protocol
0 will pick the highest supported version, BTRFS_SEND_STREAM_VERSION,
that's also exported in sysfs.
The version is still unchanged and will be increased once we have new
incompatible commands or stream updates.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 95ea0486b2 ("btrfs: allow read-write for 4K sectorsize on 64K
page size systems") added write support for 4K sectorsize on a 64K
systems. Fix the now stale comments.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Christoph pointed out that I'm updating bdev->bd_inode for the device
time when we remove block devices from a btrfs file system, however this
isn't actually exposed to anything. The inode we want to update is the
one that's associated with the path to the device, usually on devtmpfs,
so that blkid notices the difference.
We still don't want to do the blkdev_open, so use kern_path() to get the
path to the given device and do the update time on that inode.
Fixes: 8f96a5bfa1 ("btrfs: update the bdev time directly when closing")
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Attempting to defragment a Btrfs file containing a transparent huge page
immediately deadlocks with the following stack trace:
#0 context_switch (kernel/sched/core.c:4940:2)
#1 __schedule (kernel/sched/core.c:6287:8)
#2 schedule (kernel/sched/core.c:6366:3)
#3 io_schedule (kernel/sched/core.c:8389:2)
#4 wait_on_page_bit_common (mm/filemap.c:1356:4)
#5 __lock_page (mm/filemap.c:1648:2)
#6 lock_page (./include/linux/pagemap.h:625:3)
#7 pagecache_get_page (mm/filemap.c:1910:4)
#8 find_or_create_page (./include/linux/pagemap.h:420:9)
#9 defrag_prepare_one_page (fs/btrfs/ioctl.c:1068:9)
#10 defrag_one_range (fs/btrfs/ioctl.c:1326:14)
#11 defrag_one_cluster (fs/btrfs/ioctl.c:1421:9)
#12 btrfs_defrag_file (fs/btrfs/ioctl.c:1523:9)
#13 btrfs_ioctl_defrag (fs/btrfs/ioctl.c:3117:9)
#14 btrfs_ioctl (fs/btrfs/ioctl.c:4872:10)
#15 vfs_ioctl (fs/ioctl.c:51:10)
#16 __do_sys_ioctl (fs/ioctl.c:874:11)
#17 __se_sys_ioctl (fs/ioctl.c:860:1)
#18 __x64_sys_ioctl (fs/ioctl.c:860:1)
#19 do_syscall_x64 (arch/x86/entry/common.c:50:14)
#20 do_syscall_64 (arch/x86/entry/common.c:80:7)
#21 entry_SYSCALL_64+0x7c/0x15b (arch/x86/entry/entry_64.S:113)
A huge page is represented by a compound page, which consists of a
struct page for each PAGE_SIZE page within the huge page. The first
struct page is the "head page", and the remaining are "tail pages".
Defragmentation attempts to lock each page in the range. However,
lock_page() on a tail page actually locks the corresponding head page.
So, if defragmentation tries to lock more than one struct page in a
compound page, it tries to lock the same head page twice and deadlocks
with itself.
Ideally, we should be able to defragment transparent huge pages.
However, THP for filesystems is currently read-only, so a lot of code is
not ready to use huge pages for I/O. For now, let's just return
ETXTBUSY.
This can be reproduced with the following on a kernel with
CONFIG_READ_ONLY_THP_FOR_FS=y:
$ cat create_thp_file.c
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
static const char zeroes[1024 * 1024];
static const size_t FILE_SIZE = 2 * 1024 * 1024;
int main(int argc, char **argv)
{
if (argc != 2) {
fprintf(stderr, "usage: %s PATH\n", argv[0]);
return EXIT_FAILURE;
}
int fd = creat(argv[1], 0777);
if (fd == -1) {
perror("creat");
return EXIT_FAILURE;
}
size_t written = 0;
while (written < FILE_SIZE) {
ssize_t ret = write(fd, zeroes,
sizeof(zeroes) < FILE_SIZE - written ?
sizeof(zeroes) : FILE_SIZE - written);
if (ret < 0) {
perror("write");
return EXIT_FAILURE;
}
written += ret;
}
close(fd);
fd = open(argv[1], O_RDONLY);
if (fd == -1) {
perror("open");
return EXIT_FAILURE;
}
/*
* Reserve some address space so that we can align the file mapping to
* the huge page size.
*/
void *placeholder_map = mmap(NULL, FILE_SIZE * 2, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (placeholder_map == MAP_FAILED) {
perror("mmap (placeholder)");
return EXIT_FAILURE;
}
void *aligned_address =
(void *)(((uintptr_t)placeholder_map + FILE_SIZE - 1) & ~(FILE_SIZE - 1));
void *map = mmap(aligned_address, FILE_SIZE, PROT_READ | PROT_EXEC,
MAP_SHARED | MAP_FIXED, fd, 0);
if (map == MAP_FAILED) {
perror("mmap");
return EXIT_FAILURE;
}
if (madvise(map, FILE_SIZE, MADV_HUGEPAGE) < 0) {
perror("madvise");
return EXIT_FAILURE;
}
char *line = NULL;
size_t line_capacity = 0;
FILE *smaps_file = fopen("/proc/self/smaps", "r");
if (!smaps_file) {
perror("fopen");
return EXIT_FAILURE;
}
for (;;) {
for (size_t off = 0; off < FILE_SIZE; off += 4096)
((volatile char *)map)[off];
ssize_t ret;
bool this_mapping = false;
while ((ret = getline(&line, &line_capacity, smaps_file)) > 0) {
unsigned long start, end, huge;
if (sscanf(line, "%lx-%lx", &start, &end) == 2) {
this_mapping = (start <= (uintptr_t)map &&
(uintptr_t)map < end);
} else if (this_mapping &&
sscanf(line, "FilePmdMapped: %ld", &huge) == 1 &&
huge > 0) {
return EXIT_SUCCESS;
}
}
sleep(6);
rewind(smaps_file);
fflush(smaps_file);
}
}
$ ./create_thp_file huge
$ btrfs fi defrag -czstd ./huge
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 2efc459d06 ("sysfs: Add sysfs_emit and sysfs_emit_at to format
sysfs out") merged in 5.10 introduced two new functions sysfs_emit() and
sysfs_emit_at() which are aware of the PAGE_SIZE limit of the output
buffer.
Use the above two new functions instead of scnprintf() and snprintf()
in various sysfs show().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's a common practice to avoid use sizeof(struct btrfs_super_block)
(3531), but to use BTRFS_SUPER_INFO_SIZE (4096).
The problem is that, sizeof(struct btrfs_super_block) doesn't match
BTRFS_SUPER_INFO_SIZE from the very beginning.
Furthermore, for all call sites except selftests, we always allocate
BTRFS_SUPER_INFO_SIZE space for super block, there isn't any real reason
to use the smaller value, and it doesn't really save any space.
So let's get rid of such confusing behavior, and unify those two values.
This modification also adds a new static_assert() to verify the size,
and moves the BTRFS_SUPER_INFO_* macros to the definition of
btrfs_super_block for the static_assert().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Update the comments at btrfs_chunk_alloc() and do_chunk_alloc() that
describe which cases can lead to a failure to allocate metadata and system
space despite having previously reserved space. This adds one more reason
that I previously forgot to mention.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When a task is doing some modification to the chunk btree and it is not in
the context of a chunk allocation or a chunk removal, it can deadlock with
another task that is currently allocating a new data or metadata chunk.
These contexts are the following:
* When relocating a system chunk, when we need to COW the extent buffers
that belong to the chunk btree;
* When adding a new device (ioctl), where we need to add a new device item
to the chunk btree;
* When removing a device (ioctl), where we need to remove a device item
from the chunk btree;
* When resizing a device (ioctl), where we need to update a device item in
the chunk btree and may need to relocate a system chunk that lies beyond
the new device size when shrinking a device.
The problem happens due to a sequence of steps like the following:
1) Task A starts a data or metadata chunk allocation and it locks the
chunk mutex;
2) Task B is relocating a system chunk, and when it needs to COW an extent
buffer of the chunk btree, it has locked both that extent buffer as
well as its parent extent buffer;
3) Since there is not enough available system space, either because none
of the existing system block groups have enough free space or because
the only one with enough free space is in RO mode due to the relocation,
task B triggers a new system chunk allocation. It blocks when trying to
acquire the chunk mutex, currently held by task A;
4) Task A enters btrfs_chunk_alloc_add_chunk_item(), in order to insert
the new chunk item into the chunk btree and update the existing device
items there. But in order to do that, it has to lock the extent buffer
that task B locked at step 2, or its parent extent buffer, but task B
is waiting on the chunk mutex, which is currently locked by task A,
therefore resulting in a deadlock.
One example report when the deadlock happens with system chunk relocation:
INFO: task kworker/u9:5:546 blocked for more than 143 seconds.
Not tainted 5.15.0-rc3+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u9:5 state:D stack:25936 pid: 546 ppid: 2 flags:0x00004000
Workqueue: events_unbound btrfs_async_reclaim_metadata_space
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
rwsem_down_read_slowpath+0x4ee/0x9d0 kernel/locking/rwsem.c:993
__down_read_common kernel/locking/rwsem.c:1214 [inline]
__down_read kernel/locking/rwsem.c:1223 [inline]
down_read_nested+0xe6/0x440 kernel/locking/rwsem.c:1590
__btrfs_tree_read_lock+0x31/0x350 fs/btrfs/locking.c:47
btrfs_tree_read_lock fs/btrfs/locking.c:54 [inline]
btrfs_read_lock_root_node+0x8a/0x320 fs/btrfs/locking.c:191
btrfs_search_slot_get_root fs/btrfs/ctree.c:1623 [inline]
btrfs_search_slot+0x13b4/0x2140 fs/btrfs/ctree.c:1728
btrfs_update_device+0x11f/0x500 fs/btrfs/volumes.c:2794
btrfs_chunk_alloc_add_chunk_item+0x34d/0xea0 fs/btrfs/volumes.c:5504
do_chunk_alloc fs/btrfs/block-group.c:3408 [inline]
btrfs_chunk_alloc+0x84d/0xf50 fs/btrfs/block-group.c:3653
flush_space+0x54e/0xd80 fs/btrfs/space-info.c:670
btrfs_async_reclaim_metadata_space+0x396/0xa90 fs/btrfs/space-info.c:953
process_one_work+0x9df/0x16d0 kernel/workqueue.c:2297
worker_thread+0x90/0xed0 kernel/workqueue.c:2444
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
INFO: task syz-executor:9107 blocked for more than 143 seconds.
Not tainted 5.15.0-rc3+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:23200 pid: 9107 ppid: 7792 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
__mutex_lock_common kernel/locking/mutex.c:669 [inline]
__mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729
btrfs_chunk_alloc+0x31a/0xf50 fs/btrfs/block-group.c:3631
find_free_extent_update_loop fs/btrfs/extent-tree.c:3986 [inline]
find_free_extent+0x25cb/0x3a30 fs/btrfs/extent-tree.c:4335
btrfs_reserve_extent+0x1f1/0x500 fs/btrfs/extent-tree.c:4415
btrfs_alloc_tree_block+0x203/0x1120 fs/btrfs/extent-tree.c:4813
__btrfs_cow_block+0x412/0x1620 fs/btrfs/ctree.c:415
btrfs_cow_block+0x2f6/0x8c0 fs/btrfs/ctree.c:570
btrfs_search_slot+0x1094/0x2140 fs/btrfs/ctree.c:1768
relocate_tree_block fs/btrfs/relocation.c:2694 [inline]
relocate_tree_blocks+0xf73/0x1770 fs/btrfs/relocation.c:2757
relocate_block_group+0x47e/0xc70 fs/btrfs/relocation.c:3673
btrfs_relocate_block_group+0x48a/0xc60 fs/btrfs/relocation.c:4070
btrfs_relocate_chunk+0x96/0x280 fs/btrfs/volumes.c:3181
__btrfs_balance fs/btrfs/volumes.c:3911 [inline]
btrfs_balance+0x1f03/0x3cd0 fs/btrfs/volumes.c:4301
btrfs_ioctl_balance+0x61e/0x800 fs/btrfs/ioctl.c:4137
btrfs_ioctl+0x39ea/0x7b70 fs/btrfs/ioctl.c:4949
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
So fix this by making sure that whenever we try to modify the chunk btree
and we are neither in a chunk allocation context nor in a chunk remove
context, we reserve system space before modifying the chunk btree.
Reported-by: Hao Sun <sunhao.th@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CACkBjsax51i4mu6C0C3vJqQN3NR_iVuucoeG3U1HXjrgzn5FFQ@mail.gmail.com/
Fixes: 79bd37120b ("btrfs: rework chunk allocation to avoid exhaustion of the system chunk array")
CC: stable@vger.kernel.org # 5.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently auto reclaim of unusable zones reclaims the block-groups in
the order they have been added to the reclaim list.
Change this to a greedy algorithm by sorting the list so we have the
block-groups with the least amount of valid bytes reclaimed first.
Note: we can't splice the block groups from reclaim_bgs to let the sort
happen outside of the lock. The block groups can be still in use by
other parts eg. via bg_list and we must hold unused_bgs_lock while
processing them.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ write note and comment why we can't splice the list ]
Signed-off-by: David Sterba <dsterba@suse.com>
Just use the %pg format specifier in all the debug printks previously
using it. Note that both bdevname and the %pg specifier never print
a pathname, so the kbasename call wasn't needed to start with.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
[ adjust messages and indentation ]
Signed-off-by: David Sterba <dsterba@suse.com>
For device removal and replace we call btrfs_find_device_by_devspec,
which if we give it a device path and nothing else will call
btrfs_get_dev_args_from_path, which opens the block device and reads the
super block and then looks up our device based on that.
However at this point we're holding the sb write "lock", so reading the
block device pulls in the dependency of ->open_mutex, which produces the
following lockdep splat
======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2+ #405 Not tainted
------------------------------------------------------
losetup/11576 is trying to acquire lock:
ffff9bbe8cded938 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0
but task is already holding lock:
ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&lo->lo_mutex){+.+.}-{3:3}:
__mutex_lock+0x7d/0x750
lo_open+0x28/0x60 [loop]
blkdev_get_whole+0x25/0xf0
blkdev_get_by_dev.part.0+0x168/0x3c0
blkdev_open+0xd2/0xe0
do_dentry_open+0x161/0x390
path_openat+0x3cc/0xa20
do_filp_open+0x96/0x120
do_sys_openat2+0x7b/0x130
__x64_sys_openat+0x46/0x70
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #3 (&disk->open_mutex){+.+.}-{3:3}:
__mutex_lock+0x7d/0x750
blkdev_get_by_dev.part.0+0x56/0x3c0
blkdev_get_by_path+0x98/0xa0
btrfs_get_bdev_and_sb+0x1b/0xb0
btrfs_find_device_by_devspec+0x12b/0x1c0
btrfs_rm_device+0x127/0x610
btrfs_ioctl+0x2a31/0x2e70
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #2 (sb_writers#12){.+.+}-{0:0}:
lo_write_bvec+0xc2/0x240 [loop]
loop_process_work+0x238/0xd00 [loop]
process_one_work+0x26b/0x560
worker_thread+0x55/0x3c0
kthread+0x140/0x160
ret_from_fork+0x1f/0x30
-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
process_one_work+0x245/0x560
worker_thread+0x55/0x3c0
kthread+0x140/0x160
ret_from_fork+0x1f/0x30
-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
__lock_acquire+0x10ea/0x1d90
lock_acquire+0xb5/0x2b0
flush_workqueue+0x91/0x5e0
drain_workqueue+0xa0/0x110
destroy_workqueue+0x36/0x250
__loop_clr_fd+0x9a/0x660 [loop]
block_ioctl+0x3f/0x50
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of:
(wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&lo->lo_mutex);
lock(&disk->open_mutex);
lock(&lo->lo_mutex);
lock((wq_completion)loop0);
*** DEADLOCK ***
1 lock held by losetup/11576:
#0: ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]
stack backtrace:
CPU: 0 PID: 11576 Comm: losetup Not tainted 5.14.0-rc2+ #405
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
dump_stack_lvl+0x57/0x72
check_noncircular+0xcf/0xf0
? stack_trace_save+0x3b/0x50
__lock_acquire+0x10ea/0x1d90
lock_acquire+0xb5/0x2b0
? flush_workqueue+0x67/0x5e0
? lockdep_init_map_type+0x47/0x220
flush_workqueue+0x91/0x5e0
? flush_workqueue+0x67/0x5e0
? verify_cpu+0xf0/0x100
drain_workqueue+0xa0/0x110
destroy_workqueue+0x36/0x250
__loop_clr_fd+0x9a/0x660 [loop]
? blkdev_ioctl+0x8d/0x2a0
block_ioctl+0x3f/0x50
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f31b02404cb
Instead what we want to do is populate our device lookup args before we
grab any locks, and then pass these args into btrfs_rm_device(). From
there we can find the device and do the appropriate removal.
Suggested-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are going to want to populate our device lookup args outside of any
locks and then do the actual device lookup later, so add a helper to do
this work and make btrfs_find_device_by_devspec() use this helper for
now.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Josef Bacik