Unlike mirror based profiles, RAID5/6 recovery needs to read out the
whole full stripe.
And if we don't do proper protection, it can easily cause race condition.
Introduce 2 new functions: lock_full_stripe() and unlock_full_stripe()
for RAID5/6.
Which store a rb_tree of mutexes for full stripes, so scrub callers can
use them to lock a full stripe to avoid race.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor comment adjustments ]
Signed-off-by: David Sterba <dsterba@suse.com>
This is fixing code pieces where we use div_u64 when passing a u64 divisor.
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 3d8da67817 ("Btrfs: fix divide error upon chunk's stripe_len")
changed stripe_len in struct map_lookup to u64, but didn't update
stripe_len in struct scrub_parity.
This updates the type and switches to div64_u64_rem to match u64 divisor.
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's a helper to clear whole page, with a arch-specific optimized
code. The replaced cases do not seem to be in performace critical code,
but we still might get some percent gain.
Signed-off-by: David Sterba <dsterba@suse.com>
scrub_setup_recheck_block() calls btrfs_map_sblock() and then accesses
bbio without protection of bio_counter.
This can lead to use-after-free if racing with dev replace cancel.
Fix it by increasing bio_counter before calling btrfs_map_sblock() and
decreasing the bio_counter when corresponding recover is finished.
Cc: Liu Bo <bo.li.liu@oracle.com>
Reported-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When raid56 dev-replace is cancelled by running scrub, we will free
target device without waiting for in-flight bios, causing the following
NULL pointer deference or general protection failure.
BUG: unable to handle kernel NULL pointer dereference at 00000000000005e0
IP: generic_make_request_checks+0x4d/0x610
CPU: 1 PID: 11676 Comm: kworker/u4:14 Tainted: G O 4.11.0-rc2 #72
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
Workqueue: btrfs-endio-raid56 btrfs_endio_raid56_helper [btrfs]
task: ffff88002875b4c0 task.stack: ffffc90001334000
RIP: 0010:generic_make_request_checks+0x4d/0x610
Call Trace:
? generic_make_request+0xc7/0x360
generic_make_request+0x24/0x360
? generic_make_request+0xc7/0x360
submit_bio+0x64/0x120
? page_in_rbio+0x4d/0x80 [btrfs]
? rbio_orig_end_io+0x80/0x80 [btrfs]
finish_rmw+0x3f4/0x540 [btrfs]
validate_rbio_for_rmw+0x36/0x40 [btrfs]
raid_rmw_end_io+0x7a/0x90 [btrfs]
bio_endio+0x56/0x60
end_workqueue_fn+0x3c/0x40 [btrfs]
btrfs_scrubparity_helper+0xef/0x620 [btrfs]
btrfs_endio_raid56_helper+0xe/0x10 [btrfs]
process_one_work+0x2af/0x720
? process_one_work+0x22b/0x720
worker_thread+0x4b/0x4f0
kthread+0x10f/0x150
? process_one_work+0x720/0x720
? kthread_create_on_node+0x40/0x40
ret_from_fork+0x2e/0x40
RIP: generic_make_request_checks+0x4d/0x610 RSP: ffffc90001337bb8
In btrfs_dev_replace_finishing(), we will call
btrfs_rm_dev_replace_blocked() to wait bios before destroying the target
device when scrub is finished normally.
However when dev-replace is aborted, either due to error or cancelled by
scrub, we didn't wait for bios, this can lead to use-after-free if there
are bios holding the target device.
Furthermore, for raid56 scrub, at least 2 places are calling
btrfs_map_sblock() without protection of bio_counter, leading to the
problem.
This patch fixes the problem:
1) Wait for bio_counter before freeing target device when canceling
replace
2) When calling btrfs_map_sblock() for raid56, use bio_counter to
protect the call.
Cc: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the following situation, scrub will calculate wrong parity to
overwrite the correct one:
RAID5 full stripe:
Before
| Dev 1 | Dev 2 | Dev 3 |
| Data stripe 1 | Data stripe 2 | Parity Stripe |
--------------------------------------------------- 0
| 0x0000 (Bad) | 0xcdcd | 0x0000 |
--------------------------------------------------- 4K
| 0xcdcd | 0xcdcd | 0x0000 |
...
| 0xcdcd | 0xcdcd | 0x0000 |
--------------------------------------------------- 64K
After scrubbing dev3 only:
| Dev 1 | Dev 2 | Dev 3 |
| Data stripe 1 | Data stripe 2 | Parity Stripe |
--------------------------------------------------- 0
| 0xcdcd (Good) | 0xcdcd | 0xcdcd (Bad) |
--------------------------------------------------- 4K
| 0xcdcd | 0xcdcd | 0x0000 |
...
| 0xcdcd | 0xcdcd | 0x0000 |
--------------------------------------------------- 64K
The reason is that after raid56 read rebuild rbio->stripe_pages are all
correctly recovered (0xcd for data stripes).
However when we check and repair parity in
scrub_parity_check_and_repair(), we will append pages in sparity->spages
list to rbio->bio_pages[], which contains old on-disk data.
And when we submit parity data to disk, we calculate parity using
rbio->bio_pages[] first, if rbio->bio_pages[] not found, then fallback
to rbio->stripe_pages[].
The patch fix it by not appending pages from sparity->spages.
So finish_parity_scrub() will use rbio->stripe_pages[] which is correct.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Scrub repairs data by the unit called scrub_block, which may contain
several pages. Scrub always tries to look up a good copy of a whole
block, but if there's no such copy, it tries to do repair page by page.
If we don't set page's io_error when checking this bad copy, in the last
step, we may skip this page when repairing bad copy from good copy.
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_inc_block_group_ro is either passed the extent root or the dev
root, but it doesn't do anything with the dev tree. Let's convert
to passing an fs_info and using the extent root.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull btrfs updates from Chris Mason:
"Jeff Mahoney and Dave Sterba have a really nice set of cleanups in
here, and Christoph pitched in corrections/improvements to make btrfs
use proper helpers for bio walking instead of doing it by hand.
There are some key fixes as well, including some long standing bugs
that took forever to track down in btrfs_drop_extents and during
balance"
* 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (77 commits)
btrfs: limit async_work allocation and worker func duration
Revert "Btrfs: adjust len of writes if following a preallocated extent"
Btrfs: don't WARN() in btrfs_transaction_abort() for IO errors
btrfs: opencode chunk locking, remove helpers
btrfs: remove root parameter from transaction commit/end routines
btrfs: split btrfs_wait_marked_extents into normal and tree log functions
btrfs: take an fs_info directly when the root is not used otherwise
btrfs: simplify btrfs_wait_cache_io prototype
btrfs: convert extent-tree tracepoints to use fs_info
btrfs: root->fs_info cleanup, access fs_info->delayed_root directly
btrfs: root->fs_info cleanup, add fs_info convenience variables
btrfs: root->fs_info cleanup, update_block_group{,flags}
btrfs: root->fs_info cleanup, lock/unlock_chunks
btrfs: root->fs_info cleanup, btrfs_calc_{trans,trunc}_metadata_size
btrfs: pull node/sector/stripe sizes out of root and into fs_info
btrfs: root->fs_info cleanup, io_ctl_init
btrfs: root->fs_info cleanup, use fs_info->dev_root everywhere
btrfs: struct reada_control.root -> reada_control.fs_info
btrfs: struct btrfsic_state->root should be an fs_info
btrfs: alloc_reserved_file_extent trace point should use extent_root
...
Now we only use the root parameter to print the root objectid in
a tracepoint. We can use the root parameter from the transaction
handle for that. It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer. Let's convert those to
just accept an fs_info pointer directly.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In routines where someptr->fs_info is referenced multiple times, we
introduce a convenience variable. This makes the code considerably
more readable.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We track the node sizes per-root, but they never vary from the values
in the superblock. This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_map_block supports different types of mappings, which to a large
extent resemble block layer operations. But they don't always do, and
currently btrfs dangerously overlays it's own flag over the block layer
flags. This is just asking for a conflict, so introduce a different
map flags enum inside of btrfs instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly. Where applicable this also drops usage of the
bio_set_op_attrs wrapper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
CodingStyle chapter 2:
"[...] never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."
This patch unsplits user-visible strings.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull more btrfs updates from Chris Mason:
"This is part two of my btrfs pull, which is some cleanups and a batch
of fixes.
Most of the code here is from Jeff Mahoney, making the pointers we
pass around internally more consistent and less confusing overall. I
noticed a small problem right before I sent this out yesterday, so I
fixed it up and re-tested overnight"
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (40 commits)
Btrfs: fix __MAX_CSUM_ITEMS
btrfs: btrfs_abort_transaction, drop root parameter
btrfs: add btrfs_trans_handle->fs_info pointer
btrfs: btrfs_relocate_chunk pass extent_root to btrfs_end_transaction
btrfs: convert nodesize macros to static inlines
btrfs: introduce BTRFS_MAX_ITEM_SIZE
btrfs: cleanup, remove prototype for btrfs_find_root_ref
btrfs: copy_to_sk drop unused root parameter
btrfs: simpilify btrfs_subvol_inherit_props
btrfs: tests, use BTRFS_FS_STATE_DUMMY_FS_INFO instead of dummy root
btrfs: tests, require fs_info for root
btrfs: tests, move initialization into tests/
btrfs: btrfs_test_opt and friends should take a btrfs_fs_info
btrfs: prefix fsid to all trace events
btrfs: plumb fs_info into btrfs_work
btrfs: remove obsolete part of comment in statfs
btrfs: hide test-only member under ifdef
btrfs: Ratelimit "no csum found" info message
btrfs: Add ratelimit to btrfs printing
Btrfs: fix unexpected balance crash due to BUG_ON
...
In order to provide an fsid for trace events, we'll need a btrfs_fs_info
pointer. The most lightweight way to do that for btrfs_work structures
is to associate it with the __btrfs_workqueue structure. Each queued
btrfs_work structure has a workqueue associated with it, so that's
a natural fit. It's a privately defined structures, so we add accessors
to retrieve the fs_info pointer.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs/073 invokes scrub ioctl in a tight loop. In subpage-blocksize
scenario this results in a lot of "scrub: size assumption sectorsize !=
PAGE_SIZE " messages being printed on the console. To reduce the number
of such messages this commit uses btrfs_err_rl() instead of
btrfs_err().
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This should be the easier cases to convert btrfs to
bio_set_op_attrs/bio_op.
They are mostly just cut and replace type of changes.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Fixed up fs/ext4/crypto.c
Signed-off-by: Jens Axboe <axboe@fb.com>
After it finishes processing a device extent, the device replace code sets
back the block group to RW mode and then after that it sets the left cursor
to match the logical end address of the block group, so that future writes
into extents belonging to the block group go both the source (old) and
target (new) devices. However from the moment we turn the block group
back to RW mode we have a short time window, that lasts until we update
the left cursor's value, where extents can be allocated from the block
group and written to, in which case they will not be copied/written to
the target (new) device. Fix this by updating the left cursor's value
before turning the block group back to RW mode.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
We were assigning new values to fields of the device replace object
without holding the respective lock after processing each device extent.
This is important for the left cursor field which can be accessed by a
concurrent task running __btrfs_map_block (which, correctly, takes the
device replace lock).
So change these fields while holding the device replace lock.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
When we do a device replace, for each device extent we find from the
source device, we set the corresponding block group to readonly mode to
prevent writes into it from happening while we are copying the device
extent from the source to the target device. However just before we set
the block group to readonly mode some concurrent task might have already
allocated an extent from it or decided it could perform a nocow write
into one of its extents, which can make the device replace process to
miss copying an extent since it uses the extent tree's commit root to
search for extents and only once it finishes searching for all extents
belonging to the block group it does set the left cursor to the logical
end address of the block group - this is a problem if the respective
ordered extents finish while we are searching for extents using the
extent tree's commit root and no transaction commit happens while we
are iterating the tree, since it's the delayed references created by the
ordered extents (when they complete) that insert the extent items into
the extent tree (using the non-commit root of course).
Example:
CPU 1 CPU 2
btrfs_dev_replace_start()
btrfs_scrub_dev()
scrub_enumerate_chunks()
--> finds device extent belonging
to block group X
<transaction N starts>
starts buffered write
against some inode
writepages is run against
that inode forcing dellaloc
to run
btrfs_writepages()
extent_writepages()
extent_write_cache_pages()
__extent_writepage()
writepage_delalloc()
run_delalloc_range()
cow_file_range()
btrfs_reserve_extent()
--> allocates an extent
from block group X
(which is not yet
in RO mode)
btrfs_add_ordered_extent()
--> creates ordered extent Y
flush_epd_write_bio()
--> bio against the extent from
block group X is submitted
btrfs_inc_block_group_ro(bg X)
--> sets block group X to readonly
scrub_chunk(bg X)
scrub_stripe(device extent from srcdev)
--> keeps searching for extent items
belonging to the block group using
the extent tree's commit root
--> it never blocks due to
fs_info->scrub_pause_req as no
one tries to commit transaction N
--> copies all extents found from the
source device into the target device
--> finishes search loop
bio completes
ordered extent Y completes
and creates delayed data
reference which will add an
extent item to the extent
tree when run (typically
at transaction commit time)
--> so the task doing the
scrub/device replace
at CPU 1 misses this
and does not copy this
extent into the new/target
device
btrfs_dec_block_group_ro(bg X)
--> turns block group X back to RW mode
dev_replace->cursor_left is set to the
logical end offset of block group X
So fix this by waiting for all cow and nocow writes after setting a block
group to readonly mode.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
We usually call btrfs_put_bbio() when btrfs_map_block() failed,
btrfs_put_bbio() works right whether bbio is a valid value, or NULL.
But there is a exception, in some case, btrfs_map_block() will return
fail without touching *bbio(keeping its original value), and if bbio
was not initialized yet, invalid memory accessing will happened.
Above case is in scrub_missing_raid56_pages(), and similar case in
scrub_raid56_parity().
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A 'struct bio' is allocated in scrub_missing_raid56_pages(), but it was never
freed anywhere.
Signed-off-by: Scott Talbert <scott.talbert@hgst.com>
Signed-off-by: David Sterba <dsterba@suse.com>
pagev array in scrub_block{} is of size SCRUB_MAX_PAGES_PER_BLOCK.
page_index should be checked with the same to trigger BUG_ON().
Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The struct 'map_lookup' uses type int for @stripe_len, while
btrfs_chunk_stripe_len() can return a u64 value, and it may end up with
@stripe_len being undefined value and it can lead to 'divide error' in
__btrfs_map_block().
This changes 'map_lookup' to use type u64 for stripe_len, also right now
we only use BTRFS_STRIPE_LEN for stripe_len, so this adds a valid checker for
BTRFS_STRIPE_LEN.
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ folded division fix to scrub_raid56_parity ]
Signed-off-by: David Sterba <dsterba@suse.com>
The key variable occupies 17 bytes, the key_start is used once, we can
simply reuse existing 'key' for that purpose. As the key is not a simple
type, compiler doest not do it on itself.
Signed-off-by: David Sterba <dsterba@suse.com>
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's basically harmless if "ref_level" isn't initialized since it's only
used for an error message, but it causes a static checker warning.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Xfstests btrfs/011 complains about a deadlock warning,
[ 1226.649039] =========================================================
[ 1226.649039] [ INFO: possible irq lock inversion dependency detected ]
[ 1226.649039] 4.1.0+ #270 Not tainted
[ 1226.649039] ---------------------------------------------------------
[ 1226.652955] kswapd0/46 just changed the state of lock:
[ 1226.652955] (&delayed_node->mutex){+.+.-.}, at: [<ffffffff81458735>] __btrfs_release_delayed_node+0x45/0x1d0
[ 1226.652955] but this lock took another, RECLAIM_FS-unsafe lock in the past:
[ 1226.652955] (&fs_info->dev_replace.lock){+.+.+.}
and interrupts could create inverse lock ordering between them.
[ 1226.652955]
other info that might help us debug this:
[ 1226.652955] Chain exists of:
&delayed_node->mutex --> &found->groups_sem --> &fs_info->dev_replace.lock
[ 1226.652955] Possible interrupt unsafe locking scenario:
[ 1226.652955] CPU0 CPU1
[ 1226.652955] ---- ----
[ 1226.652955] lock(&fs_info->dev_replace.lock);
[ 1226.652955] local_irq_disable();
[ 1226.652955] lock(&delayed_node->mutex);
[ 1226.652955] lock(&found->groups_sem);
[ 1226.652955] <Interrupt>
[ 1226.652955] lock(&delayed_node->mutex);
[ 1226.652955]
*** DEADLOCK ***
Commit 084b6e7c76 ("btrfs: Fix a lockdep warning when running xfstest.") tried
to fix a similar one that has the exactly same warning, but with that, we still
run to this.
The above lock chain comes from
btrfs_commit_transaction
->btrfs_run_delayed_items
...
->__btrfs_update_delayed_inode
...
->__btrfs_cow_block
...
->find_free_extent
->cache_block_group
->load_free_space_cache
->btrfs_readpages
->submit_one_bio
...
->__btrfs_map_block
->btrfs_dev_replace_lock
However, with high memory pressure, tasks which hold dev_replace.lock can
be interrupted by kswapd and then kswapd is intended to release memory occupied
by superblock, inodes and dentries, where we may call evict_inode, and it comes
to
[ 1226.652955] [<ffffffff81458735>] __btrfs_release_delayed_node+0x45/0x1d0
[ 1226.652955] [<ffffffff81459e74>] btrfs_remove_delayed_node+0x24/0x30
[ 1226.652955] [<ffffffff8140c5fe>] btrfs_evict_inode+0x34e/0x700
delayed_node->mutex may be acquired in __btrfs_release_delayed_node(), and it leads
to a ABBA deadlock.
To fix this, we can use "blocking rwlock" used in the case of extent_buffer, but
things are simpler here since we only needs read's spinlock to blocking lock.
With this, btrfs/011 no more produces warnings in dmesg.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Scrub is not on the critical writeback path we don't need to use
GFP_NOFS for all allocations. The failures are handled and stats passed
back to userspace.
Let's use GFP_KERNEL on the paths where everything is ok, ie. setup the
global structures and the IO submission paths.
Functions that do the repair and fixups still use GFP_NOFS as we might
want to skip any other filesystem activity if we encounter an error.
This could turn out to be unnecessary, but requires more review compared
to the easy cases in this patch.
Signed-off-by: David Sterba <dsterba@suse.com>
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).
Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Current code is trying to calculate rbio->dbitmap's size to make it
align to sizeof(long), but implement haven't achived this object,
it is align to sizeof(char) instead.
This patch fixed above calculation, and use sizeof(long) instead of
fixed "8" to increate compatibility.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Overloading extent_map->bdev to struct map_lookup * might have started out
as a means to an end, but it's a pattern that's used all over the place
now. Let's get rid of the casting and just add a union instead.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Replace the integers by enums for better readability. The value 2 does
not have any meaning since a717531942
"Btrfs: do less aggressive btree readahead" (2009-01-22).
Signed-off-by: David Sterba <dsterba@suse.com>
Currently scrub can race with the cleaner kthread when the later attempts
to delete an unused block group, and the result is preventing the cleaner
kthread from ever deleting later the block group - unless the block group
becomes used and unused again. The following diagram illustrates that
race:
CPU 1 CPU 2
cleaner kthread
btrfs_delete_unused_bgs()
gets block group X from
fs_info->unused_bgs and
removes it from that list
scrub_enumerate_chunks()
searches device tree using
its commit root
finds device extent for
block group X
gets block group X from the tree
fs_info->block_group_cache_tree
(via btrfs_lookup_block_group())
sets bg X to RO
sees the block group is
already RO and therefore
doesn't delete it nor adds
it back to unused list
So fix this by making scrub add the block group again to the list of
unused block groups if the block group is still unused when it finished
scrubbing it and it hasn't been removed already.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Scrub can race with the cleaner kthread deleting block groups that are
unused (and with relocation too) leading to a failure with error -EINVAL
that gets returned to user space.
The following diagram illustrates how it happens:
CPU 1 CPU 2
cleaner kthread
btrfs_delete_unused_bgs()
gets block group X from
fs_info->unused_bgs
sets block group to RO
btrfs_remove_chunk(bg X)
deletes device extents
scrub_enumerate_chunks()
searches device tree using
its commit root
finds device extent for
block group X
gets block group X from the tree
fs_info->block_group_cache_tree
(via btrfs_lookup_block_group())
sets bg X to RO (again)
btrfs_remove_block_group(bg X)
deletes block group from
fs_info->block_group_cache_tree
removes extent map from
fs_info->mapping_tree
scrub_chunk(offset X)
searches fs_info->mapping_tree
for extent map starting at
offset X
--> doesn't find any such
extent map
--> returns -EINVAL and scrub
errors out to userspace
with -EINVAL
Fix this by dealing with an extent map lookup failure as an indicator of
block group deletion.
Issue reproduced with fstest btrfs/071.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
xfstests/011 failed in node with small_size filesystem.
Can be reproduced by following script:
DEV_LIST="/dev/vdd /dev/vde"
DEV_REPLACE="/dev/vdf"
do_test()
{
local mkfs_opt="$1"
local size="$2"
dmesg -c >/dev/null
umount $SCRATCH_MNT &>/dev/null
echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}"
mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1
mount "${DEV_LIST[0]}" $SCRATCH_MNT
echo -n "Writing big files"
dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1
for ((i = 1; i <= size; i++)); do
echo -n .
/bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1
done
echo
echo Start replace
btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || {
dmesg
return 1
}
return 0
}
# Set size to value near fs size
# for example, 1897 can trigger this bug in 2.6G device.
#
./do_test "-d raid1 -m raid1" 1897
System will report replace fail with following warning in dmesg:
[ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started
[ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28
[ 135.543505] ------------[ cut here ]------------
[ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440()
[ 135.545276] Modules linked in:
[ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256
[ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
[ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000
[ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4
[ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70
[ 135.550758] Call Trace:
[ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55
[ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0
[ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20
[ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440
[ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0
[ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0
[ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0
[ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580
[ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0
[ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70
[ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90
[ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80
[ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f
[ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]---
Reason:
When big data writen to fs, the whole free space will be allocated
for data chunk.
And operation as scrub need to set_block_ro(), and when there is
only one metadata chunk in system(or other metadata chunks
are all full), the function will try to allocate a new chunk,
and failed because no space in device.
Fix:
When set_block_ro failed for metadata chunk, it is not a problem
because scrub_lock paused commit_trancaction in same time, and
metadata are always cowed, so the on-the-fly writepages will not
write data into same place with scrub/replace.
Let replace continue in this case is no problem.
Tested by above script, and xfstests/011, plus 100 times xfstests/070.
Changelog v1->v2:
1: Add detail comments in source and commit-message.
2: Add dmesg detail into commit-message.
3: Limit return value of -ENOSPC to be passed.
All suggested by: Filipe Manana <fdmanana@gmail.com>
Suggested-by: Filipe Manana <fdmanana@gmail.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
We don't need pass so many arguments for recheck sblock now,
this patch cleans them.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
We can use existing scrub_checksum_data() and scrub_checksum_tree_block()
for scrub_recheck_block_checksum(), instead of write duplicated code.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
We should reset sblock->xxx_error stats before calling
scrub_recheck_block_checksum().
Current code run correctly because all sblock are allocated by
k[cz]alloc(), and the error stats are not got changed.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
scrub_setup_recheck_block() isn't setup all necessary fields for
sblock_to_check because history reason.
So current code need more arguments in severial functions,
and more local variables, just to passing these lacked values to
necessary place.
This patch setup above fields to sblock_to_check in
scrub_setup_recheck_block(), for:
1: more cleanup for function arg, local variable
2: to make sblock_to_check complete, then we can use sblock_to_check
without concern about some uninitialized member.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
It is better to show error stats to user when we found tree block
spanning stripes.
On a btrfs created by old version of btrfs-convert:
Before patch:
# btrfs scrub start -B /dev/vdh
scrub done for 8b342d35-2904-41ab-b3cb-2f929709cf47
scrub started at Tue Aug 25 21:19:09 2015 and finished after 00:00:00
total bytes scrubbed: 53.54MiB with 0 errors
# dmesg
...
[ 128.711434] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27000832
[ 128.712744] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27066368
...
After patch:
# btrfs scrub start -B /dev/vdh
scrub done for ff7f844b-7a4e-4b1a-88a9-8252ab25be1b
scrub started at Tue Aug 25 21:42:29 2015 and finished after 00:00:00
total bytes scrubbed: 53.60MiB with 2 errors
error details:
corrected errors: 0, uncorrectable errors: 2, unverified errors: 0
ERROR: There are uncorrectable errors.
# dmesg
...omit...
#
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Pull btrfs cleanups and fixes from Chris Mason:
"These are small cleanups, and also some fixes for our async worker
thread initialization.
I was having some trouble testing these, but it ended up being a
combination of changing around my test servers and a shiny new
schedule while atomic from the new start/finish_plug in
writeback_sb_inodes().
That one only hits on btrfs raid5/6 or MD raid10, and if I wasn't
changing a bunch of things in my test setup at once it would have been
really clear. Fix for writeback_sb_inodes() on the way as well"
* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: cleanup: remove unnecessary check before btrfs_free_path is called
btrfs: async_thread: Fix workqueue 'max_active' value when initializing
btrfs: Add raid56 support for updating num_tolerated_disk_barrier_failures in btrfs_balance
btrfs: Cleanup for btrfs_calc_num_tolerated_disk_barrier_failures
btrfs: Remove noused chunk_tree and chunk_objectid from scrub_enumerate_chunks and scrub_chunk
btrfs: Update out-of-date "skip parity stripe" comment
Pull btrfs updates from Chris Mason:
"This has Jeff Mahoney's long standing trim patch that fixes corners
where trims were missing. Omar has some raid5/6 fixes, especially for
using scrub and device replace when devices are missing.
Zhao Lie continues cleaning and fixing things, this series fixes some
really hard to hit corners in xfstests. I had to pull it last merge
window due to some deadlocks, but those are now resolved.
I added support for Tejun's new blkio controllers. It seems to work
well for single devices, we'll expand to multi-device as well"
* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (47 commits)
btrfs: fix compile when block cgroups are not enabled
Btrfs: fix file read corruption after extent cloning and fsync
Btrfs: check if previous transaction aborted to avoid fs corruption
btrfs: use __GFP_NOFAIL in alloc_btrfs_bio
btrfs: Prevent from early transaction abort
btrfs: Remove unused arguments in tree-log.c
btrfs: Remove useless condition in start_log_trans()
Btrfs: add support for blkio controllers
Btrfs: remove unused mutex from struct 'btrfs_fs_info'
Btrfs: fix parity scrub of RAID 5/6 with missing device
Btrfs: fix device replace of a missing RAID 5/6 device
Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation
Btrfs: count devices correctly in readahead during RAID 5/6 replace
Btrfs: remove misleading handling of missing device scrub
btrfs: fix clone / extent-same deadlocks
Btrfs: fix defrag to merge tail file extent
Btrfs: fix warning in backref walking
btrfs: Add WARN_ON() for double lock in btrfs_tree_lock()
btrfs: Remove root argument in extent_data_ref_count()
btrfs: Fix wrong comment of btrfs_alloc_tree_block()
...
These variables are not used from introduced version, remove them.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
We can always fill up the bio now, no need to estimate the possible
size based on queue parameters.
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[hch: rebased and wrote a changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When testing the previous patch, Zhao Lei reported a similar bug when
attempting to scrub a degraded RAID 5/6 filesystem with a missing
device, leading to NULL pointer dereferences from the RAID 5/6 parity
scrubbing code.
The first cause was the same as in the previous patch: attempting to
call bio_add_page() on a missing block device. To fix this,
scrub_extent_for_parity() can just mark the sectors on the missing
device as errors instead of attempting to read from it.
Additionally, the code uses scrub_remap_extent() to map the extent of
the corresponding data stripe, but the extent wasn't already mapped. If
scrub_remap_extent() finds a missing block device, it doesn't initialize
extent_dev, so we're left with a NULL struct btrfs_device. The solution
is to use btrfs_map_block() directly.
Reported-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The original implementation of device replace on RAID 5/6 seems to have
missed support for replacing a missing device. When this is attempted,
we end up calling bio_add_page() on a bio with a NULL ->bi_bdev, which
crashes when we try to dereference it. This happens because
btrfs_map_block() has no choice but to return us the missing device
because RAID 5/6 don't have any alternate mirrors to read from, and a
missing device has a NULL bdev.
The idea implemented here is to handle the missing device case
separately, which better only happen when we're replacing a missing RAID
5/6 device. We use the new BTRFS_RBIO_REBUILD_MISSING operation to
reconstruct the data from parity, check it with
scrub_recheck_block_checksum(), and write it out with
scrub_write_block_to_dev_replace().
Reported-by: Philip <bugzilla@philip-seeger.de>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=96141
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The current RAID 5/6 recovery code isn't quite prepared to handle
missing devices. In particular, it expects a bio that we previously
attempted to use in the read path, meaning that it has valid pages
allocated. However, missing devices have a NULL blkdev, and we can't
call bio_add_page() on a bio with a NULL blkdev. We could do manual
manipulation of bio->bi_io_vec, but that's pretty gross. So instead, add
a separate path that allows us to manually add pages to the rbio.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
scrub_submit() claims that it can handle a bio with a NULL block device,
but this is misleading, as calling bio_add_page() on a bio with a NULL
->bi_bdev would've already crashed. Delete this, as we're about to
properly handle a missing block device.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
xfstests btrfs/070 sometimes failed.
In my test machine, its fail rate is about 30%.
In another vm(vmware), its fail rate is about 50%.
Reason:
btrfs/070 do replace and defrag with fsstress simultaneously,
after above operation, checksum error is found by scrub.
Actually, it have no relationship with defrag operation, only
replace with fsstress can trigger this bug.
New data writen to target device have possibility rewrited by
old data from source device by replace code in debug, to avoid
above problem, we can set target block group to readonly in
replace period, so new data requested by other operation will
not write to same place with replace code.
Before patch(4.1-rc3):
30% failed in 100 xfstests.
After patch:
0% failed in 300 xfstests.
It also happened in btrfs/071 as it's another scrub with IO load tests.
Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Use new intruduced scrub_pause_on/off() can make this code block
clean and more readable.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
It can reduce current duplicated code which is similar to
scrub_blocked_if_needed() but can not call it because little
different.
It also used by my next patch which is in same case.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we access extent_root in scrub_stripe() and
scrub_raid56_parity(), we need bypass unrelated tree item firstly
before using its contents to do other condition.
It is not a bug fix, only making code sequence in logic.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
We need not load csum of whole strip in scrub because strip is trimed
before use, it is to say, what we really need to calculate csum is
data between [extent_logical, extent_len).
This patch changed to use above segment for btrfs_lookup_csums_range()
in scrub_stripe()
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
For example, in scrub_raid56_parity(), following lines are used
to judge is all data processed:
place1: if (key.objectid > logic_end) ...
place2: if (logic_start >= logic_end) ...
...
(place2 is typo, is should be ">", it is copied from other
place, where logic_end's meaning is different, long story...)
We can fix above typo directly, but the root reason is ambiguous
meaning of logic_end in scrub raid56 parity.
In other place, XXX_end is pointed to data which is not included,
and we need to process segment of [XXX_start, XXX_end).
But for scrub raid56 parity, logic_end is pointed to lattest data
need to process, and introduced many "+ 1" and "- 1" in code as
below:
length = sparity->logic_end - sparity->logic_start + 1
logic_end - logic_start + 1
stripe_logical + increment - 1
This patch changed logic_end's meaning to make it in normal understanding
in raid56 parity functions and data struct alone with above bugfix.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When scrub_extent() failed, we need to free previois created
checksum list.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Old code checking cancel and pause request inside scrub stripe
operation, like:
loop() {
if (parity) {
scrub_parity_stripe();
continue;
}
check_cancel_and_pause()
scrub_normal_stripe();
}
Reason is when introduce raid56 stripe scrub, new code is inserted
simplely to front of loop.
Better to:
loop() {
check_cancel_and_pause()
if (parity)
scrub_parity_stripe();
else
scrub_normal_stripe();
}
This patch adjusted code place to realize above sequence.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Scrub panic in following operation:
mkfs.ext4 /dev/vdh
btrfs-convert /dev/vdh
mount /dev/vdh /mnt/tmp1
btrfs scrub start -B /dev/vdh
(panic)
Reason:
1: In some case, leaf created by btrfs-convert was splited into 2
strips.
2: Scrub bypassed part of above wrong leaf data, but remain data
caused panic in scrub_checksum_tree_block().
For reason 1:
we can get following information after some simple operation.
a. mkfs.ext4 /dev/vdh
btrfs-convert /dev/vdh
b. btrfs-debug-tree /dev/vdh
we can see following item in extent tree:
item 25 key (27054080 METADATA_ITEM 0) itemoff 15083 itemsize 33
Its logical address is [27054080, 27070464)
and acrossed 2 strips:
[27000832, 27066368)
[27066368, 27131904)
Will be fixed in btrfs-progs(btrfs-convert, btrfsck, ...)
For reason 2:
Scrub is trying to do a "bypass" in this case, but the result is
"panic", because current code lacks of some condition in bypass,
and let some wrong leaf data escaped.
This patch fixed above scrub code.
Before patch:
# btrfs scrub start -B /dev/vdh
(panic)
After patch:
# btrfs scrub start -B /dev/vdh
scrub done for 353cec8f-da31-4a94-aa35-be72d997b06e
...
# dmesg
...
[ 59.088697] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27000832
[ 59.089929] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27066368
#
Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently we have two different ways to signal an I/O error on a BIO:
(1) by clearing the BIO_UPTODATE flag
(2) by returning a Linux errno value to the bi_end_io callback
The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario. Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.
So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Although it is a rare case, we'd better free previous allocated
memory on error.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
lockdep report following warning in test:
[25176.843958] =================================
[25176.844519] [ INFO: inconsistent lock state ]
[25176.845047] 4.1.0-rc3 #22 Tainted: G W
[25176.845591] ---------------------------------
[25176.846153] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[25176.846713] fsstress/26661 [HC0[0]:SC1[1]:HE1:SE0] takes:
[25176.847246] (&wr_ctx->wr_lock){+.?...}, at: [<ffffffffa04cdc6d>] scrub_free_ctx+0x2d/0xf0 [btrfs]
[25176.847838] {SOFTIRQ-ON-W} state was registered at:
[25176.848396] [<ffffffff810bf460>] __lock_acquire+0x6a0/0xe10
[25176.848955] [<ffffffff810bfd1e>] lock_acquire+0xce/0x2c0
[25176.849491] [<ffffffff816489af>] mutex_lock_nested+0x7f/0x410
[25176.850029] [<ffffffffa04d04ff>] scrub_stripe+0x4df/0x1080 [btrfs]
[25176.850575] [<ffffffffa04d11b1>] scrub_chunk.isra.19+0x111/0x130 [btrfs]
[25176.851110] [<ffffffffa04d144c>] scrub_enumerate_chunks+0x27c/0x510 [btrfs]
[25176.851660] [<ffffffffa04d3b87>] btrfs_scrub_dev+0x1c7/0x6c0 [btrfs]
[25176.852189] [<ffffffffa04e918e>] btrfs_dev_replace_start+0x36e/0x450 [btrfs]
[25176.852771] [<ffffffffa04a98e0>] btrfs_ioctl+0x1e10/0x2d20 [btrfs]
[25176.853315] [<ffffffff8121c5b8>] do_vfs_ioctl+0x318/0x570
[25176.853868] [<ffffffff8121c851>] SyS_ioctl+0x41/0x80
[25176.854406] [<ffffffff8164da17>] system_call_fastpath+0x12/0x6f
[25176.854935] irq event stamp: 51506
[25176.855511] hardirqs last enabled at (51506): [<ffffffff810d4ce5>] vprintk_emit+0x225/0x5e0
[25176.856059] hardirqs last disabled at (51505): [<ffffffff810d4b77>] vprintk_emit+0xb7/0x5e0
[25176.856642] softirqs last enabled at (50886): [<ffffffff81067a23>] __do_softirq+0x363/0x640
[25176.857184] softirqs last disabled at (50949): [<ffffffff8106804d>] irq_exit+0x10d/0x120
[25176.857746]
other info that might help us debug this:
[25176.858845] Possible unsafe locking scenario:
[25176.859981] CPU0
[25176.860537] ----
[25176.861059] lock(&wr_ctx->wr_lock);
[25176.861705] <Interrupt>
[25176.862272] lock(&wr_ctx->wr_lock);
[25176.862881]
*** DEADLOCK ***
Reason:
Above warning is caused by:
Interrupt
-> bio_endio()
-> ...
-> scrub_put_ctx()
-> scrub_free_ctx() *1
-> ...
-> mutex_lock(&wr_ctx->wr_lock);
scrub_put_ctx() is allowed to be called in end_bio interrupt, but
in code design, it will never call scrub_free_ctx(sctx) in interrupe
context(above *1), because btrfs_scrub_dev() get one additional
reference of sctx->refs, which makes scrub_free_ctx() only called
withine btrfs_scrub_dev().
Now the code runs out of our wish, because free sequence in
scrub_pending_bio_dec() have a gap.
Current code:
-----------------------------------+-----------------------------------
scrub_pending_bio_dec() | btrfs_scrub_dev
-----------------------------------+-----------------------------------
atomic_dec(&sctx->bios_in_flight); |
wake_up(&sctx->list_wait); |
| scrub_put_ctx()
| -> atomic_dec_and_test(&sctx->refs)
scrub_put_ctx(sctx); |
-> atomic_dec_and_test(&sctx->refs)|
-> scrub_free_ctx() |
-----------------------------------+-----------------------------------
We expected:
-----------------------------------+-----------------------------------
scrub_pending_bio_dec() | btrfs_scrub_dev
-----------------------------------+-----------------------------------
atomic_dec(&sctx->bios_in_flight); |
wake_up(&sctx->list_wait); |
scrub_put_ctx(sctx); |
-> atomic_dec_and_test(&sctx->refs)|
| scrub_put_ctx()
| -> atomic_dec_and_test(&sctx->refs)
| -> scrub_free_ctx()
-----------------------------------+-----------------------------------
Fix:
Move scrub_pending_bio_dec() to a workqueue, to avoid this function run
in interrupt context.
Tested by check tracelog in debug.
Changelog v1->v2:
Use workqueue instead of adjust function call sequence in v1,
because v1 will introduce a bug pointed out by:
Filipe David Manana <fdmanana@gmail.com>
Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The divisor is derived from nodesize or PAGE_SIZE, fits into 32bit type.
Get rid of a few more do_div instances.
Signed-off-by: David Sterba <dsterba@suse.cz>
Convert kmalloc(nr * size, ..) to kmalloc_array that does additional
overflow checks, the zeroing variant is kcalloc.
Signed-off-by: David Sterba <dsterba@suse.cz>
Pull btrfs updates from Chris Mason:
"This pull is mostly cleanups and fixes:
- The raid5/6 cleanups from Zhao Lei fixup some long standing warts
in the code and add improvements on top of the scrubbing support
from 3.19.
- Josef has round one of our ENOSPC fixes coming from large btrfs
clusters here at FB.
- Dave Sterba continues a long series of cleanups (thanks Dave), and
Filipe continues hammering on corner cases in fsync and others
This all was held up a little trying to track down a use-after-free in
btrfs raid5/6. It's not clear yet if this is just made easier to
trigger with this pull or if its a new bug from the raid5/6 cleanups.
Dave Sterba is the only one to trigger it so far, but he has a
consistent way to reproduce, so we'll get it nailed shortly"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (68 commits)
Btrfs: don't remove extents and xattrs when logging new names
Btrfs: fix fsync data loss after adding hard link to inode
Btrfs: fix BUG_ON in btrfs_orphan_add() when delete unused block group
Btrfs: account for large extents with enospc
Btrfs: don't set and clear delalloc for O_DIRECT writes
Btrfs: only adjust outstanding_extents when we do a short write
btrfs: Fix out-of-space bug
Btrfs: scrub, fix sleep in atomic context
Btrfs: fix scheduler warning when syncing log
Btrfs: Remove unnecessary placeholder in btrfs_err_code
btrfs: cleanup init for list in free-space-cache
btrfs: delete chunk allocation attemp when setting block group ro
btrfs: clear bio reference after submit_one_bio()
Btrfs: fix scrub race leading to use-after-free
Btrfs: add missing cleanup on sysfs init failure
Btrfs: fix race between transaction commit and empty block group removal
btrfs: add more checks to btrfs_read_sys_array
btrfs: cleanup, rename a few variables in btrfs_read_sys_array
btrfs: add checks for sys_chunk_array sizes
btrfs: more superblock checks, lower bounds on devices and sectorsize/nodesize
...
Qu Wenruo