Commit Graph

216 Commits

Author SHA1 Message Date
Linus Torvalds 8745889a7f New code for 6.0:
- Remove iomap_writepage and all callers, since the mm apparently never
    called the zonefs or gfs2 writepage functions.
 
 Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'iomap-6.0-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull more iomap updates from Darrick Wong:
 "In the past 10 days or so I've not heard any ZOMG STOP style
  complaints about removing ->writepage support from gfs2 or zonefs, so
  here's the pull request removing them (and the underlying fs iomap
  support) from the kernel:

   - Remove iomap_writepage and all callers, since the mm apparently
     never called the zonefs or gfs2 writepage functions"

* tag 'iomap-6.0-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: remove iomap_writepage
  zonefs: remove ->writepage
  gfs2: remove ->writepage
  gfs2: stop using generic_writepages in gfs2_ail1_start_one
2022-08-11 13:11:49 -07:00
Christoph Hellwig b2b0a5e978 gfs2: stop using generic_writepages in gfs2_ail1_start_one
Use filemap_fdatawrite_wbc instead of generic_writepages in
gfs2_ail1_start_one so that the functin can also cope with address_space
operations that only implement ->writepages and to properly account
for cgroup writeback.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-07-22 10:59:15 -07:00
Bart Van Assche 67688c08b7 fs/gfs2: Use the enum req_op and blk_opf_t types
Improve static type checking by using the enum req_op type for variables
that represent a request operation and the new blk_opf_t type for
variables that represent request flags. Combine the first two
gfs2_submit_bhs() arguments into a single argument.

Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-54-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14 12:14:32 -06:00
Bob Peterson dc7674eda0 gfs2: tiny cleanup in gfs2_log_reserve
Function gfs2_log_reserve was setting revoke_blks to 0. There's no
need because it calculates it shortly thereafter. This patch removes
the unnecessary set.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2021-08-19 12:31:17 -05:00
Bob Peterson f5456b5d67 gfs2: Clean up revokes on normal withdraws
Before this patch, the system ail lists were cleaned up if the logd
process withdrew, but on other withdraws, they were not cleaned up.
This included the cleaning up of the revokes as well.

This patch reorganizes things a bit so that all withdraws (not just logd)
clean up the ail lists, including any pending revokes.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-05-20 13:31:37 +02:00
Linus Torvalds f2c80837e2 Changes in gfs2:
- Fix some compiler and kernel-doc warnings.
 
 - Various minor cleanups and optimizations.
 
 - Add a new sysfs gfs2 status file with some filesystem wide
   information.
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Merge tag 'gfs2-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 updates from Andreas Gruenbacher:

 - Fix some compiler and kernel-doc warnings

 - Various minor cleanups and optimizations

 - Add a new sysfs gfs2 status file with some filesystem wide
   information

* tag 'gfs2-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix fall-through warnings for Clang
  gfs2: Fix a number of kernel-doc warnings
  gfs2: Make gfs2_setattr_simple static
  gfs2: Add new sysfs file for gfs2 status
  gfs2: Silence possible null pointer dereference warning
  gfs2: Turn gfs2_meta_indirect_buffer into gfs2_meta_buffer
  gfs2: Replace gfs2_lblk_to_dblk with gfs2_get_extent
  gfs2: Turn gfs2_extent_map into gfs2_{get,alloc}_extent
  gfs2: Add new gfs2_iomap_get helper
  gfs2: Remove unused variable sb_format
  gfs2: Fix dir.c function parameter descriptions
  gfs2: Eliminate gh parameter from go_xmote_bh func
  gfs2: don't create empty buffers for NO_CREATE
2021-04-29 10:33:35 -07:00
Lee Jones c551f66c5d gfs2: Fix a number of kernel-doc warnings
Building the kernel with W=1 results in a number of kernel-doc warnings
like incorrect function names and parameter descriptions.  Fix those,
mostly by adding missing parameter descriptions, removing left-over
descriptions, and demoting some less important kernel-doc comments into
regular comments.

Originally proposed by Lee Jones; improved and combined into a single
patch by Andreas.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-04-09 22:14:13 +02:00
Sami Tolvanen 4f0f586bf0 treewide: Change list_sort to use const pointers
list_sort() internally casts the comparison function passed to it
to a different type with constant struct list_head pointers, and
uses this pointer to call the functions, which trips indirect call
Control-Flow Integrity (CFI) checking.

Instead of removing the consts, this change defines the
list_cmp_func_t type and changes the comparison function types of
all list_sort() callers to use const pointers, thus avoiding type
mismatches.

Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-10-samitolvanen@google.com
2021-04-08 16:04:22 -07:00
Andreas Gruenbacher 152f58c9af gfs2: Replace gfs2_lblk_to_dblk with gfs2_get_extent
We don't need two very similar functions for mapping logical blocks to physical
blocks.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-04-03 21:38:12 +02:00
Bob Peterson 0efc4976e3 gfs2: bypass log flush if the journal is not live
Patch fe3e397668 ("gfs2: Rework the log space allocation logic")
changed gfs2_log_flush to reserve a set of journal blocks in case no
transaction is active.  However, gfs2_log_flush also gets called in
cases where we don't have an active journal, for example, for spectator
mounts.  In that case, trying to reserve blocks would sleep forever, but
we want gfs2_log_flush to be a no-op instead.

Fixes: fe3e397668 ("gfs2: Rework the log space allocation logic")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-03-12 15:52:48 +01:00
Bob Peterson 1a5a2cfd34 gfs2: fix use-after-free in trans_drain
This patch adds code to function trans_drain to remove drained
bd elements from the ail lists, if queued, before freeing the bd.
If we don't remove the bd from the ail, function ail_drain will
try to reference the bd after it has been freed by trans_drain.

Thanks to Andy Price for his analysis of the problem.

Reported-by: Andy Price <anprice@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-03-07 17:04:55 +01:00
Bob Peterson 17d7768408 gfs2: Don't get stuck with I/O plugged in gfs2_ail1_flush
In gfs2_ail1_flush, we're using I/O plugging to give the block layer a
better chance of merging I/O requests.  If we're too aggressive here, we
can end up waiting on I/O to complete while still plugged.  Fix that in
a way similar to writeback_sb_inodes, except that we can't use
blk_flush_plug because blk_flush_plug_list is not exported.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-23 19:01:42 +01:00
Andreas Gruenbacher 803074ad77 Merge branches 'rgrp-glock-sharing' and 'gfs2-revoke' from https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git
Merge the resource group glock sharing feature and the revoke accounting rework.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-23 18:54:22 +01:00
Andreas Gruenbacher 2129b42888 gfs2: Per-revoke accounting in transactions
In the log, revokes are stored as a revoke descriptor (struct
gfs2_log_descriptor), followed by zero or more additional revoke blocks
(struct gfs2_meta_header).  On filesystems with a blocksize of 4k, the
revoke descriptor contains up to 503 revokes, and the metadata blocks
contain up to 509 revokes each.  We've so far been reserving space for
revokes in transactions in block granularity, so a lot more space than
necessary was being allocated and then released again.

This patch switches to assigning revokes to transactions individually
instead.  Initially, space for the revoke descriptor is reserved and
handed out to transactions.  When more revokes than that are reserved,
additional revoke blocks are added.  When the log is flushed, the space
for the additional revoke blocks is released, but we keep the space for
the revoke descriptor block allocated.

Transactions may still reserve more revokes than they will actually need
in the end, but now we won't overshoot the target as much, and by only
returning the space for excess revokes at log flush time, we further
reduce the amount of contention between processes.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-22 21:16:23 +01:00
Andreas Gruenbacher fe3e397668 gfs2: Rework the log space allocation logic
The current log space allocation logic is hard to understand or extend.
The principle it that when the log is flushed, we may or may not have a
transaction active that has space allocated in the log.  To deal with
that, we set aside a magical number of blocks to be used in case we
don't have an active transaction.  It isn't clear that the pool will
always be big enough.  In addition, we can't return unused log space at
the end of a transaction, so the number of blocks allocated must exactly
match the number of blocks used.

Simplify this as follows:
 * When transactions are allocated or merged, always reserve enough
   blocks to flush the transaction (err on the safe side).
 * In gfs2_log_flush, return any allocated blocks that haven't been used.
 * Maintain a pool of spare blocks big enough to do one log flush, as
   before.
 * In gfs2_log_flush, when we have no active transaction, allocate a
   suitable number of blocks.  For that, use the spare pool when
   called from logd, and leave the pool alone otherwise.  This means
   that when the log is almost full, logd will still be able to do one
   more log flush, which will result in more log space becoming
   available.

This will make the log space allocator code easier to work with in
the future.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-22 21:16:22 +01:00
Andreas Gruenbacher 71b219f4e5 gfs2: Minor calc_reserved cleanup
No functional change.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-22 21:16:22 +01:00
Andreas Gruenbacher 76fce65489 gfs2: Move function gfs2_ail_empty_tr
Move this function further up in log.c so that we can use it in the next patch.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:25 +01:00
Andreas Gruenbacher 5cb738b5fb gfs2: Get rid of current_tail()
Keep the current value of the updated log tail in the super block as
sb_log_flush_tail instead of computing it on the fly.  This avoids
unnecessary sd_ail_lock taking and cleans up the code.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:25 +01:00
Andreas Gruenbacher 5ae8fff8d0 gfs2: Clean up gfs2_log_reserve
Wake up log waiters in gfs2_log_release when log space has actually become
available.  This is a much better place for the wakeup than gfs2_logd.

Check if enough log space is immeditely available before anything else.  If
there isn't, use io_wait_event to wait instead of open-coding it.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:24 +01:00
Andreas Gruenbacher 4a3d049db4 gfs2: Don't wait for journal flush in clean_journal
Commit 588bff95c9 added gfs2_write_log_header() and started using it in
clean_journal(), with an additional call to log_flush_wait() at the end of
gfs2_write_log_header() which is unnecessary for clean_journal().  Move
that call out of gfs2_write_log_header() to restore the previous behavior.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:24 +01:00
Andreas Gruenbacher c1eba1b0bc gfs2: Move lock flush locking to gfs2_trans_{begin,end}
Move the read locking of sd_log_flush_lock from gfs2_log_reserve to
gfs2_trans_begin, and its unlocking from gfs2_log_release to
gfs2_trans_end.  Use gfs2_log_release in two places in which it was open
coded before.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:24 +01:00
Andreas Gruenbacher f3708fb59f gfs2: Get rid of sd_reserving_log
This counter and the associated wait queue are only used so that
gfs2_make_fs_ro can efficiently wait for all pending log space
allocations to fail after setting the filesystem to read-only.  This
comes at the cost of waking up that wait queue very frequently.

Instead, when gfs2_log_reserve fails because the filesystem has become
read-only, Wake up sd_log_waitq.  In gfs2_make_fs_ro, set the file
system read-only and then wait until all the log space has been
released.  Give up and report the problem after a while.  With that,
sd_reserving_log and sd_reserving_log_wait can be removed.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:24 +01:00
Andreas Gruenbacher c968f5788b gfs2: Clean up on-stack transactions
Replace the TR_ALLOCED flag by its inverse, TR_ONSTACK: that way, the flag only
needs to be set in the exceptional case of on-stack transactions.  Split off
__gfs2_trans_begin from gfs2_trans_begin and use it to replace the open-coded
version in gfs2_ail_empty_gl.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-02-03 18:37:10 +01:00
Bob Peterson 8221894305 gfs2: keep bios separate for each journal
The recovery func can recover multiple journals, but they were all using
the same bio. This resulted in use-after-free related to sdp->sd_log_bio.
This patch moves the variable to the journal descriptor, jd, so that
every recovery can operate on its own bio. And hopefully we never run out.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2021-01-25 08:08:44 -05:00
Bob Peterson 4a011849f7 Revert "GFS2: Re-add a call to log_flush_wait when flushing the journal"
This reverts commit 428fd95d85.
Patch 428fd95d85b2 added a call to log_flush_wait to function
gfs2_log_flush. Then gfs2_log_flush calls log_write_header which submits
a write request with the REQ_PREFLUSH flag which also forces it to wait.
This patch removes the unnecessary call to log_flush_wait.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2021-01-25 08:08:44 -05:00
Andreas Gruenbacher 6e80674af0 gfs2: Clean up ail2_empty
Clean up the logic in ail2_empty (no functional change).

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-01-19 21:17:50 +01:00
Andreas Gruenbacher e7501bf88c gfs2: Rename gfs2_{write => flush}_revokes
Function gfs2_write_revokes doesn't actually write any revokes; instead, it
adds revokes to the system transaction during a flush.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-01-19 21:17:49 +01:00
Andreas Gruenbacher 6188e8777d gfs2: Some documentation updates
The calc_reserved description claims that buf_limit is 502 (on 4k
filesystems), but it is actually 503.  Fix / clarify the entire
description.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-01-19 21:17:07 +01:00
Andreas Gruenbacher 5a4e9c607e gfs2: Minor gfs2_write_revokes cleanups
Clean up the computations in gfs2_write_revokes (no change in functionality).

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-01-19 21:17:07 +01:00
Bob Peterson 4e79e3f08e gfs2: Fix case in which ail writes are done to jdata holes
Patch b2a846dbef ("gfs2: Ignore journal log writes for jdata holes")
tried (unsuccessfully) to fix a case in which writes were done to jdata
blocks, the blocks are sent to the ail list, then a punch_hole or truncate
operation caused the blocks to be freed. In other words, the ail items
are for jdata holes. Before b2a846dbef, the jdata hole caused function
gfs2_block_map to return -EIO, which was eventually interpreted as an
IO error to the journal, and then withdraw.

This patch changes function gfs2_get_block_noalloc, which is only used
for jdata writes, so it returns -ENODATA rather than -EIO, and when
-ENODATA is returned to gfs2_ail1_start_one, the error is ignored.
We can safely ignore it because gfs2_ail1_start_one is only called
when the jdata pages have already been written and truncated, so the
ail1 content no longer applies.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-11-12 18:55:20 +01:00
Bob Peterson 36c783092d gfs2: make gfs2_ail1_empty_one return the count of active items
This patch is one baby step toward simplifying the journal management.
It simply changes function gfs2_ail1_empty_one from a void to an int and
makes it return a count of active items. This allows the caller to check
the return code rather than list_empty on the tr_ail1_list. This way
we can, in a later patch, combine transaction ail1 and ail2 lists.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-10-15 14:29:03 +02:00
Bob Peterson 68942870c6 gfs2: Wipe jdata and ail1 in gfs2_journal_wipe, formerly gfs2_meta_wipe
Before this patch, when blocks were freed, it called gfs2_meta_wipe to
take the metadata out of the pending journal blocks. It did this mostly
by calling another function called gfs2_remove_from_journal. This is
shortsighted because it does not do anything with jdata blocks which
may also be in the journal.

This patch expands the function so that it wipes out jdata blocks from
the journal as well, and it wipes it from the ail1 list if it hasn't
been written back yet. Since it now processes jdata blocks as well,
the function has been renamed from gfs2_meta_wipe to gfs2_journal_wipe.

New function gfs2_ail1_wipe wants a static view of the ail list, so it
locks the sd_ail_lock when removing items. To accomplish this, function
gfs2_remove_from_journal no longer locks the sd_ail_lock, and it's now
the caller's responsibility to do so.

I was going to make sd_ail_lock locking conditional, but the practice is
generally frowned upon. For details, see: https://lwn.net/Articles/109066/

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-10-15 14:29:03 +02:00
Bob Peterson 77650bdbd2 gfs2: add missing log_blocks trace points in gfs2_write_revokes
Function gfs2_write_revokes was incrementing and decrementing the number
of log blocks free, but there was never a log_blocks trace point for it.
Thus, the free blocks from a log_blocks trace would jump around
mysteriously.

This patch adds the missing trace points so the trace makes more sense.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-10-15 14:29:03 +02:00
Bob Peterson 521031fa97 gfs2: Fix bad comment for trans_drain
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-10-14 23:54:41 +02:00
Andreas Gruenbacher 5a61ae1402 gfs2: Make sure we don't miss any delayed withdraws
Commit ca399c96e9 changes gfs2_log_flush to not withdraw the
filesystem while holding the log flush lock, but it fails to check if
the filesystem needs to be withdrawn once the log flush lock has been
released.  Likewise, commit f05b86db31 depends on gfs2_log_flush to
trigger for delayed withdraws.  Add that and clean up the code flow
somewhat.

In gfs2_put_super, add a check for delayed withdraws that have been
missed to prevent these kinds of bugs in the future.

Fixes: ca399c96e9 ("gfs2: flesh out delayed withdraw for gfs2_log_flush")
Fixes: f05b86db31 ("gfs2: Prepare to withdraw as soon as an IO error occurs in log write")
Cc: stable@vger.kernel.org # v5.7+: 462582b99b607: gfs2: add some much needed cleanup for log flushes that fail
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-10-14 23:54:41 +02:00
Bob Peterson 462582b99b gfs2: add some much needed cleanup for log flushes that fail
When a log flush fails due to io errors, it signals the failure but does
not clean up after itself very well. This is because buffers are added to
the transaction tr_buf and tr_databuf queue, but the io error causes
gfs2_log_flush to bypass the "after_commit" functions responsible for
dequeueing the bd elements. If the bd elements are added to the ail list
before the error, function ail_drain takes care of dequeueing them.
But if they haven't gotten that far, the elements are forgotten and
make the transactions unable to be freed.

This patch introduces new function trans_drain which drains the bd
elements from the transaction so they can be freed properly.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-08-24 13:54:07 +02:00
Bob Peterson b57bc0fb2f gfs2: Fix inaccurate comment
The comment regarding journal flush thresholds is wrong. This patch fixes it.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-08-07 12:18:06 +02:00
Bob Peterson 7542486b89 gfs2: eliminate GIF_ORDERED in favor of list_empty
In several places, we used the GIF_ORDERED inode flag to determine
if an inode was on the ordered writes list. However, since we always
held the sd_ordered_lock spin_lock during the manipulation, we can
just as easily check list_empty(&ip->i_ordered) instead.
This allows us to keep more than one ordered writes list to make
journal writing improvements.

This patch eliminates GIF_ORDERED in favor of checking list_empty.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-07-03 12:05:34 +02:00
Bob Peterson 58e08e8d83 gfs2: fix trans slab error when withdraw occurs inside log_flush
Log flush operations (gfs2_log_flush()) can target a specific transaction.
But if the function encounters errors (e.g. io errors) and withdraws,
the transaction was only freed it if was queued to one of the ail lists.
If the withdraw occurred before the transaction was queued to the ail1
list, function ail_drain never freed it. The result was:

BUG gfs2_trans: Objects remaining in gfs2_trans on __kmem_cache_shutdown()

This patch makes log_flush() add the targeted transaction to the ail1
list so that function ail_drain() will find and free it properly.

Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-06-30 13:04:45 +02:00
Bob Peterson 83d060ca8d gfs2: fix use-after-free on transaction ail lists
Before this patch, transactions could be merged into the system
transaction by function gfs2_merge_trans(), but the transaction ail
lists were never merged. Because the ail flushing mechanism can run
separately, bd elements can be attached to the transaction's buffer
list during the transaction (trans_add_meta, etc) but quickly moved
to its ail lists. Later, in function gfs2_trans_end, the transaction
can be freed (by gfs2_trans_end) while it still has bd elements
queued to its ail lists, which can cause it to either lose track of
the bd elements altogether (memory leak) or worse, reference the bd
elements after the parent transaction has been freed.

Although I've not seen any serious consequences, the problem becomes
apparent with the previous patch's addition of:

	gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));

to function gfs2_trans_free().

This patch adds logic into gfs2_merge_trans() to move the merged
transaction's ail lists to the sdp transaction. This prevents the
use-after-free. To do this properly, we need to hold the ail lock,
so we pass sdp into the function instead of the transaction itself.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-06-05 21:24:25 +02:00
Bob Peterson b839dadae8 gfs2: new slab for transactions
This patch adds a new slab for gfs2 transactions. That allows us to
reduce kernel memory fragmentation, have better organization of data
for analysis of vmcore dumps. A new centralized function is added to
free the slab objects, and it exposes use-after-free by giving
warnings if a transaction is freed while it still has bd elements
attached to its buffers or ail lists. We make sure to initialize
those transaction ail lists so we can check their integrity when freeing.

At a later time, we should add a slab initialization function to
make it more efficient, but for this initial patch I wanted to
minimize the impact.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-06-05 21:24:25 +02:00
Bob Peterson cbcc89b630 gfs2: initialize transaction tr_ailX_lists earlier
Since transactions may be freed shortly after they're created, before
a log_flush occurs, we need to initialize their ail1 and ail2 lists
earlier. Before this patch, the ail1 list was initialized in gfs2_log_flush().
This moves the initialization to the point when the transaction is first
created.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-06-05 21:24:25 +02:00
Bob Peterson d5dc3d9677 gfs2: instrumentation wrt log_flush stuck
This adds checks for gfs2_log_flush being stuck, similarly to the check
in gfs2_ail1_flush. To faciliate this and make the strings easy to grep
we move the ail1 emptying to its own function, empty_ail1_list.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-06-05 19:35:54 +02:00
Andreas Gruenbacher f4e2f5e1a5 gfs2: Grab glock reference sooner in gfs2_add_revoke
This patch rearranges gfs2_add_revoke so that the extra glock
reference is added earlier on in the function to avoid races in which
the glock is freed before the new reference is taken.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-05-08 18:49:04 +02:00
Bob Peterson d22f69a08d gfs2: Fix use-after-free in gfs2_logd after withdraw
When the gfs2_logd daemon withdrew, the withdraw sequence called
into make_fs_ro() to make the file system read-only. That caused the
journal descriptors to be freed. However, those journal descriptors
were used by gfs2_logd's call to gfs2_ail_flush_reqd(). This caused
a use-after free and NULL pointer dereference.

This patch changes function gfs2_logd() so that it stops all logd
work until the thread is told to stop. Once a withdraw is done,
it only does an interruptible sleep.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-05-08 15:15:12 +02:00
Bob Peterson 75b46c437f gfs2: Fix oversight in gfs2_ail1_flush
Ordinarily, function gfs2_ail1_start_one issues a write request
for one item on the ail1 list, then returns -EBUSY. This makes the
caller, gfs2_ail1_flush, loop around and start another. However,
it was not clearing the -EBUSY return code each time through the loop.
So on rare occasions, like when the wbc runs out of nr_to_write, it
remained set to -EBUSY, which triggered an error and withdraw.

This patch sets the return code to 0 each time through the restart
loop so this won't happen anymore.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-03-30 07:55:35 -05:00
Bob Peterson 9592ea80ad gfs2: instrumentation wrt ail1 stuck
Before this patch, if the ail1 flush got stuck for some reason, there
were no clues as to why. This patch introduces a check for getting
stuck for more than a minute, and if it happens, it dumps the items
still remaining on the ail1 list.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-03-27 14:08:05 -05:00
Andreas Gruenbacher 969183bc68 gfs2: Switch to list_{first,last}_entry
Replace open-coded versions of list_first_entry and list_last_entry with those
functions.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-03-27 14:08:04 -05:00
Bob Peterson 490031281d gfs2: Additional information when gfs2_ail1_flush withdraws
Before this patch, if gfs2_ail1_flush gets an error from function
gfs2_ail1_start_one (which comes indirectly from generic_writepages)
the file system is withdrawn, but without any explanation why.

This patch adds an error message if gfs2_ail1_flush gets an error
from gfs2_ail1_start_one.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-03-06 10:15:03 -06:00
Bob Peterson ca399c96e9 gfs2: flesh out delayed withdraw for gfs2_log_flush
Function gfs2_log_flush() had a few places where it tried to withdraw
from the file system when errors were encountered. The problem is,
it should delay those withdraws until the log flush lock is no longer
held.

This patch creates a new function just for delayed withdraws for
situations like this. If errors=panic was specified on mount, we
still want to do it the old fashioned way because the panic it does
not help to delay in that situation.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-02-27 07:53:18 -06:00