Refactor all the open-coded validation of non-static data device extents
into a single helper.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
The code that validates recovered extent-free intent items is kind of a
mess -- it doesn't use the standard xfs type validators, and it doesn't
check for things that it should. Fix the validator function to use the
standard validation helpers and look for more types of obvious errors.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
When we recover a extent-free intent from the log, we need to validate
its contents before we try to replay them. Hoist the checking code into
a separate function in preparation to refactor this code to use
validation helpers.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
There's a subtle design flaw in the deferred log item code that can lead
to pinning the log tail. Taking up the defer ops chain examples from
the previous commit, we can get trapped in sequences like this:
Caller hands us a transaction t0 with D0-D3 attached. The defer ops
chain will look like the following if the transaction rolls succeed:
t1: D0(t0), D1(t0), D2(t0), D3(t0)
t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0)
t3: d5(t1), D1(t0), D2(t0), D3(t0)
...
t9: d9(t7), D3(t0)
t10: D3(t0)
t11: d10(t10), d11(t10)
t12: d11(t10)
In transaction 9, we finish d9 and try to roll to t10 while holding onto
an intent item for D3 that we logged in t0.
The previous commit changed the order in which we place new defer ops in
the defer ops processing chain to reduce the maximum chain length. Now
make xfs_defer_finish_noroll capable of relogging the entire chain
periodically so that we can always move the log tail forward. Most
chains will never get relogged, except for operations that generate very
long chains (large extents containing many blocks with different sharing
levels) or are on filesystems with small logs and a lot of ongoing
metadata updates.
Callers are now required to ensure that the transaction reservation is
large enough to handle logging done items and new intent items for the
maximum possible chain length. Most callers are careful to keep the
chain lengths low, so the overhead should be minimal.
The decision to relog an intent item is made based on whether the intent
was logged in a previous checkpoint, since there's no point in relogging
an intent into the same checkpoint.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
In xfs_bui_item_recover, there exists a use-after-free bug with regards
to the inode that is involved in the bmap replay operation. If the
mapping operation does not complete, we call xfs_bmap_unmap_extent to
create a deferred op to finish the unmapping work, and we retain a
pointer to the incore inode.
Unfortunately, the very next thing we do is commit the transaction and
drop the inode. If reclaim tears down the inode before we try to finish
the defer ops, we dereference garbage and blow up. Therefore, create a
way to join inodes to the defer ops freezer so that we can maintain the
xfs_inode reference until we're done with the inode.
Note: This imposes the requirement that there be enough memory to keep
every incore inode in memory throughout recovery.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
When we replay unfinished intent items that have been recovered from the
log, it's possible that the replay will cause the creation of more
deferred work items. As outlined in commit 509955823c ("xfs: log
recovery should replay deferred ops in order"), later work items have an
implicit ordering dependency on earlier work items. Therefore, recovery
must replay the items (both recovered and created) in the same order
that they would have been during normal operation.
For log recovery, we enforce this ordering by using an empty transaction
to collect deferred ops that get created in the process of recovering a
log intent item to prevent them from being committed before the rest of
the recovered intent items. After we finish committing all the
recovered log items, we allocate a transaction with an enormous block
reservation, splice our huge list of created deferred ops into that
transaction, and commit it, thereby finishing all those ops.
This is /really/ hokey -- it's the one place in XFS where we allow
nested transactions; the splicing of the defer ops list is is inelegant
and has to be done twice per recovery function; and the broken way we
handle inode pointers and block reservations cause subtle use-after-free
and allocator problems that will be fixed by this patch and the two
patches after it.
Therefore, replace the hokey empty transaction with a structure designed
to capture each chain of deferred ops that are created as part of
recovering a single unfinished log intent. Finally, refactor the loop
that replays those chains to do so using one transaction per chain.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Nowadays, log recovery will call ->release on the recovered intent items
if recovery fails. Therefore, it's redundant to release them from
inside the ->recover functions when they're about to return an error.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Use kmem_cache_zalloc() directly.
With the exception of xlog_ticket_alloc() which will be dealt on the
next patch for readability.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
The only purpose of XFS_LI_RECOVERED is to prevent log recovery from
trying to replay recovered intents more than once. Therefore, we can
move the bit setting up to the ->iop_recover caller.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Now that we've made the recovered item tests all the same, we can hoist
the test and the ail locking code to the ->iop_recover caller and call
the recovery function directly.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Rename XFS_{EFI,BUI,RUI,CUI}_RECOVERED to XFS_LI_RECOVERED so that we
track recovery status in the log item, then get rid of the now unused
flags fields in each of those log item types.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
During recovery, every intent that we recover from the log has to be
added to the AIL. Replace the open-coded addition with a helper.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Replace the open-coded AIL item walking with a proper helper when we're
trying to release an intent item that has been finished. We add a new
->iop_match method to decide if an intent item matches a supplied ID.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Move the code that processes the log items created from the recovered
log items into the per-item source code files and use dispatch functions
to call them. No functional changes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Move the extent free intent and intent-done pass2 commit code into the
per-item source code files and use dispatch functions to call them. We
do these one at a time because there's a lot of code to move. No
functional changes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Create a generic dispatch structure to delegate recovery of different
log item types into various code modules. This will enable us to move
code specific to a particular log item type out of xfs_log_recover.c and
into the log item source.
The first operation we virtualize is the log item sorting.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Various intent log items call xfs_trans_ail_remove() with a log I/O
error shutdown type, but this helper historically checks whether an
item is in the AIL before calling xfs_trans_ail_delete(). This means
the shutdown check is essentially a no-op for users of
xfs_trans_ail_remove().
It is possible that some items might not be AIL resident when the
AIL remove attempt occurs, but this should be isolated to cases
where the filesystem has already shutdown. For example, this
includes abort of the transaction committing the intent and I/O
error of the iclog buffer committing the intent to the log.
Therefore, update these callsites to use xfs_trans_ail_delete() to
provide AIL state validation for the common path of items being
released and removed when associated done items commit to the
physical log.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Given how XFS is all based around btrees it doesn't make much sense
to offer a totally generic state when we can just use the btree cursor.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
All defer op instance place their own extension of the log item into
the dfp_done field. Replace that with a xfs_log_item to improve type
safety and make the code easier to follow.
Also use the opportunity to improve the ->finish_item calling conventions
to place the done log item as the higher level structure before the
list_entry used for the individual items.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
All defer op instance place their own extension of the log item into
the dfp_intent field. Replace that with a xfs_log_item to improve type
safety and make the code easier to follow.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This avoids a per-item indirect call, and also simplifies the interface
a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
These are aways called together, and my merging them we reduce the amount
of indirect calls, improve type safety and in general clean up the code
a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
We can remove it now, without needing to rework the KM_ flags.
Use kmem_cache_free() directly.
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Convert EIO to EFSCORRUPTED in the logging code when we can determine
that the log contents are invalid.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Make sure we log something to dmesg whenever we return -EFSCORRUPTED up
the call stack.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Since no caller is using KM_NOSLEEP and no callee branches on KM_SLEEP,
we can remove KM_NOSLEEP and replace KM_SLEEP with 0.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
There are many, many xfs header files which are included but
unneeded (or included twice) in the xfs code, so remove them.
nb: xfs_linux.h includes about 9 headers for everyone, so those
explicit includes get removed by this. I'm not sure what the
preference is, but if we wanted explicit includes everywhere,
a followup patch could remove those xfs_*.h includes from
xfs_linux.h and move them into the files that need them.
Or it could be left as-is.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Keep all the extree item related code together in one file.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
There is no good reason to keep these two functions separate.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
We have various items that are released from ->iop_comitting. Add a
flag to just call ->iop_release from the commit path to avoid tons
of boilerplate code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
The iop_unlock method is called when comitting or cancelling a
transaction. In the latter case, the transaction may or may not be
aborted. While there is no known problem with the current code in
practice, this implementation is limited in that any log item
implementation that might want to differentiate between a commit and a
cancellation must rely on the aborted state. The aborted bit is only
set when the cancelled transaction is dirty, however. This means that
there is no way to distinguish between a commit and a clean transaction
cancellation.
For example, intent log items currently rely on this distinction. The
log item is either transferred to the CIL on commit or released on
transaction cancel. There is currently no possibility for a clean intent
log item in a transaction, but if that state is ever introduced a cancel
of such a transaction will immediately result in memory leaks of the
associated log item(s). This is an interface deficiency and landmine.
To clean this up, replace the iop_unlock method with an iop_release
method that is specific to transaction cancel. The existing
iop_committing method occurs at the same time as iop_unlock in the
commit path and there is no need for two separate callbacks here.
Overload the iop_committing method with the current commit time
iop_unlock implementations to eliminate the need for the latter and
further simplify the interface.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Just check if they are present first.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
The inode geometry structure isn't related to ondisk format; it's
support for the mount structure. Move it to xfs_shared.h.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Owner information for static fs metadata can be defined readonly at
build time because it never changes across filesystems. This enables us
to reduce stack usage (particularly in scrub) because we can use the
statically defined oinfo structures.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Remove the verbose license text from XFS files and replace them
with SPDX tags. This does not change the license of any of the code,
merely refers to the common, up-to-date license files in LICENSES/
This change was mostly scripted. fs/xfs/Makefile and
fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected
and modified by the following command:
for f in `git grep -l "GNU General" fs/xfs/` ; do
echo $f
cat $f | awk -f hdr.awk > $f.new
mv -f $f.new $f
done
And the hdr.awk script that did the modification (including
detecting the difference between GPL-2.0 and GPL-2.0+ licenses)
is as follows:
$ cat hdr.awk
BEGIN {
hdr = 1.0
tag = "GPL-2.0"
str = ""
}
/^ \* This program is free software/ {
hdr = 2.0;
next
}
/any later version./ {
tag = "GPL-2.0+"
next
}
/^ \*\// {
if (hdr > 0.0) {
print "// SPDX-License-Identifier: " tag
print str
print $0
str=""
hdr = 0.0
next
}
print $0
next
}
/^ \* / {
if (hdr > 1.0)
next
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
next
}
/^ \*/ {
if (hdr > 0.0)
next
print $0
next
}
// {
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
}
END { }
$
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Freed extents are unconditionally discarded when online discard is
enabled. Define XFS_BMAPI_NODISCARD to allow callers to bypass
discards when unnecessary. For example, this will be useful for
eofblocks trimming.
This patch does not change behavior.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
The log item flags contain a field that is protected by the AIL
lock - the XFS_LI_IN_AIL flag. We use non-atomic RMW operations to
set and clear these flags, but most of the updates and checks are
not done with the AIL lock held and so are susceptible to update
races.
Fix this by changing the log item flags to use atomic bitops rather
than be reliant on the AIL lock for update serialisation.
Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
When an intent is aborted during it's initial commit through
xfs_defer_trans_abort(), there is a use after free. The current
report is for a RUI through this path in generic/388:
Freed by task 6274:
__kasan_slab_free+0x136/0x180
kmem_cache_free+0xe7/0x4b0
xfs_trans_free_items+0x198/0x2e0
__xfs_trans_commit+0x27f/0xcc0
xfs_trans_roll+0x17b/0x2a0
xfs_defer_trans_roll+0x6ad/0xe60
xfs_defer_finish+0x2a6/0x2140
xfs_alloc_file_space+0x53a/0xf90
xfs_file_fallocate+0x5c6/0xac0
vfs_fallocate+0x2f5/0x930
ioctl_preallocate+0x1dc/0x320
do_vfs_ioctl+0xfe4/0x1690
The problem is that the RUI has two active references - one in the
current transaction, and another held by the defer_ops structure
that is passed to the RUD (intent done) so that both the intent and
the intent done structures are freed on commit of the intent done.
Hence during abort, we need to release the intent item, because the
defer_ops reference is released separately via ->abort_intent
callback. Fix all the intent code to do this correctly.
Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Calling xfs_rmap_free with an unknown owner is supposed to remove any
rmaps covering that range regardless of owner. This is used by the EFI
recovery code to say "we're freeing this, it mustn't be owned by
anything anymore", but for whatever reason xfs_free_ag_extent filters
them out.
Therefore, remove the filter and make xfs_rmap_unmap actually treat it
as a wildcard owner -- free anything that's already there, and if
there's no owner at all then that's fine too.
There are two existing callers of bmap_add_free that take care the rmap
deferred ops themselves and use OWN_UNKNOWN to skip the EFI-based rmap
cleanup; convert these to use OWN_NULL (via helpers), and now we really
require that an RUI (if any) gets added to the defer ops before any EFI.
Lastly, now that xfs_free_extent filters out OWN_NULL rmap free requests,
growfs will have to consult directly with the rmap to ensure that there
aren't any rmaps in the grown region.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Use ASSERTs on the log intent item refcounts so that we fail noisily if
anyone tries to double-free the item.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
For the rmap btree to work, we have to feed the extent owner
information to the the allocation and freeing functions. This
information is what will end up in the rmap btree that tracks
allocated extents. While we technically don't need the owner
information when freeing extents, passing it allows us to validate
that the extent we are removing from the rmap btree actually
belonged to the owner we expected it to belong to.
We also define a special set of owner values for internal metadata
that would otherwise have no owner. This allows us to tell the
difference between metadata owned by different per-ag btrees, as
well as static fs metadata (e.g. AG headers) and internal journal
blocks.
There are also a couple of special cases we need to take care of -
during EFI recovery, we don't actually know who the original owner
was, so we need to pass a wildcard to indicate that we aren't
checking the owner for validity. We also need special handling in
growfs, as we "free" the space in the last AG when extending it, but
because it's new space it has no actual owner...
While touching the xfs_bmap_add_free() function, re-order the
parameters to put the struct xfs_mount first.
Extend the owner field to include both the owner type and some sort
of index within the owner. The index field will be used to support
reverse mappings when reflink is enabled.
When we're freeing extents from an EFI, we don't have the owner
information available (rmap updates have their own redo items).
xfs_free_extent therefore doesn't need to do an rmap update. Make
sure that the log replay code signals this correctly.
This is based upon a patch originally from Dave Chinner. It has been
extended to add more owner information with the intent of helping
recovery operations when things go wrong (e.g. offset of user data
block in a file).
[dchinner: de-shout the xfs_rmap_*_owner helpers]
[darrick: minor style fixes suggested by Christoph Hellwig]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Refactor the EFI intent item recovery (and cancellation) functions
into a general function that scans the AIL and an intent item type
specific handler. Move the function that recovers a single EFI item
into the extent free item code. We'll want the generalized function
when we start wiring up more redo item types.
Furthermore, ensure that log recovery only replays the redo items
that were in the AIL prior to recovery by checking the item LSN
against the largest LSN seen during log scanning. As written this
should never happen, but we can be defensive anyway.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
One of the problems we currently have with delayed logging is that
under serious memory pressure we can deadlock memory reclaim. THis
occurs when memory reclaim (such as run by kswapd) is reclaiming XFS
inodes and issues a log force to unpin inodes that are dirty in the
CIL.
The CIL is pushed, but this will only occur once it gets the CIL
context lock to ensure that all committing transactions are complete
and no new transactions start being committed to the CIL while the
push switches to a new context.
The deadlock occurs when the CIL context lock is held by a
committing process that is doing memory allocation for log vector
buffers, and that allocation is then blocked on memory reclaim
making progress. Memory reclaim, however, is blocked waiting for
a log force to make progress, and so we effectively deadlock at this
point.
To solve this problem, we have to move the CIL log vector buffer
allocation outside of the context lock so that memory reclaim can
always make progress when it needs to force the log. The problem
with doing this is that a CIL push can take place while we are
determining if we need to allocate a new log vector buffer for
an item and hence the current log vector may go away without
warning. That means we canot rely on the existing log vector being
present when we finally grab the context lock and so we must have a
replacement buffer ready to go at all times.
To ensure this, introduce a "shadow log vector" buffer that is
always guaranteed to be present when we gain the CIL context lock
and format the item. This shadow buffer may or may not be used
during the formatting, but if the log item does not have an existing
log vector buffer or that buffer is too small for the new
modifications, we swap it for the new shadow buffer and format
the modifications into that new log vector buffer.
The result of this is that for any object we modify more than once
in a given CIL checkpoint, we double the memory required
to track dirty regions in the log. For single modifications then
we consume the shadow log vectorwe allocate on commit, and that gets
consumed by the checkpoint. However, if we make multiple
modifications, then the second transaction commit will allocate a
shadow log vector and hence we will end up with double the memory
usage as only one of the log vectors is consumed by the CIL
checkpoint. The remaining shadow vector will be freed when th elog
item is freed.
This can probably be optimised in future - access to the shadow log
vector is serialised by the object lock (as opposited to the active
log vector, which is controlled by the CIL context lock) and so we
can probably free shadow log vector from some objects when the log
item is marked clean on removal from the AIL.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Several areas of code duplicate a pattern where we take the AIL lock,
check whether an item is in the AIL and remove it if so. Create a new
helper for this pattern and use it where appropriate.
Signed-off-by: Brian Foster <bfoster@redhat.com>
The EFI is initialized with a reference count of 2. One for the EFI to
ensure the item makes it to the AIL and one for the subsequently created
EFD to release the EFI once the EFD is committed. Log recovery uses the
EFI in a similar manner, but implements a hack to remove both references
in one call once the EFD is handled.
Update log recovery to use EFI reference counting in a manner consistent
with the log. When an EFI is encountered during recovery, an EFI item is
allocated and inserted to the AIL directly. Since the EFI reference is
typically dropped when the EFI is unpinned and this is analogous with
AIL insertion, drop the EFI reference at this point.
When a corresponding EFD is encountered in the log, this indicates that
the extents were freed, no processing is required and the EFI can be
dropped. Update xlog_recover_efd_pass2() to simply drop the EFD
reference at this point rather than open code the AIL removal and EFI
free.
Remaining EFIs (i.e., with no corresponding EFD) are processed in
xlog_recover_finish(). An EFD transaction is allocated and the extents
are freed, which transfers ownership of the EFI reference to the EFD
item in the log.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Freeing an extent in XFS involves logging an EFI (extent free
intention), freeing the actual extent, and logging an EFD (extent
free done). The EFI object is created with a reference count of 2:
one for the current transaction and one for the subsequently created
EFD. Under normal circumstances, the first reference is dropped when
the EFI is unpinned and the second reference is dropped when the EFD
is committed to the on-disk log.
In event of errors or filesystem shutdown, there are various
potential cleanup scenarios depending on the state of the EFI/EFD.
The cleanup scenarios are confusing and racy, as demonstrated by the
following test sequence:
# mount $dev $mnt
# fsstress -d $mnt -n 99999 -p 16 -z -f fallocate=1 \
-f punch=1 -f creat=1 -f unlink=1 &
# sleep 5
# killall -9 fsstress; wait
# godown -f $mnt
# umount
... in which the final umount can hang due to the AIL being pinned
indefinitely by one or more EFI items. This can occur due to several
conditions. For example, if the shutdown occurs after the EFI is
committed to the on-disk log and the EFD committed to the CIL, but
before the EFD committed to the log, the EFD iop_committed() abort
handler does not drop its reference to the EFI. Alternatively,
manual error injection in the xfs_bmap_finish() codepath shows that
if an error occurs after the EFI transaction is committed but before
the EFD is constructed and logged, the EFI is never released from
the AIL.
Update the EFI/EFD item handling code to use a more straightforward
and reliable approach to error handling. If an error occurs after
the EFI transaction is committed and before the EFD is constructed,
release the EFI explicitly from xfs_bmap_finish(). If the EFI
transaction is cancelled, release the EFI in the unlock handler.
Once the EFD is constructed, it is responsible for releasing the EFI
under any circumstances (including whether the EFI item aborts due
to log I/O error). Update the EFD item handlers to release the EFI
if the transaction is cancelled or aborts due to log I/O error.
Finally, update xfs_bmap_finish() to log at least one EFD extent to
the transaction before xfs_free_extent() errors are handled to
ensure the transaction is dirty and EFD item error handling is
triggered.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Release of the EFI either occurs based on the reference count or the
extent count. The extent count used is either the count tracked in
the EFI or EFD, depending on the particular situation. In either
case, the count is initialized to the final value and thus always
matches the current efi_next_extent value once the EFI is completely
constructed. For example, the EFI extent count is increased as the
extents are logged in xfs_bmap_finish() and the full free list is
always completely processed. Therefore, the count is guaranteed to
be complete once the EFI transaction is committed. The EFD uses the
efd_nextents counter to release the EFI. This counter is initialized
to the count of the EFI when the EFD is created. Thus the EFD, as
currently used, has no concept of partial EFI release based on
extent count.
Given that the EFI extent count is always released in whole, use of
the extent count for reference counting is unnecessary. Remove this
level of the API and release the EFI based on the core reference
count. The efi_next_extent counter remains because it is still used
to track the slot to log the next extent to free.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
