During growfs, if new ag in memory has been initialized, however
sb_agcount has not been updated, if an error occurs at this time it
will cause perag leaks as follows, these new AGs will not been freed
during umount , because of these new AGs are not visible(that is
included in mp->m_sb.sb_agcount).

unreferenced object 0xffff88810be40200 (size 512):
  comm "xfs_growfs", pid 857, jiffies 4294909093
  hex dump (first 32 bytes):
    00 c0 c1 05 81 88 ff ff 04 00 00 00 00 00 00 00  ................
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 381741e2):
    [<ffffffff8191aef6>] __kmalloc+0x386/0x4f0
    [<ffffffff82553e65>] kmem_alloc+0xb5/0x2f0
    [<ffffffff8238dac5>] xfs_initialize_perag+0xc5/0x810
    [<ffffffff824f679c>] xfs_growfs_data+0x9bc/0xbc0
    [<ffffffff8250b90e>] xfs_file_ioctl+0x5fe/0x14d0
    [<ffffffff81aa5194>] __x64_sys_ioctl+0x144/0x1c0
    [<ffffffff83c3d81f>] do_syscall_64+0x3f/0xe0
    [<ffffffff83e00087>] entry_SYSCALL_64_after_hwframe+0x62/0x6a
unreferenced object 0xffff88810be40800 (size 512):
  comm "xfs_growfs", pid 857, jiffies 4294909093
  hex dump (first 32 bytes):
    20 00 00 00 00 00 00 00 57 ef be dc 00 00 00 00   .......W.......
    10 08 e4 0b 81 88 ff ff 10 08 e4 0b 81 88 ff ff  ................
  backtrace (crc bde50e2d):
    [<ffffffff8191b43a>] __kmalloc_node+0x3da/0x540
    [<ffffffff81814489>] kvmalloc_node+0x99/0x160
    [<ffffffff8286acff>] bucket_table_alloc.isra.0+0x5f/0x400
    [<ffffffff8286bdc5>] rhashtable_init+0x405/0x760
    [<ffffffff8238dda3>] xfs_initialize_perag+0x3a3/0x810
    [<ffffffff824f679c>] xfs_growfs_data+0x9bc/0xbc0
    [<ffffffff8250b90e>] xfs_file_ioctl+0x5fe/0x14d0
    [<ffffffff81aa5194>] __x64_sys_ioctl+0x144/0x1c0
    [<ffffffff83c3d81f>] do_syscall_64+0x3f/0xe0
    [<ffffffff83e00087>] entry_SYSCALL_64_after_hwframe+0x62/0x6a

Factor out xfs_free_unused_perag_range() from xfs_initialize_perag(),
used for freeing unused perag within a specified range in error handling,
included in the error path of the growfs failure.

Fixes: 1c1c6ebc

 ("xfs: Replace per-ag array with a radix tree")
Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Take mp->m_perag_lock for deletions from the perag radix tree in
xfs_initialize_perag to prevent racing with tagging operations.
Lookups are fine - they are RCU protected so already deal with the
tree changing shape underneath the lookup - but tagging operations
require the tree to be stable while the tags are propagated back up
to the root.

Right now there's nothing stopping radix tree tagging from operating
while a growfs operation is progress and adding/removing new entries
into the radix tree.

Hence we can have traversals that require a stable tree occurring at
the same time we are removing unused entries from the radix tree which
causes the shape of the tree to change.

Likely this hasn't caused a problem in the past because we are only
doing append addition and removal so the active AG part of the tree
is not changing shape, but that doesn't mean it is safe. Just making
the radix tree modifications serialise against each other is obviously
correct.

Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Merge tag 'repair-quota-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux

 into xfs-6.8-mergeB

xfs: online repair of quota and rt metadata files

XFS stores quota records and free space bitmap information in files.
Add the necessary infrastructure to enable repairing metadata inodes and
their forks, and then make it so that we can repair the file metadata
for the rtbitmap.  Repairing the bitmap contents (and the summary file)
is left for subsequent patchsets.

We also add the ability to repair file metadata the quota files.  As
part of these repairs, we also reinitialize the ondisk dquot records as
necessary to get the incore dquots working.  We can also correct
obviously bad dquot record attributes, but we leave checking the
resource usage counts for the next patchsets.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-quota-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: repair quotas
  xfs: improve dquot iteration for scrub
  xfs: check dquot resource timers
  xfs: check the ondisk space mapping behind a dquot

Merge tag 'repair-rtbitmap-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux

 into xfs-6.8-mergeB

xfs: online repair of rt bitmap file

Add in the necessary infrastructure to check the inode and data forks of
metadata files, then apply that to the realtime bitmap file.  We won't
be able to reconstruct the contents of the rtbitmap file until rmapbt is
added for realtime volumes, but we can at least get the basics started.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-rtbitmap-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: online repair of realtime bitmaps
  xfs: create a new inode fork block unmap helper
  xfs: repair the inode core and forks of a metadata inode
  xfs: always check the rtbitmap and rtsummary files
  xfs: check rt summary file geometry more thoroughly
  xfs: check rt bitmap file geometry more thoroughly

Merge tag 'repair-file-mappings-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux

 into xfs-6.8-mergeB

xfs: online repair of file fork mappings

In this series, online repair gains the ability to rebuild data and attr
fork mappings from the reverse mapping information.  It is at this point
where we reintroduce the ability to reap file extents.

Repair of CoW forks is a little different -- on disk, CoW staging
extents are owned by the refcount btree and cannot be mapped back to
individual files.  Hence we can only detect staging extents that don't
quite look right (missing reverse mappings, shared staging extents) and
replace them with fresh allocations.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-file-mappings-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: repair problems in CoW forks
  xfs: create a ranged query function for refcount btrees
  xfs: refactor repair forcing tests into a repair.c helper
  xfs: repair inode fork block mapping data structures
  xfs: reintroduce reaping of file metadata blocks to xrep_reap_extents

Merge tag 'repair-inodes-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux

 into xfs-6.8-mergeB

xfs: online repair of inodes and forks

In this series, online repair gains the ability to repair inode records.
To do this, we must repair the ondisk inode and fork information enough
to pass the iget verifiers and hence make the inode igettable again.
Once that's done, we can perform higher level repairs on the incore
inode.  The fstests counterpart of this patchset implements stress
testing of repair.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-inodes-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: skip the rmapbt search on an empty attr fork unless we know it was zapped
  xfs: abort directory parent scrub scans if we encounter a zapped directory
  xfs: zap broken inode forks
  xfs: repair inode records
  xfs: set inode sick state flags when we zap either ondisk fork
  xfs: dont cast to char * for XFS_DFORK_*PTR macros
  xfs: add missing nrext64 inode flag check to scrub
  xfs: try to attach dquots to files before repairing them
  xfs: disable online repair quota helpers when quota not enabled

Merge tag 'repair-ag-btrees-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux

 into xfs-6.8-mergeB

xfs: online repair of AG btrees

Now that we've spent a lot of time reworking common code in online fsck,
we're ready to start rebuilding the AG space btrees.  This series
implements repair functions for the free space, inode, and refcount
btrees.  Rebuilding the reverse mapping btree is much more intense and
is left for a subsequent patchset.  The fstests counterpart of this
patchset implements stress testing of repair.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-ag-btrees-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: repair refcount btrees
  xfs: repair inode btrees
  xfs: repair free space btrees
  xfs: remove trivial bnobt/inobt scrub helpers
  xfs: roll the scrub transaction after completing a repair
  xfs: move the per-AG datatype bitmaps to separate files
  xfs: create separate structures and code for u32 bitmaps

Merge tag 'repair-prep-for-bulk-loading-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux

 into xfs-6.8-mergeB

xfs: prepare repair for bulk loading

Before we start merging the online repair functions, let's improve the
bulk loading code a bit.  First, we need to fix a misinteraction between
the AIL and the btree bulkloader wherein the delwri at the end of the
bulk load fails to queue a buffer for writeback if it happens to be on
the AIL list.

Second, we introduce a defer ops barrier object so that the process of
reaping blocks after a repair cannot queue more than two extents per EFI
log item.  This increases our exposure to leaking blocks if the system
goes down during a reap, but also should prevent transaction overflows,
which result in the system going down.

Third, we change the bulkloader itself to copy multiple records into a
block if possible, and add some debugging knobs so that developers can
control the slack factors, just like they can do for xfs_repair.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'repair-prep-for-bulk-loading-6.8_2023-12-15' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: constrain dirty buffers while formatting a staged btree
  xfs: move btree bulkload record initialization to ->get_record implementations
  xfs: add debug knobs to control btree bulk load slack factors
  xfs: read leaf blocks when computing keys for bulkloading into node blocks
  xfs: set XBF_DONE on newly formatted btree block that are ready for writing
  xfs: force all buffers to be written during btree bulk load

Fix anything that causes the quota verifiers to fail.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Upon a closer inspection of the quota record scrubber, I noticed that
dqiterate wasn't actually walking all possible dquots for the mapped
blocks in the quota file.  This is due to xfs_qm_dqget_next skipping all
XFS_IS_DQUOT_UNINITIALIZED dquots.

For a fsck program, we really want to look at all the dquots, even if
all counters and limits in the dquot record are zero.  Rewrite the
implementation to do this, as well as switching to an iterator paradigm
to reduce the number of indirect calls.

This enables removal of the old broken dqiterate code from xfs_dquot.c.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

For each dquot resource, ensure either (a) the resource usage is over
the soft limit and there is a nonzero timer; or (b) usage is at or under
the soft limit and the timer is unset.  (a) is redundant with the dquot
buffer verifier, but (b) isn't checked anywhere.

Found by fuzzing xfs/426 and noticing that diskdq.btimer = add didn't
trip any kind of warning for having a timer set even with no limits.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Each xfs_dquot object caches the file offset and daddr of the ondisk
block that backs the dquot.  Make sure these cached values are the same
as the bmapi data, and that the block state is written.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Fix all the file metadata surrounding the realtime bitmap file, which
includes the rt geometry, file size, forks, and space mappings.  The
bitmap contents themselves cannot be fixed without rt rmap, so that will
come later.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Create a new helper to unmap blocks from an inode's fork.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Add a helper function to repair the core and forks of a metadata inode,
so that we can get move onto the task of repairing higher level metadata
that lives in an inode.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

XFS filesystems always have a realtime bitmap and summary file, even if
there has never been a realtime volume attached.  Always check them.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

I forgot that the xfs_mount tracks the size and number of levels in the
realtime summary file, and that the rt summary file can have more blocks
mapped to the data fork than m_rsumsize implies if growfsrt fails.

So.  Add to the rtsummary scrubber an explicit check that all the
summary geometry values are correct, then adjust the rtsummary i_size
checks to allow for the growfsrt failure case.  Finally, flag post-eof
blocks in the summary file.

While we're at it, split the extent map checking so that we only call
xfs_bmapi_read once per extent instead of once per rtsummary block.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

I forgot that the superblock tracks the number of blocks that are in the
realtime bitmap, and that the rt bitmap file can have more blocks mapped
to the data fork than sb_rbmblocks if growfsrt fails.

So.  Add to the rtbitmap scrubber an explicit check that sb_rextents and
sb_rbmblocks are correct, then adjust the rtbitmap i_size checks to
allow for the growfsrt failure case.  Finally, flag post-eof blocks in
the rtbitmap.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Try to repair errors that we see in file CoW forks so that we don't do
stupid things like remap garbage into a file.  There's not a lot we can
do with the COW fork -- the ondisk metadata record only that the COW
staging extents are owned by the refcount btree, which effectively means
that we can't reconstruct this incore structure from scratch.

Actually, this is even worse -- we can't touch written extents, because
those map space that are actively under writeback, and there's not much
to do with delalloc reservations.  Hence we can only detect crosslinked
unwritten extents and fix them by punching out the problematic parts and
replacing them with delalloc extents.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Implement ranged queries for refcount records.  The next patch will use
this to scan refcount data.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

There are a couple of conditions that userspace can set to force repairs
of metadata.  These really belong in the repair code and not open-coded
into the check code, so refactor them into a helper.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Use the reverse-mapping btree information to rebuild an inode block map.
Update the btree bulk loading code as necessary to support inode rooted
btrees and fix some bitrot problems.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

The attribute fork scrubber can optionally scan the reverse mapping
records of the filesystem to determine if the fork is missing mappings
that it should have.  However, this is a very expensive operation, so we
only want to do this if we suspect that the fork is missing records.
For attribute forks the criteria for suspicion is that the attr fork is
in EXTENTS format and has zero extents.

However, there are several ways that a file can end up in this state
through regular filesystem usage.  For example, an LSM can set a
s_security hook but then decide not to set an ACL; or an attr set can
create the attr fork but then the actual set operation fails with
ENOSPC; or we can delete all the attrs on a file whose data fork is in
btree format, in which case we do not delete the attr fork.  We don't
want to run the expensive check for any case that can be arrived at
through regular operations.

However.

When online inode repair decides to zap an attribute fork, it cannot
determine if it is zapping ACL information.  As a precaution it removes
all the discretionary access control permissions and sets the user and
group ids to zero.  Check these three additional conditions to decide if
we want to scan the rmap records.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Back in commit a55e0730

 ("xfs: only allow reaping of per-AG
blocks in xrep_reap_extents"), we removed from the reaping code the
ability to handle bmbt blocks.  At the time, the reaping code only
walked single blocks, didn't correctly detect crosslinked blocks, and
the special casing made the function hard to understand.  It was easier
to remove unneeded functionality prior to fixing all the bugs.

Now that we've fixed the problems, we want again the ability to reap
file metadata blocks.  Reintroduce the per-file reaping functionality
atop the current implementation.  We require that sc->sa is
uninitialized, so that we can use it to hold all the per-AG context for
a given extent.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

In a previous patch, we added some code to perform sufficient repairs
to an ondisk inode record such that the inode cache would be willing to
load the inode.  If the broken inode was a shortform directory, it will
reset the directory to something plausible, which is to say an empty
subdirectory of the root.  The telltale signs that something is
seriously wrong is the broken link count.

Such directories look clean, but they shouldn't participate in a
filesystem scan to find or confirm a directory parent pointer.  Create a
predicate that identifies such directories and abort the scrub.

Found by fuzzing xfs/1554 with multithreaded xfs_scrub enabled and
u3.bmx[0].startblock = zeroes.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Determine if inode fork damage is responsible for the inode being unable
to pass the ifork verifiers in xfs_iget and zap the fork contents if
this is true.  Once this is done the fork will be empty but we'll be
able to construct an in-core inode, and a subsequent call to the inode
fork repair ioctl will search the rmapbt to rebuild the records that
were in the fork.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

If an inode is so badly damaged that it cannot be loaded into the cache,
fix the ondisk metadata and try again.  If there /is/ a cached inode,
fix any problems and apply any optimizations that can be solved incore.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

In a few patches, we'll add some online repair code that tries to
massage the ondisk inode record just enough to get it to pass the inode
verifiers so that we can continue with more file repairs.  Part of that
massaging can include zapping the ondisk forks to clear errors.  After
that point, the bmap fork repair functions will rebuild the zapped
forks.

Christoph asked for stronger protections against online repair zapping a
fork to get the inode to load vs. other threads trying to access the
partially repaired file.  Do this by adding a special "[DA]FORK_ZAPPED"
inode health flag whenever repair zaps a fork, and sprinkling checks for
that flag into the various file operations for things that don't like
handling an unexpected zero-extents fork.

In practice xfs_scrub will scrub and fix the forks almost immediately
after zapping them, so the window is very small.  However, if a crash or
unmount should occur, we can still detect these zapped inode forks by
looking for a zero-extents fork when data was expected.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Code in the next patch will assign the return value of XFS_DFORK_*PTR
macros to a struct pointer.  gcc complains about casting char* strings
to struct pointers, so let's fix the macro's cast to void* to shut up
the warnings.

While we're at it, fix one of the scrub tests that uses PTR to use BOFF
instead for a simpler integer comparison, since other linters whine
about char* and void* comparisons.

Can't satisfy all these dman bots.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Add this missing check that the superblock nrext64 flag is set if the
inode flag is set.

Fixes: 9b7d16e3

 ("xfs: Introduce XFS_DIFLAG2_NREXT64 and associated helpers")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Inode resource usage is tracked in the quota metadata.  Repairing a file
might change the resources used by that file, which means that we need
to attach dquots to the file that we're examining before accessing
anything in the file protected by the ILOCK.

However, there's a twist: a dquot cache miss requires the dquot to be
read in from the quota file, during which we drop the ILOCK on the file
being examined.  This means that we *must* try to attach the dquots
before taking the ILOCK.

Therefore, dquots must be attached to files in the scrub setup function.
If doing so yields corruption errors (or unknown dquot errors), we
instead clear the quotachecked status, which will cause a quotacheck on
next mount.  A future series will make this trigger live quotacheck.

While we're here, change the xrep_ino_dqattach function to use the
unlocked dqattach functions so that we avoid cycling the ILOCK if the
inode already has dquots attached.  This makes the naming and locking
requirements consistent with the rest of the filesystem.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Reconstruct the refcount data from the rmap btree.

Link: https://docs.kernel.org/filesystems/xfs-online-fsck-design.html#case-study-rebuilding-the-space-reference-counts


Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Don't compile the quota helper functions if quota isn't being built into
the XFS module.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Use the rmapbt to find inode chunks, query the chunks to compute hole
and free masks, and with that information rebuild the inobt and finobt.
Refer to the case study in
Documentation/filesystems/xfs-online-fsck-design.rst for more details.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Rebuild the free space btrees from the gaps in the rmap btree.  Refer to
the case study in Documentation/filesystems/xfs-online-fsck-design.rst
for more details.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Christoph Hellwig complained about awkward code in the next two repair
patches such as:

	sc->sm->sm_type = XFS_SCRUB_TYPE_BNOBT;
	error = xchk_bnobt(sc);

This is a little silly, so let's export the xchk_{,i}allocbt functions
to the dispatch table in scrub.c directly and get rid of the helpers.
Originally I had planned each btree gets its own separate entry point,
but since repair doesn't work that way, it no longer makes sense to
complicate the call chain that way.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

When we've finished repairing an AG header, roll the scrub transaction.
This ensure that any failures caused by defer ops failing are captured
by the xrep_done tracepoint and that any stacktraces that occur will
point to the repair code that caused it, instead of xchk_teardown.

Going forward, repair functions should commit the transaction if they're
going to return success.  Usually the space reaping functions that run
after a successful atomic commit of the new metadata will take care of
that for us.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Move struct xagb_bitmap to its own pair of C and header files per
request of Christoph.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Create a version of the xbitmap that handles 32-bit integer intervals
and adapt the xfs_agblock_t bitmap to use it.  This reduces the size of
the interval tree nodes from 48 to 36 bytes and enables us to use a more
efficient slab (:0000040 instead of :0000048) which allows us to pack
more nodes into a single slab page (102 vs 85).

As a side effect, the users of these bitmaps no longer have to convert
between u32 and u64 quantities just to use the bitmap; and the hairy
overflow checking code in xagb_bitmap_test goes away.

Later in this patchset we're going to add bitmaps for xfs_agino_t,
xfs_rgblock_t, and xfs_dablk_t, so the increase in code size (5622 vs.
9959 bytes) seems worth it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Constrain the number of dirty buffers that are locked by the btree
staging code at any given time by establishing a threshold at which we
put them all on the delwri queue and push them to disk.  This limits
memory consumption while writing out new btrees.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>