Commit graph

91 commits

Author SHA1 Message Date
Darrick J. Wong
5049ff4d14 xfs: create a helper to decide if a file mapping targets the rt volume
Create a helper so that we can stop open-coding this decision
everywhere.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:43:36 -08:00
Darrick J. Wong
8f71bede8e xfs: repair inode fork block mapping data structures
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>
2023-12-15 10:03:39 -08:00
Darrick J. Wong
c3a22c2e4b xfs: skip the rmapbt search on an empty attr fork unless we know it was zapped
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>
2023-12-15 10:03:38 -08:00
Darrick J. Wong
d9041681dd xfs: set inode sick state flags when we zap either ondisk fork
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>
2023-12-15 10:03:35 -08:00
Darrick J. Wong
259ba1d36f xfs: try to attach dquots to files before repairing them
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>
2023-12-15 10:03:34 -08:00
Darrick J. Wong
3d2b6d034f xfs: rename xfs_verify_rtext to xfs_verify_rtbext
This helper function validates that a range of *blocks* in the
realtime section is completely contained within the realtime section.
It does /not/ validate ranges of *rtextents*.  Rename the function to
avoid suggesting that it does, and change the type of the @len parameter
since xfs_rtblock_t is a position unit, not a length unit.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-10-17 16:24:22 -07:00
Darrick J. Wong
e27a1369a9 xfs: don't check reflink iflag state when checking cow fork
Any inode on a reflink filesystem can have a cow fork, even if the inode
does not have the reflink iflag set.  This happens either because the
inode once had the iflag set but does not now, because we don't free the
incore cow fork until the icache deletes the inode; or because we're
running in alwayscow mode.

Either way, we can collapse both of the xfs_is_reflink_inode calls into
one, and change it to xfs_has_reflink, now that the bmap checker will
return ENOENT if there is no pointer to the incore fork.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:13 -07:00
Darrick J. Wong
65092ca140 xfs: simplify returns in xchk_bmap
Remove the pointless goto and return code in xchk_bmap, since it only
serves to obscure what's going on in the function.  Instead, return
whichever error code is appropriate there.  For nonexistent forks,
this should have been ENOENT.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:13 -07:00
Darrick J. Wong
294012fb07 xfs: wrap ilock/iunlock operations on sc->ip
Scrub tracks the resources that it's holding onto in the xfs_scrub
structure.  This includes the inode being checked (if applicable) and
the inode lock state of that inode.  Replace the open-coded structure
manipulation with a trivial helper to eliminate sources of error.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:08 -07:00
Darrick J. Wong
6be73cecb5 xfs: fix broken logic when detecting mergeable bmap records
Commit 6bc6c99a944c was a well-intentioned effort to initiate
consolidation of adjacent bmbt mapping records by setting the PREEN
flag.  Consolidation can only happen if the length of the combined
record doesn't overflow the 21-bit blockcount field of the bmbt
recordset.  Unfortunately, the length test is inverted, leading to it
triggering on data forks like these:

 EXT: FILE-OFFSET           BLOCK-RANGE        AG AG-OFFSET               TOTAL
   0: [0..16777207]:        76110848..92888055  0 (76110848..92888055) 16777208
   1: [16777208..20639743]: 92888056..96750591  0 (92888056..96750591)  3862536

Note that record 0 has a length of 16777208 512b blocks.  This
corresponds to 2097151 4k fsblocks, which is the maximum.  Hence the two
records cannot be merged.

However, the logic is still wrong even if we change the in-loop
comparison, because the scope of our examination isn't broad enough
inside the loop to detect mappings like this:

   0: [0..9]:               76110838..76110847  0 (76110838..76110847)       10
   1: [10..16777217]:       76110848..92888055  0 (76110848..92888055) 16777208
   2: [16777218..20639753]: 92888056..96750591  0 (92888056..96750591)  3862536

These three records could be merged into two, but one cannot determine
this purely from looking at records 0-1 or 1-2 in isolation.

Hoist the mergability detection outside the loop, and base its decision
making on whether or not a merged mapping could be expressed in fewer
bmbt records.  While we're at it, fix the incorrect return type of the
iter function.

Fixes: 336642f792 ("xfs: alert the user about data/attr fork mappings that could be merged")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2023-06-05 14:48:12 +10:00
Darrick J. Wong
397b2d7e0f xfs: flush dirty data and drain directios before scrubbing cow fork
When we're scrubbing the COW fork, we need to take MMAPLOCK_EXCL to
prevent page_mkwrite from modifying any inode state.  The ILOCK should
suffice to avoid confusing online fsck, but let's take the same locks
that we do everywhere else.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2023-05-02 09:14:43 +10:00
Darrick J. Wong
1e59fdb7d6 xfs: don't call xchk_bmap_check_rmaps for btree-format file forks
The logic at the end of xchk_bmap_want_check_rmaps tries to detect a
file fork that has been zapped by what will become the online inode
repair code.  Zapped forks are in FMT_EXTENTS with zero extents, and
some sort of hint that there's supposed to be data somewhere in the
filesystem.

Unfortunately, the inverted logic here is confusing and has the effect
that we always call xchk_bmap_check_rmaps for FMT_BTREE forks.  This is
horribly inefficient and unnecessary, so invert the logic to get rid of
this performance problem.  This has caused 8h delays in generic/333 and
generic/334.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:26 -07:00
Darrick J. Wong
e8882f69b9 xfs: split the xchk_bmap_check_rmaps into a predicate
This function has two parts: the second part scans every reverse mapping
record for this file fork to make sure that there's a corresponding
mapping in the fork, and the first part decides if we even want to do
that.

Split the first part into a separate predicate so that we can make more
changes to it in the next patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:25 -07:00
Darrick J. Wong
336642f792 xfs: alert the user about data/attr fork mappings that could be merged
If the data or attr forks have mappings that could be merged, let the
user know that the structure could be optimized.  This isn't a
filesystem corruption since the regular filesystem does not try to be
smart about merging bmbt records.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:25 -07:00
Darrick J. Wong
c0d5a92f7a xfs: split xchk_bmap_xref_rmap into two functions
There's more special-cased functionality than not in this function.
Split it into two so that each can be far more cohesive.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:24 -07:00
Darrick J. Wong
634d4a79e7 xfs: accumulate iextent records when checking bmap
Currently, the bmap scrubber checks file fork mappings individually.  In
the case that the file uses multiple mappings to a single contiguous
piece of space, the scrubber repeatedly locks the AG to check the
existence of a reverse mapping that overlaps this file mapping.  If the
reverse mapping starts before or ends after the mapping we're checking,
it will also crawl around in the bmbt checking correspondence for
adjacent extents.

This is not very time efficient because it does the crawling while
holding the AGF buffer, and checks the middle mappings multiple times.
Instead, create a custom iextent record iterator function that combines
multiple adjacent allocated mappings into one large incore bmbt record.
This is feasible because the incore bmbt record length is 64-bits wide.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:24 -07:00
Darrick J. Wong
971ee3a670 xfs: change bmap scrubber to store the previous mapping
Convert the inode data/attr/cow fork scrubber to remember the entire
previous mapping, not just the next expected offset.  No behavior
changes here, but this will enable some better checking in subsequent
patches.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:23 -07:00
Darrick J. Wong
1fc7a0597d xfs: don't take the MMAPLOCK when scrubbing file metadata
The MMAPLOCK stabilizes mappings in a file's pagecache.  Therefore, we
do not need it to check directories, symlinks, extended attributes, or
file-based metadata.  Reduce its usage to the one case that requires it,
which is when we want to scrub the data fork of a regular file.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:22 -07:00
Darrick J. Wong
46e0dd8965 xfs: rename xchk_get_inode -> xchk_iget_for_scrubbing
Dave Chinner suggested renaming this function to make more obvious what
it does.  The function returns an incore inode to callers that want to
scrub a metadata structure that hangs off an inode.  If the iget fails
with EINVAL, it will single-step the loading process to distinguish
between actually free inodes or impossible inumbers (ENOENT);
discrepancies between the inobt freemask and the free status in the
inode record (EFSCORRUPTED).  Any other negative errno is returned
unchanged.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:21 -07:00
Darrick J. Wong
30f8ee5e7e xfs: ensure that single-owner file blocks are not owned by others
For any file fork mapping that can only have a single owner, make sure
that there are no other rmap owners for that mapping.  This patch
requires the more detailed checking provided by xfs_rmap_count_owners so
that we can know how many rmap records for a given range of space had a
matching owner, how many had a non-matching owner, and how many
conflicted with the records that have a matching owner.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:16 -07:00
Darrick J. Wong
7ac14fa2bd xfs: ensure that all metadata and data blocks are not cow staging extents
Make sure that all filesystem metadata blocks and file data blocks are
not also marked as CoW staging extents.  The extra checking added here
was inspired by an actual VM host filesystem corruption incident due to
bugs in the CoW handling of 4.x kernels.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:12 -07:00
Darrick J. Wong
69010fe3ac xfs: standardize ondisk to incore conversion for bmap btrees
Fix all xfs_bmbt_disk_get_all callsites to call xfs_bmap_validate_extent
and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:04 -07:00
Darrick J. Wong
466c525d6d xfs: minimize overhead of drain wakeups by using jump labels
To reduce the runtime overhead even further when online fsck isn't
running, use a static branch key to decide if we call wake_up on the
drain.  For compilers that support jump labels, the call to wake_up is
replaced by a nop sled when nobody is waiting for intents to drain.

From my initial microbenchmarking, every transition of the static key
between the on and off states takes about 22000ns to complete; this is
paid entirely by the xfs_scrub process.  When the static key is off
(which it should be when fsck isn't running), the nop sled adds an
overhead of approximately 0.36ns to runtime code.  The post-atomic
lockless waiter check adds about 0.03ns, which is basically free.

For the few compilers that don't support jump labels, runtime code pays
the cost of calling wake_up on an empty waitqueue, which was observed to
be about 30ns.  However, most architectures that have sufficient memory
and CPU capacity to run XFS also support jump labels, so this is not
much of a worry.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:59 -07:00
Darrick J. Wong
ecc73f8a58 xfs: update copyright years for scrub/ files
Update the copyright years in the scrub/ source code files.  This isn't
required, but it's helpful to remind myself just how long it's taken to
develop this feature.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:57 -07:00
Darrick J. Wong
739a2fe042 xfs: fix author and spdx headers on scrub/ files
Fix the spdx tags to match current practice, and update the author
contact information.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:56 -07:00
Dave Chinner
c4d5660afb xfs: active perag reference counting
We need to be able to dynamically remove instantiated AGs from
memory safely, either for shrinking the filesystem or paging AG
state in and out of memory (e.g. supporting millions of AGs). This
means we need to be able to safely exclude operations from accessing
perags while dynamic removal is in progress.

To do this, introduce the concept of active and passive references.
Active references are required for high level operations that make
use of an AG for a given operation (e.g. allocation) and pin the
perag in memory for the duration of the operation that is operating
on the perag (e.g. transaction scope). This means we can fail to get
an active reference to an AG, hence callers of the new active
reference API must be able to handle lookup failure gracefully.

Passive references are used in low level code, where we might need
to access the perag structure for the purposes of completing high
level operations. For example, buffers need to use passive
references because:
- we need to be able to do metadata IO during operations like grow
  and shrink transactions where high level active references to the
  AG have already been blocked
- buffers need to pin the perag until they are reclaimed from
  memory, something that high level code has no direct control over.
- unused cached buffers should not prevent a shrink from being
  started.

Hence we have active references that will form exclusion barriers
for operations to be performed on an AG, and passive references that
will prevent reclaim of the perag until all objects with passive
references have been reclaimed themselves.

This patch introduce xfs_perag_grab()/xfs_perag_rele() as the API
for active AG reference functionality. We also need to convert the
for_each_perag*() iterators to use active references, which will
start the process of converting high level code over to using active
references. Conversion of non-iterator based code to active
references will be done in followup patches.

Note that the implementation using reference counting is really just
a development vehicle for the API to ensure we don't have any leaks
in the callers. Once we need to remove perag structures from memory
dyanmically, we will need a much more robust per-ag state transition
mechanism for preventing new references from being taken while we
wait for existing references to drain before removal from memory can
occur....

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-02-13 09:14:42 +11:00
Darrick J. Wong
5eef46358f xfs: teach scrub to flag non-extents format cow forks
CoW forks only exist in memory, which means that they can only ever have
an incore extent tree.  Hence they must always be FMT_EXTENTS, so check
this when we're scrubbing them.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:05 -08:00
Darrick J. Wong
3178553701 xfs: check that CoW fork extents are not shared
Ensure that extents in an inode's CoW fork are not marked as shared in
the refcount btree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
830ffa09fb xfs: block map scrub should handle incore delalloc reservations
Enhance the block map scrubber to check delayed allocation reservations.
Though there are no physical space allocations to check, we do need to
make sure that the range of file offsets being mapped are correct, and
to bump the lastoff cursor so that key order checking works correctly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
6a5777865e xfs: teach scrub to check for adjacent bmaps when rmap larger than bmap
When scrub is checking file fork mappings against rmap records and
the rmap record starts before or ends after the bmap record, check the
adjacent bmap records to make sure that they're adjacent to the one
we're checking.  This helps us to detect cases where the rmaps cover
territory that the bmaps do not.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
033985b6fe xfs: fix perag loop in xchk_bmap_check_rmaps
sparse complains that we can return an uninitialized error from this
function and that pag could be uninitialized.  We know that there are no
zero-AG filesystems and hence we had to call xchk_bmap_check_ag_rmaps at
least once, so this is not actually possible, but I'm too worn out from
automated complaints from unsophisticated AIs so let's just fix this and
move on to more interesting problems, eh?

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
732436ef91 xfs: convert XFS_IFORK_PTR to a static inline helper
We're about to make this logic do a bit more, so convert the macro to a
static inline function for better typechecking and fewer shouty macros.
No functional changes here.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-09 15:17:21 -07:00
Dave Chinner
08d3e84fee xfs: pass perag to xfs_alloc_read_agf()
xfs_alloc_read_agf() initialises the perag if it hasn't been done
yet, so it makes sense to pass it the perag rather than pull a
reference from the buffer. This allows callers to be per-ag centric
rather than passing mount/agno pairs everywhere.

Whilst modifying the xfs_reflink_find_shared() function definition,
declare it static and remove the extern declaration as it is an
internal function only these days.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-07-07 19:07:40 +10:00
Darrick J. Wong
5b7ca8b313 xfs: simplify xfs_rmap_lookup_le call sites
Most callers of xfs_rmap_lookup_le will retrieve the btree record
immediately if the lookup succeeds.  The overlapped version of this
function (xfs_rmap_lookup_le_range) will return the record if the lookup
succeeds, so make the regular version do it too.  Get rid of the useless
len argument, since it's not part of the lookup key.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2022-04-27 10:47:19 -07:00
Chandan Babu R
95f0b95e2b xfs: Define max extent length based on on-disk format definition
The maximum extent length depends on maximum block count that can be stored in
a BMBT record. Hence this commit defines MAXEXTLEN based on
BMBT_BLOCKCOUNT_BITLEN.

While at it, the commit also renames MAXEXTLEN to XFS_MAX_BMBT_EXTLEN.

Suggested-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11 04:11:17 +00:00
Darrick J. Wong
6ca444cfd6 xfs: prepare xfs_btree_cur for dynamic cursor heights
Split out the btree level information into a separate struct and put it
at the end of the cursor structure as a VLA.  Files with huge data forks
(and in the future, the realtime rmap btree) will require the ability to
support many more levels than a per-AG btree cursor, which means that
we're going to create per-btree type cursor caches to conserve memory
for the more common case.

Note that a subsequent patch actually introduces dynamic cursor heights.
This one merely rearranges the structure to prepare for that.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-10-19 11:45:14 -07:00
Darrick J. Wong
61e0d0cc51 xfs: fix perag structure refcounting error when scrub fails
The kernel test robot found the following bug when running xfs/355 to
scrub a bmap btree:

XFS: Assertion failed: !sa->pag, file: fs/xfs/scrub/common.c, line: 412
------------[ cut here ]------------
kernel BUG at fs/xfs/xfs_message.c:110!
invalid opcode: 0000 [#1] SMP PTI
CPU: 2 PID: 1415 Comm: xfs_scrub Not tainted 5.14.0-rc4-00021-g48c6615cc557 #1
Hardware name: Hewlett-Packard p6-1451cx/2ADA, BIOS 8.15 02/05/2013
RIP: 0010:assfail+0x23/0x28 [xfs]
RSP: 0018:ffffc9000aacb890 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffc9000aacbcc8 RCX: 0000000000000000
RDX: 00000000ffffffc0 RSI: 000000000000000a RDI: ffffffffc09e7dcd
RBP: ffffc9000aacbc80 R08: ffff8881fdf17d50 R09: 0000000000000000
R10: 000000000000000a R11: f000000000000000 R12: 0000000000000000
R13: ffff88820c7ed000 R14: 0000000000000001 R15: ffffc9000aacb980
FS:  00007f185b955700(0000) GS:ffff8881fdf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f6ef43000 CR3: 000000020de38002 CR4: 00000000001706e0
Call Trace:
 xchk_ag_read_headers+0xda/0x100 [xfs]
 xchk_ag_init+0x15/0x40 [xfs]
 xchk_btree_check_block_owner+0x76/0x180 [xfs]
 xchk_btree_get_block+0xd0/0x140 [xfs]
 xchk_btree+0x32e/0x440 [xfs]
 xchk_bmap_btree+0xd4/0x140 [xfs]
 xchk_bmap+0x1eb/0x3c0 [xfs]
 xfs_scrub_metadata+0x227/0x4c0 [xfs]
 xfs_ioc_scrub_metadata+0x50/0xc0 [xfs]
 xfs_file_ioctl+0x90c/0xc40 [xfs]
 __x64_sys_ioctl+0x83/0xc0
 do_syscall_64+0x3b/0xc0

The unusual handling of errors while initializing struct xchk_ag is the
root cause here.  Since the beginning of xfs_scrub, the goal of
xchk_ag_read_headers has been to read all three AG header buffers and
attach them both to the xchk_ag structure and the scrub transaction.
Corruption errors on any of the three headers doesn't necessarily
trigger an immediate return to userspace, because xfs_scrub can also
tell us to /fix/ the problem.

In other words, it's possible for the xchk_ag init functions to return
an error code and a partially filled out structure so that scrub can use
however much information it managed to pull.  Before 5.15, it was
sufficient to cancel (or commit) the scrub transaction on the way out of
the scrub code to release the buffers.

Ccommit 48c6615cc5 added a reference to the perag structure to struct
xchk_ag.  Since perag structures are not attached to transactions like
buffers are, this adds the requirement that the perag ref be released
explicitly.  The scrub teardown function xchk_teardown was amended to do
this for the xchk_ag embedded in struct xfs_scrub.

Unfortunately, I forgot that certain parts of the scrub code probe
multiple AGs and therefore handle the initialization and cleanup on
their own.  Specifically, the bmbt scrubber will initialize it long
enough to cross-reference AG metadata for btree blocks and for the
extent mappings in the bmbt.

If one of the AG headers is corrupt, the init function returns with a
live perag structure reference and some of the AG header buffers.  If an
error occurs, the cross referencing will be noted as XCORRUPTion and
skipped, but the main scrub process will move on to the next record.
It is now necessary to release the perag reference before we try to
analyze something from a different AG, or else we'll trip over the
assertion noted above.

Fixes: 48c6615cc5 ("xfs: grab active perag ref when reading AG headers")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
2021-08-20 13:20:33 -07:00
Dave Chinner
ebd9027d08 xfs: convert xfs_sb_version_has checks to use mount features
This is a conversion of the remaining xfs_sb_version_has..(sbp)
checks to use xfs_has_..(mp) feature checks.

This was largely done with a vim replacement macro that did:

:0,$s/xfs_sb_version_has\(.*\)&\(.*\)->m_sb/xfs_has_\1\2/g<CR>

A couple of other variants were also used, and the rest touched up
by hand.

$ size -t fs/xfs/built-in.a
	   text    data     bss     dec     hex filename
before	1127533  311352     484 1439369  15f689 (TOTALS)
after	1125360  311352     484 1437196  15ee0c (TOTALS)

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-19 10:07:14 -07:00
Dave Chinner
38c26bfd90 xfs: replace xfs_sb_version checks with feature flag checks
Convert the xfs_sb_version_hasfoo() to checks against
mp->m_features. Checks of the superblock itself during disk
operations (e.g. in the read/write verifiers and the to/from disk
formatters) are not converted - they operate purely on the
superblock state. Everything else should use the mount features.

Large parts of this conversion were done with sed with commands like
this:

for f in `git grep -l xfs_sb_version_has fs/xfs/*.c`; do
	sed -i -e 's/xfs_sb_version_has\(.*\)(&\(.*\)->m_sb)/xfs_has_\1(\2)/' $f
done

With manual cleanups for things like "xfs_has_extflgbit" and other
little inconsistencies in naming.

The result is ia lot less typing to check features and an XFS binary
size reduced by a bit over 3kB:

$ size -t fs/xfs/built-in.a
	text	   data	    bss	    dec	    hex	filenam
before	1130866  311352     484 1442702  16038e (TOTALS)
after	1127727  311352     484 1439563  15f74b (TOTALS)

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-19 10:07:12 -07:00
Darrick J. Wong
22ece4e836 xfs: mark the record passed into xchk_btree functions as const
xchk_btree calls a user-supplied function to validate each btree record
that it finds.  Those functions are not supposed to change the record
data, so mark the parameter const.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-08-18 18:46:01 -07:00
Darrick J. Wong
159eb69dba xfs: make the record pointer passed to query_range functions const
The query_range functions are supposed to call a caller-supplied
function on each record found in the dataset.  These functions don't
own the memory storing the record, so don't let them change the record.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-08-18 18:46:01 -07:00
Darrick J. Wong
48c6615cc5 xfs: grab active perag ref when reading AG headers
This patch prepares scrub to deal with the possibility of tearing down
entire AGs by changing the order of resource acquisition to match the
rest of the XFS codebase.  In other words, scrub now grabs AG resources
in order of: perag structure, then AGI/AGF/AGFL buffers, then btree
cursors; and releases them in reverse order.

This requires us to distinguish xchk_ag_init callers -- some are
responding to a user request to check AG metadata, in which case we can
return ENOENT to userspace; but other callers have an ondisk reference
to an AG that they're trying to cross-reference.  In this second case,
the lack of an AG means there's ondisk corruption, since ondisk metadata
cannot point into nonexistent space.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
2021-08-09 11:13:17 -07:00
Linus Torvalds
9f7b640f00 New code for 5.14:
- Refactor the buffer cache to use bulk page allocation
 - Convert agnumber-based AG iteration to walk per-AG structures
 - Clean up some unit conversions and other code warts
 - Reduce spinlock contention in the directio fastpath
 - Collapse all the inode cache walks into a single function
 - Remove indirect function calls from the inode cache walk code
 - Dramatically reduce the number of cache flushes sent when writing log
   buffers
 - Preserve inode sickness reports for longer
 - Rename xfs_eofblocks since it controls inode cache walks
 - Refactor the extended attribute code to prepare it for the addition
   of log intent items to make xattrs fully transactional
 - A few fixes to earlier large patchsets
 - Log recovery fixes so that we don't accidentally mark the log clean
   when log intent recovery fails
 - Fix some latent SOB errors
 - Clean up shutdown messages that get logged to dmesg
 - Fix a regression in the online shrink code
 - Fix a UAF in the buffer logging code if the fs goes offline
 - Fix uninitialized error variables
 - Fix a UAF in the CIL when commited log item callbacks race with a
   shutdown
 - Fix a bug where the CIL could hang trying to push part of the log ring
   buffer that hasn't been filled yet
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Merge tag 'xfs-5.14-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Darrick Wong:
 "Most of the work this cycle has been on refactoring various parts of
  the codebase. The biggest non-cleanup changes are (1) reducing the
  number of cache flushes sent when writing the log; (2) a substantial
  number of log recovery fixes; and (3) I started accepting pull
  requests from contributors if the commits in their branches match
  what's been sent to the list.

  For a week or so I /had/ staged a major cleanup of the logging code
  from Dave Chinner, but it exposed so many lurking bugs in other parts
  of the logging and log recovery code that I decided to defer that
  patchset until we can address those latent bugs.

  Larger cleanups this time include walking the incore inode cache (me)
  and rework of the extended attribute code (Allison) to prepare it for
  adding logged xattr updates (and directory tree parent pointers) in
  future releases.

  Summary:

   - Refactor the buffer cache to use bulk page allocation

   - Convert agnumber-based AG iteration to walk per-AG structures

   - Clean up some unit conversions and other code warts

   - Reduce spinlock contention in the directio fastpath

   - Collapse all the inode cache walks into a single function

   - Remove indirect function calls from the inode cache walk code

   - Dramatically reduce the number of cache flushes sent when writing
     log buffers

   - Preserve inode sickness reports for longer

   - Rename xfs_eofblocks since it controls inode cache walks

   - Refactor the extended attribute code to prepare it for the addition
     of log intent items to make xattrs fully transactional

   - A few fixes to earlier large patchsets

   - Log recovery fixes so that we don't accidentally mark the log clean
     when log intent recovery fails

   - Fix some latent SOB errors

   - Clean up shutdown messages that get logged to dmesg

   - Fix a regression in the online shrink code

   - Fix a UAF in the buffer logging code if the fs goes offline

   - Fix uninitialized error variables

   - Fix a UAF in the CIL when commited log item callbacks race with a
     shutdown

   - Fix a bug where the CIL could hang trying to push part of the log
     ring buffer that hasn't been filled yet"

* tag 'xfs-5.14-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (102 commits)
  xfs: don't wait on future iclogs when pushing the CIL
  xfs: Fix a CIL UAF by getting get rid of the iclog callback lock
  xfs: remove callback dequeue loop from xlog_state_do_iclog_callbacks
  xfs: don't nest icloglock inside ic_callback_lock
  xfs: Initialize error in xfs_attr_remove_iter
  xfs: fix endianness issue in xfs_ag_shrink_space
  xfs: remove dead stale buf unpin handling code
  xfs: hold buffer across unpin and potential shutdown processing
  xfs: force the log offline when log intent item recovery fails
  xfs: fix log intent recovery ENOSPC shutdowns when inactivating inodes
  xfs: shorten the shutdown messages to a single line
  xfs: print name of function causing fs shutdown instead of hex pointer
  xfs: fix type mismatches in the inode reclaim functions
  xfs: separate primary inode selection criteria in xfs_iget_cache_hit
  xfs: refactor the inode recycling code
  xfs: add iclog state trace events
  xfs: xfs_log_force_lsn isn't passed a LSN
  xfs: Fix CIL throttle hang when CIL space used going backwards
  xfs: journal IO cache flush reductions
  xfs: remove need_start_rec parameter from xlog_write()
  ...
2021-07-02 14:30:27 -07:00
Dave Chinner
50f02fe333 xfs: remove agno from btree cursor
Now that everything passes a perag, the agno is not needed anymore.
Convert all the users to use pag->pag_agno instead and remove the
agno from the cursor. This was largely done as an automated search
and replace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02 10:48:24 +10:00
Dave Chinner
a81a06211f xfs: convert refcount btree cursor to use perags
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02 10:48:24 +10:00
Dave Chinner
fa9c3c1973 xfs: convert rmap btree cursor to using a perag
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02 10:48:24 +10:00
Dave Chinner
be9fb17d88 xfs: add a perag to the btree cursor
Which will eventually completely replace the agno in it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-06-02 10:48:24 +10:00
Dave Chinner
934933c3ee xfs: convert raw ag walks to use for_each_perag
Convert the raw walks to an iterator, pulling the current AG out of
pag->pag_agno instead of the loop iterator variable.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02 10:48:24 +10:00
Gustavo A. R. Silva
53004ee78d xfs: Fix fall-through warnings for Clang
In preparation to enable -Wimplicit-fallthrough for Clang, fix
the following warnings by replacing /* fall through */ comments,
and its variants, with the new pseudo-keyword macro fallthrough:

fs/xfs/libxfs/xfs_alloc.c:3167:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_da_btree.c:286:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_ag_resv.c:346:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_ag_resv.c:388:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_bmap_util.c:246:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_export.c:88:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_export.c:96:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_file.c:867:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_ioctl.c:562:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_ioctl.c:1548:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_iomap.c:1040:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_inode.c:852:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_log.c:2627:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_trans_buf.c:298:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/bmap.c:275:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/btree.c:48:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/common.c:85:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/common.c:138:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/common.c:698:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/dabtree.c:51:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/repair.c:951:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/agheader.c:89:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]

Notice that Clang doesn't recognize /* fall through */ comments as
implicit fall-through markings, so in order to globally enable
-Wimplicit-fallthrough for Clang, these comments need to be
replaced with fallthrough; in the whole codebase.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2021-05-26 14:51:26 -05:00
Christoph Hellwig
b2197a36c0 xfs: remove XFS_IFEXTENTS
The in-memory XFS_IFEXTENTS is now only used to check if an inode with
extents still needs the extents to be read into memory before doing
operations that need the extent map.  Add a new xfs_need_iread_extents
helper that returns true for btree format forks that do not have any
entries in the in-memory extent btree, and use that instead of checking
the XFS_IFEXTENTS flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-15 09:35:51 -07:00