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Now that we've established (again!) that empty xattr leaf buffers are
ok, we no longer need to bhold them to transactions when we're creating
new leaf blocks. Get rid of the entire mechanism, which should simplify
the xattr code quite a bit.
The original justification for using bhold here was to prevent the AIL
from trying to write the empty leaf block into the fs during the brief
time that we release the buffer lock. The reason for /that/ was to
prevent recovery from tripping over the empty ondisk block.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
TLDR: Revert commit 51e6104fdb95 ("xfs: detect empty attr leaf blocks in
xfs_attr3_leaf_verify") because it was wrong.
Every now and then we get a corruption report from the kernel or
xfs_repair about empty leaf blocks in the extended attribute structure.
We've long thought that these shouldn't be possible, but prior to 5.18
one would shake loose in the recoveryloop fstests about once a month.
A new addition to the xattr leaf block verifier in 5.19-rc1 makes this
happen every 7 minutes on my testing cloud. I added a ton of logging to
detect any time we set the header count on an xattr leaf block to zero.
This produced the following dmesg output on generic/388:
XFS (sda4): ino 0x21fcbaf leaf 0x129bf78 hdcount==0!
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
xfs_attr3_leaf_create+0x187/0x230
xfs_attr_shortform_to_leaf+0xd1/0x2f0
xfs_attr_set_iter+0x73e/0xa90
xfs_xattri_finish_update+0x45/0x80
xfs_attr_finish_item+0x1b/0xd0
xfs_defer_finish_noroll+0x19c/0x770
__xfs_trans_commit+0x153/0x3e0
xfs_attr_set+0x36b/0x740
xfs_xattr_set+0x89/0xd0
__vfs_setxattr+0x67/0x80
__vfs_setxattr_noperm+0x6e/0x120
vfs_setxattr+0x97/0x180
setxattr+0x88/0xa0
path_setxattr+0xc3/0xe0
__x64_sys_setxattr+0x27/0x30
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
So now we know that someone is creating empty xattr leaf blocks as part
of converting a sf xattr structure into a leaf xattr structure. The
conversion routine logs any existing sf attributes in the same
transaction that creates the leaf block, so we know this is a setxattr
to a file that has no attributes at all.
Next, g/388 calls the shutdown ioctl and cycles the mount to trigger log
recovery. I also augmented buffer item recovery to call ->verify_struct
on any attr leaf blocks and complain if it finds a failure:
XFS (sda4): Unmounting Filesystem
XFS (sda4): Mounting V5 Filesystem
XFS (sda4): Starting recovery (logdev: internal)
XFS (sda4): xattr leaf daddr 0x129bf78 hdrcount == 0!
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
xfs_attr3_leaf_verify+0x3b8/0x420
xlog_recover_buf_commit_pass2+0x60a/0x6c0
xlog_recover_items_pass2+0x4e/0xc0
xlog_recover_commit_trans+0x33c/0x350
xlog_recovery_process_trans+0xa5/0xe0
xlog_recover_process_data+0x8d/0x140
xlog_do_recovery_pass+0x19b/0x720
xlog_do_log_recovery+0x62/0xc0
xlog_do_recover+0x33/0x1d0
xlog_recover+0xda/0x190
xfs_log_mount+0x14c/0x360
xfs_mountfs+0x517/0xa60
xfs_fs_fill_super+0x6bc/0x950
get_tree_bdev+0x175/0x280
vfs_get_tree+0x1a/0x80
path_mount+0x6f5/0xaa0
__x64_sys_mount+0x103/0x140
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fc61e241eae
And a moment later, the _delwri_submit of the recovered buffers trips
the same verifier and recovery fails:
XFS (sda4): Metadata corruption detected at xfs_attr3_leaf_verify+0x393/0x420 [xfs], xfs_attr3_leaf block 0x129bf78
XFS (sda4): Unmount and run xfs_repair
XFS (sda4): First 128 bytes of corrupted metadata buffer:
00000000: 00 00 00 00 00 00 00 00 3b ee 00 00 00 00 00 00 ........;.......
00000010: 00 00 00 00 01 29 bf 78 00 00 00 00 00 00 00 00 .....).x........
00000020: a5 1b d0 02 b2 9a 49 df 8e 9c fb 8d f8 31 3e 9d ......I......1>.
00000030: 00 00 00 00 02 1f cb af 00 00 00 00 10 00 00 00 ................
00000040: 00 50 0f b0 00 00 00 00 00 00 00 00 00 00 00 00 .P..............
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
XFS (sda4): Corruption of in-memory data (0x8) detected at _xfs_buf_ioapply+0x37f/0x3b0 [xfs] (fs/xfs/xfs_buf.c:1518). Shutting down filesystem.
XFS (sda4): Please unmount the filesystem and rectify the problem(s)
XFS (sda4): log mount/recovery failed: error -117
XFS (sda4): log mount failed
I think I see what's going on here -- setxattr is racing with something
that shuts down the filesystem:
Thread 1 Thread 2
-------- --------
xfs_attr_sf_addname
xfs_attr_shortform_to_leaf
<create empty leaf>
xfs_trans_bhold(leaf)
xattri_dela_state = XFS_DAS_LEAF_ADD
<roll transaction>
<flush log>
<shut down filesystem>
xfs_trans_bhold_release(leaf)
<discover fs is dead, bail>
Thread 3
--------
<cycle mount, start recovery>
xlog_recover_buf_commit_pass2
xlog_recover_do_reg_buffer
<replay empty leaf buffer from recovered buf item>
xfs_buf_delwri_queue(leaf)
xfs_buf_delwri_submit
_xfs_buf_ioapply(leaf)
xfs_attr3_leaf_write_verify
<trip over empty leaf buffer>
<fail recovery>
As you can see, the bhold keeps the leaf buffer locked and thus prevents
the *AIL* from tripping over the ichdr.count==0 check in the write
verifier. Unfortunately, it doesn't prevent the log from getting
flushed to disk, which sets up log recovery to fail.
So. It's clear that the kernel has always had the ability to persist
attr leaf blocks with ichdr.count==0, which means that it's part of the
ondisk format now.
Unfortunately, this check has been added and removed multiple times
throughout history. It first appeared in[1] kernel 3.10 as part of the
early V5 format patches. The check was later discovered to break log
recovery and hence disabled[2] during log recovery in kernel 4.10.
Simultaneously, the check was added[3] to xfs_repair 4.9.0 to try to
weed out the empty leaf blocks. This was still not correct because log
recovery would recover an empty attr leaf block successfully only for
regular xattr operations to trip over the empty block during of the
block during regular operation. Therefore, the check was removed
entirely[4] in kernel 5.7 but removal of the xfs_repair check was
forgotten. The continued complaints from xfs_repair lead to us
mistakenly re-adding[5] the verifier check for kernel 5.19. Remove it
once again.
[1] 517c22207b04 ("xfs: add CRCs to attr leaf blocks")
[2] 2e1d23370e75 ("xfs: ignore leaf attr ichdr.count in verifier
during log replay")
[3] f7140161 ("xfs_repair: junk leaf attribute if count == 0")
[4] f28cef9e4dac ("xfs: don't fail verifier on empty attr3 leaf
block")
[5] 51e6104fdb95 ("xfs: detect empty attr leaf blocks in
xfs_attr3_leaf_verify")
Looking at the rest of the xattr code, it seems that files with empty
leaf blocks behave as expected -- listxattr reports no attributes;
getxattr on any xattr returns nothing as expected; removexattr does
nothing; and setxattr can add attributes just fine.
Original-bug: 517c22207b04 ("xfs: add CRCs to attr leaf blocks")
Still-not-fixed-by: 2e1d23370e75 ("xfs: ignore leaf attr ichdr.count in verifier during log replay")
Removed-in: f28cef9e4dac ("xfs: don't fail verifier on empty attr3 leaf block")
Fixes: 51e6104fdb95 ("xfs: detect empty attr leaf blocks in xfs_attr3_leaf_verify")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
The variable @args is fed to a tracepoint, and that's the only place
it's used. This is fine for the kernel, but for userspace, tracepoints
are #define'd out of existence, which results in this warning on gcc
11.2:
xfs_attr.c: In function ‘xfs_attr_node_try_addname’:
xfs_attr.c:1440:42: warning: unused variable ‘args’ [-Wunused-variable]
1440 | struct xfs_da_args *args = attr->xattri_da_args;
| ^~~~
Clean this up.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
I found a race involving the larp control knob, aka the debugging knob
that lets developers enable logging of extended attribute updates:
Thread 1 Thread 2
echo 0 > /sys/fs/xfs/debug/larp
setxattr(REPLACE)
xfs_has_larp (returns false)
xfs_attr_set
echo 1 > /sys/fs/xfs/debug/larp
xfs_attr_defer_replace
xfs_attr_init_replace_state
xfs_has_larp (returns true)
xfs_attr_init_remove_state
<oops, wrong DAS state!>
This isn't a particularly severe problem right now because xattr logging
is only enabled when CONFIG_XFS_DEBUG=y, and developers *should* know
what they're doing.
However, the eventual intent is that callers should be able to ask for
the assistance of the log in persisting xattr updates. This capability
might not be required for /all/ callers, which means that dynamic
control must work correctly. Once an xattr update has decided whether
or not to use logged xattrs, it needs to stay in that mode until the end
of the operation regardless of what subsequent parallel operations might
do.
Therefore, it is an error to continue sampling xfs_globals.larp once
xfs_attr_change has made a decision about larp, and it was not correct
for me to have told Allison that ->create_intent functions can sample
the global log incompat feature bitfield to decide to elide a log item.
Instead, create a new op flag for the xfs_da_args structure, and convert
all other callers of xfs_has_larp and xfs_sb_version_haslogxattrs within
the attr update state machine to look for the operations flag.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
This series contains a two key cleanups for the new LARP code. Most
of it is refactoring and tweaking the code that creates kernel log
messages about enabling and disabling features -- we should be
warning about LARP being turned on once per mount, instead of once
per insmod cycle; we shouldn't be spamming the logs so aggressively
about turning *off* log incompat features.
The second part of the series refactors the LARP code responsible
for getting (and releasing) permission to use xattr log items. The
implementation code doesn't belong in xfs_log.c, and calls to
logging functions don't belong in libxfs -- they really should be
done by the VFS implementation functions before they start calling
into libraries.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
As part of solving the memory leaks and UAF problems in the new LARP
code, kmemleak also reported that log recovery will leak the table
used to hash buffer cancellations if the recovery fails. Fix this
problem by creating alloc/free helpers that initialize and free the
hashtable contents correctly.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The LARP patchset added an awkward coupling point between libxfs and
what would be libxlog, if the XFS log were actually its own library.
Move the code that sets up logged xattr updates out of libxfs and into
xfs_xattr.c so that libxfs no longer has to know about xlog_* functions.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The LARP patchset added an awkward coupling point between libxfs and
what would be libxlog, if the XFS log were actually its own library.
Move the code that enables logged xattr updates out of "lib"xlog and into
xfs_xattr.c so that it no longer has to know about xlog_* functions.
While we're at it, give xfs_xattr.c its own header file.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
While we're messing around with how recovery allocates and frees the
buffer cancellation table, convert the allocation to use kmalloc_array
instead of the old kmem_alloc APIs, and make it handle a null return,
even though that's not likely.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move the code that allocates and frees the buffer cancellation tables
used by log recovery into the file that actually uses the tables. This
is a precursor to some cleanups and a memory leak fix.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The recent patch to improve btree cycle checking caused a regression
when I rebased the in-memory btree branch atop the 5.19 for-next branch,
because in-memory short-pointer btrees do not have AG numbers. This
produced the following complaint from kmemleak:
unreferenced object 0xffff88803d47dde8 (size 264):
comm "xfs_io", pid 4889, jiffies 4294906764 (age 24.072s)
hex dump (first 32 bytes):
90 4d 0b 0f 80 88 ff ff 00 a0 bd 05 80 88 ff ff .M..............
e0 44 3a a0 ff ff ff ff 00 df 08 06 80 88 ff ff .D:.............
backtrace:
[<ffffffffa0388059>] xfbtree_dup_cursor+0x49/0xc0 [xfs]
[<ffffffffa029887b>] xfs_btree_dup_cursor+0x3b/0x200 [xfs]
[<ffffffffa029af5d>] __xfs_btree_split+0x6ad/0x820 [xfs]
[<ffffffffa029b130>] xfs_btree_split+0x60/0x110 [xfs]
[<ffffffffa029f6da>] xfs_btree_make_block_unfull+0x19a/0x1f0 [xfs]
[<ffffffffa029fada>] xfs_btree_insrec+0x3aa/0x810 [xfs]
[<ffffffffa029fff3>] xfs_btree_insert+0xb3/0x240 [xfs]
[<ffffffffa02cb729>] xfs_rmap_insert+0x99/0x200 [xfs]
[<ffffffffa02cf142>] xfs_rmap_map_shared+0x192/0x5f0 [xfs]
[<ffffffffa02cf60b>] xfs_rmap_map_raw+0x6b/0x90 [xfs]
[<ffffffffa0384a85>] xrep_rmap_stash+0xd5/0x1d0 [xfs]
[<ffffffffa0384dc0>] xrep_rmap_visit_bmbt+0xa0/0xf0 [xfs]
[<ffffffffa0384fb6>] xrep_rmap_scan_iext+0x56/0xa0 [xfs]
[<ffffffffa03850d8>] xrep_rmap_scan_ifork+0xd8/0x160 [xfs]
[<ffffffffa0385195>] xrep_rmap_scan_inode+0x35/0x80 [xfs]
[<ffffffffa03852ee>] xrep_rmap_find_rmaps+0x10e/0x270 [xfs]
I noticed that xfs_btree_insrec has a bunch of debug code that return
out of the function immediately, without freeing the "new" btree cursor
that can be returned when _make_block_unfull calls xfs_btree_split. Fix
the error return in this function to free the btree cursor.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs/538 on a 1kB block filesystem failed with this assert:
XFS: Assertion failed: cur->bc_btnum != XFS_BTNUM_BMAP || cur->bc_ino.allocated == 0 || xfs_is_shutdown(cur->bc_mp), file: fs/xfs/libxfs/xfs_btree.c, line: 448
The problem was that an allocation failed unexpectedly in
xfs_bmbt_alloc_block() after roughly 150,000 minlen allocation error
injections, resulting in an EFSCORRUPTED error being returned to
xfs_bmapi_write(). The error occurred on extent-to-btree format
conversion allocating the new root block:
RIP: 0010:xfs_bmbt_alloc_block+0x177/0x210
Call Trace:
<TASK>
xfs_btree_new_iroot+0xdf/0x520
xfs_btree_make_block_unfull+0x10d/0x1c0
xfs_btree_insrec+0x364/0x790
xfs_btree_insert+0xaa/0x210
xfs_bmap_add_extent_hole_real+0x1fe/0x9a0
xfs_bmapi_allocate+0x34c/0x420
xfs_bmapi_write+0x53c/0x9c0
xfs_alloc_file_space+0xee/0x320
xfs_file_fallocate+0x36b/0x450
vfs_fallocate+0x148/0x340
__x64_sys_fallocate+0x3c/0x70
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa
Why the allocation failed at this point is unknown, but is likely
that we ran the transaction out of reserved space and filesystem out
of space with bmbt blocks because of all the minlen allocations
being done causing worst case fragmentation of a large allocation.
Regardless of the cause, we've then called xfs_bmapi_finish() which
calls xfs_btree_del_cursor(cur, error) to tear down the cursor.
So we have a failed operation, error != 0, cur->bc_ino.allocated > 0
and the filesystem is still up. The assert fails to take into
account that allocation can fail with an error and the transaction
teardown will shut the filesystem down if necessary. i.e. the
assert needs to check "|| error != 0" as well, because at this point
shutdown is pending because the current transaction is dirty....
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Not fatal, the assert is there to catch developer attention. I'm
seeing this occasionally during recoveryloop testing after a
shutdown, and I don't want this to stop an overnight recoveryloop
run as it is currently doing.
Convert the ASSERT to a XFS_IS_CORRUPT() check so it will dump a
corruption report into the log and cause a test failure that way,
but it won't stop the machine dead.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Commit dc04db2aa7c9 has caused a small aim7 regression, showing a
small increase in CPU usage in __xfs_btree_check_sblock() as a
result of the extra checking.
This is likely due to the endian conversion of the sibling poitners
being unconditional instead of relying on the compiler to endian
convert the NULL pointer at compile time and avoiding the runtime
conversion for this common case.
Rework the checks so that endian conversion of the sibling pointers
is only done if they are not null as the original code did.
.... and these need to be "inline" because the compiler completely
fails to inline them automatically like it should be doing.
$ size fs/xfs/libxfs/xfs_btree.o*
text data bss dec hex filename
51874 240 0 52114 cb92 fs/xfs/libxfs/xfs_btree.o.orig
51562 240 0 51802 ca5a fs/xfs/libxfs/xfs_btree.o.inline
Just when you think the tools have advanced sufficiently we don't
have to care about stuff like this anymore, along comes a reminder
that *our tools still suck*.
Fixes: dc04db2aa7c9 ("xfs: detect self referencing btree sibling pointers")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
While running xfs/297 and generic/642, I noticed a crash in
xfs_attri_item_relog when it tries to copy the attr name to the new
xattri log item. I think what happened here was that we called
->iop_commit on the old attri item (which nulls out the pointers) as
part of a log force at the same time that a chained attr operation was
ongoing. The system was busy enough that at some later point, the defer
ops operation decided it was necessary to relog the attri log item, but
as we've detached the name buffer from the old attri log item, we can't
copy it to the new one, and kaboom.
I think there's a broader refcounting problem with LARP mode -- the
setxattr code can return to userspace before the CIL actually formats
and commits the log item, which results in a UAF bug. Therefore, the
xattr log item needs to be able to retain a reference to the name and
value buffers until the log items have completely cleared the log.
Furthermore, each time we create an intent log item, we allocate new
memory and (re)copy the contents; sharing here would be very useful.
Solve the UAF and the unnecessary memory allocations by having the log
code create a single refcounted buffer to contain the name and value
contents. This buffer can be passed from old to new during a relog
operation, and the logging code can (optionally) attach it to the
xfs_attr_item for reuse when LARP mode is enabled.
This also fixes a problem where the xfs_attri_log_item objects weren't
being freed back to the same cache where they came from.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
V4 superblocks do not contain the log_incompat feature bit, which means
that we cannot protect xattr log items against kernels that are too old
to know how to recover them. Turn off the log items for such
filesystems and adjust the "delayed" name to reflect what it's really
controlling.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Everywhere else in XFS, structures that capture the state of an ongoing
deferred work item all have names that end with "_intent". The new
extended attribute deferred work items are not named as such, so fix it
to follow the naming convention used elsewhere.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The state variable is now a local variable pointing to a heap
allocation, so we don't need to zero-initialize it, nor do we need the
conditional to decide if we should free it.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Initialize and destroy the xattr log item caches in the same places that
we do all the other log item caches.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Nobody uses this field, so get rid of it and the unused flag definition.
Rearrange the structure layout to reduce its size from 104 to 96 bytes.
This gets us from 39 to 42 objects per page.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Create a separate slab cache for struct xfs_attr_item objects, since we
can pack the (104-byte) intent items more tightly than we can with the
general slab cache objects. On x86, this means 39 intents per memory
page instead of 32.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The flags that are stored in the extended attr intent log item really
should have a separate namespace from the rest of the XFS_ATTR_* flags.
Give them one to make it a little more obvious that they're intent item
flags.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The calling conventions of this function are a mess -- callers /can/
provide a pointer to a pointer to a state structure, but it's not
required, and as evidenced by the last two patches, the callers that do
weren't be careful enough about how to deal with an existing da state.
Push the allocation and freeing responsibilty to the callers, which
means that callers from the xattr node state machine steps now have the
visibility to allocate or free the da state structure as they please.
As a bonus, the node remove/add paths for larp-mode replaces can reset
the da state structure instead of freeing and immediately reallocating
it.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Make sure we screen the "attr flags" field of recovered xattr intent log
items to reject flag bits that we don't know about. This is really the
attr *filter* field from xfs_da_args, so rename the field and create
a mask to make checking for invalid bits easier.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
If a setxattr operation finds an xattr structure in leaf format, adding
the attr can fail due to lack of space and hence requires an upgrade to
node format. After this happens, we'll roll the transaction and
re-enter the state machine, at which time we need to perform a second
lookup of the attribute name to find its new location. This lookup
attaches a new da state structure to the xfs_attr_item but doesn't free
the old one (from the leaf lookup) and leaks it. Fix that.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
kmemleak reported that we lost an xfs_da_state while removing xattrs in
generic/020:
unreferenced object 0xffff88801c0e4b40 (size 480):
comm "attr", pid 30515, jiffies 4294931061 (age 5.960s)
hex dump (first 32 bytes):
78 bc 65 07 00 c9 ff ff 00 30 60 1c 80 88 ff ff x.e......0`.....
02 00 00 00 00 00 00 00 80 18 83 4e 80 88 ff ff ...........N....
backtrace:
[<ffffffffa023ef4a>] xfs_da_state_alloc+0x1a/0x30 [xfs]
[<ffffffffa021b6f3>] xfs_attr_node_hasname+0x23/0x90 [xfs]
[<ffffffffa021c6f1>] xfs_attr_set_iter+0x441/0xa30 [xfs]
[<ffffffffa02b5104>] xfs_xattri_finish_update+0x44/0x80 [xfs]
[<ffffffffa02b515e>] xfs_attr_finish_item+0x1e/0x40 [xfs]
[<ffffffffa0244744>] xfs_defer_finish_noroll+0x184/0x740 [xfs]
[<ffffffffa02a6473>] __xfs_trans_commit+0x153/0x3e0 [xfs]
[<ffffffffa021d149>] xfs_attr_set+0x469/0x7e0 [xfs]
[<ffffffffa02a78d9>] xfs_xattr_set+0x89/0xd0 [xfs]
[<ffffffff812e6512>] __vfs_removexattr+0x52/0x70
[<ffffffff812e6a08>] __vfs_removexattr_locked+0xb8/0x150
[<ffffffff812e6af6>] vfs_removexattr+0x56/0x100
[<ffffffff812e6bf8>] removexattr+0x58/0x90
[<ffffffff812e6cce>] path_removexattr+0x9e/0xc0
[<ffffffff812e6d44>] __x64_sys_lremovexattr+0x14/0x20
[<ffffffff81786b35>] do_syscall_64+0x35/0x80
I think this is a consequence of xfs_attr_node_removename_setup
attaching a new da(btree) state to xfs_attr_item and never freeing it.
I /think/ it's the case that the remove paths could detach the da state
earlier in the remove state machine since nothing else accesses the
state. However, let's future-proof the new xattr code by adding a
catch-all when we free the xfs_attr_item to make sure we never leak the
da state.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs_repair flags these as a corruption error, so the verifier should
catch software bugs that result in empty leaf blocks being written
to disk, too.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We can't use the same algorithm for replacing an existing attribute
when logging attributes. The existing algorithm is essentially:
1. create new attr w/ INCOMPLETE
2. atomically flip INCOMPLETE flags between old + new attribute
3. remove old attr which is marked w/ INCOMPLETE
This algorithm guarantees that we see either the old or new
attribute, and if we fail after the atomic flag flip, we don't have
to recover the removal of the old attr because we never see
INCOMPLETE attributes in lookups.
For logged attributes, however, this does not work. The logged
attribute intents do not track the work that has been done as the
transaction rolls, and hence the only recovery mechanism we have is
"run the replace operation from scratch".
This is further exacerbated by the attempt to avoid needing the
INCOMPLETE flag to create an atomic swap. This means we can create
a second active attribute of the same name before we remove the
original. If we fail at any point after the create but before the
removal has completed, we end up with duplicate attributes in
the attr btree and recovery only tries to replace one of them.
There are several other failure modes where we can leave partially
allocated remote attributes that expose stale data, partially free
remote attributes that enable UAF based stale data exposure, etc.
TO fix this, we need a different algorithm for replace operations
when LARP is enabled. Luckily, it's not that complex if we take the
right first step. That is, the first thing we log is the attri
intent with the new name/value pair and mark the old attr as
INCOMPLETE in the same transaction.
From there, we then remove the old attr and keep relogging the
new name/value in the intent, such that we always know that we have
to create the new attr in recovery. Once the old attr is removed,
we then run a normal ATTR_CREATE operation relogging the intent as
we go. If the new attr is local, then it gets created in a single
atomic transaction that also logs the final intent done. If the new
attr is remote, the we set INCOMPLETE on the new attr while we
allocate and set the remote value, and then we clear the INCOMPLETE
flag at in the last transaction taht logs the final intent done.
If we fail at any point in this algorithm, log recovery will always
see the same state on disk: the new name/value in the intent, and
either an INCOMPLETE attr or no attr in the attr btree. If we find
an INCOMPLETE attr, we run the full replace starting with removing
the INCOMPLETE attr. If we don't find it, then we simply create the
new attr.
Notably, recovery of a failed create that has an INCOMPLETE flag set
is now the same - we start with the lookup of the INCOMPLETE attr,
and if that exists then we do the full replace recovery process,
otherwise we just create the new attr.
Hence changing the way we do the replace operation when LARP is
enabled allows us to use the same log recovery algorithm for both
the ATTR_CREATE and ATTR_REPLACE operations. This is also the same
algorithm we use for runtime ATTR_REPLACE operations (except for the
step setting up the initial conditions).
The result is that:
- ATTR_CREATE uses the same algorithm regardless of whether LARP is
enabled or not
- ATTR_REPLACE with larp=0 is identical to the old algorithm
- ATTR_REPLACE with larp=1 runs an unmodified attr removal algorithm
from the larp=0 code and then runs the unmodified ATTR_CREATE
code.
- log recovery when larp=1 runs the same ATTR_REPLACE algorithm as
it uses at runtime.
Because the state machine is now quite clean, changing the algorithm
is really just a case of changing the initial state and how the
states link together for the ATTR_REPLACE case. Hence it's not a
huge amount of code for what is a fairly substantial rework
of the attr logging and recovery algorithm....
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We currently store the high level attr operation in
args->attr_flags. This field contains what the VFS is telling us to
do, but don't necessarily match what we are doing in the low level
modification state machine. e.g. XATTR_REPLACE implies both
XFS_DA_OP_ADDNAME and XFS_DA_OP_RENAME because it is doing both a
remove and adding a new attr.
However, deep in the individual state machine operations, we check
errors against this high level VFS op flags, not the low level
XFS_DA_OP flags. Indeed, we don't even have a low level flag for
a REMOVE operation, so the only way we know we are doing a remove
is the complete absence of XATTR_REPLACE, XATTR_CREATE,
XFS_DA_OP_ADDNAME and XFS_DA_OP_RENAME. And because there are other
flags in these fields, this is a pain to check if we need to.
As the XFS_DA_OP flags are only needed once the deferred operations
are set up, set these flags appropriately when we set the initial
operation state. We also introduce a XFS_DA_OP_REMOVE flag to make
it easy to know that we are doing a remove operation.
With these, we can remove the use of XATTR_REPLACE and XATTR_CREATE
in low level lookup operations, and manipulate the low level flags
according to the low level context that is operating. e.g. log
recovery does not have a VFS xattr operation state to copy into
args->attr_flags, and the low level state machine ops we do for
recovery do not match the high level VFS operations that were in
progress when the system failed...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
xfs_attri_remove_iter is not used anymore, so remove it and all the
infrastructure it uses and is needed to drive it. THe
xfs_attr_refillstate() function now throws an unused warning, so
isolate the xfs_attr_fillstate()/xfs_attr_refillstate() code pair
with an #if 0 and a comment explaining why we want to keep this code
and restore the optimisation it provides in the near future.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Now that xfs_attri_set_iter() has initial states for removing
attributes, switch the pure attribute removal code over to using it.
This requires attrs being removed to always be marked as INCOMPLETE
before we start the removal due to the fact we look up the attr to
remove again in xfs_attr_node_remove_attr().
Note: this drops the fillstate/refillstate optimisations from
the remove path that avoid having to look up the path again after
setting the incomplete flag and removing remote attrs. Restoring
that optimisation to this path is future Dave's problem.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We need to merge the add and remove code paths to enable safe
recovery of replace operations. Hoist the initial remove states from
xfs_attr_remove_iter into xfs_attr_set_iter. We will make use of
them in the next patches.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Now that the full xfs_attr_set_iter() state machine always
terminates with either the state being XFS_DAS_DONE on success or
an error on failure, we can get rid of the need for it to return
-EAGAIN whenever it needs to roll the transaction before running
the next state.
That is, we don't need to spray -EAGAIN return states everywhere,
the caller just check the state machine state for completion to
determine what action should be taken next. This greatly simplifies
the code within the state machine implementation as it now only has
to handle 0 for success or -errno for error and it doesn't need to
tell the caller to retry.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Clean up the final leaf/node states in xfs_attr_set_iter() to
further simplify the high level state machine and to set the
completion state correctly. As we are adding a separate state
for node format removal, we need to ensure that node formats
are collapsed back to shortform or empty correctly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We may not have a remote value for the old xattr we have to remove,
so skip over the remote value removal states and go straight to
the xattr name removal in the leaf/node block.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We can skip the REPLACE state when LARP is enabled, but that means
the XFS_DAS_FLIP_LFLAG state is now poorly named - it indicates
something that has been done rather than what the state is going to
do. Rename it to "REMOVE_OLD" to indicate that we are now going to
perform removal of the old attr.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
When we set a new xattr, we have three exit paths:
1. nothing else to do
2. allocate and set the remote xattr value
3. perform the rest of a replace operation
Currently we push both 2 and 3 into the same state, regardless of
whether we just set a remote attribute or not. Once we've set the
remote xattr, we have two exit states:
1. nothing else to do
2. perform the rest of a replace operation
Hence we can split the remote xattr allocation and setting into
their own states and factor it out of xfs_attr_set_iter() to further
clean up the state machine and the implementation of the state
machine.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The operations performed from XFS_DAS_FOUND_LBLK through to
XFS_DAS_RM_LBLK are now identical to XFS_DAS_FOUND_NBLK through to
XFS_DAS_RM_NBLK. We can collapse these down into a single set of
code.
To do this, define the states that leaf and node run through as
separate sets of sequential states. Then as we move to the next
state, we can use increments rather than specific state assignments
to move through the states. This means the state progression is set
by the initial state that enters the series and we don't need to
duplicate the code anymore.
At the exit point of the series we need to select the correct leaf
or node state, but that can also be done by state increment rather
than assignment.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We re-enter the XFS_DAS_FOUND_LBLK state when we have to allocate
multiple extents for a remote xattr. We currently have a flag
called XFS_DAC_LEAF_ADDNAME_INIT to avoid running the remote attr
hole finding code more than once.
However, for the node format tree, we have a separate state for this
so we never reenter the state machine at XFS_DAS_FOUND_NBLK and so
it does not need a special flag to skip over the remote attr hold
finding code.
Convert the leaf block code to use the same state machine as the
node blocks and kill the XFS_DAC_LEAF_ADDNAME_INIT flag.
This further points out that this "ALLOC" state is only traversed
if we have remote xattrs or we are doing a rename operation. Rename
both the leaf and node alloc states to _ALLOC_RMT to indicate they
are iterating to do allocation of remote xattr blocks.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We current use XFS_DAS_UNINIT for several steps in the attr_set
state machine. We use it for setting shortform xattrs, converting
from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
these things are essentially known before we start the state machine
iterating, so we really should separate them out:
XFS_DAS_SF_ADD:
- tries to do a shortform add
- on success -> done
- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
- on error, dies.
XFS_DAS_LEAF_ADD:
- tries to do leaf add
- on success:
- inline attr -> done
- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
- on error, dies
XFS_DAS_NODE_ADD:
- tries to do node add
- on success:
- inline attr -> done
- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
- on error, dies
This makes it easier to understand how the state machine starts
up and sets us up on the path to further state machine
simplifications.
This also converts the DAS state tracepoints to use strings rather
than numbers, as converting between enums and numbers requires
manual counting rather than just reading the name.
This also introduces a XFS_DAS_DONE state so that we can trace
successful operation completions easily.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Warning counts are not used anywhere in the kernel. In addition, there
are no use cases, test coverage, or documentation for this functionality.
Remove the 'warnings' field from struct xfs_dquot_res and any other
related code.
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Logged attribute intents only have set and remove types - there is
no separate intent type for a replace operation. We should have a
separate type for a replace operation, as it needs to perform
operations that neither SET or REMOVE can perform.
Add this type to the intent items and rearrange the deferred
operation setup to reflect the different operations we are
performing.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We currently set it and hold it when converting from short to leaf
form, then release it only to immediately look it back up again
to do the leaf insert.
Do a bit of refactoring to xfs_attr_leaf_try_add() to avoid this
messy handling of the newly allocated leaf buffer.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
generic/642 triggered a reproducable assert failure in
xlog_cil_commit() that resulted from a xfs_attr_set() committing
an empty but dirty transaction. When the CIL is empty and this
occurs, xlog_cil_commit() tries a background push and this triggers
a "pushing an empty CIL" assert.
XFS: Assertion failed: !list_empty(&cil->xc_cil), file: fs/xfs/xfs_log_cil.c, line: 1274
Call Trace:
<TASK>
xlog_cil_commit+0xa5a/0xad0
__xfs_trans_commit+0xb8/0x330
xfs_trans_commit+0x10/0x20
xfs_attr_set+0x3e2/0x4c0
xfs_xattr_set+0x8d/0xe0
__vfs_setxattr+0x6b/0x90
__vfs_setxattr_noperm+0x76/0x220
__vfs_setxattr_locked+0xdf/0x100
vfs_setxattr+0x94/0x170
setxattr+0x110/0x200
path_setxattr+0xbf/0xe0
__x64_sys_setxattr+0x2b/0x30
do_syscall_64+0x35/0x80
The problem is related to the breakdown of attribute addition in
xfs_attr_set_iter() and how it is called from deferred operations.
When we have a pure leaf xattr insert, we add the xattr to the leaf
and set the next state to XFS_DAS_FOUND_LBLK and return -EAGAIN.
This requeues the xattr defered work, rolls the transaction and
runs xfs_attr_set_iter() again. This then checks the xattr for
being remote (it's not) and whether a replace op is being done (this
is a create op) and if neither are true it returns without having
done anything.
xfs_xattri_finish_update() then unconditionally sets the transaction
dirty, and the deferops finishes and returns to __xfs_trans_commit()
which sees the transaction dirty and tries to commit it by calling
xlog_cil_commit(). The transaction is empty, and then the assert
fires if this happens when the CIL is empty.
This patch addresses the structure of xfs_attr_set_iter() that
requires re-entry on leaf add even when nothing will be done. This
gets rid of the trailing empty transaction and so doesn't trigger
the XFS_TRANS_DIRTY assignment in xfs_xattri_finish_update()
incorrectly. Addressing that is for a different patch.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Add an error tag on xfs_attr3_leaf_to_node to test log attribute
recovery and replay.
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Add an error tag on xfs_da3_split to test log attribute recovery
and replay.
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Quick helper function to collapse duplicate code to initialize
transactions for attributes
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
