[PATCH 5.15 v4 0/7] xfs stable patches for 5.15.y

[PATCH 5.15 v4 0/7] xfs stable patches for 5.15.y

[Leah Rumancik]

Hi Greg and Sasha,

This is the 5.15.y series corresponding to the 5.10.y set that Amir
recently sent out [1]. These patches have been tested on both 5.10.y
and 5.15.y with no regressions found. This series has been ACK'ed by
the XFS developers for 5.15.y and are ready for 5.15 stable.

Best,
Leah

Changes from [v3]:
- Post to stable

Changes from [v2]:
- Drop SGID fix [2]
- Added Acks from Darrick for remaining patches

Changes from [v1]:
- Increased testing
- Reduced patch set to overlap with 5.10 patches


[v1]: https://lore.kernel.org/linux-xfs/20220603184701.3117780-1-leah.rumancik@gmail.com/
[v2]: https://lore.kernel.org/linux-xfs/20220616182749.1200971-1-leah.rumancik@gmail.com/
[v3]: https://lore.kernel.org/linux-xfs/20220623203641.1710377-1-leah.rumancik@gmail.com/

[1] https://lore.kernel.org/linux-xfs/20220627065140.2798412-1-amir73il@gmail.com/
[2] https://lore.kernel.org/linux-xfs/20220617100641.1653164-12-amir73il@gmail.com/


Brian Foster (1):
  xfs: punch out data fork delalloc blocks on COW writeback failure

Darrick J. Wong (3):
  xfs: remove all COW fork extents when remounting readonly
  xfs: prevent UAF in xfs_log_item_in_current_chkpt
  xfs: only bother with sync_filesystem during readonly remount

Dave Chinner (1):
  xfs: check sb_meta_uuid for dabuf buffer recovery

Rustam Kovhaev (1):
  xfs: use kmem_cache_free() for kmem_cache objects

Yang Xu (1):
  xfs: Fix the free logic of state in xfs_attr_node_hasname

 fs/xfs/libxfs/xfs_attr.c      | 17 +++++++----------
 fs/xfs/xfs_aops.c             | 15 ++++++++++++---
 fs/xfs/xfs_buf_item_recover.c |  2 +-
 fs/xfs/xfs_extfree_item.c     |  6 +++---
 fs/xfs/xfs_log_cil.c          |  6 +++---
 fs/xfs/xfs_super.c            | 21 ++++++++++++++++-----
 6 files changed, 42 insertions(+), 25 deletions(-)

-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 1/7] xfs: use kmem_cache_free() for kmem_cache objects

[Leah Rumancik]

From: Rustam Kovhaev <rkovhaev@gmail.com>

[ Upstream commit c30a0cbd07ecc0eec7b3cd568f7b1c7bb7913f93 ]

For kmalloc() allocations SLOB prepends the blocks with a 4-byte header,
and it puts the size of the allocated blocks in that header.
Blocks allocated with kmem_cache_alloc() allocations do not have that
header.

SLOB explodes when you allocate memory with kmem_cache_alloc() and then
try to free it with kfree() instead of kmem_cache_free().
SLOB will assume that there is a header when there is none, read some
garbage to size variable and corrupt the adjacent objects, which
eventually leads to hang or panic.

Let's make XFS work with SLOB by using proper free function.

Fixes: 9749fee83f38 ("xfs: enable the xfs_defer mechanism to process extents to free")
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_extfree_item.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index 3f8a0713573a..a4b8caa2c601 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -482,7 +482,7 @@ xfs_extent_free_finish_item(
 			free->xefi_startblock,
 			free->xefi_blockcount,
 			&free->xefi_oinfo, free->xefi_skip_discard);
-	kmem_free(free);
+	kmem_cache_free(xfs_bmap_free_item_zone, free);
 	return error;
 }
 
@@ -502,7 +502,7 @@ xfs_extent_free_cancel_item(
 	struct xfs_extent_free_item	*free;
 
 	free = container_of(item, struct xfs_extent_free_item, xefi_list);
-	kmem_free(free);
+	kmem_cache_free(xfs_bmap_free_item_zone, free);
 }
 
 const struct xfs_defer_op_type xfs_extent_free_defer_type = {
@@ -564,7 +564,7 @@ xfs_agfl_free_finish_item(
 	extp->ext_len = free->xefi_blockcount;
 	efdp->efd_next_extent++;
 
-	kmem_free(free);
+	kmem_cache_free(xfs_bmap_free_item_zone, free);
 	return error;
 }
 
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 2/7] xfs: punch out data fork delalloc blocks on COW writeback failure

[Leah Rumancik]

From: Brian Foster <bfoster@redhat.com>

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for
COW fork blocks to overlap non-shared data fork blocks (due to
cowextsz hint prealloc), however, and writeback unconditionally maps
to the COW fork whenever blocks exist at the corresponding offset of
the page undergoing writeback. This means it's quite possible for a
COW fork extent to overlap delalloc data fork blocks, writeback to
convert and map to the COW fork blocks, writeback to fail, and
finally for ioend completion to cancel the COW fork blocks and leave
stale data fork delalloc blocks around in the inode. The blocks are
effectively stale because writeback failure also discards dirty page
state.

If this occurs, it is likely to trigger assert failures, free space
accounting corruption and failures in unrelated file operations. For
example, a subsequent reflink attempt of the affected file to a new
target file will trip over the stale delalloc in the source file and
fail. Several of these issues are occasionally reproduced by
generic/648, but are reproducible on demand with the right sequence
of operations and timely I/O error injection.

To fix this problem, update the ioend failure path to also punch out
underlying data fork delalloc blocks on I/O error. This is analogous
to the writeback submission failure path in xfs_discard_page() where
we might fail to map data fork delalloc blocks and consistent with
the successful COW writeback completion path, which is responsible
for unmapping from the data fork and remapping in COW fork blocks.

Fixes: 787eb485509f ("xfs: fix and streamline error handling in xfs_end_io")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_aops.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 34fc6148032a..c8c15c3c3147 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -82,6 +82,7 @@ xfs_end_ioend(
 	struct iomap_ioend	*ioend)
 {
 	struct xfs_inode	*ip = XFS_I(ioend->io_inode);
+	struct xfs_mount	*mp = ip->i_mount;
 	xfs_off_t		offset = ioend->io_offset;
 	size_t			size = ioend->io_size;
 	unsigned int		nofs_flag;
@@ -97,18 +98,26 @@ xfs_end_ioend(
 	/*
 	 * Just clean up the in-memory structures if the fs has been shut down.
 	 */
-	if (xfs_is_shutdown(ip->i_mount)) {
+	if (xfs_is_shutdown(mp)) {
 		error = -EIO;
 		goto done;
 	}
 
 	/*
-	 * Clean up any COW blocks on an I/O error.
+	 * Clean up all COW blocks and underlying data fork delalloc blocks on
+	 * I/O error. The delalloc punch is required because this ioend was
+	 * mapped to blocks in the COW fork and the associated pages are no
+	 * longer dirty. If we don't remove delalloc blocks here, they become
+	 * stale and can corrupt free space accounting on unmount.
 	 */
 	error = blk_status_to_errno(ioend->io_bio->bi_status);
 	if (unlikely(error)) {
-		if (ioend->io_flags & IOMAP_F_SHARED)
+		if (ioend->io_flags & IOMAP_F_SHARED) {
 			xfs_reflink_cancel_cow_range(ip, offset, size, true);
+			xfs_bmap_punch_delalloc_range(ip,
+						      XFS_B_TO_FSBT(mp, offset),
+						      XFS_B_TO_FSB(mp, size));
+		}
 		goto done;
 	}
 
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 3/7] xfs: Fix the free logic of state in xfs_attr_node_hasname

[Leah Rumancik]

From: Yang Xu <xuyang2018.jy@fujitsu.com>

[ Upstream commit a1de97fe296c52eafc6590a3506f4bbd44ecb19a ]

When testing xfstests xfs/126 on lastest upstream kernel, it will hang on some machine.
Adding a getxattr operation after xattr corrupted, I can reproduce it 100%.

The deadlock as below:
[983.923403] task:setfattr        state:D stack:    0 pid:17639 ppid: 14687 flags:0x00000080
[  983.923405] Call Trace:
[  983.923410]  __schedule+0x2c4/0x700
[  983.923412]  schedule+0x37/0xa0
[  983.923414]  schedule_timeout+0x274/0x300
[  983.923416]  __down+0x9b/0xf0
[  983.923451]  ? xfs_buf_find.isra.29+0x3c8/0x5f0 [xfs]
[  983.923453]  down+0x3b/0x50
[  983.923471]  xfs_buf_lock+0x33/0xf0 [xfs]
[  983.923490]  xfs_buf_find.isra.29+0x3c8/0x5f0 [xfs]
[  983.923508]  xfs_buf_get_map+0x4c/0x320 [xfs]
[  983.923525]  xfs_buf_read_map+0x53/0x310 [xfs]
[  983.923541]  ? xfs_da_read_buf+0xcf/0x120 [xfs]
[  983.923560]  xfs_trans_read_buf_map+0x1cf/0x360 [xfs]
[  983.923575]  ? xfs_da_read_buf+0xcf/0x120 [xfs]
[  983.923590]  xfs_da_read_buf+0xcf/0x120 [xfs]
[  983.923606]  xfs_da3_node_read+0x1f/0x40 [xfs]
[  983.923621]  xfs_da3_node_lookup_int+0x69/0x4a0 [xfs]
[  983.923624]  ? kmem_cache_alloc+0x12e/0x270
[  983.923637]  xfs_attr_node_hasname+0x6e/0xa0 [xfs]
[  983.923651]  xfs_has_attr+0x6e/0xd0 [xfs]
[  983.923664]  xfs_attr_set+0x273/0x320 [xfs]
[  983.923683]  xfs_xattr_set+0x87/0xd0 [xfs]
[  983.923686]  __vfs_removexattr+0x4d/0x60
[  983.923688]  __vfs_removexattr_locked+0xac/0x130
[  983.923689]  vfs_removexattr+0x4e/0xf0
[  983.923690]  removexattr+0x4d/0x80
[  983.923693]  ? __check_object_size+0xa8/0x16b
[  983.923695]  ? strncpy_from_user+0x47/0x1a0
[  983.923696]  ? getname_flags+0x6a/0x1e0
[  983.923697]  ? _cond_resched+0x15/0x30
[  983.923699]  ? __sb_start_write+0x1e/0x70
[  983.923700]  ? mnt_want_write+0x28/0x50
[  983.923701]  path_removexattr+0x9b/0xb0
[  983.923702]  __x64_sys_removexattr+0x17/0x20
[  983.923704]  do_syscall_64+0x5b/0x1a0
[  983.923705]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[  983.923707] RIP: 0033:0x7f080f10ee1b

When getxattr calls xfs_attr_node_get function, xfs_da3_node_lookup_int fails with EFSCORRUPTED in
xfs_attr_node_hasname because we have use blocktrash to random it in xfs/126. So it
free state in internal and xfs_attr_node_get doesn't do xfs_buf_trans release job.

Then subsequent removexattr will hang because of it.

This bug was introduced by kernel commit 07120f1abdff ("xfs: Add xfs_has_attr and subroutines").
It adds xfs_attr_node_hasname helper and said caller will be responsible for freeing the state
in this case. But xfs_attr_node_hasname will free state itself instead of caller if
xfs_da3_node_lookup_int fails.

Fix this bug by moving the step of free state into caller.

Also, use "goto error/out" instead of returning error directly in xfs_attr_node_addname_find_attr and
xfs_attr_node_removename_setup function because we should free state ourselves.

Fixes: 07120f1abdff ("xfs: Add xfs_has_attr and subroutines")
Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/libxfs/xfs_attr.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index fbc9d816882c..23523b802539 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -1077,21 +1077,18 @@ xfs_attr_node_hasname(
 
 	state = xfs_da_state_alloc(args);
 	if (statep != NULL)
-		*statep = NULL;
+		*statep = state;
 
 	/*
 	 * Search to see if name exists, and get back a pointer to it.
 	 */
 	error = xfs_da3_node_lookup_int(state, &retval);
-	if (error) {
-		xfs_da_state_free(state);
-		return error;
-	}
+	if (error)
+		retval = error;
 
-	if (statep != NULL)
-		*statep = state;
-	else
+	if (!statep)
 		xfs_da_state_free(state);
+
 	return retval;
 }
 
@@ -1112,7 +1109,7 @@ xfs_attr_node_addname_find_attr(
 	 */
 	retval = xfs_attr_node_hasname(args, &dac->da_state);
 	if (retval != -ENOATTR && retval != -EEXIST)
-		return retval;
+		goto error;
 
 	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
 		goto error;
@@ -1337,7 +1334,7 @@ int xfs_attr_node_removename_setup(
 
 	error = xfs_attr_node_hasname(args, state);
 	if (error != -EEXIST)
-		return error;
+		goto out;
 	error = 0;
 
 	ASSERT((*state)->path.blk[(*state)->path.active - 1].bp != NULL);
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 4/7] xfs: remove all COW fork extents when remounting readonly

[Leah Rumancik]

From: "Darrick J. Wong" <djwong@kernel.org>

[ Upstream commit 089558bc7ba785c03815a49c89e28ad9b8de51f9 ]

As part of multiple customer escalations due to file data corruption
after copy on write operations, I wrote some fstests that use fsstress
to hammer on COW to shake things loose.  Regrettably, I caught some
filesystem shutdowns due to incorrect rmap operations with the following
loop:

mount <filesystem>				# (0)
fsstress <run only readonly ops> &		# (1)
while true; do
	fsstress <run all ops>
	mount -o remount,ro			# (2)
	fsstress <run only readonly ops>
	mount -o remount,rw			# (3)
done

When (2) happens, notice that (1) is still running.  xfs_remount_ro will
call xfs_blockgc_stop to walk the inode cache to free all the COW
extents, but the blockgc mechanism races with (1)'s reader threads to
take IOLOCKs and loses, which means that it doesn't clean them all out.
Call such a file (A).

When (3) happens, xfs_remount_rw calls xfs_reflink_recover_cow, which
walks the ondisk refcount btree and frees any COW extent that it finds.
This function does not check the inode cache, which means that incore
COW forks of inode (A) is now inconsistent with the ondisk metadata.  If
one of those former COW extents are allocated and mapped into another
file (B) and someone triggers a COW to the stale reservation in (A), A's
dirty data will be written into (B) and once that's done, those blocks
will be transferred to (A)'s data fork without bumping the refcount.

The results are catastrophic -- file (B) and the refcount btree are now
corrupt.  Solve this race by forcing the xfs_blockgc_free_space to run
synchronously, which causes xfs_icwalk to return to inodes that were
skipped because the blockgc code couldn't take the IOLOCK.  This is safe
to do here because the VFS has already prohibited new writer threads.

Fixes: 10ddf64e420f ("xfs: remove leftover CoW reservations when remounting ro")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_super.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 170fee98c45c..23673703618a 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1768,7 +1768,10 @@ static int
 xfs_remount_ro(
 	struct xfs_mount	*mp)
 {
-	int error;
+	struct xfs_icwalk	icw = {
+		.icw_flags	= XFS_ICWALK_FLAG_SYNC,
+	};
+	int			error;
 
 	/*
 	 * Cancel background eofb scanning so it cannot race with the final
@@ -1776,8 +1779,13 @@ xfs_remount_ro(
 	 */
 	xfs_blockgc_stop(mp);
 
-	/* Get rid of any leftover CoW reservations... */
-	error = xfs_blockgc_free_space(mp, NULL);
+	/*
+	 * Clear out all remaining COW staging extents and speculative post-EOF
+	 * preallocations so that we don't leave inodes requiring inactivation
+	 * cleanups during reclaim on a read-only mount.  We must process every
+	 * cached inode, so this requires a synchronous cache scan.
+	 */
+	error = xfs_blockgc_free_space(mp, &icw);
 	if (error) {
 		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
 		return error;
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 5/7] xfs: check sb_meta_uuid for dabuf buffer recovery

[Leah Rumancik]

From: Dave Chinner <dchinner@redhat.com>

[ Upstream commit 09654ed8a18cfd45027a67d6cbca45c9ea54feab ]

Got a report that a repeated crash test of a container host would
eventually fail with a log recovery error preventing the system from
mounting the root filesystem. It manifested as a directory leaf node
corruption on writeback like so:

 XFS (loop0): Mounting V5 Filesystem
 XFS (loop0): Starting recovery (logdev: internal)
 XFS (loop0): Metadata corruption detected at xfs_dir3_leaf_check_int+0x99/0xf0, xfs_dir3_leaf1 block 0x12faa158
 XFS (loop0): Unmount and run xfs_repair
 XFS (loop0): First 128 bytes of corrupted metadata buffer:
 00000000: 00 00 00 00 00 00 00 00 3d f1 00 00 e1 9e d5 8b  ........=.......
 00000010: 00 00 00 00 12 fa a1 58 00 00 00 29 00 00 1b cc  .......X...)....
 00000020: 91 06 78 ff f7 7e 4a 7d 8d 53 86 f2 ac 47 a8 23  ..x..~J}.S...G.#
 00000030: 00 00 00 00 17 e0 00 80 00 43 00 00 00 00 00 00  .........C......
 00000040: 00 00 00 2e 00 00 00 08 00 00 17 2e 00 00 00 0a  ................
 00000050: 02 35 79 83 00 00 00 30 04 d3 b4 80 00 00 01 50  .5y....0.......P
 00000060: 08 40 95 7f 00 00 02 98 08 41 fe b7 00 00 02 d4  .@.......A......
 00000070: 0d 62 ef a7 00 00 01 f2 14 50 21 41 00 00 00 0c  .b.......P!A....
 XFS (loop0): Corruption of in-memory data (0x8) detected at xfs_do_force_shutdown+0x1a/0x20 (fs/xfs/xfs_buf.c:1514).  Shutting down.
 XFS (loop0): Please unmount the filesystem and rectify the problem(s)
 XFS (loop0): log mount/recovery failed: error -117
 XFS (loop0): log mount failed

Tracing indicated that we were recovering changes from a transaction
at LSN 0x29/0x1c16 into a buffer that had an LSN of 0x29/0x1d57.
That is, log recovery was overwriting a buffer with newer changes on
disk than was in the transaction. Tracing indicated that we were
hitting the "recovery immediately" case in
xfs_buf_log_recovery_lsn(), and hence it was ignoring the LSN in the
buffer.

The code was extracting the LSN correctly, then ignoring it because
the UUID in the buffer did not match the superblock UUID. The
problem arises because the UUID check uses the wrong UUID - it
should be checking the sb_meta_uuid, not sb_uuid. This filesystem
has sb_uuid != sb_meta_uuid (which is fine), and the buffer has the
correct matching sb_meta_uuid in it, it's just the code checked it
against the wrong superblock uuid.

The is no corruption in the filesystem, and failing to recover the
buffer due to a write verifier failure means the recovery bug did
not propagate the corruption to disk. Hence there is no corruption
before or after this bug has manifested, the impact is limited
simply to an unmountable filesystem....

This was missed back in 2015 during an audit of incorrect sb_uuid
usage that resulted in commit fcfbe2c4ef42 ("xfs: log recovery needs
to validate against sb_meta_uuid") that fixed the magic32 buffers to
validate against sb_meta_uuid instead of sb_uuid. It missed the
magicda buffers....

Fixes: ce748eaa65f2 ("xfs: create new metadata UUID field and incompat flag")
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>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_buf_item_recover.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c
index a476c7ef5d53..991fbf1eb564 100644
--- a/fs/xfs/xfs_buf_item_recover.c
+++ b/fs/xfs/xfs_buf_item_recover.c
@@ -816,7 +816,7 @@ xlog_recover_get_buf_lsn(
 	}
 
 	if (lsn != (xfs_lsn_t)-1) {
-		if (!uuid_equal(&mp->m_sb.sb_uuid, uuid))
+		if (!uuid_equal(&mp->m_sb.sb_meta_uuid, uuid))
 			goto recover_immediately;
 		return lsn;
 	}
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 6/7] xfs: prevent UAF in xfs_log_item_in_current_chkpt

[Leah Rumancik]

From: "Darrick J. Wong" <djwong@kernel.org>

[ Upstream commit f8d92a66e810acbef6ddbc0bd0cbd9b117ce8acd ]

While I was running with KASAN and lockdep enabled, I stumbled upon an
KASAN report about a UAF to a freed CIL checkpoint.  Looking at the
comment for xfs_log_item_in_current_chkpt, it seems pretty obvious to me
that the original patch to xfs_defer_finish_noroll should have done
something to lock the CIL to prevent it from switching the CIL contexts
while the predicate runs.

For upper level code that needs to know if a given log item is new
enough not to need relogging, add a new wrapper that takes the CIL
context lock long enough to sample the current CIL context.  This is
kind of racy in that the CIL can switch the contexts immediately after
sampling, but that's ok because the consequence is that the defer ops
code is a little slow to relog items.

 ==================================================================
 BUG: KASAN: use-after-free in xfs_log_item_in_current_chkpt+0x139/0x160 [xfs]
 Read of size 8 at addr ffff88804ea5f608 by task fsstress/527999

 CPU: 1 PID: 527999 Comm: fsstress Tainted: G      D      5.16.0-rc4-xfsx #rc4
 Call Trace:
  <TASK>
  dump_stack_lvl+0x45/0x59
  print_address_description.constprop.0+0x1f/0x140
  kasan_report.cold+0x83/0xdf
  xfs_log_item_in_current_chkpt+0x139/0x160
  xfs_defer_finish_noroll+0x3bb/0x1e30
  __xfs_trans_commit+0x6c8/0xcf0
  xfs_reflink_remap_extent+0x66f/0x10e0
  xfs_reflink_remap_blocks+0x2dd/0xa90
  xfs_file_remap_range+0x27b/0xc30
  vfs_dedupe_file_range_one+0x368/0x420
  vfs_dedupe_file_range+0x37c/0x5d0
  do_vfs_ioctl+0x308/0x1260
  __x64_sys_ioctl+0xa1/0x170
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f2c71a2950b
 Code: 0f 1e fa 48 8b 05 85 39 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff
ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 8b 0d 55 39 0d 00 f7 d8 64 89 01 48
 RSP: 002b:00007ffe8c0e03c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 00005600862a8740 RCX: 00007f2c71a2950b
 RDX: 00005600862a7be0 RSI: 00000000c0189436 RDI: 0000000000000004
 RBP: 000000000000000b R08: 0000000000000027 R09: 0000000000000003
 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000005a
 R13: 00005600862804a8 R14: 0000000000016000 R15: 00005600862a8a20
  </TASK>

 Allocated by task 464064:
  kasan_save_stack+0x1e/0x50
  __kasan_kmalloc+0x81/0xa0
  kmem_alloc+0xcd/0x2c0 [xfs]
  xlog_cil_ctx_alloc+0x17/0x1e0 [xfs]
  xlog_cil_push_work+0x141/0x13d0 [xfs]
  process_one_work+0x7f6/0x1380
  worker_thread+0x59d/0x1040
  kthread+0x3b0/0x490
  ret_from_fork+0x1f/0x30

 Freed by task 51:
  kasan_save_stack+0x1e/0x50
  kasan_set_track+0x21/0x30
  kasan_set_free_info+0x20/0x30
  __kasan_slab_free+0xed/0x130
  slab_free_freelist_hook+0x7f/0x160
  kfree+0xde/0x340
  xlog_cil_committed+0xbfd/0xfe0 [xfs]
  xlog_cil_process_committed+0x103/0x1c0 [xfs]
  xlog_state_do_callback+0x45d/0xbd0 [xfs]
  xlog_ioend_work+0x116/0x1c0 [xfs]
  process_one_work+0x7f6/0x1380
  worker_thread+0x59d/0x1040
  kthread+0x3b0/0x490
  ret_from_fork+0x1f/0x30

 Last potentially related work creation:
  kasan_save_stack+0x1e/0x50
  __kasan_record_aux_stack+0xb7/0xc0
  insert_work+0x48/0x2e0
  __queue_work+0x4e7/0xda0
  queue_work_on+0x69/0x80
  xlog_cil_push_now.isra.0+0x16b/0x210 [xfs]
  xlog_cil_force_seq+0x1b7/0x850 [xfs]
  xfs_log_force_seq+0x1c7/0x670 [xfs]
  xfs_file_fsync+0x7c1/0xa60 [xfs]
  __x64_sys_fsync+0x52/0x80
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

 The buggy address belongs to the object at ffff88804ea5f600
  which belongs to the cache kmalloc-256 of size 256
 The buggy address is located 8 bytes inside of
  256-byte region [ffff88804ea5f600, ffff88804ea5f700)
 The buggy address belongs to the page:
 page:ffffea00013a9780 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88804ea5ea00 pfn:0x4ea5e
 head:ffffea00013a9780 order:1 compound_mapcount:0
 flags: 0x4fff80000010200(slab|head|node=1|zone=1|lastcpupid=0xfff)
 raw: 04fff80000010200 ffffea0001245908 ffffea00011bd388 ffff888004c42b40
 raw: ffff88804ea5ea00 0000000000100009 00000001ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  ffff88804ea5f500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff88804ea5f580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 >ffff88804ea5f600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                       ^
  ffff88804ea5f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff88804ea5f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ==================================================================

Fixes: 4e919af7827a ("xfs: periodically relog deferred intent items")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_log_cil.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 6c93c8ada6f3..b59cc9c0961c 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -1442,9 +1442,9 @@ xlog_cil_force_seq(
  */
 bool
 xfs_log_item_in_current_chkpt(
-	struct xfs_log_item *lip)
+	struct xfs_log_item	*lip)
 {
-	struct xfs_cil_ctx *ctx = lip->li_mountp->m_log->l_cilp->xc_ctx;
+	struct xfs_cil		*cil = lip->li_mountp->m_log->l_cilp;
 
 	if (list_empty(&lip->li_cil))
 		return false;
@@ -1454,7 +1454,7 @@ xfs_log_item_in_current_chkpt(
 	 * first checkpoint it is written to. Hence if it is different to the
 	 * current sequence, we're in a new checkpoint.
 	 */
-	return lip->li_seq == ctx->sequence;
+	return lip->li_seq == READ_ONCE(cil->xc_current_sequence);
 }
 
 /*
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5.15 v4 7/7] xfs: only bother with sync_filesystem during readonly remount

[Leah Rumancik]

From: "Darrick J. Wong" <djwong@kernel.org>

[ Upstream commit b97cca3ba9098522e5a1c3388764ead42640c1a5 ]

In commit 02b9984d6408, we pushed a sync_filesystem() call from the VFS
into xfs_fs_remount.  The only time that we ever need to push dirty file
data or metadata to disk for a remount is if we're remounting the
filesystem read only, so this really could be moved to xfs_remount_ro.

Once we've moved the call site, actually check the return value from
sync_filesystem.

Fixes: 02b9984d6408 ("fs: push sync_filesystem() down to the file system's remount_fs()")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_super.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 23673703618a..e8d19916ba99 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1773,6 +1773,11 @@ xfs_remount_ro(
 	};
 	int			error;
 
+	/* Flush all the dirty data to disk. */
+	error = sync_filesystem(mp->m_super);
+	if (error)
+		return error;
+
 	/*
 	 * Cancel background eofb scanning so it cannot race with the final
 	 * log force+buftarg wait and deadlock the remount.
@@ -1851,8 +1856,6 @@ xfs_fs_reconfigure(
 	if (error)
 		return error;
 
-	sync_filesystem(mp->m_super);
-
 	/* inode32 -> inode64 */
 	if (xfs_has_small_inums(mp) && !xfs_has_small_inums(new_mp)) {
 		mp->m_features &= ~XFS_FEAT_SMALL_INUMS;
-- 
2.37.0.rc0.161.g10f37bed90-goog

Re: [PATCH 5.15 v4 0/7] xfs stable patches for 5.15.y

[Greg KH]

On Tue, Jun 28, 2022 at 11:39:44AM -0700, Leah Rumancik wrote:
> Hi Greg and Sasha,
> 
> This is the 5.15.y series corresponding to the 5.10.y set that Amir
> recently sent out [1]. These patches have been tested on both 5.10.y
> and 5.15.y with no regressions found. This series has been ACK'ed by
> the XFS developers for 5.15.y and are ready for 5.15 stable.

All now queued up, thanks.

greg k-h