Pull xfs fix from Chandan Babu:

 - Validate quota records recovered from the log before writing them to
   the disk.

* tag 'xfs-6.7-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: dquot recovery does not validate the recovered dquot
  xfs: clean up dqblk extraction

Pull vfs fixes from Christian Brauner:

 - Avoid calling back into LSMs from vfs_getattr_nosec() calls.

   IMA used to query inode properties accessing raw inode fields without
   dedicated helpers. That was finally fixed a few releases ago by
   forcing IMA to use vfs_getattr_nosec() helpers.

   The goal of the vfs_getattr_nosec() helper is to query for attributes
   without calling into the LSM layer which would be quite problematic
   because incredibly IMA is called from __fput()...

     __fput()
       -> ima_file_free()

   What it does is to call back into the filesystem to update the file's
   IMA xattr. Querying the inode without using vfs_getattr_nosec() meant
   that IMA didn't handle stacking filesystems such as overlayfs
   correctly. So the switch to vfs_getattr_nosec() is quite correct. But
   the switch to vfs_getattr_nosec() revealed another bug when used on
   stacking filesystems:

     __fput()
       -> ima_file_free()
          -> vfs_getattr_nosec()
             -> i_op->getattr::ovl_getattr()
                -> vfs_getattr()
                   -> i_op->getattr::$WHATEVER_UNDERLYING_FS_getattr()
                      -> security_inode_getattr() # calls back into LSMs

   Now, if that __fput() happens from task_work_run() of an exiting task
   current->fs and various other pointer could already be NULL. So
   anything in the LSM layer relying on that not being NULL would be
   quite surprised.

   Fix that by passing the information that this is a security request
   through to the stacking filesystem by adding a new internal
   ATT_GETATTR_NOSEC flag. Now the callchain becomes:

     __fput()
       -> ima_file_free()
          -> vfs_getattr_nosec()
             -> i_op->getattr::ovl_getattr()
                -> if (AT_GETATTR_NOSEC)
                          vfs_getattr_nosec()
                   else
                          vfs_getattr()
                   -> i_op->getattr::$WHATEVER_UNDERLYING_FS_getattr()

 - Fix a bug introduced with the iov_iter rework from last cycle.

   This broke /proc/kcore by copying too much and without the correct
   offset.

 - Add a missing NULL check when allocating the root inode in
   autofs_fill_super().

 - Fix stable writes for multi-device filesystems (xfs, btrfs etc) and
   the block device pseudo filesystem.

   Stable writes used to be a superblock flag only, making it a per
   filesystem property. Add an additional AS_STABLE_WRITES mapping flag
   to allow for fine-grained control.

 - Ensure that offset_iterate_dir() returns 0 after reaching the end of
   a directory so it adheres to getdents() convention.

* tag 'vfs-6.7-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  libfs: getdents() should return 0 after reaching EOD
  xfs: respect the stable writes flag on the RT device
  xfs: clean up FS_XFLAG_REALTIME handling in xfs_ioctl_setattr_xflags
  block: update the stable_writes flag in bdev_add
  filemap: add a per-mapping stable writes flag
  autofs: add: new_inode check in autofs_fill_super()
  iov_iter: fix copy_page_to_iter_nofault()
  fs: Pass AT_GETATTR_NOSEC flag to getattr interface function

When we're recovering ondisk quota records from the log, we need to
validate the recovered buffer contents before writing them to disk.

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

Since the introduction of xfs_dqblk in V5, xfs really ought to find the
dqblk pointer from the dquot buffer, then compute the xfs_disk_dquot
pointer from the dqblk pointer.  Fix the open-coded xfs_buf_offset calls
and do the type checking in the correct order.

Note that this has made no practical difference since the start of the
xfs_disk_dquot is coincident with the start of the xfs_dqblk.

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

Update the per-folio stable writes flag dependening on which device an
inode resides on.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231025141020.192413-5-hch@lst.de
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Introduce a local boolean variable if FS_XFLAG_REALTIME to make the
checks for it more obvious, and de-densify a few of the conditionals
using it to make them more readable while at it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231025141020.192413-4-hch@lst.de
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Because on v3 inodes, di_flushiter doesn't exist. It overlaps with
zero padding in the inode, except when NREXT64=1 configurations are
in use and the zero padding is no longer padding but holds the 64
bit extent counter.

This manifests obviously on big endian platforms (e.g. s390) because
the log dinode is in host order and the overlap is the LSBs of the
extent count field. It is not noticed on little endian machines
because the overlap is at the MSB end of the extent count field and
we need to get more than 2^^48 extents in the inode before it
manifests. i.e. the heat death of the universe will occur before we
see the problem in little endian machines.

This is a zero-day issue for NREXT64=1 configuraitons on big endian
machines. Fix it by only clearing di_flushiter on v2 inodes during
recovery.

Fixes: 9b7d16e34bbe ("xfs: Introduce XFS_DIFLAG2_NREXT64 and associated helpers")
cc: stable@kernel.org # 5.19+
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Discovered when trying to track down a weird recovery corruption
issue that wasn't detected at recovery time.

The specific corruption was a zero extent count field when big
extent counts are in use, and it turns out the dinode verifier
doesn't detect that specific corruption case, either. So fix it too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Commit 57c0f4a8ea3a attempted to fix the select in the kconfig entry
XFS_ONLINE_SCRUB_STATS by selecting XFS_DEBUG, but the original
intention was to select DEBUG_FS, since the feature relies on debugfs to
export the related scrub statistics.

Fixes: 57c0f4a8ea3a ("xfs: fix select in config XFS_ONLINE_SCRUB_STATS")

Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

We've been seeing XFS errors like the following:

XFS: Internal error i != 1 at line 3526 of file fs/xfs/libxfs/xfs_btree.c.  Caller xfs_btree_insert+0x1ec/0x280
...
Call Trace:
 xfs_corruption_error+0x94/0xa0
 xfs_btree_insert+0x221/0x280
 xfs_alloc_fixup_trees+0x104/0x3e0
 xfs_alloc_ag_vextent_size+0x667/0x820
 xfs_alloc_fix_freelist+0x5d9/0x750
 xfs_free_extent_fix_freelist+0x65/0xa0
 __xfs_free_extent+0x57/0x180
...

This is the XFS_IS_CORRUPT() check in xfs_btree_insert() when
xfs_btree_insrec() fails.

After converting this into a panic and dissecting the core dump, I found
that xfs_btree_insrec() is failing because it's trying to split a leaf
node in the cntbt when the AG free list is empty. In particular, it's
failing to get a block from the AGFL _while trying to refill the AGFL_.

If a single operation splits every level of the bnobt and the cntbt (and
the rmapbt if it is enabled) at once, the free list will be empty. Then,
when the next operation tries to refill the free list, it allocates
space. If the allocation does not use a full extent, it will need to
insert records for the remaining space in the bnobt and cntbt. And if
those new records go in full leaves, the leaves (and potentially more
nodes up to the old root) need to be split.

Fix it by accounting for the additional splits that may be required to
refill the free list in the calculation for the minimum free list size.

P.S. As far as I can tell, this bug has existed for a long time -- maybe
back to xfs-history commit afdf80ae7405 ("Add XFS_AG_MAXLEVELS macros
...") in April 1994! It requires a very unlucky sequence of events, and
in fact we didn't hit it until a particular sparse mmap workload updated
from 5.12 to 5.19. But this bug existed in 5.12, so it must've been
exposed by some other change in allocation or writeback patterns. It's
also much less likely to be hit with the rmapbt enabled, since that
increases the minimum free list size and is unlikely to split at the
same time as the bnobt and cntbt.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>