Merge tag 'repair-pptrs-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux...

Merge tag 'repair-pptrs-6.10_2024-04-23' of https://git./linux/kernel/git/djwong/xfs-linux into xfs-6.10-mergeC

xfs: online repair for parent pointers

This series implements online repair for directory parent pointer
metadata.  The checking half is fairly straightforward -- for each
outgoing directory link (forward or backwards), grab the inode at the
other end, and confirm that there's a corresponding link.  If we can't
grab an inode or lock it, we'll save that link for a slower loop that
cycles all the locks, confirms the continued existence of the link, and
rechecks the link if it's actually still there.

Repairs are a bit more involved -- for directories, we walk the entire
filesystem to rebuild the dirents from parent pointer information.
Parent pointer repairs do the same walk but rebuild the pptrs from the
dirent information, but with the added twist that it duplicates all the
xattrs so that it can use the atomic extent swapping code to commit the
repairs atomically.

This introduces an added twist to the xattr repair code -- we use dirent
hooks to detect a colliding update to the pptr data while we're not
holding the ILOCKs; if one is detected, we restart the xattr salvaging
process but this time hold all the ILOCKs until the end of the scan.

For offline repair, the phase6 directory connectivity scan generates an
index of all the expected parent pointers in the filesystem.  Then it
walks each file and compares the parent pointers attached to that file
against the index generated, and resyncs the results as necessary.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
* tag 'repair-pptrs-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: inode repair should ensure there's an attr fork to store parent pointers
  xfs: repair link count of nondirectories after rebuilding parent pointers
  xfs: adapt the orphanage code to handle parent pointers
  xfs: actually rebuild the parent pointer xattrs
  xfs: add a per-leaf block callback to xchk_xattr_walk
  xfs: split xfs_bmap_add_attrfork into two pieces
  xfs: remove pointless unlocked assertion
  xfs: implement live updates for parent pointer repairs
  xfs: repair directory parent pointers by scanning for dirents
  xfs: replay unlocked parent pointer updates that accrue during xattr repair
  xfs: implement live updates for directory repairs
  xfs: repair directories by scanning directory parent pointers
  xfs: add raw parent pointer apis to support repair
  xfs: salvage parent pointers when rebuilding xattr structures
  xfs: make the reserved block permission flag explicit in xfs_attr_set
  xfs: remove some boilerplate from xfs_attr_set