Hi all, This series employs atomic extent swapping to enable safe reconstruction of extended attribute data attached to a file. Because xattrs do not have any redundant information to draw off of, we can at best salvage as much data as we can and build a new structure. Rebuilding an extended attribute structure consists of these three steps: First, we walk the existing attributes to salvage as many of them as we can, by adding them as new attributes attached to the repair tempfile. We need to add a new xfile-based data structure to hold blobs of arbitrary length to stage the xattr names and values. Second, we write the salvaged attributes to a temporary file, and use atomic extent swaps to exchange the entire attribute fork between the two files. Finally, we reap the old xattr blocks (which are now in the temporary file) as carefully as we can. If you're going to start using this code, I strongly recommend pulling from my git trees, which are linked below. This has been running on the djcloud for months with no problems. Enjoy! Comments and questions are, as always, welcome. --D kernel git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=repair-xattrs xfsprogs git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=repair-xattrs fstests git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=repair-xattrs --- Commits in this patchset: * xfs: enable discarding of folios backing an xfile * xfs: create a blob array data structure * xfs: use atomic extent swapping to fix user file fork data * xfs: repair extended attributes * xfs: scrub should set preen if attr leaf has holes * xfs: flag empty xattr leaf blocks for optimization * xfs: create an xattr iteration function for scrub --- fs/xfs/Makefile | 3 fs/xfs/libxfs/xfs_attr.c | 2 fs/xfs/libxfs/xfs_attr.h | 2 fs/xfs/libxfs/xfs_da_format.h | 5 fs/xfs/libxfs/xfs_exchmaps.c | 2 fs/xfs/libxfs/xfs_exchmaps.h | 1 fs/xfs/scrub/attr.c | 158 +++-- fs/xfs/scrub/attr.h | 7 fs/xfs/scrub/attr_repair.c | 1206 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/scrub/attr_repair.h | 11 fs/xfs/scrub/dab_bitmap.h | 37 + fs/xfs/scrub/dabtree.c | 16 + fs/xfs/scrub/dabtree.h | 3 fs/xfs/scrub/listxattr.c | 312 +++++++++++ fs/xfs/scrub/listxattr.h | 17 + fs/xfs/scrub/repair.c | 46 ++ fs/xfs/scrub/repair.h | 6 fs/xfs/scrub/scrub.c | 2 fs/xfs/scrub/tempexch.h | 2 fs/xfs/scrub/tempfile.c | 204 +++++++ fs/xfs/scrub/tempfile.h | 3 fs/xfs/scrub/trace.h | 85 +++ fs/xfs/scrub/xfarray.c | 17 + fs/xfs/scrub/xfarray.h | 2 fs/xfs/scrub/xfblob.c | 168 ++++++ fs/xfs/scrub/xfblob.h | 26 + fs/xfs/scrub/xfile.c | 12 fs/xfs/scrub/xfile.h | 6 fs/xfs/xfs_buf.c | 3 fs/xfs/xfs_trace.h | 2 30 files changed, 2283 insertions(+), 83 deletions(-) create mode 100644 fs/xfs/scrub/attr_repair.c create mode 100644 fs/xfs/scrub/attr_repair.h create mode 100644 fs/xfs/scrub/dab_bitmap.h create mode 100644 fs/xfs/scrub/listxattr.c create mode 100644 fs/xfs/scrub/listxattr.h create mode 100644 fs/xfs/scrub/xfblob.c create mode 100644 fs/xfs/scrub/xfblob.h
