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Diffstat (limited to 'fs/xfs/libxfs/xfs_inode_buf.c')
-rw-r--r--fs/xfs/libxfs/xfs_inode_buf.c46
1 files changed, 42 insertions, 4 deletions
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 5c9a7440d9e4..f3254a4f4cb4 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -559,8 +559,17 @@ xfs_dinode_calc_crc(
/*
* Validate di_extsize hint.
*
- * The rules are documented at xfs_ioctl_setattr_check_extsize().
- * These functions must be kept in sync with each other.
+ * 1. Extent size hint is only valid for directories and regular files.
+ * 2. FS_XFLAG_EXTSIZE is only valid for regular files.
+ * 3. FS_XFLAG_EXTSZINHERIT is only valid for directories.
+ * 4. Hint cannot be larger than MAXTEXTLEN.
+ * 5. Can be changed on directories at any time.
+ * 6. Hint value of 0 turns off hints, clears inode flags.
+ * 7. Extent size must be a multiple of the appropriate block size.
+ * For realtime files, this is the rt extent size.
+ * 8. For non-realtime files, the extent size hint must be limited
+ * to half the AG size to avoid alignment extending the extent beyond the
+ * limits of the AG.
*/
xfs_failaddr_t
xfs_inode_validate_extsize(
@@ -580,6 +589,28 @@ xfs_inode_validate_extsize(
inherit_flag = (flags & XFS_DIFLAG_EXTSZINHERIT);
extsize_bytes = XFS_FSB_TO_B(mp, extsize);
+ /*
+ * This comment describes a historic gap in this verifier function.
+ *
+ * On older kernels, the extent size hint verifier doesn't check that
+ * the extent size hint is an integer multiple of the realtime extent
+ * size on a directory with both RTINHERIT and EXTSZINHERIT flags set.
+ * The verifier has always enforced the alignment rule for regular
+ * files with the REALTIME flag set.
+ *
+ * If a directory with a misaligned extent size hint is allowed to
+ * propagate that hint into a new regular realtime file, the result
+ * is that the inode cluster buffer verifier will trigger a corruption
+ * shutdown the next time it is run.
+ *
+ * Unfortunately, there could be filesystems with these misconfigured
+ * directories in the wild, so we cannot add a check to this verifier
+ * at this time because that will result a new source of directory
+ * corruption errors when reading an existing filesystem. Instead, we
+ * permit the misconfiguration to pass through the verifiers so that
+ * callers of this function can correct and mitigate externally.
+ */
+
if (rt_flag)
blocksize_bytes = mp->m_sb.sb_rextsize << mp->m_sb.sb_blocklog;
else
@@ -616,8 +647,15 @@ xfs_inode_validate_extsize(
/*
* Validate di_cowextsize hint.
*
- * The rules are documented at xfs_ioctl_setattr_check_cowextsize().
- * These functions must be kept in sync with each other.
+ * 1. CoW extent size hint can only be set if reflink is enabled on the fs.
+ * The inode does not have to have any shared blocks, but it must be a v3.
+ * 2. FS_XFLAG_COWEXTSIZE is only valid for directories and regular files;
+ * for a directory, the hint is propagated to new files.
+ * 3. Can be changed on files & directories at any time.
+ * 4. Hint value of 0 turns off hints, clears inode flags.
+ * 5. Extent size must be a multiple of the appropriate block size.
+ * 6. The extent size hint must be limited to half the AG size to avoid
+ * alignment extending the extent beyond the limits of the AG.
*/
xfs_failaddr_t
xfs_inode_validate_cowextsize(