xfs: (re-)implement FIEMAP_FLAG_XATTR
Use a special read-only iomap_ops implementation to support fiemap on
the attr fork.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 1cce760..697c8fd 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1106,3 +1106,48 @@
.iomap_begin = xfs_file_iomap_begin,
.iomap_end = xfs_file_iomap_end,
};
+
+static int
+xfs_xattr_iomap_begin(
+ struct inode *inode,
+ loff_t offset,
+ loff_t length,
+ unsigned flags,
+ struct iomap *iomap)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
+ xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
+ struct xfs_bmbt_irec imap;
+ int nimaps = 1, error = 0;
+ unsigned lockmode;
+
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+
+ lockmode = xfs_ilock_data_map_shared(ip);
+
+ /* if there are no attribute fork or extents, return ENOENT */
+ if (XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
+ error = -ENOENT;
+ goto out_unlock;
+ }
+
+ ASSERT(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL);
+ error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
+ &nimaps, XFS_BMAPI_ENTIRE | XFS_BMAPI_ATTRFORK);
+out_unlock:
+ xfs_iunlock(ip, lockmode);
+
+ if (!error) {
+ ASSERT(nimaps);
+ xfs_bmbt_to_iomap(ip, iomap, &imap);
+ }
+
+ return error;
+}
+
+struct iomap_ops xfs_xattr_iomap_ops = {
+ .iomap_begin = xfs_xattr_iomap_begin,
+};