xfs: dirent dtype presence is dependent on directory magic numbers

The determination of whether a directory entry contains a dtype
field originally was dependent on the filesystem having CRCs
enabled. This meant that the format for dtype beign enabled could be
determined by checking the directory block magic number rather than
doing a feature bit check. This was useful in that it meant that we
didn't need to pass a struct xfs_mount around to functions that
were already supplied with a directory block header.

Unfortunately, the introduction of dtype fields into the v4
structure via a feature bit meant this "use the directory block
magic number" method of discriminating the dirent entry sizes is
broken. Hence we need to convert the places that use magic number
checks to use feature bit checks so that they work correctly and not
by chance.

The current code works on v4 filesystems only because the dirent
size roundup covers the extra byte needed by the dtype field in the
places where this problem occurs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
(cherry picked from commit 367993e7c6428cb7617ab7653d61dca54e2fdede)

diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index 0957aa98b6c0d6bb1fdc3fa23161d761aeb58567..12dad188939df2e29c4420574bd20bfb319aae35 100644 (file)
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -1158,7 +1158,7 @@ xfs_dir2_sf_to_block(
        /*
         * Create entry for .
         */
-       dep = xfs_dir3_data_dot_entry_p(hdr);
+       dep = xfs_dir3_data_dot_entry_p(mp, hdr);
        dep->inumber = cpu_to_be64(dp->i_ino);
        dep->namelen = 1;
        dep->name[0] = '.';
@@ -1172,7 +1172,7 @@ xfs_dir2_sf_to_block(
        /*
         * Create entry for ..
         */
-       dep = xfs_dir3_data_dotdot_entry_p(hdr);
+       dep = xfs_dir3_data_dotdot_entry_p(mp, hdr);
        dep->inumber = cpu_to_be64(xfs_dir2_sf_get_parent_ino(sfp));
        dep->namelen = 2;
        dep->name[0] = dep->name[1] = '.';
@@ -1183,7 +1183,7 @@ xfs_dir2_sf_to_block(
        blp[1].hashval = cpu_to_be32(xfs_dir_hash_dotdot);
        blp[1].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
                                (char *)dep - (char *)hdr));
-       offset = xfs_dir3_data_first_offset(hdr);
+       offset = xfs_dir3_data_first_offset(mp);
        /*
         * Loop over existing entries, stuff them in.
         */

diff --git a/fs/xfs/xfs_dir2_format.h b/fs/xfs/xfs_dir2_format.h
index a0961a61ac1a9a419fd537cd47dbb7337fbbc3a0..9cf67381adf6769d0b6fc984b6fe5ecaf8cef5b4 100644 (file)
--- a/fs/xfs/xfs_dir2_format.h
+++ b/fs/xfs/xfs_dir2_format.h
@@ -497,69 +497,58 @@ xfs_dir3_data_unused_p(struct xfs_dir2_data_hdr *hdr)
 /*
  * Offsets of . and .. in data space (always block 0)
  *
- * The macros are used for shortform directories as they have no headers to read
- * the magic number out of. Shortform directories need to know the size of the
- * data block header because the sfe embeds the block offset of the entry into
- * it so that it doesn't change when format conversion occurs. Bad Things Happen
- * if we don't follow this rule.
- *
  * XXX: there is scope for significant optimisation of the logic here. Right
  * now we are checking for "dir3 format" over and over again. Ideally we should
  * only do it once for each operation.
  */
-#define        XFS_DIR3_DATA_DOT_OFFSET(mp)    \
-       xfs_dir3_data_hdr_size(xfs_sb_version_hascrc(&(mp)->m_sb))
-#define        XFS_DIR3_DATA_DOTDOT_OFFSET(mp) \
-       (XFS_DIR3_DATA_DOT_OFFSET(mp) + xfs_dir3_data_entsize(mp, 1))
-#define        XFS_DIR3_DATA_FIRST_OFFSET(mp)          \
-       (XFS_DIR3_DATA_DOTDOT_OFFSET(mp) + xfs_dir3_data_entsize(mp, 2))
-
 static inline xfs_dir2_data_aoff_t
-xfs_dir3_data_dot_offset(struct xfs_dir2_data_hdr *hdr)
+xfs_dir3_data_dot_offset(struct xfs_mount *mp)
 {
-       return xfs_dir3_data_entry_offset(hdr);
+       return xfs_dir3_data_hdr_size(xfs_sb_version_hascrc(&mp->m_sb));
 }
 
 static inline xfs_dir2_data_aoff_t
-xfs_dir3_data_dotdot_offset(struct xfs_dir2_data_hdr *hdr)
+xfs_dir3_data_dotdot_offset(struct xfs_mount *mp)
 {
-       bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
-                   hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
-       return xfs_dir3_data_dot_offset(hdr) +
-               __xfs_dir3_data_entsize(dir3, 1);
+       return xfs_dir3_data_dot_offset(mp) +
+               xfs_dir3_data_entsize(mp, 1);
 }
 
 static inline xfs_dir2_data_aoff_t
-xfs_dir3_data_first_offset(struct xfs_dir2_data_hdr *hdr)
+xfs_dir3_data_first_offset(struct xfs_mount *mp)
 {
-       bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
-                   hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
-       return xfs_dir3_data_dotdot_offset(hdr) +
-               __xfs_dir3_data_entsize(dir3, 2);
+       return xfs_dir3_data_dotdot_offset(mp) +
+               xfs_dir3_data_entsize(mp, 2);
 }
 
 /*
  * location of . and .. in data space (always block 0)
  */
 static inline struct xfs_dir2_data_entry *
-xfs_dir3_data_dot_entry_p(struct xfs_dir2_data_hdr *hdr)
+xfs_dir3_data_dot_entry_p(
+       struct xfs_mount        *mp,
+       struct xfs_dir2_data_hdr *hdr)
 {
        return (struct xfs_dir2_data_entry *)
-               ((char *)hdr + xfs_dir3_data_dot_offset(hdr));
+               ((char *)hdr + xfs_dir3_data_dot_offset(mp));
 }
 
 static inline struct xfs_dir2_data_entry *
-xfs_dir3_data_dotdot_entry_p(struct xfs_dir2_data_hdr *hdr)
+xfs_dir3_data_dotdot_entry_p(
+       struct xfs_mount        *mp,
+       struct xfs_dir2_data_hdr *hdr)
 {
        return (struct xfs_dir2_data_entry *)
-               ((char *)hdr + xfs_dir3_data_dotdot_offset(hdr));
+               ((char *)hdr + xfs_dir3_data_dotdot_offset(mp));
 }
 
 static inline struct xfs_dir2_data_entry *
-xfs_dir3_data_first_entry_p(struct xfs_dir2_data_hdr *hdr)
+xfs_dir3_data_first_entry_p(
+       struct xfs_mount        *mp,
+       struct xfs_dir2_data_hdr *hdr)
 {
        return (struct xfs_dir2_data_entry *)
-               ((char *)hdr + xfs_dir3_data_first_offset(hdr));
+               ((char *)hdr + xfs_dir3_data_first_offset(mp));
 }
 
 /*

diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index 8993ec17452cd7bd62794e71585ea003badad0c0..8f84153e98a8c0f52e27aa9a0a1352779e29e61e 100644 (file)
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -119,9 +119,9 @@ xfs_dir2_sf_getdents(
         * mp->m_dirdatablk.
         */
        dot_offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
-                                            XFS_DIR3_DATA_DOT_OFFSET(mp));
+                                            xfs_dir3_data_dot_offset(mp));
        dotdot_offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
-                                               XFS_DIR3_DATA_DOTDOT_OFFSET(mp));
+                                               xfs_dir3_data_dotdot_offset(mp));
 
        /*
         * Put . entry unless we're starting past it.

diff --git a/fs/xfs/xfs_dir2_sf.c b/fs/xfs/xfs_dir2_sf.c
index bb6e2848f473d024d5ff1dd70a1232443901ea9f..3ef6d402084ccf9dabc622ee5db22b41170e3e54 100644 (file)
--- a/fs/xfs/xfs_dir2_sf.c
+++ b/fs/xfs/xfs_dir2_sf.c
@@ -557,7 +557,7 @@ xfs_dir2_sf_addname_hard(
         * to insert the new entry.
         * If it's going to end up at the end then oldsfep will point there.
         */
-       for (offset = XFS_DIR3_DATA_FIRST_OFFSET(mp),
+       for (offset = xfs_dir3_data_first_offset(mp),
              oldsfep = xfs_dir2_sf_firstentry(oldsfp),
              add_datasize = xfs_dir3_data_entsize(mp, args->namelen),
              eof = (char *)oldsfep == &buf[old_isize];
@@ -640,7 +640,7 @@ xfs_dir2_sf_addname_pick(
 
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        size = xfs_dir3_data_entsize(mp, args->namelen);
-       offset = XFS_DIR3_DATA_FIRST_OFFSET(mp);
+       offset = xfs_dir3_data_first_offset(mp);
        sfep = xfs_dir2_sf_firstentry(sfp);
        holefit = 0;
        /*
@@ -713,7 +713,7 @@ xfs_dir2_sf_check(
        mp = dp->i_mount;
 
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
-       offset = XFS_DIR3_DATA_FIRST_OFFSET(mp);
+       offset = xfs_dir3_data_first_offset(mp);
        ino = xfs_dir2_sf_get_parent_ino(sfp);
        i8count = ino > XFS_DIR2_MAX_SHORT_INUM;