xfs: Add read-only support for dirent filetype field

Add support for the file type field in directory entries so that
readdir can return the type of the inode the dirent points to to
userspace without first having to read the inode off disk.

The encoding of the type field is a single byte that is added to the
end of the directory entry name length. For all intents and
purposes, it appends a "hidden" byte to the name field which
contains the type information. As the directory entry is already of
dynamic size, helpers are already required to access and decode the
direct entry structures.

Hence the relevent extraction and iteration helpers are updated to
understand the hidden byte.  Helpers for reading and writing the
filetype field from the directory entries are also added. Only the
read helpers are used by this patch.  It also adds all the code
necessary to read the type information out of the dirents on disk.

Further we add the superblock feature bit and helpers to indicate
that we understand the on-disk format change. This is not a
compatible change - existing kernels cannot read the new format
successfully - so an incompatible feature flag is added. We don't
yet allow filesystems to mount with this flag yet - that will be
added once write support is added.

Finally, the code to take the type from the VFS, convert it to an
XFS on-disk type and put it into the xfs_name structures passed
around is added, but the directory code does not use this field yet.
That will be in the next patch.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 72 insertions, 49 deletions

diff --git a/fs/xfs/xfs_dir2_sf.c b/fs/xfs/xfs_dir2_sf.c
index 65b65c5f8c3c..bd14e1a72c62 100644
--- a/fs/xfs/xfs_dir2_sf.c
+++ b/fs/xfs/xfs_dir2_sf.c
@@ -105,31 +105,38 @@ xfs_dir2_sf_put_parent_ino(
 
 /*
  * In short-form directory entries the inode numbers are stored at variable
- * offset behind the entry name.  The inode numbers may only be accessed
- * through the helpers below.
+ * offset behind the entry name. If the entry stores a filetype value, then it
+ * sits between the name and the inode number. Hence the inode numbers may only
+ * be accessed through the helpers below.
  */
 static xfs_dir2_inou_t *
-xfs_dir2_sfe_inop(
+xfs_dir3_sfe_inop(
+	struct xfs_mount	*mp,
 	struct xfs_dir2_sf_entry *sfep)
 {
-	return (xfs_dir2_inou_t *)&sfep->name[sfep->namelen];
+	__uint8_t	*ptr = &sfep->name[sfep->namelen];
+	if (xfs_sb_version_hasftype(&mp->m_sb))
+		ptr++;
+	return (xfs_dir2_inou_t *)ptr;
 }
 
 xfs_ino_t
-xfs_dir2_sfe_get_ino(
+xfs_dir3_sfe_get_ino(
+	struct xfs_mount	*mp,
 	struct xfs_dir2_sf_hdr	*hdr,
 	struct xfs_dir2_sf_entry *sfep)
 {
-	return xfs_dir2_sf_get_ino(hdr, xfs_dir2_sfe_inop(sfep));
+	return xfs_dir2_sf_get_ino(hdr, xfs_dir3_sfe_inop(mp, sfep));
 }
 
 void
-xfs_dir2_sfe_put_ino(
+xfs_dir3_sfe_put_ino(
+	struct xfs_mount	*mp,
 	struct xfs_dir2_sf_hdr	*hdr,
 	struct xfs_dir2_sf_entry *sfep,
 	xfs_ino_t		ino)
 {
-	xfs_dir2_sf_put_ino(hdr, xfs_dir2_sfe_inop(sfep), ino);
+	xfs_dir2_sf_put_ino(hdr, xfs_dir3_sfe_inop(mp, sfep), ino);
 }
 
 /*
@@ -157,9 +164,16 @@ xfs_dir2_block_sfsize(
 	int			namelen;	/* total name bytes */
 	xfs_ino_t		parent = 0;	/* parent inode number */
 	int			size=0;		/* total computed size */
+	int			has_ftype;
 
 	mp = dp->i_mount;
 
+	/*
+	 * if there is a filetype field, add the extra byte to the namelen
+	 * for each entry that we see.
+	 */
+	has_ftype = xfs_sb_version_hasftype(&mp->m_sb) ? 1 : 0;
+
 	count = i8count = namelen = 0;
 	btp = xfs_dir2_block_tail_p(mp, hdr);
 	blp = xfs_dir2_block_leaf_p(btp);
@@ -188,9 +202,10 @@ xfs_dir2_block_sfsize(
 		if (!isdot)
 			i8count += be64_to_cpu(dep->inumber) > XFS_DIR2_MAX_SHORT_INUM;
 #endif
+		/* take into account the file type field */
 		if (!isdot && !isdotdot) {
 			count++;
-			namelen += dep->namelen;
+			namelen += dep->namelen + has_ftype;
 		} else if (isdotdot)
 			parent = be64_to_cpu(dep->inumber);
 		/*
@@ -316,12 +331,12 @@ xfs_dir2_block_to_sf(
 				(xfs_dir2_data_aoff_t)
 				((char *)dep - (char *)hdr));
 			memcpy(sfep->name, dep->name, dep->namelen);
-			xfs_dir2_sfe_put_ino(sfp, sfep,
+			xfs_dir3_sfe_put_ino(mp, sfp, sfep,
 					     be64_to_cpu(dep->inumber));
 
-			sfep = xfs_dir2_sf_nextentry(sfp, sfep);
+			sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
 		}
-		ptr += xfs_dir2_data_entsize(dep->namelen);
+		ptr += xfs_dir3_data_entsize(mp, dep->namelen);
 	}
 	ASSERT((char *)sfep - (char *)sfp == size);
 	xfs_dir2_sf_check(args);
@@ -372,7 +387,7 @@ xfs_dir2_sf_addname(
 	/*
 	 * Compute entry (and change in) size.
 	 */
-	add_entsize = xfs_dir2_sf_entsize(sfp, args->namelen);
+	add_entsize = xfs_dir3_sf_entsize(dp->i_mount, sfp, args->namelen);
 	incr_isize = add_entsize;
 	objchange = 0;
 #if XFS_BIG_INUMS
@@ -466,8 +481,9 @@ xfs_dir2_sf_addname_easy(
 	/*
 	 * Grow the in-inode space.
 	 */
-	xfs_idata_realloc(dp, xfs_dir2_sf_entsize(sfp, args->namelen),
-		XFS_DATA_FORK);
+	xfs_idata_realloc(dp,
+			  xfs_dir3_sf_entsize(dp->i_mount, sfp, args->namelen),
+			  XFS_DATA_FORK);
 	/*
 	 * Need to set up again due to realloc of the inode data.
 	 */
@@ -479,7 +495,7 @@ xfs_dir2_sf_addname_easy(
 	sfep->namelen = args->namelen;
 	xfs_dir2_sf_put_offset(sfep, offset);
 	memcpy(sfep->name, args->name, sfep->namelen);
-	xfs_dir2_sfe_put_ino(sfp, sfep, args->inumber);
+	xfs_dir3_sfe_put_ino(dp->i_mount, sfp, sfep, args->inumber);
 	/*
 	 * Update the header and inode.
 	 */
@@ -519,11 +535,13 @@ xfs_dir2_sf_addname_hard(
 	xfs_dir2_sf_hdr_t	*oldsfp;	/* original shortform dir */
 	xfs_dir2_sf_entry_t	*sfep;		/* entry in new dir */
 	xfs_dir2_sf_hdr_t	*sfp;		/* new shortform dir */
+	struct xfs_mount	*mp;
 
 	/*
 	 * Copy the old directory to the stack buffer.
 	 */
 	dp = args->dp;
+	mp = dp->i_mount;
 
 	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
 	old_isize = (int)dp->i_d.di_size;
@@ -535,13 +553,13 @@ 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(dp->i_mount),
+	for (offset = XFS_DIR3_DATA_FIRST_OFFSET(mp),
 	      oldsfep = xfs_dir2_sf_firstentry(oldsfp),
-	      add_datasize = xfs_dir2_data_entsize(args->namelen),
+	      add_datasize = xfs_dir3_data_entsize(mp, args->namelen),
 	      eof = (char *)oldsfep == &buf[old_isize];
 	     !eof;
-	     offset = new_offset + xfs_dir2_data_entsize(oldsfep->namelen),
-	      oldsfep = xfs_dir2_sf_nextentry(oldsfp, oldsfep),
+	     offset = new_offset + xfs_dir3_data_entsize(mp, oldsfep->namelen),
+	      oldsfep = xfs_dir3_sf_nextentry(mp, oldsfp, oldsfep),
 	      eof = (char *)oldsfep == &buf[old_isize]) {
 		new_offset = xfs_dir2_sf_get_offset(oldsfep);
 		if (offset + add_datasize <= new_offset)
@@ -570,7 +588,7 @@ xfs_dir2_sf_addname_hard(
 	sfep->namelen = args->namelen;
 	xfs_dir2_sf_put_offset(sfep, offset);
 	memcpy(sfep->name, args->name, sfep->namelen);
-	xfs_dir2_sfe_put_ino(sfp, sfep, args->inumber);
+	xfs_dir3_sfe_put_ino(mp, sfp, sfep, args->inumber);
 	sfp->count++;
 #if XFS_BIG_INUMS
 	if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && !objchange)
@@ -580,7 +598,7 @@ xfs_dir2_sf_addname_hard(
 	 * If there's more left to copy, do that.
 	 */
 	if (!eof) {
-		sfep = xfs_dir2_sf_nextentry(sfp, sfep);
+		sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
 		memcpy(sfep, oldsfep, old_isize - nbytes);
 	}
 	kmem_free(buf);
@@ -616,7 +634,7 @@ xfs_dir2_sf_addname_pick(
 	mp = dp->i_mount;
 
 	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
-	size = xfs_dir2_data_entsize(args->namelen);
+	size = xfs_dir3_data_entsize(mp, args->namelen);
 	offset = XFS_DIR3_DATA_FIRST_OFFSET(mp);
 	sfep = xfs_dir2_sf_firstentry(sfp);
 	holefit = 0;
@@ -629,8 +647,8 @@ xfs_dir2_sf_addname_pick(
 		if (!holefit)
 			holefit = offset + size <= xfs_dir2_sf_get_offset(sfep);
 		offset = xfs_dir2_sf_get_offset(sfep) +
-			 xfs_dir2_data_entsize(sfep->namelen);
-		sfep = xfs_dir2_sf_nextentry(sfp, sfep);
+			 xfs_dir3_data_entsize(mp, sfep->namelen);
+		sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
 	}
 	/*
 	 * Calculate data bytes used excluding the new entry, if this
@@ -684,31 +702,34 @@ xfs_dir2_sf_check(
 	int			offset;		/* data offset */
 	xfs_dir2_sf_entry_t	*sfep;		/* shortform dir entry */
 	xfs_dir2_sf_hdr_t	*sfp;		/* shortform structure */
+	struct xfs_mount	*mp;
 
 	dp = args->dp;
+	mp = dp->i_mount;
 
 	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
-	offset = XFS_DIR3_DATA_FIRST_OFFSET(dp->i_mount);
+	offset = XFS_DIR3_DATA_FIRST_OFFSET(mp);
 	ino = xfs_dir2_sf_get_parent_ino(sfp);
 	i8count = ino > XFS_DIR2_MAX_SHORT_INUM;
 
 	for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp);
 	     i < sfp->count;
-	     i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep)) {
+	     i++, sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep)) {
 		ASSERT(xfs_dir2_sf_get_offset(sfep) >= offset);
-		ino = xfs_dir2_sfe_get_ino(sfp, sfep);
+		ino = xfs_dir3_sfe_get_ino(mp, sfp, sfep);
 		i8count += ino > XFS_DIR2_MAX_SHORT_INUM;
 		offset =
 			xfs_dir2_sf_get_offset(sfep) +
-			xfs_dir2_data_entsize(sfep->namelen);
+			xfs_dir3_data_entsize(mp, sfep->namelen);
+		ASSERT(xfs_dir3_sfe_get_ftype(mp, sfp, sfep) <
+							XFS_DIR3_FT_MAX);
 	}
 	ASSERT(i8count == sfp->i8count);
 	ASSERT(XFS_BIG_INUMS || i8count == 0);
 	ASSERT((char *)sfep - (char *)sfp == dp->i_d.di_size);
 	ASSERT(offset +
 	       (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
-	       (uint)sizeof(xfs_dir2_block_tail_t) <=
-	       dp->i_mount->m_dirblksize);
+	       (uint)sizeof(xfs_dir2_block_tail_t) <= mp->m_dirblksize);
 }
 #endif	/* DEBUG */
 
@@ -820,7 +841,7 @@ xfs_dir2_sf_lookup(
 	 */
 	ci_sfep = NULL;
 	for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
-				i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep)) {
+	     i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep)) {
 		/*
 		 * Compare name and if it's an exact match, return the inode
 		 * number. If it's the first case-insensitive match, store the
@@ -830,7 +851,8 @@ xfs_dir2_sf_lookup(
 								sfep->namelen);
 		if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
 			args->cmpresult = cmp;
-			args->inumber = xfs_dir2_sfe_get_ino(sfp, sfep);
+			args->inumber = xfs_dir3_sfe_get_ino(dp->i_mount,
+							     sfp, sfep);
 			if (cmp == XFS_CMP_EXACT)
 				return XFS_ERROR(EEXIST);
 			ci_sfep = sfep;
@@ -886,10 +908,10 @@ xfs_dir2_sf_removename(
 	 * Find the one we're deleting.
 	 */
 	for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
-				i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep)) {
+	     i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep)) {
 		if (xfs_da_compname(args, sfep->name, sfep->namelen) ==
 								XFS_CMP_EXACT) {
-			ASSERT(xfs_dir2_sfe_get_ino(sfp, sfep) ==
+			ASSERT(xfs_dir3_sfe_get_ino(dp->i_mount, sfp, sfep) ==
 			       args->inumber);
 			break;
 		}
@@ -903,7 +925,7 @@ xfs_dir2_sf_removename(
 	 * Calculate sizes.
 	 */
 	byteoff = (int)((char *)sfep - (char *)sfp);
-	entsize = xfs_dir2_sf_entsize(sfp, args->namelen);
+	entsize = xfs_dir3_sf_entsize(dp->i_mount, sfp, args->namelen);
 	newsize = oldsize - entsize;
 	/*
 	 * Copy the part if any after the removed entry, sliding it down.
@@ -1019,16 +1041,17 @@ xfs_dir2_sf_replace(
 	 * Normal entry, look for the name.
 	 */
 	else {
-		for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp);
-				i < sfp->count;
-				i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep)) {
+		for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
+		     i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep)) {
 			if (xfs_da_compname(args, sfep->name, sfep->namelen) ==
 								XFS_CMP_EXACT) {
 #if XFS_BIG_INUMS || defined(DEBUG)
-				ino = xfs_dir2_sfe_get_ino(sfp, sfep);
+				ino = xfs_dir3_sfe_get_ino(dp->i_mount,
+							   sfp, sfep);
 				ASSERT(args->inumber != ino);
 #endif
-				xfs_dir2_sfe_put_ino(sfp, sfep, args->inumber);
+				xfs_dir3_sfe_put_ino(dp->i_mount, sfp, sfep,
+						     args->inumber);
 				break;
 			}
 		}
@@ -1136,13 +1159,13 @@ xfs_dir2_sf_toino4(
 	for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp),
 		    oldsfep = xfs_dir2_sf_firstentry(oldsfp);
 	     i < sfp->count;
-	     i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep),
-		  oldsfep = xfs_dir2_sf_nextentry(oldsfp, oldsfep)) {
+	     i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep),
+		  oldsfep = xfs_dir3_sf_nextentry(dp->i_mount, oldsfp, oldsfep)) {
 		sfep->namelen = oldsfep->namelen;
 		sfep->offset = oldsfep->offset;
 		memcpy(sfep->name, oldsfep->name, sfep->namelen);
-		xfs_dir2_sfe_put_ino(sfp, sfep,
-			xfs_dir2_sfe_get_ino(oldsfp, oldsfep));
+		xfs_dir3_sfe_put_ino(dp->i_mount, sfp, sfep,
+			xfs_dir3_sfe_get_ino(dp->i_mount, oldsfp, oldsfep));
 	}
 	/*
 	 * Clean up the inode.
@@ -1211,13 +1234,13 @@ xfs_dir2_sf_toino8(
 	for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp),
 		    oldsfep = xfs_dir2_sf_firstentry(oldsfp);
 	     i < sfp->count;
-	     i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep),
-		  oldsfep = xfs_dir2_sf_nextentry(oldsfp, oldsfep)) {
+	     i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep),
+		  oldsfep = xfs_dir3_sf_nextentry(dp->i_mount, oldsfp, oldsfep)) {
 		sfep->namelen = oldsfep->namelen;
 		sfep->offset = oldsfep->offset;
 		memcpy(sfep->name, oldsfep->name, sfep->namelen);
-		xfs_dir2_sfe_put_ino(sfp, sfep,
-			xfs_dir2_sfe_get_ino(oldsfp, oldsfep));
+		xfs_dir3_sfe_put_ino(dp->i_mount, sfp, sfep,
+			xfs_dir3_sfe_get_ino(dp->i_mount, oldsfp, oldsfep));
 	}
 	/*
 	 * Clean up the inode.