xfs: kill struct xfs_dir2_sf

The list field of it is never cactually used, so all uses can simply be
replaced with the xfs_dir2_sf_hdr_t type that it has as first member.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_dir2.c

@@ -122,15 +122,15 @@ int
 xfs_dir_isempty(
 	xfs_inode_t	*dp)
 {
-	xfs_dir2_sf_t	*sfp;
+	xfs_dir2_sf_hdr_t	*sfp;
 
 	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);
 	if (dp->i_d.di_size == 0)	/* might happen during shutdown. */
 		return 1;
 	if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
 		return 0;
-	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
-	return !sfp->hdr.count;
+	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
+	return !sfp->count;
 }
 
 /*

fs/xfs/xfs_dir2_block.c

@@ -1028,8 +1028,6 @@ xfs_dir2_sf_to_block(
 	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */
 	xfs_dabuf_t		*bp;		/* block buffer */
 	xfs_dir2_block_tail_t	*btp;		/* block tail pointer */
-	char			*buf;		/* sf buffer */
-	int			buf_len;
 	xfs_dir2_data_entry_t	*dep;		/* data entry pointer */
 	xfs_inode_t		*dp;		/* incore directory inode */
 	int			dummy;		/* trash */
@@ -1043,7 +1041,8 @@ xfs_dir2_sf_to_block(
 	int			newoffset;	/* offset from current entry */
 	int			offset;		/* target block offset */
 	xfs_dir2_sf_entry_t	*sfep;		/* sf entry pointer */
-	xfs_dir2_sf_t		*sfp;		/* shortform structure */
+	xfs_dir2_sf_hdr_t	*oldsfp;	/* old shortform header  */
+	xfs_dir2_sf_hdr_t	*sfp;		/* shortform header  */
 	__be16			*tagp;		/* end of data entry */
 	xfs_trans_t		*tp;		/* transaction pointer */
 	struct xfs_name		name;
@@ -1061,32 +1060,30 @@ xfs_dir2_sf_to_block(
 		ASSERT(XFS_FORCED_SHUTDOWN(mp));
 		return XFS_ERROR(EIO);
 	}
+
+	oldsfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
+
 	ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
 	ASSERT(dp->i_df.if_u1.if_data != NULL);
-	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
-	ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->hdr.i8count));
+	ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(oldsfp->i8count));
+
 	/*
-	 * Copy the directory into the stack buffer.
+	 * Copy the directory into a temporary buffer.
 	 * Then pitch the incore inode data so we can make extents.
 	 */
+	sfp = kmem_alloc(dp->i_df.if_bytes, KM_SLEEP);
+	memcpy(sfp, oldsfp, dp->i_df.if_bytes);
 
-	buf_len = dp->i_df.if_bytes;
-	buf = kmem_alloc(buf_len, KM_SLEEP);
-
-	memcpy(buf, sfp, buf_len);
-	xfs_idata_realloc(dp, -buf_len, XFS_DATA_FORK);
+	xfs_idata_realloc(dp, -dp->i_df.if_bytes, XFS_DATA_FORK);
 	dp->i_d.di_size = 0;
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-	/*
-	 * Reset pointer - old sfp is gone.
-	 */
-	sfp = (xfs_dir2_sf_t *)buf;
+
 	/*
 	 * Add block 0 to the inode.
 	 */
 	error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE, &blkno);
 	if (error) {
-		kmem_free(buf);
+		kmem_free(sfp);
 		return error;
 	}
 	/*
@@ -1094,7 +1091,7 @@ xfs_dir2_sf_to_block(
 	 */
 	error = xfs_dir2_data_init(args, blkno, &bp);
 	if (error) {
-		kmem_free(buf);
+		kmem_free(sfp);
 		return error;
 	}
 	block = bp->data;
@@ -1103,7 +1100,7 @@ xfs_dir2_sf_to_block(
 	 * Compute size of block "tail" area.
 	 */
 	i = (uint)sizeof(*btp) +
-	    (sfp->hdr.count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);
+	    (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);
 	/*
 	 * The whole thing is initialized to free by the init routine.
 	 * Say we're using the leaf and tail area.
@@ -1117,7 +1114,7 @@ xfs_dir2_sf_to_block(
 	 * Fill in the tail.
 	 */
 	btp = xfs_dir2_block_tail_p(mp, block);
-	btp->count = cpu_to_be32(sfp->hdr.count + 2);	/* ., .. */
+	btp->count = cpu_to_be32(sfp->count + 2);	/* ., .. */
 	btp->stale = 0;
 	blp = xfs_dir2_block_leaf_p(btp);
 	endoffset = (uint)((char *)blp - (char *)block);
@@ -1159,7 +1156,8 @@ xfs_dir2_sf_to_block(
 	/*
 	 * Loop over existing entries, stuff them in.
 	 */
-	if ((i = 0) == sfp->hdr.count)
+	i = 0;
+	if (!sfp->count)
 		sfep = NULL;
 	else
 		sfep = xfs_dir2_sf_firstentry(sfp);
@@ -1208,13 +1206,13 @@ xfs_dir2_sf_to_block(
 		blp[2 + i].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,
 						 (char *)dep - (char *)block));
 		offset = (int)((char *)(tagp + 1) - (char *)block);
-		if (++i == sfp->hdr.count)
+		if (++i == sfp->count)
 			sfep = NULL;
 		else
 			sfep = xfs_dir2_sf_nextentry(sfp, sfep);
 	}
 	/* Done with the temporary buffer */
-	kmem_free(buf);
+	kmem_free(sfp);
 	/*
 	 * Sort the leaf entries by hash value.
 	 */

fs/xfs/xfs_dir2_sf.h

@@ -21,8 +21,12 @@
 /*
  * Directory layout when stored internal to an inode.
  *
- * Small directories are packed as tightly as possible so as to
- * fit into the literal area of the inode.
+ * Small directories are packed as tightly as possible so as to fit into the
+ * literal area of the inode.  They consist of a single xfs_dir2_sf_hdr header
+ * followed by zero or more xfs_dir2_sf_entry structures.  Due the different
+ * inode number storage size and the variable length name field in
+ * the xfs_dir2_sf_entry all these structure are variable length, and the
+ * accessors in this file should be used to iterate over them.
  */
 
 struct uio;
@@ -61,9 +65,9 @@ typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
  * The parent directory has a dedicated field, and the self-pointer must
  * be calculated on the fly.
  *
- * Entries are packed toward the top as tightly as possible.  The header
- * and the elements must be memcpy'd out into a work area to get correct
- * alignment for the inode number fields.
+ * Entries are packed toward the top as tightly as possible, and thus may
+ * be misaligned.  Care needs to be taken to access them through special
+ * helpers or copy them into aligned variables first.
  */
 typedef struct xfs_dir2_sf_hdr {
 	__uint8_t		count;		/* count of entries */
@@ -78,11 +82,6 @@ typedef struct xfs_dir2_sf_entry {
 	xfs_dir2_inou_t		inumber;	/* inode number, var. offset */
 } __arch_pack xfs_dir2_sf_entry_t; 
 
-typedef struct xfs_dir2_sf {
-	xfs_dir2_sf_hdr_t	hdr;		/* shortform header */
-	xfs_dir2_sf_entry_t	list[1];	/* shortform entries */
-} xfs_dir2_sf_t;
-
 static inline int xfs_dir2_sf_hdr_size(int i8count)
 {
 	return ((uint)sizeof(xfs_dir2_sf_hdr_t) - \
@@ -102,39 +101,41 @@ xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
 	INT_SET_UNALIGNED_16_BE(&(sfep)->offset.i, off);
 }
 
-static inline int xfs_dir2_sf_entsize_byname(xfs_dir2_sf_t *sfp, int len)
+static inline int xfs_dir2_sf_entsize_byname(xfs_dir2_sf_hdr_t *sfp, int len)
 {
 	return ((uint)sizeof(xfs_dir2_sf_entry_t) - 1 + (len) - \
-		((sfp)->hdr.i8count == 0) * \
+		((sfp)->i8count == 0) * \
 		((uint)sizeof(xfs_dir2_ino8_t) - (uint)sizeof(xfs_dir2_ino4_t)));
 }
 
 static inline int
-xfs_dir2_sf_entsize_byentry(xfs_dir2_sf_t *sfp, xfs_dir2_sf_entry_t *sfep)
+xfs_dir2_sf_entsize_byentry(xfs_dir2_sf_hdr_t *sfp, xfs_dir2_sf_entry_t *sfep)
 {
 	return ((uint)sizeof(xfs_dir2_sf_entry_t) - 1 + (sfep)->namelen - \
-		((sfp)->hdr.i8count == 0) * \
+		((sfp)->i8count == 0) * \
 		((uint)sizeof(xfs_dir2_ino8_t) - (uint)sizeof(xfs_dir2_ino4_t)));
 }
 
-static inline xfs_dir2_sf_entry_t *xfs_dir2_sf_firstentry(xfs_dir2_sf_t *sfp)
+static inline struct xfs_dir2_sf_entry *
+xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
 {
-	return ((xfs_dir2_sf_entry_t *) \
-		((char *)(sfp) + xfs_dir2_sf_hdr_size(sfp->hdr.i8count)));
+	return (struct xfs_dir2_sf_entry *)
+		((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
 }
 
-static inline xfs_dir2_sf_entry_t *
-xfs_dir2_sf_nextentry(xfs_dir2_sf_t *sfp, xfs_dir2_sf_entry_t *sfep)
+static inline struct xfs_dir2_sf_entry *
+xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
+		struct xfs_dir2_sf_entry *sfep)
 {
-	return ((xfs_dir2_sf_entry_t *) \
-		((char *)(sfep) + xfs_dir2_sf_entsize_byentry(sfp,sfep)));
+	return (struct xfs_dir2_sf_entry *)
+		((char *)sfep + xfs_dir2_sf_entsize_byentry(hdr, sfep));
 }
 
 /*
  * Functions.
  */
-extern xfs_ino_t xfs_dir2_sf_get_parent_ino(struct xfs_dir2_sf *sfp);
-extern xfs_ino_t xfs_dir2_sfe_get_ino(struct xfs_dir2_sf *sfp,
+extern xfs_ino_t xfs_dir2_sf_get_parent_ino(struct xfs_dir2_sf_hdr *sfp);
+extern xfs_ino_t xfs_dir2_sfe_get_ino(struct xfs_dir2_sf_hdr *sfp,
 				      struct xfs_dir2_sf_entry *sfep);
 extern int xfs_dir2_block_sfsize(struct xfs_inode *dp,
 				 struct xfs_dir2_block *block,