xfs: remove struct xfs_attr_shortform

sparse complains about struct xfs_attr_shortform because it embeds a
structure with a variable sized array in a variable sized array.

Given that xfs_attr_shortform is not a very useful structure, and the
dir2 equivalent has been removed a long time ago, remove it as well.

Provide a xfs_attr_sf_firstentry helper that returns the first
xfs_attr_sf_entry behind a xfs_attr_sf_hdr to replace the structure
dereference.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Author: Christoph Hellwig

fs/xfs/libxfs/xfs_attr.c

@@ -1052,9 +1052,9 @@ xfs_attr_set(
 
 static inline int xfs_attr_sf_totsize(struct xfs_inode *dp)
 {
-	struct xfs_attr_shortform *sf = dp->i_af.if_data;
+	struct xfs_attr_sf_hdr *sf = dp->i_af.if_data;
 
-	return be16_to_cpu(sf->hdr.totsize);
+	return be16_to_cpu(sf->totsize);
 }
 
 /*

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -704,10 +704,10 @@ struct xfs_attr_sf_entry *
 xfs_attr_sf_findname(
 	struct xfs_da_args		*args)
 {
-	struct xfs_attr_shortform	*sf = args->dp->i_af.if_data;
+	struct xfs_attr_sf_hdr		*sf = args->dp->i_af.if_data;
 	struct xfs_attr_sf_entry	*sfe;
 
-	for (sfe = &sf->list[0];
+	for (sfe = xfs_attr_sf_firstentry(sf);
 	     sfe < xfs_attr_sf_endptr(sf);
 	     sfe = xfs_attr_sf_nextentry(sfe)) {
 		if (xfs_attr_match(args, sfe->namelen, sfe->nameval,
@@ -730,7 +730,7 @@ xfs_attr_shortform_add(
 	struct xfs_inode		*dp = args->dp;
 	struct xfs_mount		*mp = dp->i_mount;
 	struct xfs_ifork		*ifp = &dp->i_af;
-	struct xfs_attr_shortform	*sf = ifp->if_data;
+	struct xfs_attr_sf_hdr		*sf = ifp->if_data;
 	struct xfs_attr_sf_entry	*sfe;
 	int				size;
 
@@ -750,8 +750,8 @@ xfs_attr_shortform_add(
 	sfe->flags = args->attr_filter;
 	memcpy(sfe->nameval, args->name, args->namelen);
 	memcpy(&sfe->nameval[args->namelen], args->value, args->valuelen);
-	sf->hdr.count++;
-	be16_add_cpu(&sf->hdr.totsize, size);
+	sf->count++;
+	be16_add_cpu(&sf->totsize, size);
 	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);
 
 	xfs_sbversion_add_attr2(mp, args->trans);
@@ -782,9 +782,9 @@ xfs_attr_sf_removename(
 {
 	struct xfs_inode		*dp = args->dp;
 	struct xfs_mount		*mp = dp->i_mount;
-	struct xfs_attr_shortform	*sf = dp->i_af.if_data;
+	struct xfs_attr_sf_hdr		*sf = dp->i_af.if_data;
 	struct xfs_attr_sf_entry	*sfe;
-	uint16_t			totsize = be16_to_cpu(sf->hdr.totsize);
+	uint16_t			totsize = be16_to_cpu(sf->totsize);
 	void				*next, *end;
 	int				size = 0;
 
@@ -809,9 +809,9 @@ xfs_attr_sf_removename(
 	end = xfs_attr_sf_endptr(sf);
 	if (next < end)
 		memmove(sfe, next, end - next);
-	sf->hdr.count--;
+	sf->count--;
 	totsize -= size;
-	sf->hdr.totsize = cpu_to_be16(totsize);
+	sf->totsize = cpu_to_be16(totsize);
 
 	/*
 	 * Fix up the start offset of the attribute fork
@@ -868,21 +868,21 @@ xfs_attr_shortform_to_leaf(
 {
 	struct xfs_inode		*dp = args->dp;
 	struct xfs_ifork		*ifp = &dp->i_af;
-	struct xfs_attr_shortform	*sf = ifp->if_data;
+	struct xfs_attr_sf_hdr		*sf = ifp->if_data;
 	struct xfs_attr_sf_entry	*sfe;
+	int				size = be16_to_cpu(sf->totsize);
 	struct xfs_da_args		nargs;
 	char				*tmpbuffer;
-	int				error, i, size;
+	int				error, i;
 	xfs_dablk_t			blkno;
 	struct xfs_buf			*bp;
 
 	trace_xfs_attr_sf_to_leaf(args);
 
-	size = be16_to_cpu(sf->hdr.totsize);
 	tmpbuffer = kmem_alloc(size, 0);
 	ASSERT(tmpbuffer != NULL);
 	memcpy(tmpbuffer, ifp->if_data, size);
-	sf = (struct xfs_attr_shortform *)tmpbuffer;
+	sf = (struct xfs_attr_sf_hdr *)tmpbuffer;
 
 	xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
 	xfs_bmap_local_to_extents_empty(args->trans, dp, XFS_ATTR_FORK);
@@ -905,8 +905,8 @@ xfs_attr_shortform_to_leaf(
 	nargs.trans = args->trans;
 	nargs.op_flags = XFS_DA_OP_OKNOENT;
 
-	sfe = &sf->list[0];
-	for (i = 0; i < sf->hdr.count; i++) {
+	sfe = xfs_attr_sf_firstentry(sf);
+	for (i = 0; i < sf->count; i++) {
 		nargs.name = sfe->nameval;
 		nargs.namelen = sfe->namelen;
 		nargs.value = &sfe->nameval[nargs.namelen];
@@ -973,10 +973,10 @@ xfs_attr_shortform_allfit(
 /* Verify the consistency of a raw inline attribute fork. */
 xfs_failaddr_t
 xfs_attr_shortform_verify(
-	struct xfs_attr_shortform	*sfp,
+	struct xfs_attr_sf_hdr		*sfp,
 	size_t				size)
 {
-	struct xfs_attr_sf_entry	*sfep;
+	struct xfs_attr_sf_entry	*sfep = xfs_attr_sf_firstentry(sfp);
 	struct xfs_attr_sf_entry	*next_sfep;
 	char				*endp;
 	int				i;
@@ -990,8 +990,7 @@ xfs_attr_shortform_verify(
 	endp = (char *)sfp + size;
 
 	/* Check all reported entries */
-	sfep = &sfp->list[0];
-	for (i = 0; i < sfp->hdr.count; i++) {
+	for (i = 0; i < sfp->count; i++) {
 		/*
 		 * struct xfs_attr_sf_entry has a variable length.
 		 * Check the fixed-offset parts of the structure are

fs/xfs/libxfs/xfs_attr_leaf.h

@@ -53,7 +53,7 @@ int	xfs_attr_sf_removename(struct xfs_da_args *args);
 struct xfs_attr_sf_entry *xfs_attr_sf_findname(struct xfs_da_args *args);
 int	xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
 int	xfs_attr_shortform_bytesfit(struct xfs_inode *dp, int bytes);
-xfs_failaddr_t xfs_attr_shortform_verify(struct xfs_attr_shortform *sfp,
+xfs_failaddr_t xfs_attr_shortform_verify(struct xfs_attr_sf_hdr *sfp,
 		size_t size);
 void	xfs_attr_fork_remove(struct xfs_inode *ip, struct xfs_trans *tp);
 

fs/xfs/libxfs/xfs_attr_sf.h

@@ -41,7 +41,14 @@ static inline int xfs_attr_sf_entsize(struct xfs_attr_sf_entry *sfep)
 	return struct_size(sfep, nameval, sfep->namelen + sfep->valuelen);
 }
 
-/* next entry in struct */
+/* first entry in the SF attr fork */
+static inline struct xfs_attr_sf_entry *
+xfs_attr_sf_firstentry(struct xfs_attr_sf_hdr *hdr)
+{
+	return (struct xfs_attr_sf_entry *)(hdr + 1);
+}
+
+/* next entry after sfep */
 static inline struct xfs_attr_sf_entry *
 xfs_attr_sf_nextentry(struct xfs_attr_sf_entry *sfep)
 {
@@ -50,9 +57,9 @@ xfs_attr_sf_nextentry(struct xfs_attr_sf_entry *sfep)
 
 /* pointer to the space after the last entry, e.g. for adding a new one */
 static inline struct xfs_attr_sf_entry *
-xfs_attr_sf_endptr(struct xfs_attr_shortform *sf)
+xfs_attr_sf_endptr(struct xfs_attr_sf_hdr *sf)
 {
-	return (void *)sf + be16_to_cpu(sf->hdr.totsize);
+	return (void *)sf + be16_to_cpu(sf->totsize);
 }
 
 #endif	/* __XFS_ATTR_SF_H__ */

fs/xfs/libxfs/xfs_da_format.h

@@ -578,20 +578,25 @@ xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
 #define XFS_ATTR_LEAF_MAPSIZE	3	/* how many freespace slots */
 
 /*
- * Entries are packed toward the top as tight as possible.
- */
-struct xfs_attr_shortform {
-	struct xfs_attr_sf_hdr {	/* constant-structure header block */
-		__be16	totsize;	/* total bytes in shortform list */
-		__u8	count;	/* count of active entries */
-		__u8	padding;
-	} hdr;
-	struct xfs_attr_sf_entry {
-		uint8_t namelen;	/* actual length of name (no NULL) */
-		uint8_t valuelen;	/* actual length of value (no NULL) */
-		uint8_t flags;	/* flags bits (see xfs_attr_leaf.h) */
-		uint8_t nameval[];	/* name & value bytes concatenated */
-	} list[];			/* variable sized array */
+ * Attribute storage when stored inside the inode.
+ *
+ * Small attribute lists are packed as tightly as possible so as to fit into the
+ * literal area of the inode.
+ *
+ * These "shortform" attribute forks consist of a single xfs_attr_sf_hdr header
+ * followed by zero or more xfs_attr_sf_entry structures.
+ */
+struct xfs_attr_sf_hdr {	/* constant-structure header block */
+	__be16	totsize;	/* total bytes in shortform list */
+	__u8	count;		/* count of active entries */
+	__u8	padding;
+};
+
+struct xfs_attr_sf_entry {
+	__u8	namelen;	/* actual length of name (no NULL) */
+	__u8	valuelen;	/* actual length of value (no NULL) */
+	__u8	flags;		/* flags bits (XFS_ATTR_*) */
+	__u8	nameval[];	/* name & value bytes concatenated */
 };
 
 typedef struct xfs_attr_leaf_map {	/* RLE map of free bytes */

fs/xfs/libxfs/xfs_inode_fork.c

@@ -279,10 +279,9 @@ static uint16_t
 xfs_dfork_attr_shortform_size(
 	struct xfs_dinode		*dip)
 {
-	struct xfs_attr_shortform	*atp =
-		(struct xfs_attr_shortform *)XFS_DFORK_APTR(dip);
+	struct xfs_attr_sf_hdr		*sf = XFS_DFORK_APTR(dip);
 
-	return be16_to_cpu(atp->hdr.totsize);
+	return be16_to_cpu(sf->totsize);
 }
 
 void

fs/xfs/libxfs/xfs_ondisk.h

@@ -93,13 +93,13 @@ xfs_check_ondisk_structs(void)
 	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen,	8);
 	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name,	9);
 	XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t,		32);
-	XFS_CHECK_STRUCT_SIZE(struct xfs_attr_shortform,	4);
-	XFS_CHECK_OFFSET(struct xfs_attr_shortform, hdr.totsize, 0);
-	XFS_CHECK_OFFSET(struct xfs_attr_shortform, hdr.count,	 2);
-	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].namelen,	4);
-	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].valuelen,	5);
-	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].flags,	6);
-	XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].nameval,	7);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_attr_sf_hdr,		4);
+	XFS_CHECK_OFFSET(struct xfs_attr_sf_hdr, totsize,	0);
+	XFS_CHECK_OFFSET(struct xfs_attr_sf_hdr, count,		2);
+	XFS_CHECK_OFFSET(struct xfs_attr_sf_entry, namelen,	0);
+	XFS_CHECK_OFFSET(struct xfs_attr_sf_entry, valuelen,	1);
+	XFS_CHECK_OFFSET(struct xfs_attr_sf_entry, flags,	2);
+	XFS_CHECK_OFFSET(struct xfs_attr_sf_entry, nameval,	3);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t,			12);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t,			16);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t,		8);

fs/xfs/scrub/attr.c

@@ -528,23 +528,22 @@ xchk_xattr_check_sf(
 {
 	struct xchk_xattr_buf		*ab = sc->buf;
 	struct xfs_ifork		*ifp = &sc->ip->i_af;
-	struct xfs_attr_shortform	*sf = ifp->if_data;
-	struct xfs_attr_sf_entry	*sfe;
+	struct xfs_attr_sf_hdr		*sf = ifp->if_data;
+	struct xfs_attr_sf_entry	*sfe = xfs_attr_sf_firstentry(sf);
 	struct xfs_attr_sf_entry	*next;
 	unsigned char			*end = ifp->if_data + ifp->if_bytes;
 	int				i;
 	int				error = 0;
 
 	bitmap_zero(ab->usedmap, ifp->if_bytes);
-	xchk_xattr_set_map(sc, ab->usedmap, 0, sizeof(sf->hdr));
+	xchk_xattr_set_map(sc, ab->usedmap, 0, sizeof(*sf));
 
-	sfe = &sf->list[0];
 	if ((unsigned char *)sfe > end) {
 		xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
 		return 0;
 	}
 
-	for (i = 0; i < sf->hdr.count; i++) {
+	for (i = 0; i < sf->count; i++) {
 		unsigned char		*name = sfe->nameval;
 		unsigned char		*value = &sfe->nameval[sfe->namelen];
 

fs/xfs/scrub/inode_repair.c

@@ -760,7 +760,7 @@ xrep_dinode_check_afork(
 	struct xfs_scrub		*sc,
 	struct xfs_dinode		*dip)
 {
-	struct xfs_attr_shortform	*afork_ptr;
+	struct xfs_attr_sf_hdr		*afork_ptr;
 	size_t				attr_size;
 	unsigned int			afork_size;
 
@@ -778,7 +778,7 @@ xrep_dinode_check_afork(
 			return true;
 
 		/* xattr structure cannot be larger than the fork */
-		attr_size = be16_to_cpu(afork_ptr->hdr.totsize);
+		attr_size = be16_to_cpu(afork_ptr->totsize);
 		if (attr_size > afork_size)
 			return true;
 

fs/xfs/xfs_attr_list.c

@@ -56,13 +56,13 @@ xfs_attr_shortform_list(
 	struct xfs_attrlist_cursor_kern	*cursor = &context->cursor;
 	struct xfs_inode		*dp = context->dp;
 	struct xfs_attr_sf_sort		*sbuf, *sbp;
-	struct xfs_attr_shortform	*sf = dp->i_af.if_data;
+	struct xfs_attr_sf_hdr		*sf = dp->i_af.if_data;
 	struct xfs_attr_sf_entry	*sfe;
 	int				sbsize, nsbuf, count, i;
 	int				error = 0;
 
 	ASSERT(sf != NULL);
-	if (!sf->hdr.count)
+	if (!sf->count)
 		return 0;
 
 	trace_xfs_attr_list_sf(context);
@@ -78,8 +78,8 @@ xfs_attr_shortform_list(
 	 */
 	if (context->bufsize == 0 ||
 	    (XFS_ISRESET_CURSOR(cursor) &&
-	     (dp->i_af.if_bytes + sf->hdr.count * 16) < context->bufsize)) {
-		for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
+	     (dp->i_af.if_bytes + sf->count * 16) < context->bufsize)) {
+		for (i = 0, sfe = xfs_attr_sf_firstentry(sf); i < sf->count; i++) {
 			if (XFS_IS_CORRUPT(context->dp->i_mount,
 					   !xfs_attr_namecheck(sfe->nameval,
 							       sfe->namelen)))
@@ -108,15 +108,15 @@ xfs_attr_shortform_list(
 	/*
 	 * It didn't all fit, so we have to sort everything on hashval.
 	 */
-	sbsize = sf->hdr.count * sizeof(*sbuf);
+	sbsize = sf->count * sizeof(*sbuf);
 	sbp = sbuf = kmem_alloc(sbsize, KM_NOFS);
 
 	/*
 	 * Scan the attribute list for the rest of the entries, storing
 	 * the relevant info from only those that match into a buffer.
 	 */
 	nsbuf = 0;
-	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
+	for (i = 0, sfe = xfs_attr_sf_firstentry(sf); i < sf->count; i++) {
 		if (unlikely(
 		    ((char *)sfe < (char *)sf) ||
 		    ((char *)sfe >= ((char *)sf + dp->i_af.if_bytes)))) {