xfs: rework xfs_buf_incore() API

Make it consistent with the other buffer APIs to return a error and
the buffer is placed in a parameter.

Signed-off-by: Dave Chinner <[e-mail]>
Reviewed-by: Darrick J. Wong <[e-mail]>

fs/xfs/libxfs/xfs_attr_remote.c

···
 {
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_buf		*bp;
+	int			error;
 
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
···
 	    XFS_IS_CORRUPT(mp, map->br_startblock == HOLESTARTBLOCK))
 		return -EFSCORRUPTED;
 
-	bp = xfs_buf_incore(mp->m_ddev_targp,
+	error = xfs_buf_incore(mp->m_ddev_targp,
 			XFS_FSB_TO_DADDR(mp, map->br_startblock),
-			XFS_FSB_TO_BB(mp, map->br_blockcount), incore_flags);
-	if (bp) {
-		xfs_buf_stale(bp);
-		xfs_buf_relse(bp);
+			XFS_FSB_TO_BB(mp, map->br_blockcount),
+			incore_flags, &bp);
+	if (error) {
+		if (error == -ENOENT)
+			return 0;
+		return error;
 	}
 
+	xfs_buf_stale(bp);
+	xfs_buf_relse(bp);
 	return 0;
 }
 

fs/xfs/scrub/repair.c

···
 	 * assume it's owned by someone else.
 	 */
 	for_each_xbitmap_block(fsbno, bmr, n, bitmap) {
+		int		error;
+
 		/* Skip AG headers and post-EOFS blocks */
 		if (!xfs_verify_fsbno(sc->mp, fsbno))
 			continue;
-		bp = xfs_buf_incore(sc->mp->m_ddev_targp,
+		error = xfs_buf_incore(sc->mp->m_ddev_targp,
 				XFS_FSB_TO_DADDR(sc->mp, fsbno),
-				XFS_FSB_TO_BB(sc->mp, 1), XBF_TRYLOCK);
-		if (bp) {
-			xfs_trans_bjoin(sc->tp, bp);
-			xfs_trans_binval(sc->tp, bp);
-		}
+				XFS_FSB_TO_BB(sc->mp, 1), XBF_TRYLOCK, &bp);
+		if (error)
+			continue;
+
+		xfs_trans_bjoin(sc->tp, bp);
+		xfs_trans_binval(sc->tp, bp);
 	}
 
 	return 0;

fs/xfs/xfs_buf.c

···
 	return 0;
 }
 
-struct xfs_buf *
-xfs_buf_incore(
-	struct xfs_buftarg	*target,
-	xfs_daddr_t		blkno,
-	size_t			numblks,
-	xfs_buf_flags_t		flags)
-{
-	struct xfs_buf		*bp;
-	int			error;
-	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
-
-	error = xfs_buf_find(target, &map, 1, flags, NULL, &bp);
-	if (error)
-		return NULL;
-	return bp;
-}
-
 /*
  * Assembles a buffer covering the specified range. The code is optimised for
  * cache hits, as metadata intensive workloads will see 3 orders of magnitude
···
 		goto found;
 	if (error != -ENOENT)
 		return error;
+	if (flags & XBF_INCORE)
+		return -ENOENT;
 
 	error = _xfs_buf_alloc(target, map, nmaps, flags, &new_bp);
 	if (error)

fs/xfs/xfs_buf.h

···
 #define _XBF_DELWRI_Q	 (1u << 22)/* buffer on a delwri queue */
 
 /* flags used only as arguments to access routines */
+#define XBF_INCORE	 (1u << 29)/* lookup only, return if found in cache */
 #define XBF_TRYLOCK	 (1u << 30)/* lock requested, but do not wait */
 #define XBF_UNMAPPED	 (1u << 31)/* do not map the buffer */
+
 
 typedef unsigned int xfs_buf_flags_t;
 
···
 	{ _XBF_KMEM,		"KMEM" }, \
 	{ _XBF_DELWRI_Q,	"DELWRI_Q" }, \
 	/* The following interface flags should never be set */ \
+	{ XBF_INCORE,		"INCORE" }, \
 	{ XBF_TRYLOCK,		"TRYLOCK" }, \
 	{ XBF_UNMAPPED,		"UNMAPPED" }
 
···
 };
 
 /* Finding and Reading Buffers */
-struct xfs_buf *xfs_buf_incore(struct xfs_buftarg *target,
-			   xfs_daddr_t blkno, size_t numblks,
-			   xfs_buf_flags_t flags);
-
 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
 		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
···
 void xfs_buf_readahead_map(struct xfs_buftarg *target,
 			       struct xfs_buf_map *map, int nmaps,
 			       const struct xfs_buf_ops *ops);
+
+static inline int
+xfs_buf_incore(
+	struct xfs_buftarg	*target,
+	xfs_daddr_t		blkno,
+	size_t			numblks,
+	xfs_buf_flags_t		flags,
+	struct xfs_buf		**bpp)
+{
+	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
+
+	return xfs_buf_get_map(target, &map, 1, XBF_INCORE | flags, bpp);
+}
 
 static inline int
 xfs_buf_get(

fs/xfs/xfs_qm.c

···
 	 */
 	if (!xfs_dqflock_nowait(dqp)) {
 		/* buf is pinned in-core by delwri list */
-		bp = xfs_buf_incore(mp->m_ddev_targp, dqp->q_blkno,
-				mp->m_quotainfo->qi_dqchunklen, 0);
-		if (!bp) {
-			error = -EINVAL;
+		error = xfs_buf_incore(mp->m_ddev_targp, dqp->q_blkno,
+				mp->m_quotainfo->qi_dqchunklen, 0, &bp);
+		if (error)
 			goto out_unlock;
-		}
+
 		xfs_buf_unlock(bp);
 
 		xfs_buf_delwri_pushbuf(bp, buffer_list);