4 files changed, 307 insertions, 183 deletions

diff --git a/fs/xfs/xfs_attr_leaf.c b/fs/xfs/xfs_attr_leaf.c
index 0bce1b348580..d788302e506a 100644
--- a/fs/xfs/xfs_attr_leaf.c
+++ b/fs/xfs/xfs_attr_leaf.c
@@ -1412,7 +1412,7 @@ xfs_attr3_leaf_add_work(
 		name_rmt->valuelen = 0;
 		name_rmt->valueblk = 0;
 		args->rmtblkno = 1;
-		args->rmtblkcnt = XFS_B_TO_FSB(mp, args->valuelen);
+		args->rmtblkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
 	}
 	xfs_trans_log_buf(args->trans, bp,
 	     XFS_DA_LOGRANGE(leaf, xfs_attr3_leaf_name(leaf, args->index),
@@ -1445,11 +1445,12 @@ xfs_attr3_leaf_add_work(
 STATIC void
 xfs_attr3_leaf_compact(
 	struct xfs_da_args	*args,
-	struct xfs_attr3_icleaf_hdr *ichdr_d,
+	struct xfs_attr3_icleaf_hdr *ichdr_dst,
 	struct xfs_buf		*bp)
 {
-	xfs_attr_leafblock_t	*leaf_s, *leaf_d;
-	struct xfs_attr3_icleaf_hdr ichdr_s;
+	struct xfs_attr_leafblock *leaf_src;
+	struct xfs_attr_leafblock *leaf_dst;
+	struct xfs_attr3_icleaf_hdr ichdr_src;
 	struct xfs_trans	*trans = args->trans;
 	struct xfs_mount	*mp = trans->t_mountp;
 	char			*tmpbuffer;
@@ -1457,29 +1458,38 @@ xfs_attr3_leaf_compact(
 	trace_xfs_attr_leaf_compact(args);
 
 	tmpbuffer = kmem_alloc(XFS_LBSIZE(mp), KM_SLEEP);
-	ASSERT(tmpbuffer != NULL);
 	memcpy(tmpbuffer, bp->b_addr, XFS_LBSIZE(mp));
 	memset(bp->b_addr, 0, XFS_LBSIZE(mp));
+	leaf_src = (xfs_attr_leafblock_t *)tmpbuffer;
+	leaf_dst = bp->b_addr;
 
 	/*
-	 * Copy basic information
+	 * Copy the on-disk header back into the destination buffer to ensure
+	 * all the information in the header that is not part of the incore
+	 * header structure is preserved.
 	 */
-	leaf_s = (xfs_attr_leafblock_t *)tmpbuffer;
-	leaf_d = bp->b_addr;
-	ichdr_s = *ichdr_d;	/* struct copy */
-	ichdr_d->firstused = XFS_LBSIZE(mp);
-	ichdr_d->usedbytes = 0;
-	ichdr_d->count = 0;
-	ichdr_d->holes = 0;
-	ichdr_d->freemap[0].base = xfs_attr3_leaf_hdr_size(leaf_s);
-	ichdr_d->freemap[0].size = ichdr_d->firstused - ichdr_d->freemap[0].base;
+	memcpy(bp->b_addr, tmpbuffer, xfs_attr3_leaf_hdr_size(leaf_src));
+
+	/* Initialise the incore headers */
+	ichdr_src = *ichdr_dst;	/* struct copy */
+	ichdr_dst->firstused = XFS_LBSIZE(mp);
+	ichdr_dst->usedbytes = 0;
+	ichdr_dst->count = 0;
+	ichdr_dst->holes = 0;
+	ichdr_dst->freemap[0].base = xfs_attr3_leaf_hdr_size(leaf_src);
+	ichdr_dst->freemap[0].size = ichdr_dst->firstused -
+						ichdr_dst->freemap[0].base;
+
+
+	/* write the header back to initialise the underlying buffer */
+	xfs_attr3_leaf_hdr_to_disk(leaf_dst, ichdr_dst);
 
 	/*
 	 * Copy all entry's in the same (sorted) order,
 	 * but allocate name/value pairs packed and in sequence.
 	 */
-	xfs_attr3_leaf_moveents(leaf_s, &ichdr_s, 0, leaf_d, ichdr_d, 0,
-				ichdr_s.count, mp);
+	xfs_attr3_leaf_moveents(leaf_src, &ichdr_src, 0, leaf_dst, ichdr_dst, 0,
+				ichdr_src.count, mp);
 	/*
 	 * this logs the entire buffer, but the caller must write the header
 	 * back to the buffer when it is finished modifying it.
@@ -2181,14 +2191,24 @@ xfs_attr3_leaf_unbalance(
 		struct xfs_attr_leafblock *tmp_leaf;
 		struct xfs_attr3_icleaf_hdr tmphdr;
 
-		tmp_leaf = kmem_alloc(state->blocksize, KM_SLEEP);
-		memset(tmp_leaf, 0, state->blocksize);
-		memset(&tmphdr, 0, sizeof(tmphdr));
+		tmp_leaf = kmem_zalloc(state->blocksize, KM_SLEEP);
 
+		/*
+		 * Copy the header into the temp leaf so that all the stuff
+		 * not in the incore header is present and gets copied back in
+		 * once we've moved all the entries.
+		 */
+		memcpy(tmp_leaf, save_leaf, xfs_attr3_leaf_hdr_size(save_leaf));
+
+		memset(&tmphdr, 0, sizeof(tmphdr));
 		tmphdr.magic = savehdr.magic;
 		tmphdr.forw = savehdr.forw;
 		tmphdr.back = savehdr.back;
 		tmphdr.firstused = state->blocksize;
+
+		/* write the header to the temp buffer to initialise it */
+		xfs_attr3_leaf_hdr_to_disk(tmp_leaf, &tmphdr);
+
 		if (xfs_attr3_leaf_order(save_blk->bp, &savehdr,
 					 drop_blk->bp, &drophdr)) {
 			xfs_attr3_leaf_moveents(drop_leaf, &drophdr, 0,
@@ -2334,8 +2354,9 @@ xfs_attr3_leaf_lookup_int(
 			args->index = probe;
 			args->valuelen = be32_to_cpu(name_rmt->valuelen);
 			args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
-			args->rmtblkcnt = XFS_B_TO_FSB(args->dp->i_mount,
-						       args->valuelen);
+			args->rmtblkcnt = xfs_attr3_rmt_blocks(
+							args->dp->i_mount,
+							args->valuelen);
 			return XFS_ERROR(EEXIST);
 		}
 	}
@@ -2386,7 +2407,8 @@ xfs_attr3_leaf_getvalue(
 		ASSERT(memcmp(args->name, name_rmt->name, args->namelen) == 0);
 		valuelen = be32_to_cpu(name_rmt->valuelen);
 		args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
-		args->rmtblkcnt = XFS_B_TO_FSB(args->dp->i_mount, valuelen);
+		args->rmtblkcnt = xfs_attr3_rmt_blocks(args->dp->i_mount,
+						       valuelen);
 		if (args->flags & ATTR_KERNOVAL) {
 			args->valuelen = valuelen;
 			return 0;
@@ -2712,7 +2734,8 @@ xfs_attr3_leaf_list_int(
 				args.valuelen = valuelen;
 				args.value = kmem_alloc(valuelen, KM_SLEEP | KM_NOFS);
 				args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
-				args.rmtblkcnt = XFS_B_TO_FSB(args.dp->i_mount, valuelen);
+				args.rmtblkcnt = xfs_attr3_rmt_blocks(
+							args.dp->i_mount, valuelen);
 				retval = xfs_attr_rmtval_get(&args);
 				if (retval)
 					return retval;
diff --git a/fs/xfs/xfs_attr_remote.c b/fs/xfs/xfs_attr_remote.c
index dee84466dcc9..ef6b0c124528 100644
--- a/fs/xfs/xfs_attr_remote.c
+++ b/fs/xfs/xfs_attr_remote.c
@@ -47,22 +47,55 @@
  * Each contiguous block has a header, so it is not just a simple attribute
  * length to FSB conversion.
  */
-static int
+int
 xfs_attr3_rmt_blocks(
 	struct xfs_mount *mp,
 	int		attrlen)
 {
-	int		buflen = XFS_ATTR3_RMT_BUF_SPACE(mp,
-							 mp->m_sb.sb_blocksize);
-	return (attrlen + buflen - 1) / buflen;
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		int buflen = XFS_ATTR3_RMT_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
+		return (attrlen + buflen - 1) / buflen;
+	}
+	return XFS_B_TO_FSB(mp, attrlen);
+}
+
+/*
+ * Checking of the remote attribute header is split into two parts. The verifier
+ * does CRC, location and bounds checking, the unpacking function checks the
+ * attribute parameters and owner.
+ */
+static bool
+xfs_attr3_rmt_hdr_ok(
+	struct xfs_mount	*mp,
+	void			*ptr,
+	xfs_ino_t		ino,
+	uint32_t		offset,
+	uint32_t		size,
+	xfs_daddr_t		bno)
+{
+	struct xfs_attr3_rmt_hdr *rmt = ptr;
+
+	if (bno != be64_to_cpu(rmt->rm_blkno))
+		return false;
+	if (offset != be32_to_cpu(rmt->rm_offset))
+		return false;
+	if (size != be32_to_cpu(rmt->rm_bytes))
+		return false;
+	if (ino != be64_to_cpu(rmt->rm_owner))
+		return false;
+
+	/* ok */
+	return true;
 }
 
 static bool
 xfs_attr3_rmt_verify(
-	struct xfs_buf		*bp)
+	struct xfs_mount	*mp,
+	void			*ptr,
+	int			fsbsize,
+	xfs_daddr_t		bno)
 {
-	struct xfs_mount	*mp = bp->b_target->bt_mount;
-	struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+	struct xfs_attr3_rmt_hdr *rmt = ptr;
 
 	if (!xfs_sb_version_hascrc(&mp->m_sb))
 		return false;
@@ -70,7 +103,9 @@ xfs_attr3_rmt_verify(
 		return false;
 	if (!uuid_equal(&rmt->rm_uuid, &mp->m_sb.sb_uuid))
 		return false;
-	if (bp->b_bn != be64_to_cpu(rmt->rm_blkno))
+	if (be64_to_cpu(rmt->rm_blkno) != bno)
+		return false;
+	if (be32_to_cpu(rmt->rm_bytes) > fsbsize - sizeof(*rmt))
 		return false;
 	if (be32_to_cpu(rmt->rm_offset) +
 				be32_to_cpu(rmt->rm_bytes) >= XATTR_SIZE_MAX)
@@ -86,17 +121,40 @@ xfs_attr3_rmt_read_verify(
 	struct xfs_buf	*bp)
 {
 	struct xfs_mount *mp = bp->b_target->bt_mount;
+	char		*ptr;
+	int		len;
+	bool		corrupt = false;
+	xfs_daddr_t	bno;
 
 	/* no verification of non-crc buffers */
 	if (!xfs_sb_version_hascrc(&mp->m_sb))
 		return;
 
-	if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
-			      XFS_ATTR3_RMT_CRC_OFF) ||
-	    !xfs_attr3_rmt_verify(bp)) {
+	ptr = bp->b_addr;
+	bno = bp->b_bn;
+	len = BBTOB(bp->b_length);
+	ASSERT(len >= XFS_LBSIZE(mp));
+
+	while (len > 0) {
+		if (!xfs_verify_cksum(ptr, XFS_LBSIZE(mp),
+				      XFS_ATTR3_RMT_CRC_OFF)) {
+			corrupt = true;
+			break;
+		}
+		if (!xfs_attr3_rmt_verify(mp, ptr, XFS_LBSIZE(mp), bno)) {
+			corrupt = true;
+			break;
+		}
+		len -= XFS_LBSIZE(mp);
+		ptr += XFS_LBSIZE(mp);
+		bno += mp->m_bsize;
+	}
+
+	if (corrupt) {
 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 		xfs_buf_ioerror(bp, EFSCORRUPTED);
-	}
+	} else
+		ASSERT(len == 0);
 }
 
 static void
@@ -105,23 +163,39 @@ xfs_attr3_rmt_write_verify(
 {
 	struct xfs_mount *mp = bp->b_target->bt_mount;
 	struct xfs_buf_log_item	*bip = bp->b_fspriv;
+	char		*ptr;
+	int		len;
+	xfs_daddr_t	bno;
 
 	/* no verification of non-crc buffers */
 	if (!xfs_sb_version_hascrc(&mp->m_sb))
 		return;
 
-	if (!xfs_attr3_rmt_verify(bp)) {
-		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
-		xfs_buf_ioerror(bp, EFSCORRUPTED);
-		return;
-	}
+	ptr = bp->b_addr;
+	bno = bp->b_bn;
+	len = BBTOB(bp->b_length);
+	ASSERT(len >= XFS_LBSIZE(mp));
+
+	while (len > 0) {
+		if (!xfs_attr3_rmt_verify(mp, ptr, XFS_LBSIZE(mp), bno)) {
+			XFS_CORRUPTION_ERROR(__func__,
+					    XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+			xfs_buf_ioerror(bp, EFSCORRUPTED);
+			return;
+		}
+		if (bip) {
+			struct xfs_attr3_rmt_hdr *rmt;
+
+			rmt = (struct xfs_attr3_rmt_hdr *)ptr;
+			rmt->rm_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+		}
+		xfs_update_cksum(ptr, XFS_LBSIZE(mp), XFS_ATTR3_RMT_CRC_OFF);
 
-	if (bip) {
-		struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
-		rmt->rm_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+		len -= XFS_LBSIZE(mp);
+		ptr += XFS_LBSIZE(mp);
+		bno += mp->m_bsize;
 	}
-	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
-			 XFS_ATTR3_RMT_CRC_OFF);
+	ASSERT(len == 0);
 }
 
 const struct xfs_buf_ops xfs_attr3_rmt_buf_ops = {
@@ -129,15 +203,16 @@ const struct xfs_buf_ops xfs_attr3_rmt_buf_ops = {
 	.verify_write = xfs_attr3_rmt_write_verify,
 };
 
-static int
+STATIC int
 xfs_attr3_rmt_hdr_set(
 	struct xfs_mount	*mp,
+	void			*ptr,
 	xfs_ino_t		ino,
 	uint32_t		offset,
 	uint32_t		size,
-	struct xfs_buf		*bp)
+	xfs_daddr_t		bno)
 {
-	struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+	struct xfs_attr3_rmt_hdr *rmt = ptr;
 
 	if (!xfs_sb_version_hascrc(&mp->m_sb))
 		return 0;
@@ -147,36 +222,107 @@ xfs_attr3_rmt_hdr_set(
 	rmt->rm_bytes = cpu_to_be32(size);
 	uuid_copy(&rmt->rm_uuid, &mp->m_sb.sb_uuid);
 	rmt->rm_owner = cpu_to_be64(ino);
-	rmt->rm_blkno = cpu_to_be64(bp->b_bn);
-	bp->b_ops = &xfs_attr3_rmt_buf_ops;
+	rmt->rm_blkno = cpu_to_be64(bno);
 
 	return sizeof(struct xfs_attr3_rmt_hdr);
 }
 
 /*
- * Checking of the remote attribute header is split into two parts. the verifier
- * does CRC, location and bounds checking, the unpacking function checks the
- * attribute parameters and owner.
+ * Helper functions to copy attribute data in and out of the one disk extents
  */
-static bool
-xfs_attr3_rmt_hdr_ok(
-	struct xfs_mount	*mp,
-	xfs_ino_t		ino,
-	uint32_t		offset,
-	uint32_t		size,
-	struct xfs_buf		*bp)
+STATIC int
+xfs_attr_rmtval_copyout(
+	struct xfs_mount *mp,
+	struct xfs_buf	*bp,
+	xfs_ino_t	ino,
+	int		*offset,
+	int		*valuelen,
+	char		**dst)
 {
-	struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+	char		*src = bp->b_addr;
+	xfs_daddr_t	bno = bp->b_bn;
+	int		len = BBTOB(bp->b_length);
 
-	if (offset != be32_to_cpu(rmt->rm_offset))
-		return false;
-	if (size != be32_to_cpu(rmt->rm_bytes))
-		return false;
-	if (ino != be64_to_cpu(rmt->rm_owner))
-		return false;
+	ASSERT(len >= XFS_LBSIZE(mp));
 
-	/* ok */
-	return true;
+	while (len > 0 && *valuelen > 0) {
+		int hdr_size = 0;
+		int byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, XFS_LBSIZE(mp));
+
+		byte_cnt = min_t(int, *valuelen, byte_cnt);
+
+		if (xfs_sb_version_hascrc(&mp->m_sb)) {
+			if (!xfs_attr3_rmt_hdr_ok(mp, src, ino, *offset,
+						  byte_cnt, bno)) {
+				xfs_alert(mp,
+"remote attribute header mismatch bno/off/len/owner (0x%llx/0x%x/Ox%x/0x%llx)",
+					bno, *offset, byte_cnt, ino);
+				return EFSCORRUPTED;
+			}
+			hdr_size = sizeof(struct xfs_attr3_rmt_hdr);
+		}
+
+		memcpy(*dst, src + hdr_size, byte_cnt);
+
+		/* roll buffer forwards */
+		len -= XFS_LBSIZE(mp);
+		src += XFS_LBSIZE(mp);
+		bno += mp->m_bsize;
+
+		/* roll attribute data forwards */
+		*valuelen -= byte_cnt;
+		*dst += byte_cnt;
+		*offset += byte_cnt;
+	}
+	return 0;
+}
+
+STATIC void
+xfs_attr_rmtval_copyin(
+	struct xfs_mount *mp,
+	struct xfs_buf	*bp,
+	xfs_ino_t	ino,
+	int		*offset,
+	int		*valuelen,
+	char		**src)
+{
+	char		*dst = bp->b_addr;
+	xfs_daddr_t	bno = bp->b_bn;
+	int		len = BBTOB(bp->b_length);
+
+	ASSERT(len >= XFS_LBSIZE(mp));
+
+	while (len > 0 && *valuelen > 0) {
+		int hdr_size;
+		int byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, XFS_LBSIZE(mp));
+
+		byte_cnt = min(*valuelen, byte_cnt);
+		hdr_size = xfs_attr3_rmt_hdr_set(mp, dst, ino, *offset,
+						 byte_cnt, bno);
+
+		memcpy(dst + hdr_size, *src, byte_cnt);
+
+		/*
+		 * If this is the last block, zero the remainder of it.
+		 * Check that we are actually the last block, too.
+		 */
+		if (byte_cnt + hdr_size < XFS_LBSIZE(mp)) {
+			ASSERT(*valuelen - byte_cnt == 0);
+			ASSERT(len == XFS_LBSIZE(mp));
+			memset(dst + hdr_size + byte_cnt, 0,
+					XFS_LBSIZE(mp) - hdr_size - byte_cnt);
+		}
+
+		/* roll buffer forwards */
+		len -= XFS_LBSIZE(mp);
+		dst += XFS_LBSIZE(mp);
+		bno += mp->m_bsize;
+
+		/* roll attribute data forwards */
+		*valuelen -= byte_cnt;
+		*src += byte_cnt;
+		*offset += byte_cnt;
+	}
 }
 
 /*
@@ -190,13 +336,12 @@ xfs_attr_rmtval_get(
 	struct xfs_bmbt_irec	map[ATTR_RMTVALUE_MAPSIZE];
 	struct xfs_mount	*mp = args->dp->i_mount;
 	struct xfs_buf		*bp;
-	xfs_daddr_t		dblkno;
 	xfs_dablk_t		lblkno = args->rmtblkno;
-	void			*dst = args->value;
+	char			*dst = args->value;
 	int			valuelen = args->valuelen;
 	int			nmap;
 	int			error;
-	int			blkcnt;
+	int			blkcnt = args->rmtblkcnt;
 	int			i;
 	int			offset = 0;
 
@@ -207,52 +352,36 @@ xfs_attr_rmtval_get(
 	while (valuelen > 0) {
 		nmap = ATTR_RMTVALUE_MAPSIZE;
 		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
-				       args->rmtblkcnt, map, &nmap,
+				       blkcnt, map, &nmap,
 				       XFS_BMAPI_ATTRFORK);
 		if (error)
 			return error;
 		ASSERT(nmap >= 1);
 
 		for (i = 0; (i < nmap) && (valuelen > 0); i++) {
-			int	byte_cnt;
-			char	*src;
+			xfs_daddr_t	dblkno;
+			int		dblkcnt;
 
 			ASSERT((map[i].br_startblock != DELAYSTARTBLOCK) &&
 			       (map[i].br_startblock != HOLESTARTBLOCK));
 			dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock);
-			blkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
+			dblkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
 			error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
-						   dblkno, blkcnt, 0, &bp,
+						   dblkno, dblkcnt, 0, &bp,
 						   &xfs_attr3_rmt_buf_ops);
 			if (error)
 				return error;
 
-			byte_cnt = min_t(int, valuelen, BBTOB(bp->b_length));
-			byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, byte_cnt);
-
-			src = bp->b_addr;
-			if (xfs_sb_version_hascrc(&mp->m_sb)) {
-				if (!xfs_attr3_rmt_hdr_ok(mp, args->dp->i_ino,
-							offset, byte_cnt, bp)) {
-					xfs_alert(mp,
-"remote attribute header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
-						offset, byte_cnt, args->dp->i_ino);
-					xfs_buf_relse(bp);
-					return EFSCORRUPTED;
-
-				}
-
-				src += sizeof(struct xfs_attr3_rmt_hdr);
-			}
-
-			memcpy(dst, src, byte_cnt);
+			error = xfs_attr_rmtval_copyout(mp, bp, args->dp->i_ino,
+							&offset, &valuelen,
+							&dst);
 			xfs_buf_relse(bp);
+			if (error)
+				return error;
 
-			offset += byte_cnt;
-			dst += byte_cnt;
-			valuelen -= byte_cnt;
-
+			/* roll attribute extent map forwards */
 			lblkno += map[i].br_blockcount;
+			blkcnt -= map[i].br_blockcount;
 		}
 	}
 	ASSERT(valuelen == 0);
@@ -270,17 +399,13 @@ xfs_attr_rmtval_set(
 	struct xfs_inode	*dp = args->dp;
 	struct xfs_mount	*mp = dp->i_mount;
 	struct xfs_bmbt_irec	map;
-	struct xfs_buf		*bp;
-	xfs_daddr_t		dblkno;
 	xfs_dablk_t		lblkno;
 	xfs_fileoff_t		lfileoff = 0;
-	void			*src = args->value;
+	char			*src = args->value;
 	int			blkcnt;
 	int			valuelen;
 	int			nmap;
 	int			error;
-	int			hdrcnt = 0;
-	bool			crcs = xfs_sb_version_hascrc(&mp->m_sb);
 	int			offset = 0;
 
 	trace_xfs_attr_rmtval_set(args);
@@ -289,24 +414,14 @@ xfs_attr_rmtval_set(
 	 * Find a "hole" in the attribute address space large enough for
 	 * us to drop the new attribute's value into. Because CRC enable
 	 * attributes have headers, we can't just do a straight byte to FSB
-	 * conversion. We calculate the worst case block count in this case
-	 * and we may not need that many, so we have to handle this when
-	 * allocating the blocks below. 
+	 * conversion and have to take the header space into account.
 	 */
-	if (!crcs)
-		blkcnt = XFS_B_TO_FSB(mp, args->valuelen);
-	else
-		blkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
-
+	blkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
 	error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
 						   XFS_ATTR_FORK);
 	if (error)
 		return error;
 
-	/* Start with the attribute data. We'll allocate the rest afterwards. */
-	if (crcs)
-		blkcnt = XFS_B_TO_FSB(mp, args->valuelen);
-
 	args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
 	args->rmtblkcnt = blkcnt;
 
@@ -349,26 +464,6 @@ xfs_attr_rmtval_set(
 		       (map.br_startblock != HOLESTARTBLOCK));
 		lblkno += map.br_blockcount;
 		blkcnt -= map.br_blockcount;
-		hdrcnt++;
-
-		/*
-		 * If we have enough blocks for the attribute data, calculate
-		 * how many extra blocks we need for headers. We might run
-		 * through this multiple times in the case that the additional
-		 * headers in the blocks needed for the data fragments spills
-		 * into requiring more blocks. e.g. for 512 byte blocks, we'll
-		 * spill for another block every 9 headers we require in this
-		 * loop.
-		 */
-		if (crcs && blkcnt == 0) {
-			int total_len;
-
-			total_len = args->valuelen +
-				    hdrcnt * sizeof(struct xfs_attr3_rmt_hdr);
-			blkcnt = XFS_B_TO_FSB(mp, total_len);
-			blkcnt -= args->rmtblkcnt;
-			args->rmtblkcnt += blkcnt;
-		}
 
 		/*
 		 * Start the next trans in the chain.
@@ -385,18 +480,19 @@ xfs_attr_rmtval_set(
 	 * the INCOMPLETE flag.
 	 */
 	lblkno = args->rmtblkno;
+	blkcnt = args->rmtblkcnt;
 	valuelen = args->valuelen;
 	while (valuelen > 0) {
-		int	byte_cnt;
-		char	*buf;
+		struct xfs_buf	*bp;
+		xfs_daddr_t	dblkno;
+		int		dblkcnt;
+
+		ASSERT(blkcnt > 0);
 
-		/*
-		 * Try to remember where we decided to put the value.
-		 */
 		xfs_bmap_init(args->flist, args->firstblock);
 		nmap = 1;
 		error = xfs_bmapi_read(dp, (xfs_fileoff_t)lblkno,
-				       args->rmtblkcnt, &map, &nmap,
+				       blkcnt, &map, &nmap,
 				       XFS_BMAPI_ATTRFORK);
 		if (error)
 			return(error);
@@ -405,41 +501,27 @@ xfs_attr_rmtval_set(
 		       (map.br_startblock != HOLESTARTBLOCK));
 
 		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
-		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
+		dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
 
-		bp = xfs_buf_get(mp->m_ddev_targp, dblkno, blkcnt, 0);
+		bp = xfs_buf_get(mp->m_ddev_targp, dblkno, dblkcnt, 0);
 		if (!bp)
 			return ENOMEM;
 		bp->b_ops = &xfs_attr3_rmt_buf_ops;
 
-		byte_cnt = BBTOB(bp->b_length);
-		byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, byte_cnt);
-		if (valuelen < byte_cnt)
-			byte_cnt = valuelen;
-
-		buf = bp->b_addr;
-		buf += xfs_attr3_rmt_hdr_set(mp, dp->i_ino, offset,
-					     byte_cnt, bp);
-		memcpy(buf, src, byte_cnt);
-
-		if (byte_cnt < BBTOB(bp->b_length))
-			xfs_buf_zero(bp, byte_cnt,
-				     BBTOB(bp->b_length) - byte_cnt);
+		xfs_attr_rmtval_copyin(mp, bp, args->dp->i_ino, &offset,
+				       &valuelen, &src);
 
 		error = xfs_bwrite(bp);	/* GROT: NOTE: synchronous write */
 		xfs_buf_relse(bp);
 		if (error)
 			return error;
 
-		src += byte_cnt;
-		valuelen -= byte_cnt;
-		offset += byte_cnt;
-		hdrcnt--;
 
+		/* roll attribute extent map forwards */
 		lblkno += map.br_blockcount;
+		blkcnt -= map.br_blockcount;
 	}
 	ASSERT(valuelen == 0);
-	ASSERT(hdrcnt == 0);
 	return 0;
 }
 
@@ -448,33 +530,40 @@ xfs_attr_rmtval_set(
  * out-of-line buffer that it is stored on.
  */
 int
-xfs_attr_rmtval_remove(xfs_da_args_t *args)
+xfs_attr_rmtval_remove(
+	struct xfs_da_args	*args)
 {
-	xfs_mount_t *mp;
-	xfs_bmbt_irec_t map;
-	xfs_buf_t *bp;
-	xfs_daddr_t dblkno;
-	xfs_dablk_t lblkno;
-	int valuelen, blkcnt, nmap, error, done, committed;
+	struct xfs_mount	*mp = args->dp->i_mount;
+	xfs_dablk_t		lblkno;
+	int			blkcnt;
+	int			error;
+	int			done;
 
 	trace_xfs_attr_rmtval_remove(args);
 
-	mp = args->dp->i_mount;
-
 	/*
-	 * Roll through the "value", invalidating the attribute value's
-	 * blocks.
+	 * Roll through the "value", invalidating the attribute value's blocks.
+	 * Note that args->rmtblkcnt is the minimum number of data blocks we'll
+	 * see for a CRC enabled remote attribute. Each extent will have a
+	 * header, and so we may have more blocks than we realise here.  If we
+	 * fail to map the blocks correctly, we'll have problems with the buffer
+	 * lookups.
 	 */
 	lblkno = args->rmtblkno;
-	valuelen = args->rmtblkcnt;
-	while (valuelen > 0) {
+	blkcnt = args->rmtblkcnt;
+	while (blkcnt > 0) {
+		struct xfs_bmbt_irec	map;
+		struct xfs_buf		*bp;
+		xfs_daddr_t		dblkno;
+		int			dblkcnt;
+		int			nmap;
+
 		/*
 		 * Try to remember where we decided to put the value.
 		 */
 		nmap = 1;
 		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
-				       args->rmtblkcnt, &map, &nmap,
-				       XFS_BMAPI_ATTRFORK);
+				       blkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK);
 		if (error)
 			return(error);
 		ASSERT(nmap == 1);
@@ -482,21 +571,20 @@ xfs_attr_rmtval_remove(xfs_da_args_t *args)
 		       (map.br_startblock != HOLESTARTBLOCK));
 
 		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
-		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
+		dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
 
 		/*
 		 * If the "remote" value is in the cache, remove it.
 		 */
-		bp = xfs_incore(mp->m_ddev_targp, dblkno, blkcnt, XBF_TRYLOCK);
+		bp = xfs_incore(mp->m_ddev_targp, dblkno, dblkcnt, XBF_TRYLOCK);
 		if (bp) {
 			xfs_buf_stale(bp);
 			xfs_buf_relse(bp);
 			bp = NULL;
 		}
 
-		valuelen -= map.br_blockcount;
-
 		lblkno += map.br_blockcount;
+		blkcnt -= map.br_blockcount;
 	}
 
 	/*
@@ -506,6 +594,8 @@ xfs_attr_rmtval_remove(xfs_da_args_t *args)
 	blkcnt = args->rmtblkcnt;
 	done = 0;
 	while (!done) {
+		int committed;
+
 		xfs_bmap_init(args->flist, args->firstblock);
 		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
 				    XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
diff --git a/fs/xfs/xfs_attr_remote.h b/fs/xfs/xfs_attr_remote.h
index c7cca60a062a..92a8fd7977cc 100644
--- a/fs/xfs/xfs_attr_remote.h
+++ b/fs/xfs/xfs_attr_remote.h
@@ -20,6 +20,14 @@
 
 #define XFS_ATTR3_RMT_MAGIC	0x5841524d	/* XARM */
 
+/*
+ * There is one of these headers per filesystem block in a remote attribute.
+ * This is done to ensure there is a 1:1 mapping between the attribute value
+ * length and the number of blocks needed to store the attribute. This makes the
+ * verification of a buffer a little more complex, but greatly simplifies the
+ * allocation, reading and writing of these attributes as we don't have to guess
+ * the number of blocks needed to store the attribute data.
+ */
 struct xfs_attr3_rmt_hdr {
 	__be32	rm_magic;
 	__be32	rm_offset;
@@ -39,6 +47,8 @@ struct xfs_attr3_rmt_hdr {
 
 extern const struct xfs_buf_ops xfs_attr3_rmt_buf_ops;
 
+int xfs_attr3_rmt_blocks(struct xfs_mount *mp, int attrlen);
+
 int xfs_attr_rmtval_get(struct xfs_da_args *args);
 int xfs_attr_rmtval_set(struct xfs_da_args *args);
 int xfs_attr_rmtval_remove(struct xfs_da_args *args);
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 0d2554299688..1b2472a46e46 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -513,6 +513,7 @@ _xfs_buf_find(
 		xfs_alert(btp->bt_mount,
 			  "%s: Block out of range: block 0x%llx, EOFS 0x%llx ",
 			  __func__, blkno, eofs);
+		WARN_ON(1);
 		return NULL;
 	}