Merge tag 'for-linus-v3.10-rc4-crc-xattr-fixes' of git://oss.sgi.com/xfs/xfs

Pull xfs extended attribute fixes for CRCs from Ben Myers:
 "Here are several fixes that are relevant on CRC enabled XFS
  filesystems.  They are followed by a rework of the remote attribute
  code so that each block of the attribute contains a header with a CRC.

  Previously there was a CRC header per extent in the remote attribute
  code, but this was untenable because it was not possible to know how
  many extents would be allocated for the attribute until after the
  allocation has completed, due to the fragmentation of free space.
  This became complicated because the size of the headers needs to be
  added to the length of the payload to get the overall length required
  for the allocation.  With a header per block, things are less
  complicated at the cost of a little space.

  I would have preferred to defer this and the rest of the CRC queue to
  3.11 to mitigate risk for existing non-crc users in 3.10.  Doing so
  would require setting a feature bit for the on-disk changes, and so I
  have been pressured into sending this pull request by Eric Sandeen and
  David Chinner from Red Hat.  I'll send another pull request or two
  with the rest of the CRC queue next week.

   - Remove assert on count of remote attribute CRC headers
   - Fix the number of blocks read in for remote attributes
   - Zero remote attribute tails properly
   - Fix mapping of remote attribute buffers to have correct length
   - initialize temp leaf properly in xfs_attr3_leaf_unbalance, and
     xfs_attr3_leaf_compact
   - Rework remote atttributes to have a header per block"

* tag 'for-linus-v3.10-rc4-crc-xattr-fixes' of git://oss.sgi.com/xfs/xfs:
  xfs: rework remote attr CRCs
  xfs: fully initialise temp leaf in xfs_attr3_leaf_compact
  xfs: fully initialise temp leaf in xfs_attr3_leaf_unbalance
  xfs: correctly map remote attr buffers during removal
  xfs: remote attribute tail zeroing does too much
  xfs: remote attribute read too short
  xfs: remote attribute allocation may be contiguous

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;

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);

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;
 	}