Merge tag 'xfs-5.4-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Darrick Wong:
 "For this cycle we have the usual pile of cleanups and bug fixes, some
  performance improvements for online metadata scrubbing, massive
  speedups in the directory entry creation code, some performance
  improvement in the file ACL lookup code, a fix for a logging stall
  during mount, and fixes for concurrency problems.

  It has survived a couple of weeks of xfstests runs and merges cleanly.

  Summary:

   - Remove KM_SLEEP/KM_NOSLEEP.

   - Ensure that memory buffers for IO are properly sector-aligned to
     avoid problems that the block layer doesn't check.

   - Make the bmap scrubber more efficient in its record checking.

   - Don't crash xfs_db when superblock inode geometry is corrupt.

   - Fix btree key helper functions.

   - Remove unneeded error returns for things that can't fail.

   - Fix buffer logging bugs in repair.

   - Clean up iterator return values.

   - Speed up directory entry creation.

   - Enable allocation of xattr value memory buffer during lookup.

   - Fix readahead racing with truncate/punch hole.

   - Other minor cleanups.

   - Fix one AGI/AGF deadlock with RENAME_WHITEOUT.

   - More BUG -> WARN whackamole.

   - Fix various problems with the log failing to advance under certain
     circumstances, which results in stalls during mount"

* tag 'xfs-5.4-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (45 commits)
  xfs: push the grant head when the log head moves forward
  xfs: push iclog state cleaning into xlog_state_clean_log
  xfs: factor iclog state processing out of xlog_state_do_callback()
  xfs: factor callbacks out of xlog_state_do_callback()
  xfs: factor debug code out of xlog_state_do_callback()
  xfs: prevent CIL push holdoff in log recovery
  xfs: fix missed wakeup on l_flush_wait
  xfs: push the AIL in xlog_grant_head_wake
  xfs: Use WARN_ON_ONCE for bailout mount-operation
  xfs: Fix deadlock between AGI and AGF with RENAME_WHITEOUT
  xfs: define a flags field for the AG geometry ioctl structure
  xfs: add a xfs_valid_startblock helper
  xfs: remove the unused XFS_ALLOC_USERDATA flag
  xfs: cleanup xfs_fsb_to_db
  xfs: fix the dax supported check in xfs_ioctl_setattr_dax_invalidate
  xfs: Fix stale data exposure when readahead races with hole punch
  fs: Export generic_fadvise()
  mm: Handle MADV_WILLNEED through vfs_fadvise()
  xfs: allocate xattr buffer on demand
  xfs: consolidate attribute value copying
  ...

1 files changed, 55 insertions, 24 deletions

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index d48fcf11cc35..510ca6974604 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -97,7 +97,10 @@ xfs_inode_hasattr(
  * Overall external interface routines.
  *========================================================================*/
 
-/* Retrieve an extended attribute and its value.  Must have ilock. */
+/*
+ * Retrieve an extended attribute and its value.  Must have ilock.
+ * Returns 0 on successful retrieval, otherwise an error.
+ */
 int
 xfs_attr_get_ilocked(
 	struct xfs_inode	*ip,
@@ -115,12 +118,28 @@ xfs_attr_get_ilocked(
 		return xfs_attr_node_get(args);
 }
 
-/* Retrieve an extended attribute by name, and its value. */
+/*
+ * Retrieve an extended attribute by name, and its value if requested.
+ *
+ * If ATTR_KERNOVAL is set in @flags, then the caller does not want the value,
+ * just an indication whether the attribute exists and the size of the value if
+ * it exists. The size is returned in @valuelenp,
+ *
+ * If the attribute is found, but exceeds the size limit set by the caller in
+ * @valuelenp, return -ERANGE with the size of the attribute that was found in
+ * @valuelenp.
+ *
+ * If ATTR_ALLOC is set in @flags, allocate the buffer for the value after
+ * existence of the attribute has been determined. On success, return that
+ * buffer to the caller and leave them to free it. On failure, free any
+ * allocated buffer and ensure the buffer pointer returned to the caller is
+ * null.
+ */
 int
 xfs_attr_get(
 	struct xfs_inode	*ip,
 	const unsigned char	*name,
-	unsigned char		*value,
+	unsigned char		**value,
 	int			*valuelenp,
 	int			flags)
 {
@@ -128,6 +147,8 @@ xfs_attr_get(
 	uint			lock_mode;
 	int			error;
 
+	ASSERT((flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || *value);
+
 	XFS_STATS_INC(ip->i_mount, xs_attr_get);
 
 	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
@@ -137,17 +158,29 @@ xfs_attr_get(
 	if (error)
 		return error;
 
-	args.value = value;
-	args.valuelen = *valuelenp;
 	/* Entirely possible to look up a name which doesn't exist */
 	args.op_flags = XFS_DA_OP_OKNOENT;
+	if (flags & ATTR_ALLOC)
+		args.op_flags |= XFS_DA_OP_ALLOCVAL;
+	else
+		args.value = *value;
+	args.valuelen = *valuelenp;
 
 	lock_mode = xfs_ilock_attr_map_shared(ip);
 	error = xfs_attr_get_ilocked(ip, &args);
 	xfs_iunlock(ip, lock_mode);
-
 	*valuelenp = args.valuelen;
-	return error == -EEXIST ? 0 : error;
+
+	/* on error, we have to clean up allocated value buffers */
+	if (error) {
+		if (flags & ATTR_ALLOC) {
+			kmem_free(args.value);
+			*value = NULL;
+		}
+		return error;
+	}
+	*value = args.value;
+	return 0;
 }
 
 /*
@@ -768,6 +801,8 @@ xfs_attr_leaf_removename(
  *
  * This leaf block cannot have a "remote" value, we only call this routine
  * if bmap_one_block() says there is only one block (ie: no remote blks).
+ *
+ * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
 xfs_attr_leaf_get(xfs_da_args_t *args)
@@ -789,9 +824,6 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
 	}
 	error = xfs_attr3_leaf_getvalue(bp, args);
 	xfs_trans_brelse(args->trans, bp);
-	if (!error && (args->rmtblkno > 0) && !(args->flags & ATTR_KERNOVAL)) {
-		error = xfs_attr_rmtval_get(args);
-	}
 	return error;
 }
 
@@ -1268,11 +1300,13 @@ xfs_attr_refillstate(xfs_da_state_t *state)
 }
 
 /*
- * Look up a filename in a node attribute list.
+ * Retrieve the attribute data from a node attribute list.
  *
  * This routine gets called for any attribute fork that has more than one
  * block, ie: both true Btree attr lists and for single-leaf-blocks with
  * "remote" values taking up more blocks.
+ *
+ * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
 xfs_attr_node_get(xfs_da_args_t *args)
@@ -1294,24 +1328,21 @@ xfs_attr_node_get(xfs_da_args_t *args)
 	error = xfs_da3_node_lookup_int(state, &retval);
 	if (error) {
 		retval = error;
-	} else if (retval == -EEXIST) {
-		blk = &state->path.blk[ state->path.active-1 ];
-		ASSERT(blk->bp != NULL);
-		ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
-
-		/*
-		 * Get the value, local or "remote"
-		 */
-		retval = xfs_attr3_leaf_getvalue(blk->bp, args);
-		if (!retval && (args->rmtblkno > 0)
-		    && !(args->flags & ATTR_KERNOVAL)) {
-			retval = xfs_attr_rmtval_get(args);
-		}
+		goto out_release;
 	}
+	if (retval != -EEXIST)
+		goto out_release;
+
+	/*
+	 * Get the value, local or "remote"
+	 */
+	blk = &state->path.blk[state->path.active - 1];
+	retval = xfs_attr3_leaf_getvalue(blk->bp, args);
 
 	/*
 	 * If not in a transaction, we have to release all the buffers.
 	 */
+out_release:
 	for (i = 0; i < state->path.active; i++) {
 		xfs_trans_brelse(args->trans, state->path.blk[i].bp);
 		state->path.blk[i].bp = NULL;