xfs: distinguish extra split from real ENOSPC from xfs_attr3_leaf_split

xfs_attr3_leaf_split propagates the need for an extra btree split as
-ENOSPC to it's only caller, but the same return value can also be
returned from xfs_da_grow_inode when it fails to find free space.

Distinguish the two cases by returning 1 for the extra split case instead
of overloading -ENOSPC.

This can be triggered relatively easily with the pending realtime group
support and a file system with a lot of small zones that use metadata
space on the main device.  In this case every about 5-10th run of
xfs/538 runs into the following assert:

	ASSERT(oldblk->magic == XFS_ATTR_LEAF_MAGIC);

in xfs_attr3_leaf_split caused by an allocation failure.  Note that
the allocation failure is caused by another bug that will be fixed
subsequently, but this commit at least sorts out the error handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 41baa8a9a67d78099a65138e9dbdd55d9519e97b..fddb55605e0cc64471190f6622a70ad7edb4f043 100644 (file)
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -1331,6 +1331,9 @@ xfs_attr3_leaf_create(
 
 /*
  * Split the leaf node, rebalance, then add the new entry.
+ *
+ * Returns 0 if the entry was added, 1 if a further split is needed or a
+ * negative error number otherwise.
  */
 int
 xfs_attr3_leaf_split(
@@ -1387,7 +1390,7 @@ xfs_attr3_leaf_split(
        oldblk->hashval = xfs_attr_leaf_lasthash(oldblk->bp, NULL);
        newblk->hashval = xfs_attr_leaf_lasthash(newblk->bp, NULL);
        if (!added)
-               return -ENOSPC;
+               return 1;
        return 0;
 }
 

diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
index 16a529a8878083aee350d746c2d98fd307b83cef..17d9e6154f1978ce5a5cb82176eea4d6b9cd768d 100644 (file)
--- a/fs/xfs/libxfs/xfs_da_btree.c
+++ b/fs/xfs/libxfs/xfs_da_btree.c
@@ -593,9 +593,8 @@ xfs_da3_split(
                switch (oldblk->magic) {
                case XFS_ATTR_LEAF_MAGIC:
                        error = xfs_attr3_leaf_split(state, oldblk, newblk);
-                       if ((error != 0) && (error != -ENOSPC)) {
+                       if (error < 0)
                                return error;   /* GROT: attr is inconsistent */
-                       }
                        if (!error) {
                                addblk = newblk;
                                break;
@@ -617,6 +616,8 @@ xfs_da3_split(
                                error = xfs_attr3_leaf_split(state, newblk,
                                                            &state->extrablk);
                        }
+                       if (error == 1)
+                               return -ENOSPC;
                        if (error)
                                return error;   /* GROT: attr inconsistent */
                        addblk = newblk;