[PATCH v6 15/18] xfs: filter out sparse regions from individual inode allocation

Brian Foster
2015-03-02T13:28:27Z

Inode allocation from an existing record with free inodes traditionally
selects the first inode available according to the ir_free mask. With
sparse inode chunks, the ir_free mask could refer to an unallocated
region. We must mask the unallocated regions out of ir_free before using
it to select a free inode in the chunk.

Update the xfs_inobt_first_free_inode() helper to find the first free
inode available of the allocated regions of the inode chunk.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/libxfs/xfs_ialloc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 9a18c0b..6451a80 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -1076,13 +1076,24 @@ xfs_ialloc_get_rec(
}

/*
- * Return the offset of the first free inode in the record.
+ * Return the offset of the first free inode in the record. If the inode chunk
+ * is sparsely allocated, we convert the record holemask to inode granularity
+ * and mask off the unallocated regions from the inode free mask.
*/
STATIC int
xfs_inobt_first_free_inode(
struct xfs_inobt_rec_incore *rec)
{
- return xfs_lowbit64(rec->ir_free);
+ xfs_inofree_t realfree;
+
+ /* if there are no holes, return the first available offset */
+ if (!xfs_inobt_issparse(rec->ir_holemask))
+ return xfs_lowbit64(rec->ir_free);
+
+ realfree = xfs_inobt_irec_to_allocmask(rec);
+ realfree &= rec->ir_free;
+
+ return xfs_lowbit64(realfree);
}

/*