[PATCH 51/55] xfs: fix calculation of the number of node entries in a dir3 node

Dave Chinner
2013-09-04T22:21:31Z

From: Dave Chinner <dchinner@redhat.com>

The calculation doesn't take into account the size of the dir v3
header, so overestimates the hash entries in a node. This causes
directory buffer overruns when splitting and merging nodes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
include/xfs_da_btree.h | 11 +++++++++--
libxfs/xfs_dir2.c | 16 ++++++++++------
2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/include/xfs_da_btree.h b/include/xfs_da_btree.h
index 8cdc77b..b1f2679 100644
--- a/include/xfs_da_btree.h
+++ b/include/xfs_da_btree.h
@@ -133,12 +133,19 @@ extern void xfs_da3_node_hdr_to_disk(struct xfs_da_intnode *to,
struct xfs_da3_icnode_hdr *from);

static inline int
-xfs_da3_node_hdr_size(struct xfs_da_intnode *dap)
+__xfs_da3_node_hdr_size(bool v3)
{
- if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC))
+ if (v3)
return sizeof(struct xfs_da3_node_hdr);
return sizeof(struct xfs_da_node_hdr);
}
+static inline int
+xfs_da3_node_hdr_size(struct xfs_da_intnode *dap)
+{
+ bool v3 = dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC);
+
+ return __xfs_da3_node_hdr_size(v3);
+}

static inline struct xfs_da_node_entry *
xfs_da3_node_tree_p(struct xfs_da_intnode *dap)
diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 521042f..010c701 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -71,6 +71,9 @@ void
xfs_dir_mount(
xfs_mount_t *mp)
{
+ int nodehdr_size;
+
+
ASSERT(xfs_sb_version_hasdirv2(&mp->m_sb));
ASSERT((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) <=
XFS_MAX_BLOCKSIZE);
@@ -79,12 +82,13 @@ xfs_dir_mount(
mp->m_dirdatablk = xfs_dir2_db_to_da(mp, XFS_DIR2_DATA_FIRSTDB(mp));
mp->m_dirleafblk = xfs_dir2_db_to_da(mp, XFS_DIR2_LEAF_FIRSTDB(mp));
mp->m_dirfreeblk = xfs_dir2_db_to_da(mp, XFS_DIR2_FREE_FIRSTDB(mp));
- mp->m_attr_node_ents =
- (mp->m_sb.sb_blocksize - (uint)sizeof(xfs_da_node_hdr_t)) /
- (uint)sizeof(xfs_da_node_entry_t);
- mp->m_dir_node_ents =
- (mp->m_dirblksize - (uint)sizeof(xfs_da_node_hdr_t)) /
- (uint)sizeof(xfs_da_node_entry_t);
+
+ nodehdr_size = __xfs_da3_node_hdr_size(xfs_sb_version_hascrc(&mp->m_sb));
+ mp->m_attr_node_ents = (mp->m_sb.sb_blocksize - nodehdr_size) /
+ (uint)sizeof(xfs_da_node_entry_t);
+ mp->m_dir_node_ents = (mp->m_dirblksize - nodehdr_size) /
+ (uint)sizeof(xfs_da_node_entry_t);
+
mp->m_dir_magicpct = (mp->m_dirblksize * 37) / 100;
if (xfs_sb_version_hasasciici(&mp->m_sb))
mp->m_dirnameops = &xfs_ascii_ci_nameops;
--
1.8.3.2