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

To: xfs@xxxxxxxxxxx
Subject: [PATCH 51/55] xfs: fix calculation of the number of node entries in a dir3 node
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Thu, 5 Sep 2013 08:05:55 +1000
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1378332359-14737-1-git-send-email-david@xxxxxxxxxxxxx>
References: <1378332359-14737-1-git-send-email-david@xxxxxxxxxxxxx>
From: Dave Chinner <dchinner@xxxxxxxxxx>

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@xxxxxxxxxx>
---
 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

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