[PATCH 5/9] xfs: reinitialise recycled VFS inode correctly

Dave Chinner
2016-02-08T04:24:37Z

From: Dave Chinner <dchinner@redhat.com>

Now that we keep certain on-disk information in the VFS inode rather
than in a separate XFS specific stucture, we have to be careful of
the VFS code clearing that information when we re-initialise
reclaimable cached inodes during lookup. If we don't do this, then
we lose critical information from the inode and that results in
corruption being detected.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_icache.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 7c26f86..9ca28655 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -135,6 +135,26 @@ xfs_inode_free(
}

/*
+ * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
+ * part of the structure. This is made more complex by the fact we store
+ * information about the on-disk values in the VFS inode and so we can't just
+ * overwrite it's values unconditionally. Hence we save the parameters we
+ * need to retain across reinitialisation, and rewrite them into the VFS inode
+ * after resetting it's state even if resetting fails.
+ */
+static int
+xfs_reinit_inode(
+ struct xfs_mount *mp,
+ struct inode *inode)
+{
+ int error;
+
+ error = inode_init_always(mp->m_super, inode);
+
+ return error;
+}
+
+/*
* Check the validity of the inode we just found it the cache
*/
static int
@@ -208,7 +228,7 @@ xfs_iget_cache_hit(
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();

- error = inode_init_always(mp->m_super, inode);
+ error = xfs_reinit_inode(mp, inode);
if (error) {
/*
* Re-initializing the inode failed, and we are in deep
--
2.5.0