fs/9p: When doing inode lookup compare qid details and inode mode bits.

This make sure we don't use wrong inode from the inode hash. The inode number
of the file deleted is reused by the next file system object created
and if we only use inode number for inode hash lookup we could end up
with wrong struct inode.

Also compare inode generation number. Not all Linux file system provide
st_gen in userspace. So it could be 0;

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 33 insertions, 3 deletions

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index a5a95372cd68..3d8a18ee78e6 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -216,7 +216,6 @@ struct inode *v9fs_alloc_inode(struct super_block *sb)
 		return NULL;
 #ifdef CONFIG_9P_FSCACHE
 	v9inode->fscache = NULL;
-	v9inode->fscache_key = NULL;
 	spin_lock_init(&v9inode->fscache_lock);
 #endif
 	v9inode->writeback_fid = NULL;
@@ -433,6 +432,37 @@ void v9fs_evict_inode(struct inode *inode)
 	}
 }
 
+static int v9fs_test_inode(struct inode *inode, void *data)
+{
+	int umode;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_wstat *st = (struct p9_wstat *)data;
+	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
+
+	umode = p9mode2unixmode(v9ses, st->mode);
+	/* don't match inode of different type */
+	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
+		return 0;
+
+	/* compare qid details */
+	if (memcmp(&v9inode->qid.version,
+		   &st->qid.version, sizeof(v9inode->qid.version)))
+		return 0;
+
+	if (v9inode->qid.type != st->qid.type)
+		return 0;
+	return 1;
+}
+
+static int v9fs_set_inode(struct inode *inode,  void *data)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_wstat *st = (struct p9_wstat *)data;
+
+	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
+	return 0;
+}
+
 static struct inode *v9fs_qid_iget(struct super_block *sb,
 				   struct p9_qid *qid,
 				   struct p9_wstat *st)
@@ -443,7 +473,7 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 	struct v9fs_session_info *v9ses = sb->s_fs_info;
 
 	i_ino = v9fs_qid2ino(qid);
-	inode = iget_locked(sb, i_ino);
+	inode = iget5_locked(sb, i_ino, v9fs_test_inode, v9fs_set_inode, st);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	if (!(inode->i_state & I_NEW))
@@ -453,6 +483,7 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 	 * FIXME!! we may need support for stale inodes
 	 * later.
 	 */
+	inode->i_ino = i_ino;
 	umode = p9mode2unixmode(v9ses, st->mode);
 	retval = v9fs_init_inode(v9ses, inode, umode);
 	if (retval)
@@ -460,7 +491,6 @@ static struct inode *v9fs_qid_iget(struct super_block *sb,
 
 	v9fs_stat2inode(st, inode, sb);
 #ifdef CONFIG_9P_FSCACHE
-	v9fs_fscache_set_key(inode, &st->qid);
 	v9fs_cache_inode_get_cookie(inode);
 #endif
 	unlock_new_inode(inode);