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

commit fd2421f54423f307ecd31bdebdca6bc317e0c492 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 37 insertions, 4 deletions

diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 691c78f..caa63ef 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -86,6 +86,38 @@ static struct dentry *v9fs_dentry_from_dir_inode(struct inode *inode)
 	return dentry;
 }
 
+static int v9fs_test_inode_dotl(struct inode *inode, void *data)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_stat_dotl *st = (struct p9_stat_dotl *)data;
+
+	/* don't match inode of different type */
+	if ((inode->i_mode & S_IFMT) != (st->st_mode & S_IFMT))
+		return 0;
+
+	if (inode->i_generation != st->st_gen)
+		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_dotl(struct inode *inode,  void *data)
+{
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_stat_dotl *st = (struct p9_stat_dotl *)data;
+
+	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
+	inode->i_generation = st->st_gen;
+	return 0;
+}
+
 static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
 					struct p9_qid *qid,
 					struct p9_fid *fid,
@@ -97,7 +129,8 @@ static struct inode *v9fs_qid_iget_dotl(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_dotl,
+			     v9fs_set_inode_dotl, st);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	if (!(inode->i_state & I_NEW))
@@ -107,13 +140,13 @@ static struct inode *v9fs_qid_iget_dotl(struct super_block *sb,
 	 * FIXME!! we may need support for stale inodes
 	 * later.
 	 */
+	inode->i_ino = i_ino;
 	retval = v9fs_init_inode(v9ses, inode, st->st_mode);
 	if (retval)
 		goto error;
 
 	v9fs_stat2inode_dotl(st, inode);
 #ifdef CONFIG_9P_FSCACHE
-	v9fs_fscache_set_key(inode, &st->qid);
 	v9fs_cache_inode_get_cookie(inode);
 #endif
 	retval = v9fs_get_acl(inode, fid);
@@ -136,7 +169,7 @@ v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 	struct p9_stat_dotl *st;
 	struct inode *inode = NULL;
 
-	st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
+	st = p9_client_getattr_dotl(fid, P9_STATS_BASIC | P9_STATS_GEN);
 	if (IS_ERR(st))
 		return ERR_CAST(st);
 
@@ -547,7 +580,7 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode)
 			inode->i_blocks = stat->st_blocks;
 	}
 	if (stat->st_result_mask & P9_STATS_GEN)
-			inode->i_generation = stat->st_gen;
+		inode->i_generation = stat->st_gen;
 
 	/* Currently we don't support P9_STATS_BTIME and P9_STATS_DATA_VERSION
 	 * because the inode structure does not have fields for them.