fs/9p: Fix race in initializing writeback fid
When two process open the same file we can end up with both of them
allocating the writeback_fid. Add a new mutex which can be used
for synchronizing v9fs_inode member values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 78bcb97..3337d58 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -90,6 +90,7 @@
}
file->private_data = fid;
+ mutex_lock(&v9inode->v_mutex);
if (v9ses->cache && !v9inode->writeback_fid) {
/*
* clone a fid and add it to writeback_fid
@@ -101,10 +102,12 @@
fid = v9fs_writeback_fid(file->f_path.dentry);
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
+ mutex_unlock(&v9inode->v_mutex);
goto out_error;
}
v9inode->writeback_fid = (void *) fid;
}
+ mutex_unlock(&v9inode->v_mutex);
#ifdef CONFIG_9P_FSCACHE
if (v9ses->cache)
v9fs_cache_inode_set_cookie(inode, file);