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authorJ. Bruce Fields <bfields@redhat.com>2013-10-23 02:59:19 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2013-11-09 06:16:35 +0100
commit78cee9a8e4b42b3f585ea3bd1c076f5a76fee722 (patch)
treeebd38a5243871c32493a9f36e71b3a2fab2e86d7 /fs/exportfs
parentexportfs: BUG_ON in crazy corner case (diff)
downloadlinux-78cee9a8e4b42b3f585ea3bd1c076f5a76fee722.tar.xz
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exportfs: more detailed comment for path_reconnect
Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/exportfs')
-rw-r--r--fs/exportfs/expfs.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 6d0a7fa9abb3..87e6dca69e43 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -93,7 +93,19 @@ find_disconnected_root(struct dentry *dentry)
/*
* Make sure target_dir is fully connected to the dentry tree.
*
- * It may already be, as the flag isn't always updated when connection happens.
+ * On successful return, DCACHE_DISCONNECTED will be cleared on
+ * target_dir, and target_dir->d_parent->...->d_parent will reach the
+ * root of the filesystem.
+ *
+ * Whenever DCACHE_DISCONNECTED is unset, target_dir is fully connected.
+ * But the converse is not true: target_dir may have DCACHE_DISCONNECTED
+ * set but already be connected. In that case we'll verify the
+ * connection to root and then clear the flag.
+ *
+ * Note that target_dir could be removed by a concurrent operation. In
+ * that case reconnect_path may still succeed with target_dir fully
+ * connected, but further operations using the filehandle will fail when
+ * necessary (due to S_DEAD being set on the directory).
*/
static int
reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)