Messages in this thread Patch in this message | | | Date | Tue, 24 Jun 2003 10:41:59 -0400 | From | Mike Waychison <> | Subject | [PATCH] 2.5.72: follow_mount / follow_link |
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Hi Al,
When a follow_link dentry call is made, the implementation expects the dentry to be followed as well as a nameidata struct to be filled in. The received nd->mnt is expected to contain the vfsmount of the dentry being followed, so that a subsequent call to vfs_follow_link may properly pivot off that mount and onto another vfsmount as the path of the link is walked, thus keeping reference counts proper.
The changes made in fs/namei.c@1.42 break this behaviour iff the dentry being follow_link'ed is a root dentry. This is because follow_mount follows down next.mnt and not nd->mnt like it used to. So, if a root dentry has a follow_link op, the nd->mnt it receives is in fact the vfsmount of the mount it is mounted upon (which breaks reference counts).
Please apply the attached patch which was made against 2.5.72.
Thanks,
Mike Waychison # This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.1348 -> 1.1349 # fs/namei.c 1.76 -> 1.77 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 03/06/23 mikew@nisserv.test.com 1.1349 # namei.c: # nameidata should have the mnt we are looking at when doing a follow_link after a follow_mount # -------------------------------------------- # diff -Nru a/fs/namei.c b/fs/namei.c --- a/fs/namei.c Tue Jun 24 13:29:37 2003 +++ b/fs/namei.c Tue Jun 24 13:29:37 2003 @@ -655,6 +655,7 @@ if (inode->i_op->follow_link) { mntget(next.mnt); + nd->mnt = next.mnt; err = do_follow_link(next.dentry, nd); dput(next.dentry); mntput(next.mnt); @@ -708,6 +709,7 @@ if ((lookup_flags & LOOKUP_FOLLOW) && inode && inode->i_op && inode->i_op->follow_link) { mntget(next.mnt); + nd->mnt = next.mnt; err = do_follow_link(next.dentry, nd); dput(next.dentry); mntput(next.mnt); | |