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);
-
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This archive was generated by hypermail 2b29 : Mon Jun 30 2003 - 22:00:16 EST