Messages in this thread Patch in this message | | | Subject | [PATCH 2/2] namespace.c: fix expiring of detached mount | From | Miklos Szeredi <> | Date | Fri, 20 May 2005 20:20:48 +0200 |
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This patch fixes a bug noticed by Al Viro:
However, we still have a problem here - just what would happen if vfsmount is detached while we were grabbing namespace semaphore? Refcount alone is not useful here - we might be held by whoever had detached the vfsmount. IOW, we should check that it's still attached (i.e. that mnt->mnt_parent != mnt). If it's not - just leave it alone, do mntput() and let whoever holds it deal with the sucker. No need to put it back on lists.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Index: linux/fs/namespace.c =================================================================== --- linux.orig/fs/namespace.c 2005-05-20 20:01:26.000000000 +0200 +++ linux/fs/namespace.c 2005-05-20 20:04:56.000000000 +0200 @@ -829,6 +829,13 @@ static void expire_mount(struct vfsmount { spin_lock(&vfsmount_lock); + /* check if mount is still attached, if not, let whoever holds + it deal with the sucker */ + if (mnt->mnt_parent == mnt) { + spin_unlock(&vfsmount_lock); + return; + } + /* check that it is still dead: the count should now be 2 - as * contributed by the vfsmount parent and the mntget above */ if (atomic_read(&mnt->mnt_count) == 2) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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