From be285c712bbbe5db43e503782fbef2bfeaa345f9 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Mon, 16 Jun 2008 13:28:07 +0200 Subject: [patch 3/3] vfs: make d_path() consistent across mount operations The path that __d_path() computes can become slightly inconsistent when it races with mount operations: it grabs the vfsmount_lock when traversing mount points but immediately drops it again, only to re-grab it when it reaches the next mount point. The result is that the filename computed is not always consisent, and the file may never have had that name. (This is unlikely, but still possible.) Fix this by grabbing the vfsmount_lock for the whole duration of __d_path(). Signed-off-by: Andreas Gruenbacher Signed-off-by: John Johansen Signed-off-by: Miklos Szeredi Acked-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/dcache.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index c4c9072d810c..2b479de10a0a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1782,6 +1782,7 @@ char *__d_path(const struct path *path, struct path *root, char * end = buffer+buflen; char * retval; + spin_lock(&vfsmount_lock); prepend(&end, &buflen, "\0", 1); if (!IS_ROOT(dentry) && d_unhashed(dentry) && (prepend(&end, &buflen, " (deleted)", 10) != 0)) @@ -1800,14 +1801,11 @@ char *__d_path(const struct path *path, struct path *root, break; if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { /* Global root? */ - spin_lock(&vfsmount_lock); if (vfsmnt->mnt_parent == vfsmnt) { - spin_unlock(&vfsmount_lock); goto global_root; } dentry = vfsmnt->mnt_mountpoint; vfsmnt = vfsmnt->mnt_parent; - spin_unlock(&vfsmount_lock); continue; } parent = dentry->d_parent; @@ -1820,6 +1818,8 @@ char *__d_path(const struct path *path, struct path *root, dentry = parent; } +out: + spin_unlock(&vfsmount_lock); return retval; global_root: @@ -1829,9 +1829,11 @@ global_root: goto Elong; root->mnt = vfsmnt; root->dentry = dentry; - return retval; + goto out; + Elong: - return ERR_PTR(-ENAMETOOLONG); + retval = ERR_PTR(-ENAMETOOLONG); + goto out; } /** -- cgit v1.2.3