Linux 3.14

[~andy/linux] / fs / dcache.c

diff --git a/fs/dcache.c b/fs/dcache.c
index 6055d61811d30f6d037daed87ffb11924b0ac5e5..ca02c13a84aa24d55b18bbced577ece923605665 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2833,9 +2833,9 @@ static int prepend_name(char **buffer, int *buflen, struct qstr *name)
        u32 dlen = ACCESS_ONCE(name->len);
        char *p;
 
-       if (*buflen < dlen + 1)
-               return -ENAMETOOLONG;
        *buflen -= dlen + 1;
+       if (*buflen < 0)
+               return -ENAMETOOLONG;
        p = *buffer -= dlen + 1;
        *p++ = '/';
        while (dlen--) {
@@ -3061,8 +3061,13 @@ char *d_path(const struct path *path, char *buf, int buflen)
         * thus don't need to be hashed.  They also don't need a name until a
         * user wants to identify the object in /proc/pid/fd/.  The little hack
         * below allows us to generate a name for these objects on demand:
+        *
+        * Some pseudo inodes are mountable.  When they are mounted
+        * path->dentry == path->mnt->mnt_root.  In that case don't call d_dname
+        * and instead have d_path return the mounted path.
         */
-       if (path->dentry->d_op && path->dentry->d_op->d_dname)
+       if (path->dentry->d_op && path->dentry->d_op->d_dname &&
+           (!IS_ROOT(path->dentry) || path->dentry != path->mnt->mnt_root))
                return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
 
        rcu_read_lock();
@@ -3111,26 +3116,28 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
-static char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
+static char *__dentry_path(struct dentry *d, char *buf, int buflen)
 {
+       struct dentry *dentry;
        char *end, *retval;
        int len, seq = 0;
        int error = 0;
 
+       if (buflen < 2)
+               goto Elong;
+
        rcu_read_lock();
 restart:
+       dentry = d;
        end = buf + buflen;
        len = buflen;
        prepend(&end, &len, "\0", 1);
-       if (buflen < 1)
-               goto Elong;
        /* Get '/' right */
        retval = end-1;
        *retval = '/';
        read_seqbegin_or_lock(&rename_lock, &seq);
        while (!IS_ROOT(dentry)) {
                struct dentry *parent = dentry->d_parent;
-               int error;
 
                prefetch(parent);
                error = prepend_name(&end, &len, &dentry->d_name);