new helper: __dentry_path()

builds path relative to fs root, called under dcache_lock,
doesn't append any nonsense to unlinked ones.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 23 insertions, 5 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 86d4db15473e..caf08574982f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2049,16 +2049,12 @@ char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
-char *dentry_path(struct dentry *dentry, char *buf, int buflen)
+char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
 {
         char *end = buf + buflen;
         char *retval;
 
-        spin_lock(&dcache_lock);
         prepend(&end, &buflen, "\0", 1);
-        if (d_unlinked(dentry) &&
-                (prepend(&end, &buflen, "//deleted", 9) != 0))
-                        goto Elong;
         if (buflen < 1)
                 goto Elong;
         /* Get '/' right */
@@ -2076,7 +2072,28 @@ char *dentry_path(struct dentry *dentry, char *buf, int buflen)
                 retval = end;
                 dentry = parent;
         }
+        return retval;
+Elong:
+        return ERR_PTR(-ENAMETOOLONG);
+}
+EXPORT_SYMBOL(__dentry_path);
+
+char *dentry_path(struct dentry *dentry, char *buf, int buflen)
+{
+        char *p = NULL;
+        char *retval;
+
+        spin_lock(&dcache_lock);
+        if (d_unlinked(dentry)) {
+                p = buf + buflen;
+                if (prepend(&p, &buflen, "//deleted", 10) != 0)
+                        goto Elong;
+                buflen++;
+        }
+        retval = __dentry_path(dentry, buf, buflen);
         spin_unlock(&dcache_lock);
+        if (!IS_ERR(retval) && p)
+                *p = '/';       /* restore '/' overriden with '\0' */
         return retval;
 Elong:
         spin_unlock(&dcache_lock);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index eebb617c17d8..d23be0386e2d 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -315,6 +315,7 @@ extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
 
 extern char *__d_path(const struct path *path, struct path *root, char *, int);
 extern char *d_path(const struct path *, char *, int);
+extern char *__dentry_path(struct dentry *, char *, int);
 extern char *dentry_path(struct dentry *, char *, int);
 
 /* Allocation counts.. */