Fix eric's extremely well-spotted locking bug. It's not clear that we even

[fs/lustre-release.git] / lustre / llite / symlink.c

diff --git a/lustre/llite/symlink.c b/lustre/llite/symlink.c
index 00f391e..ad50fab 100644 (file)
--- a/lustre/llite/symlink.c
+++ b/lustre/llite/symlink.c
@@ -1,4 +1,5 @@
-/*
+/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
+ * vim:expandtab:shiftwidth=8:tabstop=8:
  *  linux/fs/ext2/symlink.c
  *
  * This code is issued under the GNU General Public License.
@@ -9,15 +10,11 @@
  * Laboratoire MASI - Institut Blaise Pascal
  * Universite Pierre et Marie Curie (Paris VI)
  *
- *  from
- *
- *  linux/fs/minix/symlink.c
- *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
  *  ext2 symlink handling code
  *
- * Modified for OBDFS: 
+ * Modified for OBDFS:
  *  Copyright (C) 1999 Seagate Technology Inc. (author: braam@stelias.com)
  */
 
@@ -25,27 +22,58 @@
 #include <linux/mm.h>
 #include <linux/stat.h>
 #include <linux/locks.h>
-#include <linux/obd_support.h> /* for ENTRY and EXIT only */
-#include <linux/lustre_light.h>
 
+#define DEBUG_SUBSYSTEM S_LLITE
 
+#include <linux/obd_support.h> /* for ENTRY and EXIT only */
+#include <linux/lustre_lite.h>
 
-static int ll_fast_readlink(struct dentry *dentry, char *buffer, int buflen)
+static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
 {
-        char *s = ll_i2info(dentry->d_inode)->lli_inline;
-        return vfs_readlink(dentry, buffer, buflen, s);
-}
+        struct ll_sb_info *sbi = ll_i2sbi(dentry->d_inode);
+        struct ptlrpc_request *request = NULL;
+        struct inode *inode = dentry->d_inode;
+        struct ll_inode_info *lli = ll_i2info(inode);
+        int len = inode->i_size + 1;
+        char *symname;
+        int rc;
+        ENTRY;
 
-static int ll_fast_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-        char *s = ll_i2info(dentry->d_inode)->lli_inline;
-        return vfs_follow_link(nd, s); 
+        /* on symlinks lli_open_sem protects lli_symlink_name allocation/data */
+        down(&lli->lli_open_sem);
+        if (lli->lli_symlink_name) {
+                symname = lli->lli_symlink_name;
+                CDEBUG(D_INODE, "using cached symlink %s\n", symname);
+                GOTO(out_readlink, rc = 0);
+        }
+
+        rc = mdc_getattr(&sbi->ll_mdc_conn, inode->i_ino, S_IFLNK,
+                         OBD_MD_LINKNAME, len, &request);
+
+        if (rc) {
+                CERROR("inode %d readlink: rc = %ld\n", rc, inode->i_ino);
+                GOTO(out_readlink_sem, rc);
+        }
+
+        symname = lustre_msg_buf(request->rq_repmsg, 1);
+
+        OBD_ALLOC(lli->lli_symlink_name, len);
+        /* do not return an error if we cannot cache the symlink locally */
+        if (lli->lli_symlink_name)
+                memcpy(lli->lli_symlink_name, symname, len);
+
+out_readlink:
+        rc = vfs_readlink(dentry, buffer, buflen, symname);
+
+out_readlink_sem:
+        up(&lli->lli_open_sem);
+        ptlrpc_free_req(request);
+
+        RETURN(rc);
 }
 
 extern int ll_setattr(struct dentry *de, struct iattr *attr);
 struct inode_operations ll_fast_symlink_inode_operations = {
-        readlink:       ll_fast_readlink,
-        follow_link:    ll_fast_follow_link,
-       setattr:        ll_setattr
+        readlink:       ll_readlink,
+        setattr:        ll_setattr
 };
-