[PATCH] fat: Fix truncate() write ordering

The truncate() should write the file size before writing the new EOF entry.
This patch fixes it.

This bug was pointed out by Machida Hiroyuki.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/fat/file.c b/fs/fat/file.c
index e99c5a7..88aa1ae 100644 (file)
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -210,10 +210,30 @@ static int fat_free(struct inode *inode, int skip)
        if (MSDOS_I(inode)->i_start == 0)
                return 0;
 
-       /*
-        * Write a new EOF, and get the remaining cluster chain for freeing.
-        */
+       fat_cache_inval_inode(inode);
+
        wait = IS_DIRSYNC(inode);
+       i_start = free_start = MSDOS_I(inode)->i_start;
+       i_logstart = MSDOS_I(inode)->i_logstart;
+
+       /* First, we write the new file size. */
+       if (!skip) {
+               MSDOS_I(inode)->i_start = 0;
+               MSDOS_I(inode)->i_logstart = 0;
+       }
+       MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+       inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+       if (wait) {
+               err = fat_sync_inode(inode);
+               if (err) {
+                       MSDOS_I(inode)->i_start = i_start;
+                       MSDOS_I(inode)->i_logstart = i_logstart;
+                       return err;
+               }
+       } else
+               mark_inode_dirty(inode);
+
+       /* Write a new EOF, and get the remaining cluster chain for freeing. */
        if (skip) {
                struct fat_entry fatent;
                int ret, fclus, dclus;
@@ -244,35 +264,11 @@ static int fat_free(struct inode *inode, int skip)
                        return ret;
 
                free_start = ret;
-               i_start = i_logstart = 0;
-               fat_cache_inval_inode(inode);
-       } else {
-               fat_cache_inval_inode(inode);
-
-               i_start = free_start = MSDOS_I(inode)->i_start;
-               i_logstart = MSDOS_I(inode)->i_logstart;
-               MSDOS_I(inode)->i_start = 0;
-               MSDOS_I(inode)->i_logstart = 0;
        }
-       MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
-       inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
-       if (wait) {
-               err = fat_sync_inode(inode);
-               if (err)
-                       goto error;
-       } else
-               mark_inode_dirty(inode);
        inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
 
        /* Freeing the remained cluster chain */
        return fat_free_clusters(inode, free_start);
-
-error:
-       if (i_start) {
-               MSDOS_I(inode)->i_start = i_start;
-               MSDOS_I(inode)->i_logstart = i_logstart;
-       }
-       return err;
 }
 
 void fat_truncate(struct inode *inode)