fat: Check s_dirt in fat_sync_fs()

If we didn't check sb->s_dirt, it will update the FSINFO
unconditionally. It will reduce the filetime of flash base device.

So, this checks sb->s_dirt. sb->s_dirt is racy, however FSINFO is just
hint. So even if there is race, and we hit it, it would not become big
problem.

And this also is as workaround of suspend problem.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index a6c2047..63785a1 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -43,19 +43,19 @@ EXPORT_SYMBOL_GPL(fat_fs_error);
 
 /* Flushes the number of free clusters on FAT32 */
 /* XXX: Need to write one per FSINFO block.  Currently only writes 1 */
-void fat_clusters_flush(struct super_block *sb)
+int fat_clusters_flush(struct super_block *sb)
 {
 	struct msdos_sb_info *sbi = MSDOS_SB(sb);
 	struct buffer_head *bh;
 	struct fat_boot_fsinfo *fsinfo;
 
 	if (sbi->fat_bits != 32)
-		return;
+		return 0;
 
 	bh = sb_bread(sb, sbi->fsinfo_sector);
 	if (bh == NULL) {
 		printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
-		return;
+		return -EIO;
 	}
 
 	fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
@@ -74,6 +74,8 @@ void fat_clusters_flush(struct super_block *sb)
 		mark_buffer_dirty(bh);
 	}
 	brelse(bh);
+
+	return 0;
 }
 
 /*