1 files changed, 26 insertions, 2 deletions

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index e5ae1b720dde..895049b2ac9c 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -30,6 +30,29 @@ static inline loff_t fat_make_i_pos(struct super_block *sb,
                 | (de - (struct msdos_dir_entry *)bh->b_data);
 }
 
+static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
+                                     sector_t phys)
+{
+        struct super_block *sb = dir->i_sb;
+        struct msdos_sb_info *sbi = MSDOS_SB(sb);
+        struct buffer_head *bh;
+        int sec;
+
+        /* This is not a first sector of cluster, or sec_per_clus == 1 */
+        if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
+                return;
+        /* root dir of FAT12/FAT16 */
+        if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
+                return;
+
+        bh = sb_getblk(sb, phys);
+        if (bh && !buffer_uptodate(bh)) {
+                for (sec = 0; sec < sbi->sec_per_clus; sec++)
+                        sb_breadahead(sb, phys + sec);
+        }
+        brelse(bh);
+}
+
 /* Returns the inode number of the directory entry at offset pos. If bh is
    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
    returned in bh.
@@ -58,6 +81,8 @@ next:
         if (err || !phys)
                 return -1;      /* beyond EOF or error */
 
+        fat_dir_readahead(dir, iblock, phys);
+
         *bh = sb_bread(sb, phys);
         if (*bh == NULL) {
                 printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n",
@@ -635,8 +660,7 @@ RecEnd:
 EODir:
         filp->f_pos = cpos;
 FillFailed:
-        if (bh)
-                brelse(bh);
+        brelse(bh);
         if (unicode)
                 free_page((unsigned long)unicode);
 out: