fat: introduce a helper fat_get_blknr_offset()

Introduce helper function to get the block number and offset for a given
i_pos value.  Use it in __fat_write_inode() now and later on in nfs.c

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ravishankar N <ravi.n1@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index f16948e..980c034 100644 (file)
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -218,6 +218,13 @@ static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
                + sbi->data_start;
 }
 
+static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,
+                               loff_t i_pos, sector_t *blknr, int *offset)
+{
+       *blknr = i_pos >> sbi->dir_per_block_bits;
+       *offset = i_pos & (sbi->dir_per_block - 1);
+}
+
 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
                                        struct inode *inode)
 {

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 78e363c..68cb5a6 100644 (file)
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -662,7 +662,8 @@ static int __fat_write_inode(struct inode *inode, int wait)
        struct buffer_head *bh;
        struct msdos_dir_entry *raw_entry;
        loff_t i_pos;
-       int err;
+       sector_t blocknr;
+       int err, offset;
 
        if (inode->i_ino == MSDOS_ROOT_INO)
                return 0;
@@ -672,7 +673,8 @@ retry:
        if (!i_pos)
                return 0;
 
-       bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
+       fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
+       bh = sb_bread(sb, blocknr);
        if (!bh) {
                fat_msg(sb, KERN_ERR, "unable to read inode block "
                       "for updating (i_pos %lld)", i_pos);
@@ -685,8 +687,7 @@ retry:
                goto retry;
        }
 
-       raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
-           [i_pos & (sbi->dir_per_block - 1)];
+       raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
        if (S_ISDIR(inode->i_mode))
                raw_entry->size = 0;
        else