fat (exportfs): rebuild directory-inode if fat_dget()

This patch enables rebuilding of directory inodes which are not present in
the cache.This is done by traversing the disk clusters to find the
directory entry of the parent directory and using its i_pos to build the
inode.

The traversal is done by fat_scan_logstart() which is similar to
fat_scan() but matches i_pos values instead of names.fat_scan_logstart()
needs an inode parameter to work, for which a dummy inode is created by
it's caller fat_rebuild_parent().  This dummy inode is destroyed after the
traversal completes.

All this is done  only if the nostale_ro nfs mount option is specified.

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>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 413eaaf30ed5..21664fcf3616 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -296,6 +296,8 @@ extern int fat_dir_empty(struct inode *dir);
 extern int fat_subdirs(struct inode *dir);
 extern int fat_scan(struct inode *dir, const unsigned char *name,
                     struct fat_slot_info *sinfo);
+extern int fat_scan_logstart(struct inode *dir, int i_logstart,
+                             struct fat_slot_info *sinfo);
 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
                                 struct msdos_dir_entry **de);
 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
@@ -373,6 +375,7 @@ extern struct inode *fat_build_inode(struct super_block *sb,
 extern int fat_sync_inode(struct inode *inode);
 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
                           int isvfat, void (*setup)(struct super_block *));
+extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
 
 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
                             struct inode *i2);