fat: Update free_clusters even if it is untrusted

Currently, free_clusters is not updated until it is trusted, because
Windows doesn't update it correctly.

But if user is using FAT driver of Linux, it updates free_clusters
correctly.  Instead, this updates it even if it's untrusted, so if
free_clustes is correct, now keep correct value.

Signed-off-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, 1 insertions, 0 deletions

diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
index 81fb9bc53220..0bca157ddca5 100644
--- a/include/linux/msdos_fs.h
+++ b/include/linux/msdos_fs.h
@@ -233,6 +233,7 @@ struct msdos_sb_info {
         struct mutex fat_lock;
         unsigned int prev_free;      /* previously allocated cluster number */
         unsigned int free_clusters;  /* -1 if undefined */
+        unsigned int free_clus_valid; /* is free_clusters valid? */
         struct fat_mount_options options;
         struct nls_table *nls_disk;  /* Codepage used on disk */
         struct nls_table *nls_io;    /* Charset used for input and display */