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>
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 5fb3669..c7c8ab2 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -450,7 +450,8 @@
BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */
lock_fat(sbi);
- if (sbi->free_clusters != -1 && sbi->free_clusters < nr_cluster) {
+ if (sbi->free_clusters != -1 && sbi->free_clus_valid &&
+ sbi->free_clusters < nr_cluster) {
unlock_fat(sbi);
return -ENOSPC;
}
@@ -504,6 +505,7 @@
/* Couldn't allocate the free entries */
sbi->free_clusters = 0;
+ sbi->free_clus_valid = 1;
sb->s_dirt = 1;
err = -ENOSPC;
@@ -615,7 +617,7 @@
int err = 0, free;
lock_fat(sbi);
- if (sbi->free_clusters != -1)
+ if (sbi->free_clusters != -1 && sbi->free_clus_valid)
goto out;
reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
@@ -643,6 +645,7 @@
} while (fat_ent_next(sbi, &fatent));
}
sbi->free_clusters = free;
+ sbi->free_clus_valid = 1;
sb->s_dirt = 1;
fatent_brelse(&fatent);
out:
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 886f609..1604a8a 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -537,7 +537,7 @@
struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
/* If the count of free cluster is still unknown, counts it here. */
- if (sbi->free_clusters == -1) {
+ if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
int err = fat_count_free_clusters(dentry->d_sb);
if (err)
return err;
@@ -1274,6 +1274,7 @@
sbi->fat_length = le16_to_cpu(b->fat_length);
sbi->root_cluster = 0;
sbi->free_clusters = -1; /* Don't know yet */
+ sbi->free_clus_valid = 0;
sbi->prev_free = FAT_START_ENT;
if (!sbi->fat_length && b->fat32_length) {
@@ -1309,8 +1310,8 @@
sbi->fsinfo_sector);
} else {
if (sbi->options.usefree)
- sbi->free_clusters =
- le32_to_cpu(fsinfo->free_clusters);
+ sbi->free_clus_valid = 1;
+ sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
}
diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
index 81fb9bc..0bca157 100644
--- a/include/linux/msdos_fs.h
+++ b/include/linux/msdos_fs.h
@@ -233,6 +233,7 @@
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 */