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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>
This commit is contained in:
OGAWA Hirofumi 2008-04-28 02:16:27 -07:00 committed by Linus Torvalds
parent 1ae43f826b
commit 606e423e43
3 changed files with 10 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
fs/fat/fatent.c
View File

@ -450,7 +450,8 @@ int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
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 @@ int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
/* 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 fat_count_free_clusters(struct super_block *sb)
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 @@ int fat_count_free_clusters(struct super_block *sb)
} while (fat_ent_next(sbi, &fatent));
}
sbi->free_clusters = free;
sbi->free_clus_valid = 1;
sb->s_dirt = 1;
fatent_brelse(&fatent);
out:

7
fs/fat/inode.c
View File

@ -537,7 +537,7 @@ static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
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 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
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 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
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);
}

1
include/linux/msdos_fs.h
View File

@ -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 */