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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2008-04-28 02:16:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-28 08:58:47 -0700
commit606e423e43bac0c2f7b85b682eb1ddd2a634586e (patch)
tree86e7bc56e7e70cf1403aec7fd58d854490b1478f /fs/fat
parent1ae43f826b6cb951fc5b0f9c92372a8d5b63c7f9 (diff)
downloadlinux-606e423e43bac0c2f7b85b682eb1ddd2a634586e.tar.gz
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>
Diffstat (limited to 'fs/fat')
-rw-r--r--fs/fat/fatent.c7
-rw-r--r--fs/fat/inode.c7
2 files changed, 9 insertions, 5 deletions
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 5fb366992b73..c7c8ab2209e1 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -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:
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 886f6095a378..1604a8a5c01f 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -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);
 		}