fat: Update free_clusters even if it is untrusted

[safe/jmp/linux-2.6] / fs / fat / fatent.c

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 5fb3669..c7c8ab2 100644 (file)
--- 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: