diff options
| -rw-r--r-- | fs/ext3/super.c | 4 | ||||
| -rw-r--r-- | fs/ext4/super.c | 8 | ||||
| -rw-r--r-- | fs/libfs.c | 29 | ||||
| -rw-r--r-- | include/linux/fs.h | 2 |
4 files changed, 36 insertions, 7 deletions
diff --git a/fs/ext3/super.c b/fs/ext3/super.c index 5dbf4db..a367dd0 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -1849,8 +1849,8 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) goto failed_mount; } - if (le32_to_cpu(es->s_blocks_count) > - (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { + if (generic_check_addressable(sb->s_blocksize_bits, + le32_to_cpu(es->s_blocks_count))) { ext3_msg(sb, KERN_ERR, "error: filesystem is too large to mount safely"); if (sizeof(sector_t) < 8) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 2614774..7f47c36 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2831,15 +2831,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) * Test whether we have more sectors than will fit in sector_t, * and whether the max offset is addressable by the page cache. */ - if ((ext4_blocks_count(es) > - (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) || - (ext4_blocks_count(es) > - (pgoff_t)(~0ULL) >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits))) { + ret = generic_check_addressable(sb->s_blocksize_bits, + ext4_blocks_count(es)); + if (ret) { ext4_msg(sb, KERN_ERR, "filesystem" " too large to mount safely on this system"); if (sizeof(sector_t) < 8) ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled"); - ret = -EFBIG; goto failed_mount; } @@ -913,6 +913,35 @@ int generic_file_fsync(struct file *file, int datasync) } EXPORT_SYMBOL(generic_file_fsync); +/** + * generic_check_addressable - Check addressability of file system + * @blocksize_bits: log of file system block size + * @num_blocks: number of blocks in file system + * + * Determine whether a file system with @num_blocks blocks (and a + * block size of 2**@blocksize_bits) is addressable by the sector_t + * and page cache of the system. Return 0 if so and -EFBIG otherwise. + */ +int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) +{ + u64 last_fs_block = num_blocks - 1; + + if (unlikely(num_blocks == 0)) + return 0; + + if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) + return -EINVAL; + + if ((last_fs_block > + (sector_t)(~0ULL) >> (blocksize_bits - 9)) || + (last_fs_block > + (pgoff_t)(~0ULL) >> (PAGE_CACHE_SHIFT - blocksize_bits))) { + return -EFBIG; + } + return 0; +} +EXPORT_SYMBOL(generic_check_addressable); + /* * No-op implementation of ->fsync for in-memory filesystems. */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 76041b6..1a759f4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2374,6 +2374,8 @@ extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, extern int generic_file_fsync(struct file *, int); +extern int generic_check_addressable(unsigned, u64); + #ifdef CONFIG_MIGRATION extern int buffer_migrate_page(struct address_space *, struct page *, struct page *); |