diff options
Diffstat (limited to 'fs/nilfs2')
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 3b4a079c9617..d588816fdf2f 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -13,6 +13,7 @@ #include <linux/blkdev.h> #include <linux/backing-dev.h> #include <linux/random.h> +#include <linux/log2.h> #include <linux/crc32.h> #include "nilfs.h" #include "segment.h" @@ -443,11 +444,33 @@ static int nilfs_valid_sb(struct nilfs_super_block *sbp) return crc == le32_to_cpu(sbp->s_sum); } -static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset) +/** + * nilfs_sb2_bad_offset - check the location of the second superblock + * @sbp: superblock raw data buffer + * @offset: byte offset of second superblock calculated from device size + * + * nilfs_sb2_bad_offset() checks if the position on the second + * superblock is valid or not based on the filesystem parameters + * stored in @sbp. If @offset points to a location within the segment + * area, or if the parameters themselves are not normal, it is + * determined to be invalid. + * + * Return Value: true if invalid, false if valid. + */ +static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset) { - return offset < ((le64_to_cpu(sbp->s_nsegments) * - le32_to_cpu(sbp->s_blocks_per_segment)) << - (le32_to_cpu(sbp->s_log_block_size) + 10)); + unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size); + u32 blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment); + u64 nsegments = le64_to_cpu(sbp->s_nsegments); + u64 index; + + if (blocks_per_segment < NILFS_SEG_MIN_BLOCKS || + shift_bits > ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS) + return true; + + index = offset >> (shift_bits + BLOCK_SIZE_BITS); + do_div(index, blocks_per_segment); + return index < nsegments; } static void nilfs_release_super_block(struct the_nilfs *nilfs) |