diff options
author | Paulo Alcantara <pcacjr@zytor.com> | 2017-10-11 07:00:31 -0400 |
---|---|---|
committer | Gene Cumm <gene.cumm@gmail.com> | 2017-10-15 07:03:33 -0400 |
commit | af7e95c32cea40c1e443ae301e64b27f068b4915 (patch) | |
tree | aeeb026a6f13f864ef036313074b6b46890cdd18 | |
parent | c100204000cdc565e5edaec1b8a6239143173fbd (diff) | |
download | syslinux-af7e95c32cea40c1e443ae301e64b27f068b4915.tar.gz syslinux-af7e95c32cea40c1e443ae301e64b27f068b4915.tar.xz syslinux-af7e95c32cea40c1e443ae301e64b27f068b4915.zip |
ext4: Fix 64bit feature
As per ext4 specification:
> In ext2, ext3, and ext4 (when the 64bit feature is not enabled), the
> block group descriptor was only 32 bytes long and therefore ends at
> bg_checksum. On an ext4 filesystem with the 64bit feature enabled, the
> block group descriptor expands to at least the 64 bytes described below;
> the size is stored in the superblock.
Since block group descriptor has been expanded to 64 bytes long (when 64
bit feature is enabled), we cannot index ext2_group_desc and return it
*directly* -- as we did it in ext2_get_group_desc -- it's still 32 bytes
long.
Instead, use s_desc_size field from superblock to correctly index and
return block group descriptors.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Gene Cumm <gene.cumm@gmail.com>
Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
-rw-r--r-- | core/fs/ext2/ext2.c | 23 | ||||
-rw-r--r-- | core/fs/ext2/ext2_fs.h | 1 |
2 files changed, 15 insertions, 9 deletions
diff --git a/core/fs/ext2/ext2.c b/core/fs/ext2/ext2.c index 76bd1d5a..4bc0a535 100644 --- a/core/fs/ext2/ext2.c +++ b/core/fs/ext2/ext2.c @@ -25,22 +25,17 @@ static enum dirent_type ext2_cvt_type(unsigned int d_file_type) return inode_type[d_file_type]; } -/* - * get the group's descriptor of group_num - */ -static const struct ext2_group_desc * -ext2_get_group_desc(struct fs_info *fs, uint32_t group_num) +static const void *__ext2_get_group_desc(struct fs_info *fs, uint32_t group_num) { struct ext2_sb_info *sbi = EXT2_SB(fs); uint32_t desc_block, desc_index; - const struct ext2_group_desc *desc_data_block; + uint8_t *p; if (group_num >= sbi->s_groups_count) { printf ("ext2_get_group_desc" "block_group >= groups_count - " "block_group = %d, groups_count = %d", group_num, sbi->s_groups_count); - return NULL; } @@ -49,8 +44,17 @@ ext2_get_group_desc(struct fs_info *fs, uint32_t group_num) desc_block += sbi->s_first_data_block + 1; - desc_data_block = get_cache(fs->fs_dev, desc_block); - return &desc_data_block[desc_index]; + p = get_cache(fs->fs_dev, desc_block); + return p + sbi->s_desc_size * desc_index; +} + +/* + * get the group's descriptor of group_num + */ +static inline const struct ext2_group_desc * +ext2_get_group_desc(struct fs_info *fs, uint32_t group_num) +{ + return __ext2_get_group_desc(fs, group_num); } /* @@ -306,6 +310,7 @@ static int ext2_fs_init(struct fs_info *fs) if (sb.s_desc_size < sizeof(struct ext2_group_desc)) sb.s_desc_size = sizeof(struct ext2_group_desc); sbi->s_desc_per_block = BLOCK_SIZE(fs) / sb.s_desc_size; + sbi->s_desc_size = sb.s_desc_size; sbi->s_groups_count = (sb.s_blocks_count - sb.s_first_data_block + EXT2_BLOCKS_PER_GROUP(fs) - 1) / EXT2_BLOCKS_PER_GROUP(fs); diff --git a/core/fs/ext2/ext2_fs.h b/core/fs/ext2/ext2_fs.h index 803a9954..d8d07ebd 100644 --- a/core/fs/ext2/ext2_fs.h +++ b/core/fs/ext2/ext2_fs.h @@ -278,6 +278,7 @@ struct ext2_sb_info { uint32_t s_first_data_block; /* First Data Block */ int s_inode_size; uint8_t s_uuid[16]; /* 128-bit uuid for volume */ + int s_desc_size; /* size of group descriptor */ }; static inline struct ext2_sb_info *EXT2_SB(struct fs_info *fs) |