From 1beeef1b5643a16a07a465632a2cf984a4ef2119 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 12 May 2014 10:16:06 -0400 Subject: [PATCH] ext4: fix block bitmap initialization under sparse_super2 The ext4_bg_has_super() function doesn't know about the new rules for where backup superblocks go on a sparse_super2 filesystem. Therefore, block bitmap initialization doesn't know that it shouldn't reserve space for backups in groups that are never going to contain backups. The result of this is e2fsck complaining about the block bitmap being incorrect (fortunately not in a way that results in cross-linked files), so fix the whole thing. Signed-off-by: Darrick J. Wong Signed-off-by: "Theodore Ts'o" --- fs/ext4/balloc.c | 33 +++++++++++++++++++-------------- fs/ext4/ext4.h | 4 +++- 2 files changed, 22 insertions(+), 15 deletions(-) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 5c56785007e0..a4950e91f61c 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -708,16 +708,6 @@ static inline int test_root(ext4_group_t a, int b) } } -static int ext4_group_sparse(ext4_group_t group) -{ - if (group <= 1) - return 1; - if (!(group & 1)) - return 0; - return (test_root(group, 7) || test_root(group, 5) || - test_root(group, 3)); -} - /** * ext4_bg_has_super - number of blocks used by the superblock in group * @sb: superblock for filesystem @@ -728,11 +718,26 @@ static int ext4_group_sparse(ext4_group_t group) */ int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) { - if (EXT4_HAS_RO_COMPAT_FEATURE(sb, - EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && - !ext4_group_sparse(group)) + struct ext4_super_block *es = EXT4_SB(sb)->s_es; + + if (group == 0) + return 1; + if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_SPARSE_SUPER2)) { + if (group == le32_to_cpu(es->s_backup_bgs[0]) || + group == le32_to_cpu(es->s_backup_bgs[1])) + return 1; + return 0; + } + if ((group <= 1) || !EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) + return 1; + if (!(group & 1)) return 0; - return 1; + if (test_root(group, 3) || (test_root(group, 5)) || + test_root(group, 7)) + return 1; + + return 0; } static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index aeda5061a59a..4feb2d5819ae 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1160,7 +1160,8 @@ struct ext4_super_block { __le32 s_usr_quota_inum; /* inode for tracking user quota */ __le32 s_grp_quota_inum; /* inode for tracking group quota */ __le32 s_overhead_clusters; /* overhead blocks/clusters in fs */ - __le32 s_reserved[108]; /* Padding to the end of the block */ + __le32 s_backup_bgs[2]; /* groups with sparse_super2 SBs */ + __le32 s_reserved[106]; /* Padding to the end of the block */ __le32 s_checksum; /* crc32c(superblock) */ }; @@ -1506,6 +1507,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) #define EXT4_FEATURE_COMPAT_EXT_ATTR 0x0008 #define EXT4_FEATURE_COMPAT_RESIZE_INODE 0x0010 #define EXT4_FEATURE_COMPAT_DIR_INDEX 0x0020 +#define EXT4_FEATURE_COMPAT_SPARSE_SUPER2 0x0200 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001 #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE 0x0002 -- 2.34.1