Commit c9e716eb authored by Andreas Dilger's avatar Andreas Dilger Committed by Theodore Ts'o
Browse files

ext4: don't update s_rev_level if not required 



Don't update the superblock s_rev_level during mount if it isn't
actually necessary, only if superblock features are being set by
the kernel.  This was originally added for ext3 since it always
set the INCOMPAT_RECOVER and HAS_JOURNAL features during mount,
but this is not needed since no journal mode was added to ext4.

That will allow Geert to mount his 20-year-old ext2 rev 0.0 m68k
filesystem, as a testament of the backward compatibility of ext4.

Fixes: 0390131b ("ext4: Allow ext4 to run without a journal")
Signed-off-by: default avatarAndreas Dilger <adilger@dilger.ca>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent a58ca992

fs/ext4/ext4.h

+5 −1
Original line number Diff line number Diff line
@@ -1665,6 +1665,8 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) 
#define EXT4_FEATURE_INCOMPAT_INLINE_DATA	0x8000 /* data in inode */

#define EXT4_FEATURE_INCOMPAT_ENCRYPT		0x10000



extern void ext4_update_dynamic_rev(struct super_block *sb);



#define EXT4_FEATURE_COMPAT_FUNCS(name, flagname) \

static inline bool ext4_has_feature_##name(struct super_block *sb) \

{ \
@@ -1673,6 +1675,7 @@ static inline bool ext4_has_feature_##name(struct super_block *sb) \ 
} \

static inline void ext4_set_feature_##name(struct super_block *sb) \

{ \

	ext4_update_dynamic_rev(sb); \

	EXT4_SB(sb)->s_es->s_feature_compat |= \

		cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname); \

} \
@@ -1690,6 +1693,7 @@ static inline bool ext4_has_feature_##name(struct super_block *sb) \ 
} \

static inline void ext4_set_feature_##name(struct super_block *sb) \

{ \

	ext4_update_dynamic_rev(sb); \

	EXT4_SB(sb)->s_es->s_feature_ro_compat |= \

		cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname); \

} \
@@ -1707,6 +1711,7 @@ static inline bool ext4_has_feature_##name(struct super_block *sb) \ 
} \

static inline void ext4_set_feature_##name(struct super_block *sb) \

{ \

	ext4_update_dynamic_rev(sb); \

	EXT4_SB(sb)->s_es->s_feature_incompat |= \

		cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname); \

} \
@@ -2675,7 +2680,6 @@ do { \ 


#endif



extern void ext4_update_dynamic_rev(struct super_block *sb);

extern int ext4_update_compat_feature(handle_t *handle, struct super_block *sb,

					__u32 compat);

extern int ext4_update_rocompat_feature(handle_t *handle,

fs/ext4/inode.c

+0 −1
Original line number Diff line number Diff line
@@ -5345,7 +5345,6 @@ static int ext4_do_update_inode(handle_t *handle, 
		err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);

		if (err)

			goto out_brelse;

		ext4_update_dynamic_rev(sb);

		ext4_set_feature_large_file(sb);

		ext4_handle_sync(handle);

		err = ext4_handle_dirty_super(handle, sb);

fs/ext4/super.c

+0 −1
Original line number Diff line number Diff line
@@ -2249,7 +2249,6 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es, 
		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);

	le16_add_cpu(&es->s_mnt_count, 1);

	ext4_update_tstamp(es, s_mtime);

	ext4_update_dynamic_rev(sb);

	if (sbi->s_journal)

		ext4_set_feature_journal_needs_recovery(sb);

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