We just discussed this on the ext4 developer concall today, and Ted is looking into it.
Cheers, Andreas
> On Oct 3, 2019, at 09:47, Благодаренко Артём <artem.blagodarenko@xxxxxxxxx> wrote:
>
> Hello,
>
> Does anybody wants to give any feedback for this?
> e2label became really faster on large partitions with this patch. Probably it can be useful.
>
> Ted, what do you think?
>
> Thanks,
> Artem Blagodarenko.
>
>
>
>> On 5 Sep 2019, at 14:01, Artem Blagodarenko <artem.blagodarenko@xxxxxxxxx> wrote:
>>
>> tune2fs is used to make e2label duties. ext2fs_open2() reads group
>> descriptors which are not used during disk label obtaining, but takes
>> a lot of time on large partitions.
>>
>> This patch adds ext2fs_read_sb(), there only initialized superblock
>> is returned This saves time dramatically.
>>
>> Signed-off-by: Artem Blagodarenko <c17828@xxxxxxxx>
>> Cray-bug-id: LUS-5777
>> ---
>> lib/ext2fs/ext2fs.h | 2 ++
>> lib/ext2fs/openfs.c | 16 ++++++++++++++++
>> misc/tune2fs.c | 23 +++++++++++++++--------
>> 3 files changed, 33 insertions(+), 8 deletions(-)
>>
>> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
>> index 59fd9742..3a63b74d 100644
>> --- a/lib/ext2fs/ext2fs.h
>> +++ b/lib/ext2fs/ext2fs.h
>> @@ -1630,6 +1630,8 @@ extern int ext2fs_journal_sb_start(int blocksize);
>> extern errcode_t ext2fs_open(const char *name, int flags, int superblock,
>> unsigned int block_size, io_manager manager,
>> ext2_filsys *ret_fs);
>> +extern errcode_t ext2fs_read_sb(const char *name, io_manager manager,
>> + struct ext2_super_block * super);
>> extern errcode_t ext2fs_open2(const char *name, const char *io_options,
>> int flags, int superblock,
>> unsigned int block_size, io_manager manager,
>> diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
>> index 51b54a44..95f45d84 100644
>> --- a/lib/ext2fs/openfs.c
>> +++ b/lib/ext2fs/openfs.c
>> @@ -99,6 +99,22 @@ static void block_sha_map_free_entry(void *data)
>> return;
>> }
>>
>> +errcode_t ext2fs_read_sb(const char *name, io_manager manager,
>> + struct ext2_super_block * super)
>> +{
>> + io_channel io;
>> + errcode_t retval = 0;
>> +
>> + retval = manager->open(name, 0, &io);
>> + if (!retval) {
>> + retval = io_channel_read_blk(io, 1, -SUPERBLOCK_SIZE,
>> + super);
>> + io_channel_close(io);
>> + }
>> +
>> + return retval;
>> +}
>> +
>> /*
>> * Note: if superblock is non-zero, block-size must also be non-zero.
>> * Superblock and block_size can be zero to use the default size.
>> diff --git a/misc/tune2fs.c b/misc/tune2fs.c
>> index 7d2d38d7..fea607e1 100644
>> --- a/misc/tune2fs.c
>> +++ b/misc/tune2fs.c
>> @@ -2879,6 +2879,21 @@ int tune2fs_main(int argc, char **argv)
>> #endif
>> io_ptr = unix_io_manager;
>>
>> + if (print_label) {
>> + /* For e2label emulation */
>> + struct ext2_super_block sb;
>> +
>> + /* Read only superblock. Nothing else metters.*/
>> + retval = ext2fs_read_sb(device_name, io_ptr, &sb);
>> + if (!retval) {
>> + printf("%.*s\n", (int) sizeof(sb.s_volume_name),
>> + sb.s_volume_name);
>> + }
>> +
>> + remove_error_table(&et_ext2_error_table);
>> + return retval;
>> + }
>> +
>> retry_open:
>> if ((open_flag & EXT2_FLAG_RW) == 0 || f_flag)
>> open_flag |= EXT2_FLAG_SKIP_MMP;
>> @@ -2972,14 +2987,6 @@ retry_open:
>> sb = fs->super;
>> fs->flags &= ~EXT2_FLAG_MASTER_SB_ONLY;
>>
>> - if (print_label) {
>> - /* For e2label emulation */
>> - printf("%.*s\n", (int) sizeof(sb->s_volume_name),
>> - sb->s_volume_name);
>> - remove_error_table(&et_ext2_error_table);
>> - goto closefs;
>> - }
>> -
>> retval = ext2fs_check_if_mounted(device_name, &mount_flags);
>> if (retval) {
>> com_err("ext2fs_check_if_mount", retval,
>> --
>> 2.14.3
>>
>
