On Nov 28, 2018, at 9:42 AM, 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 change ext2fs_open2(), so only initialized
> superblock is returned. without block descriptors. This save
> time dramatically.
>
> Cray-bug-id: LUS-5777
> Signed-off-by: Artem Blagodarenko <artem.blagodarenko@xxxxxxxxx>
> ---
> lib/ext2fs/ext2fs.h | 1 +
> lib/ext2fs/openfs.c | 22 +++++++++++++++++++---
> misc/tune2fs.c | 7 ++++++-
> 3 files changed, 26 insertions(+), 4 deletions(-)
>
> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> index 5b87d395..5318b14d 100644
> --- a/lib/ext2fs/ext2fs.h
> +++ b/lib/ext2fs/ext2fs.h
> @@ -204,6 +204,7 @@ typedef struct ext2_file *ext2_file_t;
> #define EXT2_FLAG_IGNORE_CSUM_ERRORS 0x200000
> #define EXT2_FLAG_SHARE_DUP 0x400000
> #define EXT2_FLAG_IGNORE_SB_ERRORS 0x800000
> +#define EXT2_FLAG_LABEL 0x1000000
There are already a couple of similar flags, EXT2_FLAG_SUPER_ONLY,
but I guess that doesn't quite do the right thing either?
The only minor nit I have is that the flag name should describe what
it does, rather than what it is being used for. For example, a better
name would be "EXT2_FLAG_JOURNAL_ONLY" or similar, so that other
users might use it, instead of thinking it is specific to the label.
Cheers, Andreas
>
> /*
> * Special flag in the ext2 inode i_flag field that means that this is
> diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
> index 85d73e2a..a5e97e6d 100644
> --- a/lib/ext2fs/openfs.c
> +++ b/lib/ext2fs/openfs.c
> @@ -135,6 +135,7 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
> int j;
> #endif
> char *time_env;
> + unsigned long enough_desc_blocks;
>
> EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
>
> @@ -440,12 +441,23 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
> dest += fs->blocksize*first_meta_bg;
> }
>
> - for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
> + /*
> + * Need superblock and journal inode only. Do not read
> + * met_bg group blocks if journal inode group already loaded
> + */
> + if (flags & EXT2_FLAG_LABEL)
> + enough_desc_blocks =
> + fs->super->s_journal_inum /
> + EXT2_INODES_PER_GROUP(fs->super) + 1;
> + else
> + enough_desc_blocks = fs->desc_blocks;
> +
> + for (i = first_meta_bg; i < enough_desc_blocks; i++) {
> blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
> io_channel_cache_readahead(fs->io, blk, 1);
> }
>
> - for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
> + for (i = first_meta_bg; i < enough_desc_blocks; i++) {
> blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
> retval = io_channel_read_blk64(fs->io, blk, 1, dest);
> if (retval)
> @@ -468,8 +480,12 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
> */
> if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
> dgrp_t group;
> + dgrp_t enough_desc_count;
> +
> + enough_desc_count = enough_desc_blocks *
> + EXT2_DESC_PER_BLOCK(fs->super);
>
> - for (group = 0; group < fs->group_desc_count; group++) {
> + for (group = 0; group < enough_desc_count; group++) {
> ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
> ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
> ext2fs_bg_itable_unused_set(fs, group, 0);
> diff --git a/misc/tune2fs.c b/misc/tune2fs.c
> index cd4057c3..3d0c7d51 100644
> --- a/misc/tune2fs.c
> +++ b/misc/tune2fs.c
> @@ -2882,6 +2882,12 @@ retry_open:
> /* keep the filesystem struct around to dump MMP data */
> open_flag |= EXT2_FLAG_NOFREE_ON_ERROR;
>
> + if (print_label || L_flag) {
> + open_flag |= EXT2_FLAG_LABEL;
> + /* don't want metadata to be flushed at close */
> + //open_flag &= ~EXT2_FLAG_RW;
> + }
> +
> retval = ext2fs_open2(device_name, io_options, open_flag,
> 0, 0, io_ptr, &fs);
> if (retval) {
> @@ -2999,7 +3005,6 @@ _("Warning: The journal is dirty. You may wish to replay the journal like:\n\n"
> if ((open_flag & EXT2_FLAG_RW) && !(mount_flags & (EXT2_MF_BUSY | EXT2_MF_MOUNTED)) &&
> ext2fs_has_feature_journal_needs_recovery(fs->super)) {
> errcode_t err;
> -
> printf(_("Recovering journal.\n"));
> err = ext2fs_run_ext3_journal(&fs);
> if (err) {
> --
> 2.14.3
>
Cheers, Andreas
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