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Message-ID: <20220919102805.efbzwnu7xuv5h5ki@quack3>
Date: Mon, 19 Sep 2022 12:28:05 +0200
From: Jan Kara <jack@...e.cz>
To: Jason Yan <yanaijie@...wei.com>
Cc: tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz,
ritesh.list@...il.com, lczerner@...hat.com,
linux-ext4@...r.kernel.org
Subject: Re: [PATCH v3 14/16] ext4: unify the ext4 super block loading
operation
On Fri 16-09-22 22:15:25, Jason Yan wrote:
> Now we load the super block from the disk in two steps. First we load
> the super block with the default block size(EXT4_MIN_BLOCK_SIZE). Second
> we load the super block with the real block size. The second step is a
> little far from the first step. This patch move these two steps together
> in a new function.
>
> Signed-off-by: Jason Yan <yanaijie@...wei.com>
The patch looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@...e.cz>
Honza
> ---
> fs/ext4/super.c | 186 +++++++++++++++++++++++++++---------------------
> 1 file changed, 106 insertions(+), 80 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index a9641709b777..2301de8bddcb 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -4949,39 +4949,21 @@ static int ext4_journal_data_mode_check(struct super_block *sb)
> return 0;
> }
>
> -static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> +static int ext4_load_super(struct super_block *sb, ext4_fsblk_t *lsb,
> + int silent)
> {
> - struct buffer_head *bh;
> - struct ext4_super_block *es = NULL;
> struct ext4_sb_info *sbi = EXT4_SB(sb);
> - struct flex_groups **flex_groups;
> - ext4_fsblk_t block;
> + struct ext4_super_block *es;
> ext4_fsblk_t logical_sb_block;
> unsigned long offset = 0;
> - struct inode *root;
> - int ret = -ENOMEM;
> + struct buffer_head *bh;
> + int ret = -EINVAL;
> int blocksize;
> - unsigned int i;
> - int needs_recovery, has_huge_files;
> - int err = 0;
> - ext4_group_t first_not_zeroed;
> - struct ext4_fs_context *ctx = fc->fs_private;
> - int silent = fc->sb_flags & SB_SILENT;
> -
> - /* Set defaults for the variables that will be set during parsing */
> - if (!(ctx->spec & EXT4_SPEC_JOURNAL_IOPRIO))
> - ctx->journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
>
> - sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
> - sbi->s_sectors_written_start =
> - part_stat_read(sb->s_bdev, sectors[STAT_WRITE]);
> -
> - /* -EINVAL is default */
> - ret = -EINVAL;
> blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
> if (!blocksize) {
> ext4_msg(sb, KERN_ERR, "unable to set blocksize");
> - goto out_fail;
> + return -EINVAL;
> }
>
> /*
> @@ -4998,8 +4980,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
> if (IS_ERR(bh)) {
> ext4_msg(sb, KERN_ERR, "unable to read superblock");
> - ret = PTR_ERR(bh);
> - goto out_fail;
> + return PTR_ERR(bh);
> }
> /*
> * Note: s_es must be initialized as soon as possible because
> @@ -5011,9 +4992,106 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> if (sb->s_magic != EXT4_SUPER_MAGIC) {
> if (!silent)
> ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
> - goto failed_mount;
> + goto out;
> }
>
> + if (le32_to_cpu(es->s_log_block_size) >
> + (EXT4_MAX_BLOCK_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
> + ext4_msg(sb, KERN_ERR,
> + "Invalid log block size: %u",
> + le32_to_cpu(es->s_log_block_size));
> + goto out;
> + }
> + if (le32_to_cpu(es->s_log_cluster_size) >
> + (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
> + ext4_msg(sb, KERN_ERR,
> + "Invalid log cluster size: %u",
> + le32_to_cpu(es->s_log_cluster_size));
> + goto out;
> + }
> +
> + blocksize = EXT4_MIN_BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
> +
> + /*
> + * If the default block size is not the same as the real block size,
> + * we need to reload it.
> + */
> + if (sb->s_blocksize == blocksize) {
> + *lsb = logical_sb_block;
> + sbi->s_sbh = bh;
> + return 0;
> + }
> +
> + /*
> + * bh must be released before kill_bdev(), otherwise
> + * it won't be freed and its page also. kill_bdev()
> + * is called by sb_set_blocksize().
> + */
> + brelse(bh);
> + /* Validate the filesystem blocksize */
> + if (!sb_set_blocksize(sb, blocksize)) {
> + ext4_msg(sb, KERN_ERR, "bad block size %d",
> + blocksize);
> + bh = NULL;
> + goto out;
> + }
> +
> + logical_sb_block = sbi->s_sb_block * EXT4_MIN_BLOCK_SIZE;
> + offset = do_div(logical_sb_block, blocksize);
> + bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
> + if (IS_ERR(bh)) {
> + ext4_msg(sb, KERN_ERR, "Can't read superblock on 2nd try");
> + ret = PTR_ERR(bh);
> + bh = NULL;
> + goto out;
> + }
> + es = (struct ext4_super_block *)(bh->b_data + offset);
> + sbi->s_es = es;
> + if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
> + ext4_msg(sb, KERN_ERR, "Magic mismatch, very weird!");
> + goto out;
> + }
> + *lsb = logical_sb_block;
> + sbi->s_sbh = bh;
> + return 0;
> +out:
> + brelse(bh);
> + return ret;
> +}
> +
> +static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> +{
> + struct ext4_super_block *es = NULL;
> + struct ext4_sb_info *sbi = EXT4_SB(sb);
> + struct flex_groups **flex_groups;
> + ext4_fsblk_t block;
> + ext4_fsblk_t logical_sb_block;
> + struct inode *root;
> + int ret = -ENOMEM;
> + int blocksize;
> + unsigned int i;
> + int needs_recovery, has_huge_files;
> + int err = 0;
> + ext4_group_t first_not_zeroed;
> + struct ext4_fs_context *ctx = fc->fs_private;
> + int silent = fc->sb_flags & SB_SILENT;
> +
> + /* Set defaults for the variables that will be set during parsing */
> + if (!(ctx->spec & EXT4_SPEC_JOURNAL_IOPRIO))
> + ctx->journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
> +
> + sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
> + sbi->s_sectors_written_start =
> + part_stat_read(sb->s_bdev, sectors[STAT_WRITE]);
> +
> + /* -EINVAL is default */
> + ret = -EINVAL;
> + err = ext4_load_super(sb, &logical_sb_block, silent);
> + if (err)
> + goto out_fail;
> +
> + es = sbi->s_es;
> + blocksize = sb->s_blocksize;
> sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
>
> err = ext4_init_metadata_csum(sb, es);
> @@ -5034,23 +5112,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> */
> sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
>
> - if (le32_to_cpu(es->s_log_block_size) >
> - (EXT4_MAX_BLOCK_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
> - ext4_msg(sb, KERN_ERR,
> - "Invalid log block size: %u",
> - le32_to_cpu(es->s_log_block_size));
> - goto failed_mount;
> - }
> - if (le32_to_cpu(es->s_log_cluster_size) >
> - (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
> - ext4_msg(sb, KERN_ERR,
> - "Invalid log cluster size: %u",
> - le32_to_cpu(es->s_log_cluster_size));
> - goto failed_mount;
> - }
> -
> - blocksize = EXT4_MIN_BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
> -
> if (blocksize == PAGE_SIZE)
> set_opt(sb, DIOREAD_NOLOCK);
>
> @@ -5114,40 +5175,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> goto failed_mount;
> }
>
> - if (sb->s_blocksize != blocksize) {
> - /*
> - * bh must be released before kill_bdev(), otherwise
> - * it won't be freed and its page also. kill_bdev()
> - * is called by sb_set_blocksize().
> - */
> - brelse(bh);
> - /* Validate the filesystem blocksize */
> - if (!sb_set_blocksize(sb, blocksize)) {
> - ext4_msg(sb, KERN_ERR, "bad block size %d",
> - blocksize);
> - bh = NULL;
> - goto failed_mount;
> - }
> -
> - logical_sb_block = sbi->s_sb_block * EXT4_MIN_BLOCK_SIZE;
> - offset = do_div(logical_sb_block, blocksize);
> - bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
> - if (IS_ERR(bh)) {
> - ext4_msg(sb, KERN_ERR,
> - "Can't read superblock on 2nd try");
> - ret = PTR_ERR(bh);
> - bh = NULL;
> - goto failed_mount;
> - }
> - es = (struct ext4_super_block *)(bh->b_data + offset);
> - sbi->s_es = es;
> - if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
> - ext4_msg(sb, KERN_ERR,
> - "Magic mismatch, very weird!");
> - goto failed_mount;
> - }
> - }
> -
> has_huge_files = ext4_has_feature_huge_file(sb);
> sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
> has_huge_files);
> @@ -5184,7 +5211,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> sbi->s_itb_per_group = sbi->s_inodes_per_group /
> sbi->s_inodes_per_block;
> sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
> - sbi->s_sbh = bh;
> sbi->s_mount_state = le16_to_cpu(es->s_state) & ~EXT4_FC_REPLAY;
> sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
> sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
> @@ -5621,7 +5647,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
> #endif
> fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
> /* ext4_blkdev_remove() calls kill_bdev(), release bh before it. */
> - brelse(bh);
> + brelse(sbi->s_sbh);
> ext4_blkdev_remove(sbi);
> out_fail:
> sb->s_fs_info = NULL;
> --
> 2.31.1
>
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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