From e029c5f2798720b463e8df0e184a4d1036311b43 Mon Sep 17 00:00:00 2001 From: Harshad Shirwadkar Date: Mon, 26 Oct 2020 21:49:14 -0700 Subject: [PATCH] ext4: make num of fast commit blocks configurable This patch reserves a field in the jbd2 superblock for number of fast commit blocks. When this value is non-zero, Ext4 uses this field to set the number of fast commit blocks. Fixes: 6866d7b3f2bb ("ext4/jbd2: add fast commit initialization") Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201027044915.2553163-2-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o --- fs/ext4/fast_commit.c | 12 +++++++++++- include/linux/jbd2.h | 5 ++++- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index 1d72f8f13a05..dd7931400474 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -2077,6 +2077,8 @@ static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh, void ext4_fc_init(struct super_block *sb, journal_t *journal) { + int num_fc_blocks; + /* * We set replay callback even if fast commit disabled because we may * could still have fast commit blocks that need to be replayed even if @@ -2086,7 +2088,15 @@ void ext4_fc_init(struct super_block *sb, journal_t *journal) if (!test_opt2(sb, JOURNAL_FAST_COMMIT)) return; journal->j_fc_cleanup_callback = ext4_fc_cleanup; - if (jbd2_fc_init(journal, EXT4_NUM_FC_BLKS)) { + if (!buffer_uptodate(journal->j_sb_buffer) + && ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO, + true)) { + ext4_msg(sb, KERN_ERR, "I/O error on journal"); + return; + } + num_fc_blocks = be32_to_cpu(journal->j_superblock->s_num_fc_blks); + if (jbd2_fc_init(journal, num_fc_blocks ? num_fc_blocks : + EXT4_NUM_FC_BLKS)) { pr_warn("Error while enabling fast commits, turning off."); ext4_clear_feature_fast_commit(sb); } diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index fb3d71ad6eea..7e88bbc16ffb 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -263,7 +263,10 @@ typedef struct journal_superblock_s /* 0x0050 */ __u8 s_checksum_type; /* checksum type */ __u8 s_padding2[3]; - __u32 s_padding[42]; +/* 0x0054 */ + __be32 s_num_fc_blks; /* Number of fast commit blocks */ +/* 0x0058 */ + __u32 s_padding[41]; __be32 s_checksum; /* crc32c(superblock) */ /* 0x0100 */ -- 2.34.1