From e9f53353e166a67dfe4f8295100f8ac39d6cf10b Mon Sep 17 00:00:00 2001 From: Daejun Park Date: Wed, 6 Jan 2021 10:32:42 +0900 Subject: [PATCH] ext4: remove expensive flush on fast commit In the fast commit, it adds REQ_FUA and REQ_PREFLUSH on each fast commit block when barrier is enabled. However, in recovery phase, ext4 compares CRC value in the tail. So it is sufficient to add REQ_FUA and REQ_PREFLUSH on the block that has tail. Signed-off-by: Daejun Park Reviewed-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20210106013242epcms2p5b6b4ed8ca86f29456fdf56aa580e74b4@epcms2p5 Signed-off-by: Theodore Ts'o --- fs/ext4/fast_commit.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index ec5316fbcd1d..0a14a7c87bf8 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -604,13 +604,13 @@ void ext4_fc_track_range(handle_t *handle, struct inode *inode, ext4_lblk_t star trace_ext4_fc_track_range(inode, start, end, ret); } -static void ext4_fc_submit_bh(struct super_block *sb) +static void ext4_fc_submit_bh(struct super_block *sb, bool is_tail) { int write_flags = REQ_SYNC; struct buffer_head *bh = EXT4_SB(sb)->s_fc_bh; - /* TODO: REQ_FUA | REQ_PREFLUSH is unnecessarily expensive. */ - if (test_opt(sb, BARRIER)) + /* Add REQ_FUA | REQ_PREFLUSH only its tail */ + if (test_opt(sb, BARRIER) && is_tail) write_flags |= REQ_FUA | REQ_PREFLUSH; lock_buffer(bh); set_buffer_dirty(bh); @@ -684,7 +684,7 @@ static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc) *crc = ext4_chksum(sbi, *crc, tl, sizeof(*tl)); if (pad_len > 0) ext4_fc_memzero(sb, tl + 1, pad_len, crc); - ext4_fc_submit_bh(sb); + ext4_fc_submit_bh(sb, false); ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh); if (ret) @@ -741,7 +741,7 @@ static int ext4_fc_write_tail(struct super_block *sb, u32 crc) tail.fc_crc = cpu_to_le32(crc); ext4_fc_memcpy(sb, dst, &tail.fc_crc, sizeof(tail.fc_crc), NULL); - ext4_fc_submit_bh(sb); + ext4_fc_submit_bh(sb, true); return 0; }