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 <daejun7.park@samsung.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210106013242epcms2p5b6b4ed8ca86f29456fdf56aa580e74b4@epcms2p5
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Daejun Park 2021-01-06 10:32:42 +09:00 committed by Theodore Ts'o
parent 6b4b8e6b4a
commit e9f53353e1

View File

@ -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); 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; int write_flags = REQ_SYNC;
struct buffer_head *bh = EXT4_SB(sb)->s_fc_bh; struct buffer_head *bh = EXT4_SB(sb)->s_fc_bh;
/* TODO: REQ_FUA | REQ_PREFLUSH is unnecessarily expensive. */ /* Add REQ_FUA | REQ_PREFLUSH only its tail */
if (test_opt(sb, BARRIER)) if (test_opt(sb, BARRIER) && is_tail)
write_flags |= REQ_FUA | REQ_PREFLUSH; write_flags |= REQ_FUA | REQ_PREFLUSH;
lock_buffer(bh); lock_buffer(bh);
set_buffer_dirty(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)); *crc = ext4_chksum(sbi, *crc, tl, sizeof(*tl));
if (pad_len > 0) if (pad_len > 0)
ext4_fc_memzero(sb, tl + 1, pad_len, crc); 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); ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
if (ret) 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); tail.fc_crc = cpu_to_le32(crc);
ext4_fc_memcpy(sb, dst, &tail.fc_crc, sizeof(tail.fc_crc), NULL); 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; return 0;
} }