Message ID | 20210106013242epcms2p5b6b4ed8ca86f29456fdf56aa580e74b4@epcms2p5 |
---|---|
State | Awaiting Upstream |
Headers | show |
Series | ext4: Remove expensive flush on fast commit | expand |
Thanks Daejun! This looks good. Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> On Tue, Jan 5, 2021 at 5:32 PM Daejun Park <daejun7.park@samsung.com> wrote: > > 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 adds REQ_FUA and REQ_PREFLUSH > on the block that has tail. > > Signed-off-by: Daejun Park <daejun7.park@samsung.com> > --- > 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 4fcc21c25e79..e66507be334c 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; > } > -- > 2.25.1 >
On Wed, Jan 06, 2021 at 10:32:42AM +0900, Daejun Park wrote: > 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 adds REQ_FUA and REQ_PREFLUSH > on the block that has tail. Just out of curiosity, how does the new fastcommit code handle tests like generic/475 that simulate sudden disk failure? --D > Signed-off-by: Daejun Park <daejun7.park@samsung.com> > --- > 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 4fcc21c25e79..e66507be334c 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; > } > -- > 2.25.1 >
On Tue, Jan 5, 2021 at 5:32 PM Daejun Park <daejun7.park@samsung.com> wrote: > > 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 adds REQ_FUA and REQ_PREFLUSH > on the block that has tail. Does the tail block *always* contain a CRC, or is that dependent on EXT4_FEATURE_RO_COMPAT_METADATA_CSUM, JBD2_FEATURE_INCOMPAT_CSUM_V2, or JBD2_FEATURE_INCOMPAT_CSUM_V3 being enabled? If one of those features is *required* before the FAST_COMMIT feature can be used, then this patch looks OK. Otherwise, the CSUM feature should be checked before the FUA is skipped for non-tail blocks. Cheers, Andreas > Signed-off-by: Daejun Park <daejun7.park@samsung.com> > --- > 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 4fcc21c25e79..e66507be334c 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; > } > -- > 2.25.1 Cheers, Andreas
> > 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 adds REQ_FUA and REQ_PREFLUSH > > on the block that has tail. > > Does the tail block *always* contain a CRC, or is that dependent on > EXT4_FEATURE_RO_COMPAT_METADATA_CSUM, JBD2_FEATURE_INCOMPAT_CSUM_V2, > or JBD2_FEATURE_INCOMPAT_CSUM_V3 being enabled? In the fast commit, the tail block always contain a CRC. > If one of those features is *required* before the FAST_COMMIT feature > can be used, then this patch looks OK. Otherwise, the CSUM feature > should be checked before the FUA is skipped for non-tail blocks. So, I think it is OK without checking other CSUM feature. Thanks, Daejun
On Wed, Jan 06, 2021 at 10:32:42AM +0900, Daejun Park wrote: > 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 adds REQ_FUA and REQ_PREFLUSH > on the block that has tail. > > Signed-off-by: Daejun Park <daejun7.park@samsung.com> Thanks, applied. - Ted
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index 4fcc21c25e79..e66507be334c 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; }
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 adds REQ_FUA and REQ_PREFLUSH on the block that has tail. Signed-off-by: Daejun Park <daejun7.park@samsung.com> --- fs/ext4/fast_commit.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)