This patchset is attempt to add CoW support for fsdax, and take XFS,
which has both reflink and fsdax feature, as an example.
Changes from V5:
- Fix the lock order of xfs_inode in xfs_mmaplock_two_inodes_and_break_dax_layout()
- move dax_remap_file_range_prep() to fs/dax.c
- change type of length to uint64_t in dax_iomap_cow_copy()
- fix mistake in dax_iomap_zero()
Changes from V4:
- Fix the mistake of breaking dax layout for two inodes
- Add CONFIG_FS_DAX judgement for fsdax code in remap_range.c
- Fix other small problems and mistakes
One of the key mechanism need to be implemented in fsdax is CoW. Copy
the data from srcmap before we actually write data to the destance
iomap. And we just copy range in which data won't be changed.
Another mechanism is range comparison. In page cache case, readpage()
is used to load data on disk to page cache in order to be able to
compare data. In fsdax case, readpage() does not work. So, we need
another compare data with direct access support.
With the two mechanisms implemented in fsdax, we are able to make reflink
and fsdax work together in XFS.
Some of the patches are picked up from Goldwyn's patchset. I made some
changes to adapt to this patchset.
(Rebased on v5.13-rc2 and patchset[1])
[1]: https://lkml.org/lkml/2021/4/22/575
Shiyang Ruan (7):
fsdax: Introduce dax_iomap_cow_copy()
fsdax: Replace mmap entry in case of CoW
fsdax: Add dax_iomap_cow_copy() for dax_iomap_zero
iomap: Introduce iomap_apply2() for operations on two files
fsdax: Dedup file range to use a compare function
fs/xfs: Handle CoW for fsdax write() path
fs/xfs: Add dax dedupe support
fs/dax.c | 216 ++++++++++++++++++++++++++++++++++++-----
fs/iomap/apply.c | 52 ++++++++++
fs/iomap/buffered-io.c | 2 +-
fs/remap_range.c | 36 +++++--
fs/xfs/xfs_bmap_util.c | 3 +-
fs/xfs/xfs_file.c | 11 +--
fs/xfs/xfs_inode.c | 57 +++++++++++
fs/xfs/xfs_inode.h | 1 +
fs/xfs/xfs_iomap.c | 38 +++++++-
fs/xfs/xfs_iomap.h | 24 +++++
fs/xfs/xfs_iops.c | 7 +-
fs/xfs/xfs_reflink.c | 15 +--
include/linux/dax.h | 11 ++-
include/linux/fs.h | 12 ++-
include/linux/iomap.h | 7 +-
15 files changed, 431 insertions(+), 61 deletions(-)
--
2.31.1
On Wed, May 19, 2021 at 02:00:38PM +0800, Shiyang Ruan wrote:
> This patchset is attempt to add CoW support for fsdax, and take XFS,
> which has both reflink and fsdax feature, as an example.
Soooo... how close are we to enabling reflink for DAX?
I <cough> got rid of the lockouts in xfs_super.c and ran a quick
fstests, which showed a number of odd regressions where dedupe tests
that were supposed to fail with EBADE didn't and a bunch of clonerange
tests failed with EINVAL:
generic/122 - output mismatch (see /var/tmp/fstests/generic/122.out.bad)
--- tests/generic/122.out 2021-05-13 11:47:55.665860364 -0700
+++ /var/tmp/fstests/generic/122.out.bad 2021-05-25 17:24:03.333270522 -0700
@@ -4,7 +4,8 @@
5e3501f97fd2669babfcbd3e1972e833 TEST_DIR/test-122/file2
Files 1-2 do not match (intentional)
(Fail to) dedupe the middle blocks together
-XFS_IOC_FILE_EXTENT_SAME: Extents did not match.
+deduped 131072/131072 bytes at offset 262144
+128 KiB, 1 ops; 0.0000 sec (12.207 GiB/sec and 100000.0000 ops/sec)
Compare sections
...
(Run 'diff -u /tmp/fstests/tests/generic/122.out /var/tmp/fstests/generic/122.out.bad' to see the entire diff)
generic/136 - output mismatch (see /var/tmp/fstests/generic/136.out.bad)
--- tests/generic/136.out 2021-05-13 11:47:55.668860355 -0700
+++ /var/tmp/fstests/generic/136.out.bad 2021-05-25 17:24:05.773367756 -0700
@@ -7,7 +7,8 @@
Dedupe the last blocks together
1->2
1->3
-XFS_IOC_FILE_EXTENT_SAME: Extents did not match.
+deduped 37/37 bytes at offset 65536
+37.000000 bytes, 1 ops; 0.0000 sec (1.960 MiB/sec and 55555.5556 ops/sec)
c4fd505be25a0c91bcca9f502b9a8156 TEST_DIR/test-136/file1
...
(Run 'diff -u /tmp/fstests/tests/generic/136.out /var/tmp/fstests/generic/136.out.bad' to see the entire diff)
generic/164 - output mismatch (see /var/tmp/fstests/generic/164.out.bad)
--- tests/generic/164.out 2021-05-13 11:47:55.674860338 -0700
+++ /var/tmp/fstests/generic/164.out.bad 2021-05-25 17:25:33.339738197 -0700
@@ -2,4 +2,1028 @@
Format and mount
Initialize files
Reflink and reread the files!
+XFS_IOC_CLONE_RANGE: Invalid argument
+XFS_IOC_CLONE_RANGE: Invalid argument
+XFS_IOC_CLONE_RANGE: Invalid argument
+XFS_IOC_CLONE_RANGE: Invalid argument
...
(Run 'diff -u /tmp/fstests/tests/generic/164.out /var/tmp/fstests/generic/164.out.bad' to see the entire diff)
generic/165 - output mismatch (see /var/tmp/fstests/generic/165.out.bad)
--- tests/generic/165.out 2021-05-13 11:47:55.674860338 -0700
+++ /var/tmp/fstests/generic/165.out.bad 2021-05-25 17:25:45.247685323 -0700
@@ -2,4 +2,1028 @@
Format and mount
Initialize files
Reflink and dio reread the files!
+XFS_IOC_CLONE_RANGE: Invalid argument
+XFS_IOC_CLONE_RANGE: Invalid argument
+XFS_IOC_CLONE_RANGE: Invalid argument
+XFS_IOC_CLONE_RANGE: Invalid argument
...
(Run 'diff -u /tmp/fstests/tests/generic/165.out /var/tmp/fstests/generic/165.out.bad' to see the entire diff)
generic/175 - output mismatch (see /var/tmp/fstests/generic/175.out.bad)
--- tests/generic/175.out 2021-05-13 11:47:55.676860332 -0700
+++ /var/tmp/fstests/generic/175.out.bad 2021-05-25 17:29:55.060917807 -0700
@@ -3,3 +3,4 @@
Create a one block file
Create extents
Reflink the big file
+XFS_IOC_CLONE_RANGE: Invalid argument
...
(Run 'diff -u /tmp/fstests/tests/generic/175.out /var/tmp/fstests/generic/175.out.bad' to see the entire diff)
generic/327 - output mismatch (see /var/tmp/fstests/generic/327.out.bad)
--- tests/generic/327.out 2021-05-13 11:47:55.704860251 -0700
+++ /var/tmp/fstests/generic/327.out.bad 2021-05-25 17:35:22.338448231 -0700
@@ -7,6 +7,6 @@
root 0 0 0
fsgqa 2048 0 1024
Try to reflink again
-cp: failed to clone 'SCRATCH_MNT/test-327/file3' from 'SCRATCH_MNT/test-327/file1': Disk quota exceeded
+cp: failed to clone 'SCRATCH_MNT/test-327/file3' from 'SCRATCH_MNT/test-327/file1': Invalid argument
root 0 0 0
fsgqa 2048 0 1024
...
(Run 'diff -u /tmp/fstests/tests/generic/327.out /var/tmp/fstests/generic/327.out.bad' to see the entire diff)
generic/516 - output mismatch (see /var/tmp/fstests/generic/516.out.bad)
--- tests/generic/516.out 2021-05-13 11:47:55.739860150 -0700
+++ /var/tmp/fstests/generic/516.out.bad 2021-05-25 17:41:58.144177193 -0700
@@ -4,7 +4,8 @@
39578c21e2cb9f6049b1cf7fc7be12a6 TEST_DIR/test-516/file2
Files 1-2 do not match (intentional)
(partial) dedupe the middle blocks together
-XFS_IOC_FILE_EXTENT_SAME: Extents did not match.
+deduped XXXX/XXXX bytes at offset XXXX
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Compare sections
...
(Run 'diff -u /tmp/fstests/tests/generic/516.out /var/tmp/fstests/generic/516.out.bad' to see the entire diff)
generic/517 - output mismatch (see /var/tmp/fstests/generic/517.out.bad)
--- tests/generic/517.out 2021-05-13 11:47:55.739860150 -0700
+++ /var/tmp/fstests/generic/517.out.bad 2021-05-25 17:41:59.352000318 -0700
@@ -33,8 +33,7 @@
0786532
wrote 100/100 bytes at offset 0
XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-deduped 100/100 bytes at offset 655360
-XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+XFS_IOC_FILE_EXTENT_SAME: Invalid argument
File content after second deduplication:
...
(Run 'diff -u /tmp/fstests/tests/generic/517.out /var/tmp/fstests/generic/517.out.bad' to see the entire diff)
generic/518 1s
generic/540 - output mismatch (see /var/tmp/fstests/generic/540.out.bad)
--- tests/generic/540.out 2021-05-13 11:47:55.743860139 -0700
+++ /var/tmp/fstests/generic/540.out.bad 2021-05-25 17:42:01.999613949 -0700
@@ -7,8 +7,9 @@
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-540/file3
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-540/file3.chk
reflink across the transition
+XFS_IOC_CLONE_RANGE: Invalid argument
Compare files
bdbcf02ee0aa977795a79d25fcfdccb1 SCRATCH_MNT/test-540/file1
5a5221017d3ab8fd7583312a14d2ba80 SCRATCH_MNT/test-540/file2
...
(Run 'diff -u /tmp/fstests/tests/generic/540.out /var/tmp/fstests/generic/540.out.bad' to see the entire diff)
generic/541 - output mismatch (see /var/tmp/fstests/generic/541.out.bad)
--- tests/generic/541.out 2021-05-13 11:47:55.743860139 -0700
+++ /var/tmp/fstests/generic/541.out.bad 2021-05-25 17:42:03.623377997 -0700
@@ -8,9 +8,10 @@
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-541/file3
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-541/file3.chk
reflink across the transition
+XFS_IOC_CLONE_RANGE: Invalid argument
Compare files
bdbcf02ee0aa977795a79d25fcfdccb1 SCRATCH_MNT/test-541/file1
-51a300aae3a4b4eaa023876a397e01ef SCRATCH_MNT/test-541/file2
...
(Run 'diff -u /tmp/fstests/tests/generic/541.out /var/tmp/fstests/generic/541.out.bad' to see the entire diff)
generic/542 - output mismatch (see /var/tmp/fstests/generic/542.out.bad)
--- tests/generic/542.out 2021-05-13 11:47:55.743860139 -0700
+++ /var/tmp/fstests/generic/542.out.bad 2021-05-25 17:42:05.487108030 -0700
@@ -7,8 +7,9 @@
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-542/file3
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-542/file3.chk
reflink across the transition
+XFS_IOC_CLONE_RANGE: Invalid argument
Compare files
bdbcf02ee0aa977795a79d25fcfdccb1 SCRATCH_MNT/test-542/file1
5a5221017d3ab8fd7583312a14d2ba80 SCRATCH_MNT/test-542/file2
...
(Run 'diff -u /tmp/fstests/tests/generic/542.out /var/tmp/fstests/generic/542.out.bad' to see the entire diff)
generic/543 - output mismatch (see /var/tmp/fstests/generic/543.out.bad)
--- tests/generic/543.out 2021-05-13 11:47:55.744860136 -0700
+++ /var/tmp/fstests/generic/543.out.bad 2021-05-25 17:42:07.386833815 -0700
@@ -8,9 +8,10 @@
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-543/file3
6366fd359371414186688a0ef6988893 SCRATCH_MNT/test-543/file3.chk
reflink across the transition
+XFS_IOC_CLONE_RANGE: Invalid argument
Compare files
bdbcf02ee0aa977795a79d25fcfdccb1 SCRATCH_MNT/test-543/file1
-d93123af536c8c012f866ea383a905ce SCRATCH_MNT/test-543/file2
...
(Run 'diff -u /tmp/fstests/tests/generic/543.out /var/tmp/fstests/generic/543.out.bad' to see the entire diff)
That's all the failures to the end of the generic group; I cut it off so
that I could schedule my regular nightly testing runs.
--D
>
> Changes from V5:
> - Fix the lock order of xfs_inode in xfs_mmaplock_two_inodes_and_break_dax_layout()
> - move dax_remap_file_range_prep() to fs/dax.c
> - change type of length to uint64_t in dax_iomap_cow_copy()
> - fix mistake in dax_iomap_zero()
>
> Changes from V4:
> - Fix the mistake of breaking dax layout for two inodes
> - Add CONFIG_FS_DAX judgement for fsdax code in remap_range.c
> - Fix other small problems and mistakes
>
> One of the key mechanism need to be implemented in fsdax is CoW. Copy
> the data from srcmap before we actually write data to the destance
> iomap. And we just copy range in which data won't be changed.
>
> Another mechanism is range comparison. In page cache case, readpage()
> is used to load data on disk to page cache in order to be able to
> compare data. In fsdax case, readpage() does not work. So, we need
> another compare data with direct access support.
>
> With the two mechanisms implemented in fsdax, we are able to make reflink
> and fsdax work together in XFS.
>
> Some of the patches are picked up from Goldwyn's patchset. I made some
> changes to adapt to this patchset.
>
>
> (Rebased on v5.13-rc2 and patchset[1])
> [1]: https://lkml.org/lkml/2021/4/22/575
>
> Shiyang Ruan (7):
> fsdax: Introduce dax_iomap_cow_copy()
> fsdax: Replace mmap entry in case of CoW
> fsdax: Add dax_iomap_cow_copy() for dax_iomap_zero
> iomap: Introduce iomap_apply2() for operations on two files
> fsdax: Dedup file range to use a compare function
> fs/xfs: Handle CoW for fsdax write() path
> fs/xfs: Add dax dedupe support
>
> fs/dax.c | 216 ++++++++++++++++++++++++++++++++++++-----
> fs/iomap/apply.c | 52 ++++++++++
> fs/iomap/buffered-io.c | 2 +-
> fs/remap_range.c | 36 +++++--
> fs/xfs/xfs_bmap_util.c | 3 +-
> fs/xfs/xfs_file.c | 11 +--
> fs/xfs/xfs_inode.c | 57 +++++++++++
> fs/xfs/xfs_inode.h | 1 +
> fs/xfs/xfs_iomap.c | 38 +++++++-
> fs/xfs/xfs_iomap.h | 24 +++++
> fs/xfs/xfs_iops.c | 7 +-
> fs/xfs/xfs_reflink.c | 15 +--
> include/linux/dax.h | 11 ++-
> include/linux/fs.h | 12 ++-
> include/linux/iomap.h | 7 +-
> 15 files changed, 431 insertions(+), 61 deletions(-)
>
> --
> 2.31.1
>
>
>