Chandan Rajendra
2014-Nov-12 08:17 UTC
[RFC PATCH V8 00/16] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O.
This patchset continues with the work posted earlier at
http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg37484.html.
Changes from V1:
1. Remove usage of bio_vec->bv_{len,offset} in end_bio_extent_readpage()
and end_bio_extent_writepage().
Changes from V2:
1. Get __extent_writepage() to write only the dirty blocks of a page.
2. Fix "page private not zero on page" warning message which is
printed
when running xfstests.
Changes from V3:
1. Get "Hole punching" and "Extent preallocation" to work
correctly in
subpagesize-blocksize scenario.
2. Get btrfs_page_mkwrite() to reserve space in sectorsized units.
Changes from V4:
1. V2's "Btrfs: subpagesize-blocksize: Get rid of whole page
reads"
patch was incorrectly replaced with an older version when working
on V3 patches. Fix this.
2. Fix btrfs_endio_direct_read() to compute checksums for all possible
blocks in a page.
Changes from V5:
1. Rebased patchset on top of current btrfs-next tree (i.e. commit
8d875f95da43c6a8f18f77869f2ef26e9594fecc). This involved using
"immutable biovecs".
2. Deal with partially allocated ordered extents across a page.
3. Explicitly track I/O status of blocks of an ordered extent.
Changes from V6:
1. Fix softlockup issue that occured during unmounting a 4k blocksized
filesystem instance.
2. Track blocks of an ordered extent submitted for write I/O to avoid
I/O resubmission in certain scenarios.
Changes from V7:
1. Fix a softlockup issue that occured because the page corresponding
to the delalloc region did not exist. This bug was introduced by
the code added in btrfs_invalidatepage and related functions in V7
version.
Unfortunately until now, I have been running xfstests on a guest with
just one virtual cpu. Hence some synchronization issues had been
masked away. So the below results are applicable only for the 1 vcpu
scenario (although the synchronization issues will be fixed in future
revisions of the patchset).
Xfstests' generic tests were run on an x86_64 machine with the patches
applied. The Btrfs kernel module was compiled without ACL support and
hence tests related to that were not run.
For 2k blocksize, the following xfstests' generic tests failed:
1. generic/091
2. generic/125
3. generic/251
The following xfstests' generic tests failed for both 2k and 4k blocksize:
1. generic/224 (OOM)
This looks mostly an issue caused by non-btrfs code as the test failed
for the exact same reason when run on an ext4 filesystem instance.
2. generic/263
FALLOC_FL_ZERO_RANGE isn't supported by Btrfs. Hence the test fails.
The following is a list of known TODO items which will be implemented in
future revisions of this patchset:
1. Fix synchronization issues that occur in multiprocessor scenario.
2. Get Xfstests' generic tests to successfully run on both 4k and 2k
blocksizes.
2. Remove PAGE_CACHE_SIZE delalloc reservation in
btrfs_writepage_fixup_worker().
3. Create separate slab caches for 'extent buffer head' and 'extent
buffer'.
4. Add 'leak list' tracking for 'extent buffer' instances.
5. Rename EXTENT_BUFFER_TREE_REF and EXTENT_BUFFER_IN_TREE to
EXTENT_BUFFER_HEAD_TREE_REF and EXTENT_BUFFER_HEAD_IN_TREE respectively.
Chandan Rajendra (14):
Btrfs: subpagesize-blocksize: Get rid of whole page reads.
Btrfs: subpagesize-blocksize: Get rid of whole page writes.
Btrfs: subpagesize-blocksize: __btrfs_buffered_write: Reserve/release
extents aligned to block size.
Btrfs: subpagesize-blocksize: Read tree blocks whose size is
<PAGE_CACHE_SIZE.
Btrfs: subpagesize-blocksize: Write only dirty extent buffers
belonging to a page
Btrfs: subpagesize-blocksize: Compute and look up csums based on
sectorsized blocks.
Btrfs: subpagesize-blocksize: __extent_writepage: Write only dirty
blocks of a page.
Btrfs: subpagesize-blocksize: fallocate: Work with sectorsized units.
Btrfs: subpagesize-blocksize: btrfs_page_mkwrite: Reserve space in
sectorsized units.
Btrfs: subpagesize-blocksize: Search for all ordered extents that
could span across a page.
Btrfs: subpagesize-blocksize: Deal with partial ordered extent
allocations.
Btrfs: subpagesize-blocksize: Explicitly Track I/O status of blocks of
an ordered extent.
Btrfs: subpagesize-blocksize: Revert commit
fc4adbff823f76577ece26dcb88bf6f8392dbd43.
Btrfs: subpagesize-blocksize: Track blocks of ordered extent submitted
for write I/O.
Chandra Seetharaman (2):
Btrfs: subpagesize-blocksize: Define extent_buffer_head.
Btrfs: subpagesize-blocksize: Allow mounting filesystems where
sectorsize != PAGE_SIZE
fs/btrfs/backref.c | 2 +-
fs/btrfs/btrfs_inode.h | 2 -
fs/btrfs/ctree.c | 2 +-
fs/btrfs/ctree.h | 8 +-
fs/btrfs/disk-io.c | 117 +++--
fs/btrfs/disk-io.h | 3 +
fs/btrfs/extent-tree.c | 6 +-
fs/btrfs/extent_io.c | 1142 ++++++++++++++++++++++++++++--------------
fs/btrfs/extent_io.h | 53 +-
fs/btrfs/file-item.c | 87 ++--
fs/btrfs/file.c | 77 +--
fs/btrfs/inode.c | 580 +++++++++++++--------
fs/btrfs/ordered-data.c | 19 +
fs/btrfs/ordered-data.h | 8 +
fs/btrfs/volumes.c | 2 +-
include/trace/events/btrfs.h | 2 +-
16 files changed, 1381 insertions(+), 729 deletions(-)
--
2.1.0
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