This patchset can be fetched from the following github repo, along with the full subpage RW support: https://github.com/adam900710/linux/tree/subpage
This patchset is for metadata read write support. [FULL RW TEST] Since the data write path is not included in this patchset, we can't really test the patchset itself, but anyone can grab the patch from github repo and do fstests/generic tests. There are some known issues: - Very very rare random ASSERT() failure for data page::private It looks like we can lock a data page without page::private set for subpage. This problem seems to be caused some set_page_extent_mapped() callers are not holding the page locked, thus leaving a small window. Investigating. - Defrag related test failure Since current defrag is doing per-page defrag, to support subpage defrag, we need some change in the loop. Thus for now, defrag is disabled completely for subpage RW mount. - No compression support yet There are at least 2 known bugs if forcing compression for subpage * Some hard coded PAGE_SIZE screwing up space rsv * Subpage ASSERT() triggered This is because some compression code is unlocking locked_page by calling extent_clear_unlock_delalloc() with locked_page == NULL. So for now compression is also disabled. [DIFFERENCE AGAINST REGULAR SECTORSIZE] The metadata part in fact has more new code than data part, as it has some different behaviors compared to the regular sector size handling: - No more page locking Now metadata read/write relies on extent io tree locking, other than page locking. This is to allow behaviors like read lock one eb while also try to read lock another eb in the same page. We can't rely on page lock as now we have multiple extent buffers in the same page. - Page status update Now we use subpage wrappers to handle page status update. - How to submit dirty extent buffers Instead of just grabbing extent buffer from page::private, we need to iterate all dirty extent buffers in the page and submit them. [CHANGELOG] v2: - Rebased to latest misc-next No conflicts at all. - Add new sysfs interface to grab supported RO/RW sectorsize This will allow mkfs.btrfs to detect unmountable fs better. - Use newer naming schema for each patch No more "extent_io:" or "inode:" schema anymore. - Move two pure cleanups to the series Patch 2~3, originally in RW part. - Fix one uninitialized variable Patch 6. Qu Wenruo (15): btrfs: add sysfs interface for supported sectorsize btrfs: use min() to replace open-code in btrfs_invalidatepage() btrfs: remove unnecessary variable shadowing in btrfs_invalidatepage() btrfs: introduce helpers for subpage dirty status btrfs: introduce helpers for subpage writeback status btrfs: allow btree_set_page_dirty() to do more sanity check on subpage metadata btrfs: support subpage metadata csum calculation at write time btrfs: make alloc_extent_buffer() check subpage dirty bitmap btrfs: make the page uptodate assert to be subpage compatible btrfs: make set/clear_extent_buffer_dirty() to be subpage compatible btrfs: make set_btree_ioerr() accept extent buffer and to be subpage compatible btrfs: introduce end_bio_subpage_eb_writepage() function btrfs: introduce write_one_subpage_eb() function btrfs: make lock_extent_buffer_for_io() to be subpage compatible btrfs: introduce submit_eb_subpage() to submit a subpage metadata page fs/btrfs/disk-io.c | 143 +++++++++++---- fs/btrfs/extent_io.c | 420 ++++++++++++++++++++++++++++++++++++------- fs/btrfs/inode.c | 14 +- fs/btrfs/subpage.c | 73 ++++++++ fs/btrfs/subpage.h | 17 ++ fs/btrfs/sysfs.c | 34 ++++ 6 files changed, 598 insertions(+), 103 deletions(-) -- 2.30.1