Btrfs assumes block size to be the same as the machine's page size. This would mean that a Btrfs instance created on a 4k page size machine (e.g. x86) will not be mountable on machines with larger page sizes (e.g. PPC64/AARCH64). This patchset aims to resolve this incompatibility.
This patchset continues with the work posted previously at http://thread.gmane.org/gmane.comp.file-systems.btrfs/53073. I have reverted the upstream commit "btrfs: fix lockups from btrfs_clear_path_blocking" (f82c458a2c3ffb94b431fc6ad791a79df1b3713e) since this led to soft-lockups when the patch "Btrfs: subpagesize-blocksize: Prevent writes to an extent buffer when PG_writeback flag is set" is applied. During 2015's Vault Conference Btrfs meetup, Chris Mason had suggested that he will write up a suitable locking function to be used when writing dirty pages that map metadata blocks. Until we have a suitable locking function available, this patchset temporarily disables the commit f82c458a2c3ffb94b431fc6ad791a79df1b3713e. The commits for the Btrfs kernel module can be found at https://github.com/chandanr/linux/tree/btrfs/subpagesize-blocksize. To create a filesystem with block size < page size, a patched version of the Btrfs-progs package is required. The corresponding fixes for Btrfs-progs can be found at https://github.com/chandanr/btrfs-progs/tree/btrfs/subpagesize-blocksize. Fstests run status: 1. x86_64 - With 4k sectorsize, all the tests that succeed with the master branch at git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git branch also do so with the patches applied. 2. ppc64 - With 4k sectorsize, 16k nodesize and with "nospace_cache" mount option, except for scrub and compression tests, all the tests that succeed with the master branch at git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git branch also do so with the patches applied. - With 64k sectorsize & nodesize, all the tests that succeed with the master branch at git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git branch also do so with the patches applied. TODO: 1. The selftests code needs to be fixed to work in subpage-blocksize scenario. 2. I am planning to fix Scrub & Compression via a separate patchset. Changes from V15: 1. The invocation of cleancache_get_page() in __do_readpage() assumed blocksize to be same as PAGE_SIZE. We now invoke cleancache_get_page() only if blocksize is same as PAGE_SIZE. Thanks to David Sterba for pointing this out. 2. In __extent_writepage_io() we used to accumulate all the contiguous dirty blocks within the page before submitting the file offset range for I/O. In some cases this caused the bio to span across more than a stripe. For example, With 4k block size, 64K stripe size and 64K page size, assume - All the blocks mapped by the page are contiguous on the logical address space. - The first block of the page is mapped to the second block of the stripe. In such a scenario, we would add all the blocks of the page to bio. This would mean that we would overflow the stripe by one 4K block. Hence this patchset removes the optimization and invokes submit_extent_page() for every dirty 4K block. 3. The following patches are newly added: - Btrfs: subpage-blocksize: __btrfs_lookup_bio_sums: Set offset when moving to a new bio_vec - Btrfs: subpage-blocksize: Make file extent relocate code subpage blocksize aware - Btrfs: btrfs_clone: Flush dirty blocks of a page that do not map the clone range Changes from V14: 1. Fix usage of cleancache_get_page() in __do_readpage(). In filesystems which support subpage-blocksize scenario, a page can map one or more blocks. Hence cleancache_get_page() should be invoked only when the page maps a non-hole extent and block size being used is equal to the page size. Thanks to David Sterba for pointing this out. 2. Replace page_read_complete() and page_write_complete() functions with page_io_complete(). 3. Provide more documentation (as part of both commit message and code comments) about the usage of the per-page btrfs_page_private->io_lock. Changes from V13: 1. Enable dedup ioctl to work in subpagesize-blocksize scenario. Changes from V12: 1. The logic in the function btrfs_punch_hole() has been fixed to check for the presence of BLK_STATE_UPTODATE flags for blocks in pages which partially map the file range being punched. Changes from V11: 1. Addressed the review comments provided by Liu Bo for version V11. 2. Fixed file defragmentation code to work in subpagesize-blocksize scenario. 3. Many "hard to reproduce" bugs were fixed. Chandan Rajendra (18): Btrfs: subpage-blocksize: Fix whole page read. Btrfs: subpage-blocksize: Fix whole page write Btrfs: subpage-blocksize: Make sure delalloc range intersects with the locked page's range Btrfs: subpage-blocksize: Define extent_buffer_head. Btrfs: subpage-blocksize: Read tree blocks whose size is < PAGE_CACHE_SIZE Btrfs: subpage-blocksize: Write only dirty extent buffers belonging to a page Btrfs: subpage-blocksize: Allow mounting filesystems where sectorsize < PAGE_SIZE Btrfs: subpage-blocksize: Deal with partial ordered extent allocations. Btrfs: subpage-blocksize: Explicitly track I/O status of blocks of an ordered extent. Btrfs: subpage-blocksize: btrfs_punch_hole: Fix uptodate blocks check Btrfs: subpage-blocksize: Prevent writes to an extent buffer when PG_writeback flag is set Revert "btrfs: fix lockups from btrfs_clear_path_blocking" Btrfs: subpage-blocksize: Fix file defragmentation code Btrfs: subpage-blocksize: extent_clear_unlock_delalloc: Prevent page from being unlocked more than once Btrfs: subpage-blocksize: Enable dedupe ioctl Btrfs: btrfs_clone: Flush dirty blocks of a page that do not map the clone range Btrfs: subpage-blocksize: Make file extent relocate code subpage blocksize aware Btrfs: subpage-blocksize: __btrfs_lookup_bio_sums: Set offset when moving to a new bio_vec fs/btrfs/ctree.c | 37 +- fs/btrfs/ctree.h | 6 +- fs/btrfs/disk-io.c | 156 ++-- fs/btrfs/disk-io.h | 3 + fs/btrfs/extent-tree.c | 17 +- fs/btrfs/extent_io.c | 1611 +++++++++++++++++++++++++++++------------- fs/btrfs/extent_io.h | 145 +++- fs/btrfs/file-item.c | 7 +- fs/btrfs/file.c | 82 ++- fs/btrfs/inode.c | 491 +++++++++---- fs/btrfs/ioctl.c | 219 ++++-- fs/btrfs/locking.c | 24 +- fs/btrfs/locking.h | 2 - fs/btrfs/ordered-data.c | 19 + fs/btrfs/ordered-data.h | 4 + fs/btrfs/relocation.c | 70 +- fs/btrfs/root-tree.c | 2 +- fs/btrfs/volumes.c | 2 +- include/trace/events/btrfs.h | 2 +- 19 files changed, 2050 insertions(+), 849 deletions(-) -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
