[13/15] btrfs: handle dax page zeroing

Message ID	20190326190301.32365-14-rgoldwyn@suse.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fsdevel-owner@kernel.org> From: Goldwyn Rodrigues <rgoldwyn@suse.de> To: linux-btrfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Goldwyn Rodrigues <rgoldwyn@suse.com> Subject: [PATCH 13/15] btrfs: handle dax page zeroing Date: Tue, 26 Mar 2019 14:02:59 -0500 Message-Id: <20190326190301.32365-14-rgoldwyn@suse.de> In-Reply-To: <20190326190301.32365-1-rgoldwyn@suse.de> References: <20190326190301.32365-1-rgoldwyn@suse.de> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk
Series	[01/15] btrfs: create a mount option for dax \| expand [01/15] btrfs: create a mount option for dax [02/15] btrfs: Carve out btrfs_get_extent_map_write() out of btrfs_get_blocks_write() [03/15] btrfs: basic dax read [04/15] dax: Introduce IOMAP_F_COW for copy-on-write [05/15] btrfs: return whether extent is nocow or not [06/15] btrfs: Rename __endio_write_update_ordered() to btrfs_update_ordered_extent() [07/15] btrfs: add dax write support [08/15] dax: add dax_iomap_cow to copy a mmap page before writing [09/15] btrfs: add dax mmap support [10/15] btrfs: Add dax specific address_space_operations [11/15] fs: dedup file range to use a compare function [12/15] btrfs: trace functions for btrfs_iomap_begin/end [13/15] btrfs: handle dax page zeroing [14/15] btrfs: Disable dax-based defrag and send [15/15] btrfs: Writeprotect mmap pages on snapshot

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 750f9c70fabe..21068dc4a95a 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3806,6 +3806,7 @@ vm_fault_t btrfs_dax_fault(struct vm_fault *vmf); int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, loff_t destoff, loff_t len, bool *is_same); +int btrfs_dax_zero_block(struct inode *inode, loff_t from, loff_t len, bool front); #else static inline ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from) { diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c index 7900b5773829..d73945d50b88 100644 --- a/fs/btrfs/dax.c +++ b/fs/btrfs/dax.c @@ -31,7 +31,7 @@ static int btrfs_iomap_begin(struct inode *inode, loff_t pos, em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, pos, length, 0); - if (flags & IOMAP_WRITE) { + if (flags & (IOMAP_WRITE | IOMAP_ZERO)) { int ret = 0, nocow; struct extent_map *map = em; struct btrfs_iomap *bi; @@ -89,7 +89,8 @@ static int btrfs_iomap_begin(struct inode *inode, loff_t pos, iomap->bdev = em->bdev; iomap->dax_dev = fs_info->dax_dev; - if (em->block_start == EXTENT_MAP_HOLE) { + if (em->block_start == EXTENT_MAP_HOLE || + em->flags == EXTENT_FLAG_FILLING) { iomap->type = IOMAP_HOLE; return 0; } @@ -178,4 +179,28 @@ int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, { return dax_file_range_compare(src, srcoff, dest, destoff, len, is_same, &btrfs_iomap_ops); } + +/* + * zero a part of the page only. This should CoW (via iomap_begin) if required + */ +int btrfs_dax_zero_block(struct inode *inode, loff_t from, loff_t len, bool front) +{ + loff_t start = round_down(from, PAGE_SIZE); + loff_t end = round_up(from, PAGE_SIZE); + loff_t offset = from; + int ret = 0; + + if (front) { + len = from - start; + offset = start; + } else { + if (!len) + len = end - from; + } + + if (len) + ret = iomap_zero_range(inode, offset, len, NULL, &btrfs_iomap_ops); + + return (ret < 0) ? ret : 0; +} #endif /* CONFIG_FS_DAX */ diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 21780ea14e5a..5350e5f23728 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4833,6 +4833,10 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, (!len || IS_ALIGNED(len, blocksize))) goto out; +#ifdef CONFIG_FS_DAX + if (IS_DAX(inode)) + return btrfs_dax_zero_block(inode, from, len, front); +#endif block_start = round_down(from, blocksize); block_end = block_start + blocksize - 1; diff --git a/fs/dax.c b/fs/dax.c index 18998c5ee27a..93146142bb00 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1068,17 +1068,21 @@ static void dax_to_dax_copy(struct iomap *iomap, loff_t pos, void *daddr, blk_start = iomap->cow_addr + pos - iomap->cow_pos; blk_pg = round_down(blk_start, PAGE_SIZE); - map_len = dax_direct_access(iomap->dax_dev, PHYS_PFN(blk_pg), PAGE_SIZE, + map_len = dax_direct_access(iomap->dax_dev, PHYS_PFN(blk_pg), 1, &saddr, NULL); saddr += blk_start - blk_pg; memcpy(daddr, saddr, len); } -int __dax_zero_page_range(struct block_device *bdev, - struct dax_device *dax_dev, sector_t sector, - unsigned int offset, unsigned int size) +int __dax_zero_page_range(struct iomap *iomap, loff_t pos, + unsigned int offset, unsigned int size) { - if (dax_range_is_aligned(bdev, offset, size)) { + sector_t sector = iomap_sector(iomap, pos & PAGE_MASK); + struct block_device *bdev = iomap->bdev; + struct dax_device *dax_dev = iomap->dax_dev; + + if (!(iomap->flags & IOMAP_F_COW) && + dax_range_is_aligned(bdev, offset, size)) { sector_t start_sector = sector + (offset >> 9); return blkdev_issue_zeroout(bdev, start_sector, @@ -1098,6 +1102,9 @@ int __dax_zero_page_range(struct block_device *bdev, dax_read_unlock(id); return rc; } + if (iomap->flags & IOMAP_F_COW) + dax_to_dax_copy(iomap, pos & PAGE_MASK, + kaddr, PAGE_SIZE); memset(kaddr + offset, 0, size); dax_flush(dax_dev, kaddr + offset, size); dax_read_unlock(id); diff --git a/fs/iomap.c b/fs/iomap.c index abdd18e404f8..90698c854883 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -98,12 +98,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, return written ? written : ret; } -static sector_t -iomap_sector(struct iomap *iomap, loff_t pos) -{ - return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; -} - static struct iomap_page * iomap_page_create(struct inode *inode, struct page *page) { @@ -990,8 +984,7 @@ static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { - return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, - iomap_sector(iomap, pos & PAGE_MASK), offset, bytes); + return __dax_zero_page_range(iomap, pos, offset, bytes); } static loff_t diff --git a/include/linux/dax.h b/include/linux/dax.h index a11bc7b1f526..892c478d7073 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -9,6 +9,7 @@ typedef unsigned long dax_entry_t; +struct iomap; struct iomap_ops; struct dax_device; struct dax_operations { @@ -161,13 +162,11 @@ int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops); #ifdef CONFIG_FS_DAX -int __dax_zero_page_range(struct block_device *bdev, - struct dax_device *dax_dev, sector_t sector, - unsigned int offset, unsigned int length); +int __dax_zero_page_range(struct iomap *iomap, loff_t pos, + unsigned int offset, unsigned int size); #else -static inline int __dax_zero_page_range(struct block_device *bdev, - struct dax_device *dax_dev, sector_t sector, - unsigned int offset, unsigned int length) +static inline int __dax_zero_page_range(struct iomap *iomap, loff_t pos, + unsigned int offset, unsigned int size) { return -ENXIO; } diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 391785de1428..e5a1b2a1962d 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -7,6 +7,7 @@ #include <linux/mm.h> #include <linux/types.h> #include <linux/mm_types.h> +#include <linux/blkdev.h> struct address_space; struct fiemap_extent_info; @@ -122,6 +123,11 @@ static inline struct iomap_page *to_iomap_page(struct page *page) return NULL; } +static inline sector_t iomap_sector(struct iomap *iomap, loff_t pos) +{ + return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; +} + ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, const struct iomap_ops *ops); int iomap_readpage(struct page *page, const struct iomap_ops *ops);

[13/15] btrfs: handle dax page zeroing

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