From: Goldwyn Rodrigues <[email protected]> btrfs_dax_zero_block() zeros part of the page, either from the front or the regular rest of the block.
Signed-off-by: Goldwyn Rodrigues <[email protected]> --- fs/btrfs/ctree.h | 1 + fs/btrfs/dax.c | 27 ++++++++++++++++++++++++++- fs/btrfs/inode.c | 4 ++++ 3 files changed, 31 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index d3d044125619..ee1ed18f8b3c 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 af64696a5337..bf2ddac5b5a1 100644 --- a/fs/btrfs/dax.c +++ b/fs/btrfs/dax.c @@ -132,7 +132,8 @@ static int btrfs_iomap_begin(struct inode *inode, loff_t pos, * This will be true for reads only since we have already * allocated em */ - 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; } @@ -235,4 +236,28 @@ 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 05714ffc4894..7e88280a2c3b 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; -- 2.16.4 _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
