From b67287682688a60d03e8c2c6d4689ea3a25d5d3c Mon Sep 17 00:00:00 2001 From: Timofey Titovets Date: Wed, 2 May 2018 08:15:37 +0300 Subject: [PATCH] Btrfs: dedupe_file_range ioctl: remove 16MiB restriction Currently btrfs_dedupe_file_range silently restricts the dedupe range to to 16MiB to limit locking and working memory size and is documented in manual page as implementation specific. Let's remove that restriction by iterating over the dedup range in 16MiB steps. This is backward compatible and will not change anything for requests smaller then 16MiB. Signed-off-by: Timofey Titovets Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ioctl.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index ec0f380..a247991 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3128,11 +3128,14 @@ again: return ret; } +#define BTRFS_MAX_DEDUPE_LEN SZ_16M + static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen, struct inode *dst, u64 dst_loff) { int ret; bool same_inode = (src == dst); + u64 i, tail_len, chunk_count; if (olen == 0) return 0; @@ -3149,7 +3152,21 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen, goto out_unlock; } - ret = btrfs_extent_same_range(src, loff, olen, dst, dst_loff); + tail_len = olen % BTRFS_MAX_DEDUPE_LEN; + chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN); + + for (i = 0; i < chunk_count; i++) { + ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN, + dst, dst_loff); + if (ret) + goto out_unlock; + + loff += BTRFS_MAX_DEDUPE_LEN; + dst_loff += BTRFS_MAX_DEDUPE_LEN; + } + + if (tail_len > 0) + ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff); out_unlock: if (same_inode) @@ -3160,8 +3177,6 @@ out_unlock: return ret; } -#define BTRFS_MAX_DEDUPE_LEN SZ_16M - ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen, struct file *dst_file, u64 dst_loff) { @@ -3170,9 +3185,6 @@ ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen, u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize; ssize_t res; - if (olen > BTRFS_MAX_DEDUPE_LEN) - olen = BTRFS_MAX_DEDUPE_LEN; - if (WARN_ON_ONCE(bs < PAGE_SIZE)) { /* * Btrfs does not support blocksize < page_size. As a -- 2.7.4