From 5750676b64a561f7ec920d7c6ba130fc9c7378f3 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Wed, 13 Jul 2022 17:49:15 +1000 Subject: fs/remap: constrain dedupe of EOF blocks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If dedupe of an EOF block is not constrainted to match against only other EOF blocks with the same EOF offset into the block, it can match against any other block that has the same matching initial bytes in it, even if the bytes beyond EOF in the source file do not match. Fix this by constraining the EOF block matching to only match against other EOF blocks that have identical EOF offsets and data. This allows "whole file dedupe" to continue to work without allowing eof blocks to randomly match against partial full blocks with the same data. Reported-by: Ansgar Lößer Fixes: 1383a7ed6749 ("vfs: check file ranges before cloning files") Link: https://lore.kernel.org/linux-fsdevel/a7c93559-4ba1-df2f-7a85-55a143696405@tu-darmstadt.de/ Signed-off-by: Dave Chinner Signed-off-by: Linus Torvalds --- fs/remap_range.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/remap_range.c') diff --git a/fs/remap_range.c b/fs/remap_range.c index e112b5424cdb..881a306ee247 100644 --- a/fs/remap_range.c +++ b/fs/remap_range.c @@ -71,7 +71,8 @@ static int generic_remap_checks(struct file *file_in, loff_t pos_in, * Otherwise, make sure the count is also block-aligned, having * already confirmed the starting offsets' block alignment. */ - if (pos_in + count == size_in) { + if (pos_in + count == size_in && + (!(remap_flags & REMAP_FILE_DEDUP) || pos_out + count == size_out)) { bcount = ALIGN(size_in, bs) - pos_in; } else { if (!IS_ALIGNED(count, bs)) -- cgit v1.2.3-70-g09d2 From 4a57a8400075bc5287c5c877702c68aeae2a033d Mon Sep 17 00:00:00 2001 From: Ansgar Lößer Date: Wed, 13 Jul 2022 20:51:44 +0200 Subject: vf/remap: return the amount of bytes actually deduplicated MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When using the FIDEDUPRANGE ioctl, in case of success the requested size is returned. In some cases this might not be the actual amount of bytes deduplicated. This change modifies vfs_dedupe_file_range() to report the actual amount of bytes deduplicated, instead of the requested amount. Link: https://lore.kernel.org/linux-fsdevel/5548ef63-62f9-4f46-5793-03165ceccacc@tu-darmstadt.de/ Reported-by: Ansgar Lößer Reported-by: Max Schlecht Reported-by: Björn Scheuermann Cc: Dave Chinner Cc: Darrick J Wong Signed-off-by: Ansgar Lößer Signed-off-by: Linus Torvalds --- fs/remap_range.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/remap_range.c') diff --git a/fs/remap_range.c b/fs/remap_range.c index 881a306ee247..5e0d97e02f96 100644 --- a/fs/remap_range.c +++ b/fs/remap_range.c @@ -547,7 +547,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) else if (deduped < 0) info->status = deduped; else - info->bytes_deduped = len; + info->bytes_deduped = deduped; next_fdput: fdput(dst_fd); -- cgit v1.2.3-70-g09d2