Unverified Commit dad1b6c8 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "fsdax/xfs: unshare range fixes for 6.12" 

Darrick J. Wong <djwong@kernel.org> says:

This patchset fixes multiple data corruption bugs in the fallocate
unshare range implementation for fsdax.

* patches from https://lore.kernel.org/r/172796813251.1131942.12184885574609980777.stgit@frogsfrogsfrogs:
  fsdax: dax_unshare_iter needs to copy entire blocks
  fsdax: remove zeroing code from dax_unshare_iter
  iomap: share iomap_unshare_iter predicate code with fsdax
  xfs: don't allocate COW extents when unsharing a hole

Link: https://lore.kernel.org/r/172796813251.1131942.12184885574609980777.stgit@frogsfrogsfrogs


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 8cf0b939 50793801

fs/dax.c

+28 −17
Original line number Diff line number Diff line
@@ -1262,35 +1262,46 @@ static s64 dax_unshare_iter(struct iomap_iter *iter) 
{

	struct iomap *iomap = &iter->iomap;

	const struct iomap *srcmap = iomap_iter_srcmap(iter);

	loff_t pos = iter->pos;

	loff_t length = iomap_length(iter);

	loff_t copy_pos = iter->pos;

	u64 copy_len = iomap_length(iter);

	u32 mod;

	int id = 0;

	s64 ret = 0;

	void *daddr = NULL, *saddr = NULL;



	/* don't bother with blocks that are not shared to start with */

	if (!(iomap->flags & IOMAP_F_SHARED))

		return length;

	if (!iomap_want_unshare_iter(iter))

		return iomap_length(iter);



	/*

	 * Extend the file range to be aligned to fsblock/pagesize, because

	 * we need to copy entire blocks, not just the byte range specified.

	 * Invalidate the mapping because we're about to CoW.

	 */

	mod = offset_in_page(copy_pos);

	if (mod) {

		copy_len += mod;

		copy_pos -= mod;

	}



	mod = offset_in_page(copy_pos + copy_len);

	if (mod)

		copy_len += PAGE_SIZE - mod;



	invalidate_inode_pages2_range(iter->inode->i_mapping,

				      copy_pos >> PAGE_SHIFT,

				      (copy_pos + copy_len - 1) >> PAGE_SHIFT);



	id = dax_read_lock();

	ret = dax_iomap_direct_access(iomap, pos, length, &daddr, NULL);

	ret = dax_iomap_direct_access(iomap, copy_pos, copy_len, &daddr, NULL);

	if (ret < 0)

		goto out_unlock;



	/* zero the distance if srcmap is HOLE or UNWRITTEN */

	if (srcmap->flags & IOMAP_F_SHARED || srcmap->type == IOMAP_UNWRITTEN) {

		memset(daddr, 0, length);

		dax_flush(iomap->dax_dev, daddr, length);

		ret = length;

		goto out_unlock;

	}



	ret = dax_iomap_direct_access(srcmap, pos, length, &saddr, NULL);

	ret = dax_iomap_direct_access(srcmap, copy_pos, copy_len, &saddr, NULL);

	if (ret < 0)

		goto out_unlock;



	if (copy_mc_to_kernel(daddr, saddr, length) == 0)

		ret = length;

	if (copy_mc_to_kernel(daddr, saddr, copy_len) == 0)

		ret = iomap_length(iter);

	else

		ret = -EIO;

fs/iomap/buffered-io.c

+16 −14
Original line number Diff line number Diff line
@@ -1309,19 +1309,12 @@ void iomap_file_buffered_write_punch_delalloc(struct inode *inode, 
}

EXPORT_SYMBOL_GPL(iomap_file_buffered_write_punch_delalloc);



static loff_t iomap_unshare_iter(struct iomap_iter *iter)

bool iomap_want_unshare_iter(const struct iomap_iter *iter)

{

	struct iomap *iomap = &iter->iomap;

	loff_t pos = iter->pos;

	loff_t length = iomap_length(iter);

	loff_t written = 0;



	/* Don't bother with blocks that are not shared to start with. */

	if (!(iomap->flags & IOMAP_F_SHARED))

		return length;



	/*

	 * Don't bother with delalloc reservations, holes or unwritten extents.

	 * Don't bother with blocks that are not shared to start with; or

	 * mappings that cannot be shared, such as inline data, delalloc

	 * reservations, holes or unwritten extents.

	 *

	 * Note that we use srcmap directly instead of iomap_iter_srcmap as

	 * unsharing requires providing a separate source map, and the presence
@@ -1329,9 +1322,18 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter) 
	 * IOMAP_F_SHARED which can be set for any data that goes into the COW

	 * fork for XFS.

	 */

	if (iter->srcmap.type == IOMAP_HOLE ||

	    iter->srcmap.type == IOMAP_DELALLOC ||

	    iter->srcmap.type == IOMAP_UNWRITTEN)

	return (iter->iomap.flags & IOMAP_F_SHARED) &&

		iter->srcmap.type == IOMAP_MAPPED;

}



static loff_t iomap_unshare_iter(struct iomap_iter *iter)

{

	struct iomap *iomap = &iter->iomap;

	loff_t pos = iter->pos;

	loff_t length = iomap_length(iter);

	loff_t written = 0;



	if (!iomap_want_unshare_iter(iter))

		return length;



	do {

fs/xfs/xfs_iomap.c

+1 −1
Original line number Diff line number Diff line
@@ -707,7 +707,7 @@ imap_needs_cow( 
		return false;



	/* when zeroing we don't have to COW holes or unwritten extents */

	if (flags & IOMAP_ZERO) {

	if (flags & (IOMAP_UNSHARE | IOMAP_ZERO)) {

		if (!nimaps ||

		    imap->br_startblock == HOLESTARTBLOCK ||

		    imap->br_state == XFS_EXT_UNWRITTEN)

include/linux/iomap.h

+1 −0
Original line number Diff line number Diff line
@@ -267,6 +267,7 @@ void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len); 
bool iomap_dirty_folio(struct address_space *mapping, struct folio *folio);

int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,

		const struct iomap_ops *ops);

bool iomap_want_unshare_iter(const struct iomap_iter *iter);

int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,

		bool *did_zero, const struct iomap_ops *ops);

int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,