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Commit 47059d93 authored by Wang Shilong's avatar Wang Shilong Committed by Chris Mason
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Btrfs: make defragment work with nodatacow option 



Btrfs defragment will utilize COW feature, which means this
did not work for nodatacow option, this problem was detected
by xfstests generic/018 with nodatacow mount option.

Fix this problem by forcing cow for a extent with state
@EXTETN_DEFRAG setting.

Signed-off-by: default avatarWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 48fcc3ff

fs/btrfs/btrfs_inode.h

+6 −0
Original line number Diff line number Diff line
@@ -120,6 +120,12 @@ struct btrfs_inode { 
	 */

	u64 delalloc_bytes;



	/*

	 * total number of bytes pending defrag, used by stat to check whether

	 * it needs COW.

	 */

	u64 defrag_bytes;



	/*

	 * the size of the file stored in the metadata on disk.  data=ordered

	 * means the in-memory i_size might be larger than the size on disk

fs/btrfs/inode.c

+36 −3
Original line number Diff line number Diff line
@@ -1445,6 +1445,26 @@ static noinline int run_delalloc_nocow(struct inode *inode, 
	return ret;

}



static inline int need_force_cow(struct inode *inode, u64 start, u64 end)

{



	if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&

	    !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))

		return 0;



	/*

	 * @defrag_bytes is a hint value, no spinlock held here,

	 * if is not zero, it means the file is defragging.

	 * Force cow if given extent needs to be defragged.

	 */

	if (BTRFS_I(inode)->defrag_bytes &&

	    test_range_bit(&BTRFS_I(inode)->io_tree, start, end,

			   EXTENT_DEFRAG, 0, NULL))

		return 1;



	return 0;

}



/*

 * extent_io.c call back to do delayed allocation processing

 */
@@ -1454,11 +1474,12 @@ static int run_delalloc_range(struct inode *inode, struct page *locked_page, 
{

	int ret;

	struct btrfs_root *root = BTRFS_I(inode)->root;

	int force_cow = need_force_cow(inode, start, end);



	if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {

	if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {

		ret = run_delalloc_nocow(inode, locked_page, start, end,

					 page_started, 1, nr_written);

	} else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {

	} else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {

		ret = run_delalloc_nocow(inode, locked_page, start, end,

					 page_started, 0, nr_written);

	} else if (!btrfs_test_opt(root, COMPRESS) &&
@@ -1555,6 +1576,8 @@ static void btrfs_set_bit_hook(struct inode *inode, 
			       struct extent_state *state, unsigned long *bits)

{



	if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))

		WARN_ON(1);

	/*

	 * set_bit and clear bit hooks normally require _irqsave/restore

	 * but in this case, we are only testing for the DELALLOC
@@ -1577,6 +1600,8 @@ static void btrfs_set_bit_hook(struct inode *inode, 
				     root->fs_info->delalloc_batch);

		spin_lock(&BTRFS_I(inode)->lock);

		BTRFS_I(inode)->delalloc_bytes += len;

		if (*bits & EXTENT_DEFRAG)

			BTRFS_I(inode)->defrag_bytes += len;

		if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,

					 &BTRFS_I(inode)->runtime_flags))

			btrfs_add_delalloc_inodes(root, inode);
@@ -1591,6 +1616,13 @@ static void btrfs_clear_bit_hook(struct inode *inode, 
				 struct extent_state *state,

				 unsigned long *bits)

{

	u64 len = state->end + 1 - state->start;



	spin_lock(&BTRFS_I(inode)->lock);

	if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))

		BTRFS_I(inode)->defrag_bytes -= len;

	spin_unlock(&BTRFS_I(inode)->lock);



	/*

	 * set_bit and clear bit hooks normally require _irqsave/restore

	 * but in this case, we are only testing for the DELALLOC
@@ -1598,7 +1630,6 @@ static void btrfs_clear_bit_hook(struct inode *inode, 
	 */

	if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {

		struct btrfs_root *root = BTRFS_I(inode)->root;

		u64 len = state->end + 1 - state->start;

		bool do_list = !btrfs_is_free_space_inode(inode);



		if (*bits & EXTENT_FIRST_DELALLOC) {
@@ -8173,6 +8204,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb) 
	ei->last_sub_trans = 0;

	ei->logged_trans = 0;

	ei->delalloc_bytes = 0;

	ei->defrag_bytes = 0;

	ei->disk_i_size = 0;

	ei->flags = 0;

	ei->csum_bytes = 0;
@@ -8231,6 +8263,7 @@ void btrfs_destroy_inode(struct inode *inode) 
	WARN_ON(BTRFS_I(inode)->reserved_extents);

	WARN_ON(BTRFS_I(inode)->delalloc_bytes);

	WARN_ON(BTRFS_I(inode)->csum_bytes);

	WARN_ON(BTRFS_I(inode)->defrag_bytes);



	/*

	 * This can happen where we create an inode, but somebody else also