Re: [PATCH] make btrfs_truncate_block check NOCOW attribute

Hi,

Thanks for your patch.

On 2021/6/17 15:55, Gou Hao wrote:

From: gouhao gouhao@uniontech.com

make btrfs_truncate_block check NOCOW attribute

mainline inclusion

该补丁如果不是来自上游主线的话，不要写 mainline inclusion.

如果是自己写的补丁，可以写 uniontech inclusion.

from https://patchwork.kernel.org/project/linux-btrfs/patch/20200130052822.11765-...

参考的社区讨论链接可以写：

Reference: https://patchwork.kernel.org/project/linux-btrfs/patch/20200130052822.11765-...

category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I39MZM CVE: NA

---

ltp fallocate06 testcase failed

如果是自己写的补丁需要写一下修改思路，或解决的问题。 如果是 backport 的补丁，需要带着原来的 changelog， 如有补充，在 ------ 分割线上面添加自己补充的changelog。

Signed-off-by: gouhao gouhao@uniontech.com

changelog 和 签名都顶格写，前面不留空白。 如果是 backport 的补丁，需要带着原作者。

--- Xie XiuQi

---

fs/btrfs/ctree.h | 3 ++- fs/btrfs/file.c | 8 ++++---- fs/btrfs/inode.c | 39 +++++++++++++++++++++++++++++++++------ 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 4d1c12faada8..4f5c58d40a79 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3271,7 +3271,8 @@ int btrfs_dirty_pages(struct inode *inode, struct page **pages, int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end); int btrfs_clone_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, u64 len);

+int btrfs_check_can_nocow(struct btrfs_inode *inode, loff_t pos,

• 	size_t *write_bytes);
  

/* tree-defrag.c */ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, struct btrfs_root *root); diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index a202f2f12b1c..c204fbe512b7 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1536,8 +1536,8 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages, return ret; }

-static noinline int check_can_nocow(struct btrfs_inode *inode, loff_t pos,

• 		    size_t *write_bytes)
  

+int btrfs_check_can_nocow(struct btrfs_inode *inode, loff_t pos,

• 	  size_t *write_bytes)
  

{ struct btrfs_fs_info *fs_info = inode->root->fs_info; struct btrfs_root *root = inode->root; @@ -1647,7 +1647,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, if (ret < 0) { if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)) &&

• 	    check_can_nocow(BTRFS_I(inode), pos,
  

• 	    btrfs_check_can_nocow(BTRFS_I(inode), pos,
  		&write_bytes) > 0) {
  	/*
  	 * For nodata cow case, no need to reserve
  

@@ -1925,7 +1925,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, */ if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)) ||

•     check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) {
  

•     btrfs_check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) {
  inode_unlock(inode);
  return -EAGAIN;
  

  }

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 8c6f619c9ee6..6641fa77d4f9 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4946,11 +4946,13 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, struct extent_state *cached_state = NULL; struct extent_changeset *data_reserved = NULL; char *kaddr;

• bool only_release_metadata = false; u32 blocksize = fs_info->sectorsize; pgoff_t index = from >> PAGE_SHIFT; unsigned offset = from & (blocksize - 1); struct page *page; gfp_t mask = btrfs_alloc_write_mask(mapping);
• size_t write_bytes = blocksize; int ret = 0; u64 block_start; u64 block_end;

@@ -4962,10 +4964,26 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, block_start = round_down(from, blocksize); block_end = block_start + blocksize - 1;

• ret = btrfs_delalloc_reserve_space(inode, &data_reserved,

• 			   block_start, blocksize);
  

• if (ret)

• ret = btrfs_check_data_free_space(inode, &data_reserved,

• 	block_start, blocksize);
  

• if (ret < 0) {

• if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
  

• 			      BTRFS_INODE_PREALLOC)) &&
  

•     btrfs_check_can_nocow(BTRFS_I(inode), block_start,
  

• 			  &write_bytes) > 0) {
  

• 	/* For nocow case, no need to reserve data space */
  

• 	only_release_metadata = true;
  

• } else {
  

• 	goto out;
  

• }
  

• }
• ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), blocksize);
• if (ret < 0) {

• if (!only_release_metadata)
  

• 	btrfs_free_reserved_data_space(inode, data_reserved,
  

• 			block_start, blocksize);
  

  goto out;
• }

again: page = find_or_create_page(mapping, index, mask); @@ -5036,10 +5054,19 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len, set_page_dirty(page); unlock_extent_cached(io_tree, block_start, block_end, &cached_state);

• if (only_release_metadata)

• set_extent_bit(&BTRFS_I(inode)->io_tree, block_start,
  

• 		block_end, EXTENT_NORESERVE, NULL, NULL,
  

• 		GFP_NOFS);
  

out_unlock:

• if (ret)

• btrfs_delalloc_release_space(inode, data_reserved, block_start,
  

• 			     blocksize, true);
  

• if (ret) {

• if (only_release_metadata)
  

• 	btrfs_delalloc_release_metadata(BTRFS_I(inode),
  

• 			blocksize, true);
  

• else
  

• 	btrfs_delalloc_release_space(inode, data_reserved,
  

• 			block_start, blocksize, true);
  

• } btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize); unlock_page(page); put_page(page);