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Commit 5e4654d7 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: wait on atomic writes to count F2FS_CP_WB_DATA 



Otherwise, we can get wrong counts incurring checkpoint hang.

IO_W (CP:  -24, Data:   24, Flush: (   0    0    1), Discard: (   0    0))

Thread A                        Thread B
- f2fs_write_data_pages
 -  __write_data_page
  - f2fs_submit_page_write
   - inc_page_count(F2FS_WB_DATA)
     type is F2FS_WB_DATA due to file is non-atomic one
- f2fs_ioc_start_atomic_write
 - set_inode_flag(FI_ATOMIC_FILE)
                                - f2fs_write_end_io
                                 - dec_page_count(F2FS_WB_CP_DATA)
                                   type is F2FS_WB_DATA due to file becomes
                                   atomic one

Cc: <stable@vger.kernel.org>
Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent b8f3009c

fs/f2fs/file.c

+7 −5
Original line number Diff line number Diff line
@@ -1750,9 +1750,11 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) 


	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);



	if (!get_dirty_pages(inode))

		goto skip_flush;



	/*

	 * Should wait end_io to count F2FS_WB_CP_DATA correctly by

	 * f2fs_is_atomic_file.

	 */

	if (get_dirty_pages(inode))

		f2fs_msg(F2FS_I_SB(inode)->sb, KERN_WARNING,

		"Unexpected flush for atomic writes: ino=%lu, npages=%u",

					inode->i_ino, get_dirty_pages(inode));
@@ -1761,7 +1763,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) 
		up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);

		goto out;

	}

skip_flush:



	set_inode_flag(inode, FI_ATOMIC_FILE);

	clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);

	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);