Commit bdf03299 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: call f2fs_balance_fs outside of locked page 



Otherwise, we can hit deadlock by waiting for the locked page in
move_data_block in GC.

 Thread A                     Thread B
 - do_page_mkwrite
  - f2fs_vm_page_mkwrite
   - lock_page
                              - f2fs_balance_fs
                                  - mutex_lock(gc_mutex)
                               - f2fs_gc
                                - do_garbage_collect
                                 - ra_data_block
                                  - grab_cache_page
   - f2fs_balance_fs
    - mutex_lock(gc_mutex)

Fixes: 39a86958 ("f2fs: refactor ->page_mkwrite() flow")
Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 47501f87

fs/f2fs/file.c

+4 −3
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) 
	struct page *page = vmf->page;

	struct inode *inode = file_inode(vmf->vma->vm_file);

	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

	struct dnode_of_data dn = { .node_changed = false };

	struct dnode_of_data dn;

	int err;



	if (unlikely(f2fs_cp_error(sbi))) {
@@ -63,6 +63,9 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) 
		goto err;

	}



	/* should do out of any locked page */

	f2fs_balance_fs(sbi, true);



	sb_start_pagefault(inode->i_sb);



	f2fs_bug_on(sbi, f2fs_has_inline_data(inode));
@@ -120,8 +123,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) 
out_sem:

	up_read(&F2FS_I(inode)->i_mmap_sem);



	f2fs_balance_fs(sbi, dn.node_changed);



	sb_end_pagefault(inode->i_sb);

err:

	return block_page_mkwrite_return(err);

CRA Git | Maintained and supported by SUSTech CRA and CCSE