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Commit 21e4a495 authored by Jaegeuk Kim's avatar Jaegeuk Kim Committed by Sayali Lokhande
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)

Change-Id: I2f84aac820b5b25b691f05e42fc5e5a4071811a0
Fixes: 39a8695824510 ("f2fs: refactor ->page_mkwrite() flow")
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
Git-commit: b485ba61ef7c8dd7a1bb54f327e5914676860616
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/


Signed-off-by: default avatarSayali Lokhande <sayalil@codeaurora.org>
parent cfea929f

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))) {
@@ -58,6 +58,9 @@ 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));
@@ -115,8 +118,6 @@ 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);