Commit f082c6b2 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: fix potential deadlock due to unpaired node_write lock use 



If S_NOQUOTA is cleared from inode during data page writeback of quota
file, it may miss to unlock node_write lock, result in potential
deadlock, fix to use the lock in paired.

Kworker					Thread
- writepage
 if (IS_NOQUOTA())
   f2fs_down_read(&sbi->node_write);
					- vfs_cleanup_quota_inode
					 - inode->i_flags &= ~S_NOQUOTA;
 if (IS_NOQUOTA())
   f2fs_up_read(&sbi->node_write);

Fixes: 79963d96 ("f2fs: shrink node_write lock coverage")
Signed-off-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 36ded4c1

fs/f2fs/compress.c

+4 −3
Original line number Diff line number Diff line
@@ -1215,6 +1215,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc, 
	unsigned int last_index = cc->cluster_size - 1;

	loff_t psize;

	int i, err;

	bool quota_inode = IS_NOQUOTA(inode);



	/* we should bypass data pages to proceed the kworker jobs */

	if (unlikely(f2fs_cp_error(sbi))) {
@@ -1222,7 +1223,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc, 
		goto out_free;

	}



	if (IS_NOQUOTA(inode)) {

	if (quota_inode) {

		/*

		 * We need to wait for node_write to avoid block allocation during

		 * checkpoint. This can only happen to quota writes which can cause
@@ -1344,7 +1345,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc, 
		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);



	f2fs_put_dnode(&dn);

	if (IS_NOQUOTA(inode))

	if (quota_inode)

		f2fs_up_read(&sbi->node_write);

	else

		f2fs_unlock_op(sbi);
@@ -1370,7 +1371,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc, 
out_put_dnode:

	f2fs_put_dnode(&dn);

out_unlock_op:

	if (IS_NOQUOTA(inode))

	if (quota_inode)

		f2fs_up_read(&sbi->node_write);

	else

		f2fs_unlock_op(sbi);

fs/f2fs/data.c

+4 −3
Original line number Diff line number Diff line
@@ -2832,6 +2832,7 @@ int f2fs_write_single_data_page(struct page *page, int *submitted, 
	loff_t psize = (loff_t)(page->index + 1) << PAGE_SHIFT;

	unsigned offset = 0;

	bool need_balance_fs = false;

	bool quota_inode = IS_NOQUOTA(inode);

	int err = 0;

	struct f2fs_io_info fio = {

		.sbi = sbi,
@@ -2893,19 +2894,19 @@ int f2fs_write_single_data_page(struct page *page, int *submitted, 
		goto out;



	/* Dentry/quota blocks are controlled by checkpoint */

	if (S_ISDIR(inode->i_mode) || IS_NOQUOTA(inode)) {

	if (S_ISDIR(inode->i_mode) || quota_inode) {

		/*

		 * We need to wait for node_write to avoid block allocation during

		 * checkpoint. This can only happen to quota writes which can cause

		 * the below discard race condition.

		 */

		if (IS_NOQUOTA(inode))

		if (quota_inode)

			f2fs_down_read(&sbi->node_write);



		fio.need_lock = LOCK_DONE;

		err = f2fs_do_write_data_page(&fio);



		if (IS_NOQUOTA(inode))

		if (quota_inode)

			f2fs_up_read(&sbi->node_write);



		goto done;