[f2fs-dev] [PATCH AUTOSEL 4.19 30/40] f2fs: fix NULL pointer dereference in f2fs_write_begin()

[f2fs-dev] [PATCH AUTOSEL 4.19 30/40] f2fs: fix NULL pointer dereference in f2fs_write_begin()

[Sasha Levin]

From: Chao Yu <yuchao0@huawei.com>

[ Upstream commit 62f63eea291b50a5677ae7503ac128803174698a ]

BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:f2fs_write_begin+0x823/0xb90 [f2fs]
Call Trace:
 f2fs_quota_write+0x139/0x1d0 [f2fs]
 write_blk+0x36/0x80 [quota_tree]
 get_free_dqblk+0x42/0xa0 [quota_tree]
 do_insert_tree+0x235/0x4a0 [quota_tree]
 do_insert_tree+0x26e/0x4a0 [quota_tree]
 do_insert_tree+0x26e/0x4a0 [quota_tree]
 do_insert_tree+0x26e/0x4a0 [quota_tree]
 qtree_write_dquot+0x70/0x190 [quota_tree]
 v2_write_dquot+0x43/0x90 [quota_v2]
 dquot_acquire+0x77/0x100
 f2fs_dquot_acquire+0x2f/0x60 [f2fs]
 dqget+0x310/0x450
 dquot_transfer+0x7e/0x120
 f2fs_setattr+0x11a/0x4a0 [f2fs]
 notify_change+0x349/0x480
 chown_common+0x168/0x1c0
 do_fchownat+0xbc/0xf0
 __x64_sys_fchownat+0x20/0x30
 do_syscall_64+0x5f/0x220
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Passing fsdata parameter to .write_{begin,end} in f2fs_quota_write(),
so that if quota file is compressed one, we can avoid above NULL
pointer dereference when updating quota content.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/super.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index da348cf4ff56a..45f8f6ec22a55 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1648,6 +1648,7 @@ static ssize_t f2fs_quota_write(struct super_block *sb, int type,
 	int offset = off & (sb->s_blocksize - 1);
 	size_t towrite = len;
 	struct page *page;
+	void *fsdata = NULL;
 	char *kaddr;
 	int err = 0;
 	int tocopy;
@@ -1657,7 +1658,7 @@ static ssize_t f2fs_quota_write(struct super_block *sb, int type,
 								towrite);
 retry:
 		err = a_ops->write_begin(NULL, mapping, off, tocopy, 0,
-							&page, NULL);
+							&page, &fsdata);
 		if (unlikely(err)) {
 			if (err == -ENOMEM) {
 				congestion_wait(BLK_RW_ASYNC, HZ/50);
@@ -1672,7 +1673,7 @@ static ssize_t f2fs_quota_write(struct super_block *sb, int type,
 		flush_dcache_page(page);
 
 		a_ops->write_end(NULL, mapping, off, tocopy, tocopy,
-						page, NULL);
+						page, fsdata);
 		offset = 0;
 		towrite -= tocopy;
 		off += tocopy;
-- 
2.20.1



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[f2fs-dev] [PATCH AUTOSEL 4.19 40/40] f2fs: fix to wait all node page writeback

[Sasha Levin]

From: Chao Yu <yuchao0@huawei.com>

[ Upstream commit dc5a941223edd803f476a153abd950cc3a83c3e1 ]

There is a race condition that we may miss to wait for all node pages
writeback, fix it.

- fsync()				- shrink
 - f2fs_do_sync_file
					 - __write_node_page
					  - set_page_writeback(page#0)
					  : remove DIRTY/TOWRITE flag
  - f2fs_fsync_node_pages
  : won't find page #0 as TOWRITE flag was removeD
  - f2fs_wait_on_node_pages_writeback
  : wont' wait page #0 writeback as it was not in fsync_node_list list.
					   - f2fs_add_fsync_node_entry

Fixes: 50fa53eccf9f ("f2fs: fix to avoid broken of dnode block list")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/node.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index e5d474681471c..f0714c1258c79 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1559,15 +1559,16 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
 	if (atomic && !test_opt(sbi, NOBARRIER))
 		fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
 
-	set_page_writeback(page);
-	ClearPageError(page);
-
+	/* should add to global list before clearing PAGECACHE status */
 	if (f2fs_in_warm_node_list(sbi, page)) {
 		seq = f2fs_add_fsync_node_entry(sbi, page);
 		if (seq_id)
 			*seq_id = seq;
 	}
 
+	set_page_writeback(page);
+	ClearPageError(page);
+
 	fio.old_blkaddr = ni.blk_addr;
 	f2fs_do_write_node_page(nid, &fio);
 	set_node_addr(sbi, &ni, fio.new_blkaddr, is_fsync_dnode(page));
-- 
2.20.1



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