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Message-Id: <20190128161200.55107-47-sashal@kernel.org>
Date: Mon, 28 Jan 2019 11:09:57 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Sheng Yong <shengyong1@...wei.com>,
Jaegeuk Kim <jaegeuk@...nel.org>,
Sasha Levin <sashal@...nel.org>,
linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH AUTOSEL 4.14 047/170] f2fs: fix race between write_checkpoint and write_begin
From: Sheng Yong <shengyong1@...wei.com>
[ Upstream commit 2866fb16d67992195b0526d19e65acb6640fb87f ]
The following race could lead to inconsistent SIT bitmap:
Task A Task B
====== ======
f2fs_write_checkpoint
block_operations
f2fs_lock_all
down_write(node_change)
down_write(node_write)
... sync ...
up_write(node_change)
f2fs_file_write_iter
set_inode_flag(FI_NO_PREALLOC)
......
f2fs_write_begin(index=0, has inline data)
prepare_write_begin
__do_map_lock(AIO) => down_read(node_change)
f2fs_convert_inline_page => update SIT
__do_map_lock(AIO) => up_read(node_change)
f2fs_flush_sit_entries <= inconsistent SIT
finish write checkpoint
sudden-power-off
If SPO occurs after checkpoint is finished, SIT bitmap will be set
incorrectly.
Signed-off-by: Sheng Yong <shengyong1@...wei.com>
Reviewed-by: Chao Yu <yuchao0@...wei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
fs/f2fs/data.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index c68b319b07aa..3d37124eb63e 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1880,6 +1880,7 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
bool locked = false;
struct extent_info ei = {0,0,0};
int err = 0;
+ int flag;
/*
* we already allocated all the blocks, so we don't need to get
@@ -1889,9 +1890,15 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
!is_inode_flag_set(inode, FI_NO_PREALLOC))
return 0;
+ /* f2fs_lock_op avoids race between write CP and convert_inline_page */
+ if (f2fs_has_inline_data(inode) && pos + len > MAX_INLINE_DATA(inode))
+ flag = F2FS_GET_BLOCK_DEFAULT;
+ else
+ flag = F2FS_GET_BLOCK_PRE_AIO;
+
if (f2fs_has_inline_data(inode) ||
(pos & PAGE_MASK) >= i_size_read(inode)) {
- __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
+ __do_map_lock(sbi, flag, true);
locked = true;
}
restart:
@@ -1929,6 +1936,7 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
f2fs_put_dnode(&dn);
__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO,
true);
+ WARN_ON(flag != F2FS_GET_BLOCK_PRE_AIO);
locked = true;
goto restart;
}
@@ -1942,7 +1950,7 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
f2fs_put_dnode(&dn);
unlock_out:
if (locked)
- __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
+ __do_map_lock(sbi, flag, false);
return err;
}
--
2.19.1
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