The encrypted file may be corrupted by GC in following case:
Time 1: | segment 1 blkaddr = A | GC -> | segment 2 blkaddr = B |
Encrypted block 1 is moved from blkaddr A of segment 1 to blkaddr B of
segment 2,
Time 2: | segment 1 blkaddr = B | GC -> | segment 3 blkaddr = C |
Before page 1 is written back and if segment 2 become a victim, then
page 1 is moved from blkaddr B of segment 2 to blkaddr Cof segment 3,
during the GC process of Time 2, f2fs should wait for page 1 written back
before reading it, or move_data_block will read a garbage block from
blkaddr B since page is not written back to blkaddr B yet.
Commit 6aa58d8a ("f2fs: readahead encrypted block during GC") introduce
ra_data_block to read encrypted block, but it forgets to add
f2fs_wait_on_page_writeback to avoid racing between GC and flush.
Signed-off-by: Yunlong Song <yunlong.s...@huawei.com>
---
fs/f2fs/gc.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index a4c1a41..c55fb62 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -641,6 +641,14 @@ static int ra_data_block(struct inode *inode, pgoff_t
index)
fio.page = page;
fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
+ /*
+ * don't cache encrypted data into meta inode until previous dirty
+ * data were writebacked to avoid racing between GC and flush.
+ */
+ f2fs_wait_on_page_writeback(page, DATA, true);
+
+ f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
+
fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
dn.data_blkaddr,
FGP_LOCK | FGP_CREAT, GFP_NOFS);
@@ -723,6 +731,8 @@ static void move_data_block(struct inode *inode, block_t
bidx,
*/
f2fs_wait_on_page_writeback(page, DATA, true);
+ f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
+
err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
if (err)
goto put_out;
--
1.8.5.2
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