Re: [PATCH] f2fs: fix to align to section for fallocate() on pinned file

From: Chao Yu
Date: Tue Mar 23 2021 - 09:57:14 EST


On 2021/3/5 17:56, Chao Yu wrote:
Now, fallocate() on a pinned file only allocates blocks which aligns
to segment rather than section, so GC may try to migrate pinned file's
block, and after several times of failure, pinned file's block could
be migrated to other place, however user won't be aware of such
condition, and then old obsolete block address may be readed/written
incorrectly.

To avoid such condition, let's try to allocate pinned file's blocks
with section alignment.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>

Jaegeuk,

Could you please check and apply below diff into original patch?

---
fs/f2fs/file.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 236f3f69681a..24fa68fdcaa0 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1648,13 +1648,13 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
return 0;

if (f2fs_is_pinned_file(inode)) {
- block_t len = (map.m_len >> sbi->log_blocks_per_seg) <<
- sbi->log_blocks_per_seg;
+ block_t sec_blks = BLKS_PER_SEC(sbi);
+ block_t len = rounddown(map.m_len, sec_blks);

- if (map.m_len % sbi->blocks_per_seg)
- len += sbi->blocks_per_seg;
+ if (map.m_len % sec_blks)
+ len += sec_blks;

- map.m_len = sbi->blocks_per_seg;
+ map.m_len = sec_blks;
next_alloc:
if (has_not_enough_free_secs(sbi, 0,
GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
--
2.22.1