[PATCH 5.10 197/663] f2fs: compress: fix potential deadlock
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-03-01 23:35:20
Also in:
lkml
Subsystem:
f2fs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Jaegeuk Kim, Chao Yu, Alexander Viro, Christian Brauner, Linus Torvalds
From: Chao Yu <redacted>
[ Upstream commit 3afae09ffea5e08f523823be99a784675995d6bb ]
generic/269 reports a hangtask issue, the root cause is ABBA deadlock
described as below:
Thread A Thread B
- down_write(&sbi->gc_lock) -- A
- f2fs_write_data_pages
- lock all pages in cluster -- B
- f2fs_write_multi_pages
- f2fs_write_raw_pages
- f2fs_write_single_data_page
- f2fs_balance_fs
- down_write(&sbi->gc_lock) -- A
- f2fs_gc
- do_garbage_collect
- ra_data_block
- pagecache_get_page -- B
To fix this, it needs to avoid calling f2fs_balance_fs() if there is
still cluster pages been locked in context of cluster writeback, so
instead, let's call f2fs_balance_fs() in the end of
f2fs_write_raw_pages() when all cluster pages were unlocked.
Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Chao Yu <redacted>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/compress.c | 5 ++++-
fs/f2fs/data.c | 10 ++++++----
fs/f2fs/f2fs.h | 2 +-
3 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index c5fee4d7ea72f..d3f407ba64c9e 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c@@ -1393,7 +1393,7 @@ retry_write: ret = f2fs_write_single_data_page(cc->rpages[i], &_submitted, NULL, NULL, wbc, io_type, - compr_blocks); + compr_blocks, false); if (ret) { if (ret == AOP_WRITEPAGE_ACTIVATE) { unlock_page(cc->rpages[i]);
@@ -1428,6 +1428,9 @@ retry_write: *submitted += _submitted; } + + f2fs_balance_fs(F2FS_M_SB(mapping), true); + return 0; out_err: for (++i; i < cc->cluster_size; i++) {
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b29243ee1c3e5..4f326bce525f7 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c@@ -2757,7 +2757,8 @@ int f2fs_write_single_data_page(struct page *page, int *submitted, sector_t *last_block, struct writeback_control *wbc, enum iostat_type io_type, - int compr_blocks) + int compr_blocks, + bool allow_balance) { struct inode *inode = page->mapping->host; struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
@@ -2895,7 +2896,7 @@ out: } unlock_page(page); if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode) && - !F2FS_I(inode)->cp_task) + !F2FS_I(inode)->cp_task && allow_balance) f2fs_balance_fs(sbi, need_balance_fs); if (unlikely(f2fs_cp_error(sbi))) {
@@ -2942,7 +2943,7 @@ out: #endif return f2fs_write_single_data_page(page, NULL, NULL, NULL, - wbc, FS_DATA_IO, 0); + wbc, FS_DATA_IO, 0, true); } /*
@@ -3110,7 +3111,8 @@ continue_unlock: } #endif ret = f2fs_write_single_data_page(page, &submitted, - &bio, &last_block, wbc, io_type, 0); + &bio, &last_block, wbc, io_type, + 0, true); if (ret == AOP_WRITEPAGE_ACTIVATE) unlock_page(page); #ifdef CONFIG_F2FS_FS_COMPRESSION
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 06e5a6053f3f9..699815e94bd30 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h@@ -3507,7 +3507,7 @@ int f2fs_write_single_data_page(struct page *page, int *submitted, struct bio **bio, sector_t *last_block, struct writeback_control *wbc, enum iostat_type io_type, - int compr_blocks); + int compr_blocks, bool allow_balance); void f2fs_invalidate_page(struct page *page, unsigned int offset, unsigned int length); int f2fs_release_page(struct page *page, gfp_t wait);
--
2.27.0