[PATCH 2/2] f2fs: quota: use memalloc_nofs_{save,restore} instead of FGP_NOFS
From: Chao Yu
Date: Mon Jul 06 2026 - 06:16:59 EST
FGP_NOFS could be removed later, let's use memalloc_nofs_{save,restore}
instead, which is recommended to be used to avoid potential deadlock
when memory allocation in f2fs_quota_write() will call into filesystem
interface again, e.g. .writepages, evict_inode, shrinker due to
complicated lock race condition.
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
fs/f2fs/data.c | 2 +-
fs/f2fs/super.c | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index ac1cf4de3d62..be4c1d4ed6b2 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3994,7 +3994,7 @@ static int f2fs_write_begin(const struct kiocb *iocb,
* Will wait that below with our IO control.
*/
folio = f2fs_filemap_get_folio(mapping, index,
- FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_NOFS,
+ FGP_LOCK | FGP_WRITE | FGP_CREAT,
mapping_gfp_mask(mapping));
if (IS_ERR(folio)) {
err = PTR_ERR(folio);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index fdfd6a7203dd..d28a93657658 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3215,13 +3215,16 @@ static ssize_t f2fs_quota_write(struct super_block *sb, int type,
void *fsdata = NULL;
int err = 0;
int tocopy;
+ unsigned int nofs_flags;
while (towrite > 0) {
tocopy = min_t(unsigned long, sb->s_blocksize - offset,
towrite);
retry:
+ nofs_flags = memalloc_nofs_save();
err = a_ops->write_begin(NULL, mapping, off, tocopy,
&folio, &fsdata);
+ memalloc_nofs_restore(nofs_flags);
if (unlikely(err)) {
if (err == -ENOMEM) {
memalloc_retry_wait(GFP_NOFS);
--
2.49.0