FAILED: patch "[PATCH] f2fs: fix to avoid potential section-unaligned pinfile" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x d0a481fad5c7a3a56ecf54a099651216869f4d0a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090951-squid-storewide-6196@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d0a481fad5c7a3a56ecf54a099651216869f4d0a Mon Sep 17 00:00:00 2001
From: Chao Yu <[email protected]>
Date: Mon, 29 Jun 2026 11:49:18 +0000
Subject: [PATCH] f2fs: fix to avoid potential section-unaligned pinfile

Blocks of pinfile may not aligned to section size due to wrong use on pinfile, result in heavy overhead of GC, let avoid this by adding additional check condition in f2fs_setattr().

- truncate -s 8mb pinfile
: random checkpoint may persist filesize w/ inode
- fallocate -o 0 -l 8mb pinfile
- f2fs_fallocate
- f2fs_expand_inode_data
- f2fs_allocate_pinning_section
- f2fs_map_blocks
- f2fs_map_lock
- __allocate_data_block
- file_need_truncate
: w/ FADVISE_TRUNC_BIT, we can expect unaligned mapping can be
truncated while open() if f2fs is not umount abnormally
- f2fs_map_unlock
: following f2fs checkpoint and sudden power-cut

- mount
- open pinfile
- f2fs_file_open
- finish_preallocate_blocks
- truncate_setsize
: filesize is 8mb
- f2fs_truncate
: can only truncate block outside filesize, rather than truncating
unaligned blocks inside filesize

index 4b52c56d71f0..c54897a25981 100644
@@ -1107,17 +1107,23 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 			!IS_ALIGNED(attr->ia_size,
 			F2FS_BLK_TO_BYTES(fi->i_cluster_size)))
 			return -EINVAL;
-		/*
-		 * To prevent scattered pin block generation, we don't allow
-		 * smaller/equal size unaligned truncation for pinned file.
-		 * We only support overwrite IO to pinned file, so don't
-		 * care about larger size truncation.
-		 */
-		if (f2fs_is_pinned_file(inode) &&
-			attr->ia_size <= i_size_read(inode) &&
-			!IS_ALIGNED(attr->ia_size,
-			F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
-			return -EINVAL;
+
+		if (f2fs_is_pinned_file(inode)) {
+			/*
+			 * It may break section-aligned fallocate recovery
+			 * mechanism, so do not allow larger size truncation.
+			 */
+			if (attr->ia_size > i_size_read(inode))
+				return -EINVAL;
+			/*
+			 * To prevent scattered pin block generation, we don't
+			 * allow smaller/equal size unaligned truncation for
+			 * pinned file.
+			 */
+			else if (!IS_ALIGNED(attr->ia_size,
+				F2FS_BLK_TO_BYTES(CAP_BLKS_PER_SEC(sbi))))
+				return -EINVAL;
+		}
 	}
 
 	if (is_quota_modification(idmap, inode, attr)) {