linux-kernel - [PATCH v2] f2fs: prevent writing without fallocate() for pinned files

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Date: Tue, 12 Mar 2024 13:49:34 -0700
From: Daeho Jeong <daeho43@...il.com>
To: linux-kernel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net,
	kernel-team@...roid.com
Cc: Daeho Jeong <daehojeong@...gle.com>
Subject: [PATCH v2] f2fs: prevent writing without fallocate() for pinned files

From: Daeho Jeong <daehojeong@...gle.com>

In a case writing without fallocate(), we can't guarantee it's allocated
in the conventional area for zoned stroage.

Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
---
v2: covered the direct io case
---
 fs/f2fs/data.c | 14 ++++++++++++--
 fs/f2fs/file.c |  4 ++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index c21b92f18463..d3e5ab2736a6 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1584,8 +1584,11 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag)
 
 	/* use out-place-update for direct IO under LFS mode */
 	if (map->m_may_create &&
-	    (is_hole || (f2fs_lfs_mode(sbi) && flag == F2FS_GET_BLOCK_DIO))) {
-		if (unlikely(f2fs_cp_error(sbi))) {
+	    (is_hole || (f2fs_lfs_mode(sbi) && flag == F2FS_GET_BLOCK_DIO &&
+			 !f2fs_is_pinned_file(inode)))) {
+		if (unlikely(f2fs_cp_error(sbi)) ||
+		    (f2fs_is_pinned_file(inode) && is_hole &&
+		     flag != F2FS_GET_BLOCK_PRE_DIO)) {
 			err = -EIO;
 			goto sync_out;
 		}
@@ -3378,6 +3381,8 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
 		f2fs_map_lock(sbi, flag);
 		locked = true;
 	} else if ((pos & PAGE_MASK) >= i_size_read(inode)) {
+		if (f2fs_is_pinned_file(inode))
+			return -EIO;
 		f2fs_map_lock(sbi, flag);
 		locked = true;
 	}
@@ -3407,6 +3412,11 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
 
 	if (!f2fs_lookup_read_extent_cache_block(inode, index,
 						 &dn.data_blkaddr)) {
+		if (f2fs_is_pinned_file(inode)) {
+			err = -EIO;
+			goto out;
+		}
+
 		if (locked) {
 			err = f2fs_reserve_block(&dn, index);
 			goto out;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 82277e95c88f..f98730932fc4 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4611,6 +4611,10 @@ static int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *iter,
 			return ret;
 	}
 
+	/* For pinned files, it should be fallocate()-ed in advance. */
+	if (f2fs_is_pinned_file(inode))
+		return 0;
+
 	/* Do not preallocate blocks that will be written partially in 4KB. */
 	map.m_lblk = F2FS_BLK_ALIGN(pos);
 	map.m_len = F2FS_BYTES_TO_BLK(pos + count);
-- 
2.44.0.278.ge034bb2e1d-goog