linux-ext4 - [PATCH 09/17] fuse2fs: don't zero bytes in punch hole

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Message-ID: <175798161882.390496.14945927624239907333.stgit@frogsfrogsfrogs>
Date: Mon, 15 Sep 2025 18:01:05 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: tytso@....edu
Cc: miklos@...redi.hu, neal@...pa.dev, linux-fsdevel@...r.kernel.org,
 linux-ext4@...r.kernel.org, John@...ves.net, bernd@...ernd.com,
 joannelkoong@...il.com
Subject: [PATCH 09/17] fuse2fs: don't zero bytes in punch hole

From: Darrick J. Wong <djwong@...nel.org>

When iomap is in use for the pagecache, it will take care of zeroing the
unaligned parts of punched out regions so we don't have to do it
ourselves.

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 fuse4fs/fuse4fs.c |    8 ++++++++
 misc/fuse2fs.c    |    9 +++++++++
 2 files changed, 17 insertions(+)


diff --git a/fuse4fs/fuse4fs.c b/fuse4fs/fuse4fs.c
index 6b5d14e4f044cb..6c9e725d54b87a 100644
--- a/fuse4fs/fuse4fs.c
+++ b/fuse4fs/fuse4fs.c
@@ -5333,6 +5333,10 @@ static errcode_t fuse4fs_zero_middle(struct fuse4fs *ff, ext2_ino_t ino,
 	int retflags;
 	errcode_t err;
 
+	/* the kernel does this for us in iomap mode */
+	if (fuse4fs_iomap_enabled(ff))
+		return 0;
+
 	if (!*buf) {
 		err = ext2fs_get_mem(fs->blocksize, buf);
 		if (err)
@@ -5369,6 +5373,10 @@ static errcode_t fuse4fs_zero_edge(struct fuse4fs *ff, ext2_ino_t ino,
 	off_t residue;
 	errcode_t err;
 
+	/* the kernel does this for us in iomap mode */
+	if (fuse4fs_iomap_enabled(ff))
+		return 0;
+
 	residue = FUSE4FS_OFF_IN_FSB(ff, offset);
 	if (residue == 0)
 		return 0;
diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index afc65c774dc148..5dbd8c5a17f79d 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -570,6 +570,7 @@ static inline int fuse2fs_iomap_enabled(const struct fuse2fs *ff)
 }
 #else
 # define fuse2fs_iomap_enabled(...)	(0)
+# define fuse2fs_iomap_enabled(...)	(0)
 #endif
 
 static inline void fuse2fs_dump_extents(struct fuse2fs *ff, ext2_ino_t ino,
@@ -4776,6 +4777,10 @@ static errcode_t clean_block_middle(struct fuse2fs *ff, ext2_ino_t ino,
 	int retflags;
 	errcode_t err;
 
+	/* the kernel does this for us in iomap mode */
+	if (fuse2fs_iomap_enabled(ff))
+		return 0;
+
 	if (!*buf) {
 		err = ext2fs_get_mem(fs->blocksize, buf);
 		if (err)
@@ -4812,6 +4817,10 @@ static errcode_t clean_block_edge(struct fuse2fs *ff, ext2_ino_t ino,
 	off_t residue;
 	errcode_t err;
 
+	/* the kernel does this for us in iomap mode */
+	if (fuse2fs_iomap_enabled(ff))
+		return 0;
+
 	residue = FUSE2FS_OFF_IN_FSB(ff, offset);
 	if (residue == 0)
 		return 0;