linux-ext4 - [PATCH 03/16] fuse2fs: implement zero range

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Message-ID: <174553064980.1160461.9850792727586596449.stgit@frogsfrogsfrogs>
Date: Thu, 24 Apr 2025 14:41:34 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org
Subject: [PATCH 03/16] fuse2fs: implement zero range

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

Implement FALLOC_FL_ZERO_RANGE.

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 misc/fuse2fs.c |   20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)


diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index e5f3cec083c0f5..4f3074261d0f53 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -123,6 +123,12 @@ static ext2_filsys global_fs; /* Try not to use this directly */
 # define FL_PUNCH_HOLE_FLAG (0)
 #endif
 
+#ifdef FALLOC_FL_ZERO_RANGE
+# define FL_ZERO_RANGE_FLAG FALLOC_FL_ZERO_RANGE
+#else
+# define FL_ZERO_RANGE_FLAG (0)
+#endif
+
 errcode_t ext2fs_run_ext3_journal(ext2_filsys *fs);
 
 #ifdef CONFIG_JBD_DEBUG		/* Enabled by configure --enable-jbd-debug */
@@ -3619,6 +3625,16 @@ static int punch_helper(struct fuse_file_info *fp, int mode, off_t offset,
 	return 0;
 }
 
+static int zero_helper(struct fuse_file_info *fp, int mode, off_t offset,
+		       off_t len)
+{
+	int ret = punch_helper(fp, mode | FL_KEEP_SIZE_FLAG, offset, len);
+
+	if (!ret)
+		ret = fallocate_helper(fp, mode, offset, len);
+	return ret;
+}
+
 static int op_fallocate(const char *path EXT2FS_ATTR((unused)), int mode,
 			off_t offset, off_t len,
 			struct fuse_file_info *fp)
@@ -3637,7 +3653,9 @@ static int op_fallocate(const char *path EXT2FS_ATTR((unused)), int mode,
 		ret = -EROFS;
 		goto out;
 	}
-	if (mode & FL_PUNCH_HOLE_FLAG)
+	if (mode & FL_ZERO_RANGE_FLAG)
+		ret = zero_helper(fp, mode, offset, len);
+	else if (mode & FL_PUNCH_HOLE_FLAG)
 		ret = punch_helper(fp, mode, offset, len);
 	else
 		ret = fallocate_helper(fp, mode, offset, len);