linux-ext4 - [PATCH 11/12] fuse2fs: disable fallocate/zero range on indirect files

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Message-ID: <175573318801.4130038.5441212769275575364.stgit@frogsfrogsfrogs>
Date: Wed, 20 Aug 2025 16:43:44 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org, linux-ext4@...r.kernel.org
Subject: [PATCH 11/12] fuse2fs: disable fallocate/zero range on indirect files

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

Indirect mapped files can't have unwritten extents, so we can't do
unwritten preallocation or zero-range because both depend on unwritten
extents.

Cc: <linux-ext4@...r.kernel.org> # v1.43
Fixes: 81cbf1ef4f5dab ("misc: add fuse2fs, a FUSE server for e2fsprogs")
Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 misc/fuse2fs.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)


diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index 318bfb55345b9b..cb5620c7e2ee33 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -4137,6 +4137,10 @@ static int fallocate_helper(struct fuse_file_info *fp, int mode, off_t offset,
 		return err;
 	fsize = EXT2_I_SIZE(&inode);
 
+	/* Indirect files do not support unwritten extents */
+	if (!(inode.i_flags & EXT4_EXTENTS_FL))
+		return -EOPNOTSUPP;
+
 	/* Allocate a bunch of blocks */
 	flags = (mode & FL_KEEP_SIZE_FLAG ? 0 :
 			EXT2_FALLOCATE_INIT_BEYOND_EOF);
@@ -4279,6 +4283,14 @@ static int punch_helper(struct fuse_file_info *fp, int mode, off_t offset,
 	if (err)
 		return translate_error(fs, fh->ino, err);
 
+	/*
+	 * Indirect files do not support unwritten extents, which means we
+	 * can't support zero range.  Punch goes first in zero-range, which
+	 * is why the check is here.
+	 */
+	if ((mode & FL_ZERO_RANGE_FLAG) && !(inode.i_flags & EXT4_EXTENTS_FL))
+		return -EOPNOTSUPP;
+
 	/* Zero everything before the first block and after the last block */
 	if (FUSE2FS_B_TO_FSBT(ff, offset) == FUSE2FS_B_TO_FSBT(ff, offset + len))
 		err = clean_block_middle(ff, fh->ino, &inode, offset,