linux-ext4 - [PATCH 04/16] fuse2fs: implement directio file reads

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <174787198505.1484996.12562805540320275647.stgit@frogsfrogsfrogs>
Date: Wed, 21 May 2025 17:11:53 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: tytso@....edu
Cc: John@...ves.net, linux-ext4@...r.kernel.org, miklos@...redi.hu,
 joannelkoong@...il.com, bernd@...ernd.com, linux-fsdevel@...r.kernel.org
Subject: [PATCH 04/16] fuse2fs: implement directio file reads

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

Implement file reads via iomap.  Currently only directio is supported.

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 misc/fuse2fs.c |   26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)


diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index 91c0da096bef9c..b1f3002ec8c481 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -1103,6 +1103,11 @@ static void *op_init(struct fuse_conn_info *conn
 			goto mount_fail;
 	}
 
+#if defined(HAVE_FUSE_IOMAP) && defined(FUSE_CAP_IOMAP_DIRECTIO)
+	if (iomap_enabled(ff))
+		fuse_set_feature_flag(conn, FUSE_CAP_IOMAP_DIRECTIO);
+#endif
+
 	/* Clear the valid flag so that an unclean shutdown forces a fsck */
 	if (ff->writable) {
 		fs->super->s_mnt_count++;
@@ -4942,7 +4947,26 @@ static int fuse_iomap_begin_read(struct fuse2fs *ff, ext2_ino_t ino,
 				 uint64_t count, uint32_t opflags,
 				 struct fuse_iomap *read_iomap)
 {
-	return -ENOSYS;
+	errcode_t err;
+
+	if (!(opflags & FUSE_IOMAP_OP_DIRECT))
+		return -ENOSYS;
+
+	/* fall back to slow path for inline data reads */
+	if (inode->i_flags & EXT4_INLINE_DATA_FL)
+		return -ENOSYS;
+
+	/* flush dirty io_channel buffers to disk before iomap reads them */
+	err = io_channel_flush(ff->fs->io);
+	if (err)
+		return translate_error(ff->fs, ino, err);
+
+	if (inode->i_flags & EXT4_EXTENTS_FL)
+		return extent_iomap_begin(ff, ino, inode, pos, count, opflags,
+					 read_iomap);
+
+	return indirect_iomap_begin(ff, ino, inode, pos, count, opflags,
+				    read_iomap);
 }
 
 static int fuse_iomap_begin_write(struct fuse2fs *ff, ext2_ino_t ino,