Commit ebe4f3f6 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: correct FSDAX detection 



The detection of the primary device is skipped incorrectly
if the multiple or flattened feature is enabled.

It also fixes the FSDAX misdetection for non-block extra blobs.

Fixes: c6993c4c ("erofs: Fallback to normal access if DAX is not supported on extra device")
Reported-and-tested-by: default avatar <syzbot+31b8fb02cb8a25bd5e78@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/r/691af9f6.a70a0220.3124cb.0097.GAE@google.com


Cc: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent 6a23ae0a

fs/erofs/super.c

+11 −11
Original line number Diff line number Diff line
@@ -174,15 +174,15 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb, 
		if (!erofs_is_fileio_mode(sbi)) {

			dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),

					&dif->dax_part_off, NULL, NULL);

		} else if (!S_ISREG(file_inode(file)->i_mode)) {

			fput(file);

			return -EINVAL;

		}

		if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) {

			erofs_info(sb, "DAX unsupported by %s. Turning off DAX.",

				   dif->path);

			clear_opt(&sbi->opt, DAX_ALWAYS);

		}

		} else if (!S_ISREG(file_inode(file)->i_mode)) {

			fput(file);

			return -EINVAL;

		}

		dif->file = file;

	}
@@ -215,13 +215,13 @@ static int erofs_scan_devices(struct super_block *sb, 
			  ondisk_extradevs, sbi->devs->extra_devices);

		return -EINVAL;

	}

	if (!ondisk_extradevs) {



	if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) {

		erofs_info(sb, "DAX unsupported by block device. Turning off DAX.");

		clear_opt(&sbi->opt, DAX_ALWAYS);

	}

	if (!ondisk_extradevs)

		return 0;

	}



	if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))

		sbi->devs->flatdev = true;