erofs: ensure regular inodes for file-backed mounts

Only regular inodes are allowed for file-backed mounts, not directories
(as seen in the original syzbot case) or special inodes.

Also ensure that .read_folio() is implemented on the underlying fs
for the primary device.

Fixes: fb17675026 ("erofs: add file-backed mount support")
Reported-by: syzbot+001306cd9c92ce0df23f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/00000000000011bdde0622498ee3@google.com
Tested-by: syzbot+001306cd9c92ce0df23f@syzkaller.appspotmail.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240917130803.32418-1-hsiangkao@linux.alibaba.com
This commit is contained in:
Gao Xiang 2024-09-17 21:08:03 +08:00
parent 9852d85ec9
commit 416a8b2c02

View File

@ -191,10 +191,14 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
if (IS_ERR(file))
return PTR_ERR(file);
dif->file = file;
if (!erofs_is_fileio_mode(sbi))
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;
}
dif->file = file;
}
dif->blocks = le32_to_cpu(dis->blocks);
@ -714,7 +718,10 @@ static int erofs_fc_get_tree(struct fs_context *fc)
if (IS_ERR(sbi->fdev))
return PTR_ERR(sbi->fdev);
return get_tree_nodev(fc, erofs_fc_fill_super);
if (S_ISREG(file_inode(sbi->fdev)->i_mode) &&
sbi->fdev->f_mapping->a_ops->read_folio)
return get_tree_nodev(fc, erofs_fc_fill_super);
fput(sbi->fdev);
}
#endif
return ret;