From: Christian Brauner Date: Mon, 21 Oct 2024 12:30:29 +0000 (+0200) Subject: Merge patch series "fs/super.c: introduce get_tree_bdev_flags()" X-Git-Tag: v6.12-rc6~28^2~5 X-Git-Url: https://gentwo.org/gitweb/?a=commitdiff_plain;h=35100ae2dc33fc4b20c3648ed375a81e1f4b6e3a;p=linux%2F.git Merge patch series "fs/super.c: introduce get_tree_bdev_flags()" Allison Karlitskaya says: In context of my work on composefs/bootc I've been testing the new support for directly mounting files with erofs (ie: without a loopback device) and it's working well. Thanks for adding this feature --- it's a huge quality of life improvement for us. I've observed a strange behaviour, though: when mounting a file as an erofs, if you read() the filesystem context fd, you always get the following error message reported: Can't lookup blockdev. That's caused by the code in erofs_fc_get_tree() trying to call get_tree_bdev() and recovering from the error in case it was ENOTBLK and CONFIG_EROFS_FS_BACKED_BY_FILE. Unfortunately, get_tree_bdev() logs the error directly on the fs_context, so you get the error message even on successful mounts. It looks something like this at the syscall level: fsopen("erofs", FSOPEN_CLOEXEC) = 3 fsconfig(3, FSCONFIG_SET_FLAG, "ro", NULL, 0) = 0 fsconfig(3, FSCONFIG_SET_STRING, "source", "/home/lis/src/mountcfs/cfs", 0) = 0 fsconfig(3, FSCONFIG_CMD_CREATE, NULL, NULL, 0) = 0 fsmount(3, FSMOUNT_CLOEXEC, 0) = 5 move_mount(5, "", AT_FDCWD, "/tmp/composefs.upper.KuT5aV", MOVE_MOUNT_F_EMPTY_PATH) = 0 read(3, "e /home/lis/src/mountcfs/cfs: Can't lookup blockdev\n", 1024) = 52 This is kernel 6.12.0-0.rc0.20240926git11a299a7933e.13.fc42.x86_64 from Fedora Rawhide. It's a pretty minor issue, but it sent me on a wild goose chase for an hour or two, so probably it should get fixed before the final release. Gao Xiang : Fix this by providing a get_tree_bdev_flags() helper which can be used to silence such warnings. * patches from https://lore.kernel.org/r/20241009033151.2334888-1-hsiangkao@linux.alibaba.com: erofs: use get_tree_bdev_flags() to avoid misleading messages fs/super.c: introduce get_tree_bdev_flags() Link: https://lore.kernel.org/r/20241009033151.2334888-1-hsiangkao@linux.alibaba.com Signed-off-by: Christian Brauner --- 35100ae2dc33fc4b20c3648ed375a81e1f4b6e3a