From 34118eac06fba834f0c934419aec1b386c98665a Mon Sep 17 00:00:00 2001 From: Low-power Date: Sat, 24 Aug 2024 01:39:09 +0800 Subject: [PATCH] Make mount.zfs(8) calling zfs_mount_at for legacy mounts as well Commit 329e2ffa4bca456e65c3db7f5c5c04931c551b61 has made mount.zfs(8) to call libzfs function 'zfs_mount_at', in order to propagate dataset properties into mount options. This fix however, is limited to a special use case where mount.zfs(8) is used in initrd with option '-o zfsutil'. If either initrd or the user need to use mount.zfs(8) to mount a file system with 'mountpoint' set to 'legacy', '-o zfsutil' can't be used and the original issue #7947 will still happen. Since the existing code already excluded the possibility of calling 'zfs_mount_at' when it was invoked as a helper program from zfs(8), by checking 'ZFS_MOUNT_HELPER' environment variable, it makes no sense to avoid calling 'zfs_mount_at' without '-o zfsutil'. An exception however, is when mount.zfs(8) was invoked with '-o remount' to update the mount options for an existing mount point. In this case call mount(2) directly without modifying the mount options passed from command line. Furthermore, don't run mount.zfs(8) helper for automounting snapshot. The above change to make mount.zfs(8) to call 'zfs_mount_at' apparently caused it to trigger an automount for the snapshot directory. When the helper was invoked as a result of a snapshot automount, an infinite recursion will occur. Since the need of invoking user mode mount(8) for automounting was to overcome that the 'vfs_kern_mount' being GPL-only, just run mount(8) without the mount.zfs(8) helper by adding option '-i'. Reviewed-by: Umer Saleem Reviewed-by: Brian Behlendorf Signed-off-by: WHR Closes #16393 --- cmd/mount_zfs.c | 5 ++--- module/os/linux/zfs/zfs_ctldir.c | 8 ++++---- 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/cmd/mount_zfs.c b/cmd/mount_zfs.c index fc92209506..283074daf7 100644 --- a/cmd/mount_zfs.c +++ b/cmd/mount_zfs.c @@ -269,8 +269,7 @@ main(int argc, char **argv) return (MOUNT_USAGE); } - if (!zfsutil || sloppy || - libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) { + if (sloppy || libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) { zfs_adjust_mount_options(zhp, mntpoint, mntopts, mtabopt); } @@ -337,7 +336,7 @@ main(int argc, char **argv) dataset, mntpoint, mntflags, zfsflags, mntopts, mtabopt); if (!fake) { - if (zfsutil && !sloppy && + if (!remount && !sloppy && !libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) { error = zfs_mount_at(zhp, mntopts, mntflags, mntpoint); if (error) { diff --git a/module/os/linux/zfs/zfs_ctldir.c b/module/os/linux/zfs/zfs_ctldir.c index 54ed70d039..e042116333 100644 --- a/module/os/linux/zfs/zfs_ctldir.c +++ b/module/os/linux/zfs/zfs_ctldir.c @@ -1101,8 +1101,8 @@ zfsctl_snapshot_mount(struct path *path, int flags) zfsvfs_t *snap_zfsvfs; zfs_snapentry_t *se; char *full_name, *full_path; - char *argv[] = { "/usr/bin/env", "mount", "-t", "zfs", "-n", NULL, NULL, - NULL }; + char *argv[] = { "/usr/bin/env", "mount", "-i", "-t", "zfs", "-n", + NULL, NULL, NULL }; char *envp[] = { NULL }; int error; struct path spath; @@ -1153,8 +1153,8 @@ zfsctl_snapshot_mount(struct path *path, int flags) * value from call_usermodehelper() will be (exitcode << 8 + signal). */ dprintf("mount; name=%s path=%s\n", full_name, full_path); - argv[5] = full_name; - argv[6] = full_path; + argv[6] = full_name; + argv[7] = full_path; error = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC); if (error) { if (!(error & MOUNT_BUSY << 8)) {