From a9cd8bfde73a78a0ba02e25b712fe28d11019191 Mon Sep 17 00:00:00 2001 From: Don Brady Date: Sat, 22 Jun 2019 16:41:21 -0700 Subject: [PATCH] Let zfs mount all tolerate in-progress mounts The zfs-mount service can unexpectedly fail to start when zfs encounters a mount that is in progress. This service uses zfs mount -a, which has a window between the time it checks if the dataset was mounted and when the actual mount (via mount.zfs binary) occurs. The reason for the racing mounts is that both zfs-mount.target and zfs-share.target are allowed to execute concurrently after the import. This is more of an issue with the relatively recent addition of parallel mounting, and we should consider serializing the mount and share targets. Reviewed-by: Brian Behlendorf Reviewed by: John Kennedy Reviewed-by: Allan Jude Signed-off-by: Don Brady Closes #8881 --- cmd/zfs/zfs_main.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c index 9357bd2f38aa..634303f80992 100644 --- a/cmd/zfs/zfs_main.c +++ b/cmd/zfs/zfs_main.c @@ -6580,8 +6580,25 @@ share_mount_one(zfs_handle_t *zhp, int op, int flags, char *protocol, return (1); } - if (zfs_mount(zhp, options, flags) != 0) + if (zfs_mount(zhp, options, flags) != 0) { + /* + * Check if a mount sneaked in after we checked + */ + if (!explicit && + libzfs_errno(g_zfs) == EZFS_MOUNTFAILED) { + usleep(10 * MILLISEC); + libzfs_mnttab_cache(g_zfs, B_FALSE); + + if (zfs_is_mounted(zhp, NULL)) { + (void) fprintf(stderr, gettext( + "Ignoring previous 'already " + "mounted' error for '%s'\n"), + zfs_get_name(zhp)); + return (0); + } + } return (1); + } break; }