From ed2c2cb3d440f3bd2692f1896446c4bcc703f05c Mon Sep 17 00:00:00 2001 From: Li Xiao Keng Date: Thu, 7 Sep 2023 19:37:44 +0800 Subject: [PATCH 160/165] Fix race of "mdadm --add" and "mdadm --incremental" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There is a raid1 with sda and sdb. And we add sdc to this raid, it may return -EBUSY. The main process of --add: 1. dev_open（sdc) in Manage_add 2. store_super1(st, di->fd) in write_init_super1 3. fsync(fd) in store_super1 4. close(di->fd) in write_init_super1 5. ioctl(ADD_NEW_DISK) Step 2 and 3 will add sdc to metadata of raid1. There will be udev(change of sdc) event after step4. Then "/usr/sbin/mdadm --incremental --export $devnode --offroot $env{DEVLINKS}" will be run, and the sdc will be added to the raid1. Then step 5 will return -EBUSY because it checks if device isn't claimed in md_import_device()->lock_rdev()->blkdev_get_by_dev() ->blkdev_get(). It will be confusing for users because sdc is added first time. The "incremental" will get map_lock before add sdc to raid1. So we add map_lock before write_init_super in "mdadm --add" to fix the race of "add" and "incremental". Signed-off-by: Li Xiao Keng Signed-off-by: Guanqin Miao Reviewed-by: Mariusz Tkaczyk Signed-off-by: Jes Sorensen --- Manage.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/Manage.c b/Manage.c index f997b163..075dd720 100644 --- a/Manage.c +++ b/Manage.c @@ -704,6 +704,7 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, struct supertype *dev_st; int j; mdu_disk_info_t disc; + struct map_ent *map = NULL; if (!get_dev_size(tfd, dv->devname, &ldsize)) { if (dv->disposition == 'M') @@ -907,6 +908,9 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, disc.raid_disk = 0; } + if (map_lock(&map)) + pr_err("failed to get exclusive lock on mapfile when add disk\n"); + if (array->not_persistent==0) { int dfd; if (dv->disposition == 'j') @@ -918,9 +922,9 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, dfd = dev_open(dv->devname, O_RDWR | O_EXCL|O_DIRECT); if (tst->ss->add_to_super(tst, &disc, dfd, dv->devname, INVALID_SECTORS)) - return -1; + goto unlock; if (tst->ss->write_init_super(tst)) - return -1; + goto unlock; } else if (dv->disposition == 'A') { /* this had better be raid1. * As we are "--re-add"ing we must find a spare slot @@ -978,14 +982,14 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, pr_err("add failed for %s: could not get exclusive access to container\n", dv->devname); tst->ss->free_super(tst); - return -1; + goto unlock; } /* Check if metadata handler is able to accept the drive */ if (!tst->ss->validate_geometry(tst, LEVEL_CONTAINER, 0, 1, NULL, 0, 0, dv->devname, NULL, 0, 1)) { close(container_fd); - return -1; + goto unlock; } Kill(dv->devname, NULL, 0, -1, 0); @@ -994,7 +998,7 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, dv->devname, INVALID_SECTORS)) { close(dfd); close(container_fd); - return -1; + goto unlock; } if (!mdmon_running(tst->container_devnm)) tst->ss->sync_metadata(tst); @@ -1005,7 +1009,7 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, dv->devname); close(container_fd); tst->ss->free_super(tst); - return -1; + goto unlock; } sra->array.level = LEVEL_CONTAINER; /* Need to set data_offset and component_size */ @@ -1020,7 +1024,7 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, pr_err("add new device to external metadata failed for %s\n", dv->devname); close(container_fd); sysfs_free(sra); - return -1; + goto unlock; } ping_monitor(devnm); sysfs_free(sra); @@ -1034,7 +1038,7 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, else pr_err("add new device failed for %s as %d: %s\n", dv->devname, j, strerror(errno)); - return -1; + goto unlock; } if (dv->disposition == 'j') { pr_err("Journal added successfully, making %s read-write\n", devname); @@ -1045,7 +1049,11 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv, } if (verbose >= 0) pr_err("added %s\n", dv->devname); + map_unlock(&map); return 1; +unlock: + map_unlock(&map); + return -1; } int Manage_remove(struct supertype *tst, int fd, struct mddev_dev *dv, -- 2.40.1