/* * Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved. * Copyright (C) 2004 Red Hat, Inc. All rights reserved. * * This file is part of LVM2. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions * of the GNU General Public License v.2. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* CLVMD Cluster LVM daemon command processor. To add commands to the daemon simply add a processor in do_command and return and messages back in buf and the length in *retlen. The initial value of buflen is the maximum size of the buffer. if buf is not large enough then it may be reallocated by the functions in here to a suitable size bearing in mind that anything larger than the passed-in size will have to be returned using the system LV and so performance will suffer. The status return will be negated and passed back to the originating node. pre- and post- command routines are called only on the local node. The purpose is primarily to get and release locks, though the pre- routine should also do any other local setups required by the command (if any) and can return a failure code that prevents the command from being distributed around the cluster The pre- and post- routines are run in their own thread so can block as long they like, do_command is run in the main clvmd thread so should not block for too long. If the pre-command returns an error code (!=0) then the command will not be propogated around the cluster but the post-command WILL be called Also note that the pre and post routine are *always* called on the local node, even if the command to be executed was only requested to run on a remote node. It may peek inside the client structure to check the status of the command. The clients of the daemon must, naturally, understand the return messages and codes. Routines in here may only READ the values in the client structure passed in apart from client->private which they are free to do what they like with. */ #define _GNU_SOURCE #define _FILE_OFFSET_BITS 64 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "locking.h" #include "lvm-logging.h" #include "lvm-functions.h" #include "clvmd-comms.h" #include "clvm.h" #include "clvmd.h" extern debug_t debug; extern struct cluster_ops *clops; /* This is where all the real work happens: NOTE: client will be NULL when this is executed on a remote node */ int do_command(struct local_client *client, struct clvm_header *msg, int msglen, char **buf, int buflen, int *retlen) { char *args = msg->node + strlen(msg->node) + 1; int arglen = msglen - sizeof(struct clvm_header) - strlen(msg->node); int status = 0; char *lockname; const char *locktype; struct utsname nodeinfo; unsigned char lock_cmd; unsigned char lock_flags; /* Do the command */ switch (msg->cmd) { /* Just a test message */ case CLVMD_CMD_TEST: if (arglen > buflen) { char *new_buf; buflen = arglen + 200; new_buf = realloc(*buf, buflen); if (new_buf == NULL) { status = errno; free (*buf); } *buf = new_buf; } if (*buf) { uname(&nodeinfo); *retlen = 1 + snprintf(*buf, buflen, "TEST from %s: %s v%s", nodeinfo.nodename, args, nodeinfo.release); } break; case CLVMD_CMD_LOCK_VG: lock_cmd = args[0]; lock_flags = args[1]; lockname = &args[2]; /* Check to see if the VG is in use by LVM1 */ status = do_check_lvm1(lockname); do_lock_vg(lock_cmd, lock_flags, lockname); break; case CLVMD_CMD_LOCK_LV: /* This is the biggie */ lock_cmd = args[0] & (LCK_NONBLOCK | LCK_HOLD | LCK_SCOPE_MASK | LCK_TYPE_MASK); lock_flags = args[1]; lockname = &args[2]; status = do_lock_lv(lock_cmd, lock_flags, lockname); /* Replace EIO with something less scary */ if (status == EIO) { *retlen = 1 + snprintf(*buf, buflen, "%s", get_last_lvm_error()); return EIO; } break; case CLVMD_CMD_LOCK_QUERY: lockname = &args[2]; if (buflen < 3) return EIO; if ((locktype = do_lock_query(lockname))) *retlen = 1 + snprintf(*buf, buflen, "%s", locktype); break; case CLVMD_CMD_REFRESH: do_refresh_cache(); break; case CLVMD_CMD_SET_DEBUG: debug = args[0]; break; case CLVMD_CMD_GET_CLUSTERNAME: status = clops->get_cluster_name(*buf, buflen); if (!status) *retlen = strlen(*buf)+1; break; case CLVMD_CMD_VG_BACKUP: /* * Do not run backup on local node, caller should do that. */ if (!client) lvm_do_backup(&args[2]); break; default: /* Won't get here because command is validated in pre_command */ break; } /* Check the status of the command and return the error text */ if (status) { *retlen = 1 + snprintf(*buf, buflen, "%s", strerror(status)); } return status; } static int lock_vg(struct local_client *client) { struct dm_hash_table *lock_hash; struct clvm_header *header = (struct clvm_header *) client->bits.localsock.cmd; unsigned char lock_cmd; unsigned char lock_flags; int lock_mode; char *args = header->node + strlen(header->node) + 1; int lkid; int status = 0; char *lockname; /* Keep a track of VG locks in our own hash table. In current practice there should only ever be more than two VGs locked if a user tries to merge lots of them at once */ if (client->bits.localsock.private) { lock_hash = (struct dm_hash_table *)client->bits.localsock.private; } else { lock_hash = dm_hash_create(3); if (!lock_hash) return ENOMEM; client->bits.localsock.private = (void *)lock_hash; } lock_cmd = args[0] & (LCK_NONBLOCK | LCK_HOLD | LCK_SCOPE_MASK | LCK_TYPE_MASK); lock_mode = ((int)lock_cmd & LCK_TYPE_MASK); lock_flags = args[1]; lockname = &args[2]; DEBUGLOG("doing PRE command LOCK_VG '%s' at %x (client=%p)\n", lockname, lock_cmd, client); if (lock_mode == LCK_UNLOCK) { lkid = (int)(long)dm_hash_lookup(lock_hash, lockname); if (lkid == 0) return EINVAL; status = sync_unlock(lockname, lkid); if (status) status = errno; else dm_hash_remove(lock_hash, lockname); } else { /* Read locks need to be PR; other modes get passed through */ if (lock_mode == LCK_READ) lock_mode = LCK_PREAD; status = sync_lock(lockname, lock_mode, (lock_cmd & LCK_NONBLOCK) ? LKF_NOQUEUE : 0, &lkid); if (status) status = errno; else dm_hash_insert(lock_hash, lockname, (void *)(long)lkid); } return status; } /* Pre-command is a good place to get locks that are needed only for the duration of the commands around the cluster (don't forget to free them in post-command), and to sanity check the command arguments */ int do_pre_command(struct local_client *client) { struct clvm_header *header = (struct clvm_header *) client->bits.localsock.cmd; unsigned char lock_cmd; unsigned char lock_flags; char *args = header->node + strlen(header->node) + 1; int lockid; int status = 0; char *lockname; switch (header->cmd) { case CLVMD_CMD_TEST: status = sync_lock("CLVMD_TEST", LKM_EXMODE, 0, &lockid); client->bits.localsock.private = (void *)(long)lockid; break; case CLVMD_CMD_LOCK_VG: lockname = &args[2]; /* We take out a real lock unless LCK_CACHE was set */ if (!strncmp(lockname, "V_", 2) || !strncmp(lockname, "P_#", 3)) status = lock_vg(client); break; case CLVMD_CMD_LOCK_LV: lock_cmd = args[0]; lock_flags = args[1]; lockname = &args[2]; status = pre_lock_lv(lock_cmd, lock_flags, lockname); break; case CLVMD_CMD_REFRESH: case CLVMD_CMD_GET_CLUSTERNAME: case CLVMD_CMD_SET_DEBUG: case CLVMD_CMD_VG_BACKUP: case CLVMD_CMD_LOCK_QUERY: break; default: log_error("Unknown command %d received\n", header->cmd); status = EINVAL; } return status; } /* Note that the post-command routine is called even if the pre-command or the real command failed */ int do_post_command(struct local_client *client) { struct clvm_header *header = (struct clvm_header *) client->bits.localsock.cmd; int status = 0; unsigned char lock_cmd; unsigned char lock_flags; char *args = header->node + strlen(header->node) + 1; char *lockname; switch (header->cmd) { case CLVMD_CMD_TEST: status = sync_unlock("CLVMD_TEST", (int) (long) client->bits.localsock.private); client->bits.localsock.private = 0; break; case CLVMD_CMD_LOCK_VG: case CLVMD_CMD_VG_BACKUP: case CLVMD_CMD_LOCK_QUERY: /* Nothing to do here */ break; case CLVMD_CMD_LOCK_LV: lock_cmd = args[0]; lock_flags = args[1]; lockname = &args[2]; status = post_lock_lv(lock_cmd, lock_flags, lockname); break; } return status; } /* Called when the client is about to be deleted */ void cmd_client_cleanup(struct local_client *client) { if (client->bits.localsock.private) { struct dm_hash_node *v; struct dm_hash_table *lock_hash = (struct dm_hash_table *)client->bits.localsock.private; dm_hash_iterate(v, lock_hash) { int lkid = (int)(long)dm_hash_get_data(lock_hash, v); char *lockname = dm_hash_get_key(lock_hash, v); DEBUGLOG("cleanup: Unlocking lock %s %x\n", lockname, lkid); sync_unlock(lockname, lkid); } dm_hash_destroy(lock_hash); client->bits.localsock.private = 0; } }