diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/lockd/svclock.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/lockd/svclock.c | 965 |
1 files changed, 0 insertions, 965 deletions
diff --git a/ANDROID_3.4.5/fs/lockd/svclock.c b/ANDROID_3.4.5/fs/lockd/svclock.c deleted file mode 100644 index e46353f4..00000000 --- a/ANDROID_3.4.5/fs/lockd/svclock.c +++ /dev/null @@ -1,965 +0,0 @@ -/* - * linux/fs/lockd/svclock.c - * - * Handling of server-side locks, mostly of the blocked variety. - * This is the ugliest part of lockd because we tread on very thin ice. - * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc. - * IMNSHO introducing the grant callback into the NLM protocol was one - * of the worst ideas Sun ever had. Except maybe for the idea of doing - * NFS file locking at all. - * - * I'm trying hard to avoid race conditions by protecting most accesses - * to a file's list of blocked locks through a semaphore. The global - * list of blocked locks is not protected in this fashion however. - * Therefore, some functions (such as the RPC callback for the async grant - * call) move blocked locks towards the head of the list *while some other - * process might be traversing it*. This should not be a problem in - * practice, because this will only cause functions traversing the list - * to visit some blocks twice. - * - * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> - */ - -#include <linux/types.h> -#include <linux/slab.h> -#include <linux/errno.h> -#include <linux/kernel.h> -#include <linux/sched.h> -#include <linux/sunrpc/clnt.h> -#include <linux/sunrpc/svc.h> -#include <linux/lockd/nlm.h> -#include <linux/lockd/lockd.h> -#include <linux/kthread.h> - -#define NLMDBG_FACILITY NLMDBG_SVCLOCK - -#ifdef CONFIG_LOCKD_V4 -#define nlm_deadlock nlm4_deadlock -#else -#define nlm_deadlock nlm_lck_denied -#endif - -static void nlmsvc_release_block(struct nlm_block *block); -static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); -static void nlmsvc_remove_block(struct nlm_block *block); - -static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock); -static void nlmsvc_freegrantargs(struct nlm_rqst *call); -static const struct rpc_call_ops nlmsvc_grant_ops; - -/* - * The list of blocked locks to retry - */ -static LIST_HEAD(nlm_blocked); -static DEFINE_SPINLOCK(nlm_blocked_lock); - -#ifdef LOCKD_DEBUG -static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie) -{ - /* - * We can get away with a static buffer because we're only - * called with BKL held. - */ - static char buf[2*NLM_MAXCOOKIELEN+1]; - unsigned int i, len = sizeof(buf); - char *p = buf; - - len--; /* allow for trailing \0 */ - if (len < 3) - return "???"; - for (i = 0 ; i < cookie->len ; i++) { - if (len < 2) { - strcpy(p-3, "..."); - break; - } - sprintf(p, "%02x", cookie->data[i]); - p += 2; - len -= 2; - } - *p = '\0'; - - return buf; -} -#endif - -/* - * Insert a blocked lock into the global list - */ -static void -nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when) -{ - struct nlm_block *b; - struct list_head *pos; - - dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); - if (list_empty(&block->b_list)) { - kref_get(&block->b_count); - } else { - list_del_init(&block->b_list); - } - - pos = &nlm_blocked; - if (when != NLM_NEVER) { - if ((when += jiffies) == NLM_NEVER) - when ++; - list_for_each(pos, &nlm_blocked) { - b = list_entry(pos, struct nlm_block, b_list); - if (time_after(b->b_when,when) || b->b_when == NLM_NEVER) - break; - } - /* On normal exit from the loop, pos == &nlm_blocked, - * so we will be adding to the end of the list - good - */ - } - - list_add_tail(&block->b_list, pos); - block->b_when = when; -} - -static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when) -{ - spin_lock(&nlm_blocked_lock); - nlmsvc_insert_block_locked(block, when); - spin_unlock(&nlm_blocked_lock); -} - -/* - * Remove a block from the global list - */ -static inline void -nlmsvc_remove_block(struct nlm_block *block) -{ - if (!list_empty(&block->b_list)) { - spin_lock(&nlm_blocked_lock); - list_del_init(&block->b_list); - spin_unlock(&nlm_blocked_lock); - nlmsvc_release_block(block); - } -} - -/* - * Find a block for a given lock - */ -static struct nlm_block * -nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock) -{ - struct nlm_block *block; - struct file_lock *fl; - - dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", - file, lock->fl.fl_pid, - (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end, lock->fl.fl_type); - list_for_each_entry(block, &nlm_blocked, b_list) { - fl = &block->b_call->a_args.lock.fl; - dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", - block->b_file, fl->fl_pid, - (long long)fl->fl_start, - (long long)fl->fl_end, fl->fl_type, - nlmdbg_cookie2a(&block->b_call->a_args.cookie)); - if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { - kref_get(&block->b_count); - return block; - } - } - - return NULL; -} - -static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) -{ - if (a->len != b->len) - return 0; - if (memcmp(a->data, b->data, a->len)) - return 0; - return 1; -} - -/* - * Find a block with a given NLM cookie. - */ -static inline struct nlm_block * -nlmsvc_find_block(struct nlm_cookie *cookie) -{ - struct nlm_block *block; - - list_for_each_entry(block, &nlm_blocked, b_list) { - if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)) - goto found; - } - - return NULL; - -found: - dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block); - kref_get(&block->b_count); - return block; -} - -/* - * Create a block and initialize it. - * - * Note: we explicitly set the cookie of the grant reply to that of - * the blocked lock request. The spec explicitly mentions that the client - * should _not_ rely on the callback containing the same cookie as the - * request, but (as I found out later) that's because some implementations - * do just this. Never mind the standards comittees, they support our - * logging industries. - * - * 10 years later: I hope we can safely ignore these old and broken - * clients by now. Let's fix this so we can uniquely identify an incoming - * GRANTED_RES message by cookie, without having to rely on the client's IP - * address. --okir - */ -static struct nlm_block * -nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host, - struct nlm_file *file, struct nlm_lock *lock, - struct nlm_cookie *cookie) -{ - struct nlm_block *block; - struct nlm_rqst *call = NULL; - - nlm_get_host(host); - call = nlm_alloc_call(host); - if (call == NULL) - return NULL; - - /* Allocate memory for block, and initialize arguments */ - block = kzalloc(sizeof(*block), GFP_KERNEL); - if (block == NULL) - goto failed; - kref_init(&block->b_count); - INIT_LIST_HEAD(&block->b_list); - INIT_LIST_HEAD(&block->b_flist); - - if (!nlmsvc_setgrantargs(call, lock)) - goto failed_free; - - /* Set notifier function for VFS, and init args */ - call->a_args.lock.fl.fl_flags |= FL_SLEEP; - call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; - nlmclnt_next_cookie(&call->a_args.cookie); - - dprintk("lockd: created block %p...\n", block); - - /* Create and initialize the block */ - block->b_daemon = rqstp->rq_server; - block->b_host = host; - block->b_file = file; - block->b_fl = NULL; - file->f_count++; - - /* Add to file's list of blocks */ - list_add(&block->b_flist, &file->f_blocks); - - /* Set up RPC arguments for callback */ - block->b_call = call; - call->a_flags = RPC_TASK_ASYNC; - call->a_block = block; - - return block; - -failed_free: - kfree(block); -failed: - nlmsvc_release_call(call); - return NULL; -} - -/* - * Delete a block. - * It is the caller's responsibility to check whether the file - * can be closed hereafter. - */ -static int nlmsvc_unlink_block(struct nlm_block *block) -{ - int status; - dprintk("lockd: unlinking block %p...\n", block); - - /* Remove block from list */ - status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); - nlmsvc_remove_block(block); - return status; -} - -static void nlmsvc_free_block(struct kref *kref) -{ - struct nlm_block *block = container_of(kref, struct nlm_block, b_count); - struct nlm_file *file = block->b_file; - - dprintk("lockd: freeing block %p...\n", block); - - /* Remove block from file's list of blocks */ - mutex_lock(&file->f_mutex); - list_del_init(&block->b_flist); - mutex_unlock(&file->f_mutex); - - nlmsvc_freegrantargs(block->b_call); - nlmsvc_release_call(block->b_call); - nlm_release_file(block->b_file); - kfree(block->b_fl); - kfree(block); -} - -static void nlmsvc_release_block(struct nlm_block *block) -{ - if (block != NULL) - kref_put(&block->b_count, nlmsvc_free_block); -} - -/* - * Loop over all blocks and delete blocks held by - * a matching host. - */ -void nlmsvc_traverse_blocks(struct nlm_host *host, - struct nlm_file *file, - nlm_host_match_fn_t match) -{ - struct nlm_block *block, *next; - -restart: - mutex_lock(&file->f_mutex); - list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) { - if (!match(block->b_host, host)) - continue; - /* Do not destroy blocks that are not on - * the global retry list - why? */ - if (list_empty(&block->b_list)) - continue; - kref_get(&block->b_count); - mutex_unlock(&file->f_mutex); - nlmsvc_unlink_block(block); - nlmsvc_release_block(block); - goto restart; - } - mutex_unlock(&file->f_mutex); -} - -/* - * Initialize arguments for GRANTED call. The nlm_rqst structure - * has been cleared already. - */ -static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) -{ - locks_copy_lock(&call->a_args.lock.fl, &lock->fl); - memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); - call->a_args.lock.caller = utsname()->nodename; - call->a_args.lock.oh.len = lock->oh.len; - - /* set default data area */ - call->a_args.lock.oh.data = call->a_owner; - call->a_args.lock.svid = lock->fl.fl_pid; - - if (lock->oh.len > NLMCLNT_OHSIZE) { - void *data = kmalloc(lock->oh.len, GFP_KERNEL); - if (!data) - return 0; - call->a_args.lock.oh.data = (u8 *) data; - } - - memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); - return 1; -} - -static void nlmsvc_freegrantargs(struct nlm_rqst *call) -{ - if (call->a_args.lock.oh.data != call->a_owner) - kfree(call->a_args.lock.oh.data); - - locks_release_private(&call->a_args.lock.fl); -} - -/* - * Deferred lock request handling for non-blocking lock - */ -static __be32 -nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block) -{ - __be32 status = nlm_lck_denied_nolocks; - - block->b_flags |= B_QUEUED; - - nlmsvc_insert_block(block, NLM_TIMEOUT); - - block->b_cache_req = &rqstp->rq_chandle; - if (rqstp->rq_chandle.defer) { - block->b_deferred_req = - rqstp->rq_chandle.defer(block->b_cache_req); - if (block->b_deferred_req != NULL) - status = nlm_drop_reply; - } - dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n", - block, block->b_flags, ntohl(status)); - - return status; -} - -/* - * Attempt to establish a lock, and if it can't be granted, block it - * if required. - */ -__be32 -nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, - struct nlm_host *host, struct nlm_lock *lock, int wait, - struct nlm_cookie *cookie, int reclaim) -{ - struct nlm_block *block = NULL; - int error; - __be32 ret; - - dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", - file->f_file->f_path.dentry->d_inode->i_sb->s_id, - file->f_file->f_path.dentry->d_inode->i_ino, - lock->fl.fl_type, lock->fl.fl_pid, - (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end, - wait); - - /* Lock file against concurrent access */ - mutex_lock(&file->f_mutex); - /* Get existing block (in case client is busy-waiting) - * or create new block - */ - block = nlmsvc_lookup_block(file, lock); - if (block == NULL) { - block = nlmsvc_create_block(rqstp, host, file, lock, cookie); - ret = nlm_lck_denied_nolocks; - if (block == NULL) - goto out; - lock = &block->b_call->a_args.lock; - } else - lock->fl.fl_flags &= ~FL_SLEEP; - - if (block->b_flags & B_QUEUED) { - dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n", - block, block->b_flags); - if (block->b_granted) { - nlmsvc_unlink_block(block); - ret = nlm_granted; - goto out; - } - if (block->b_flags & B_TIMED_OUT) { - nlmsvc_unlink_block(block); - ret = nlm_lck_denied; - goto out; - } - ret = nlm_drop_reply; - goto out; - } - - if (locks_in_grace() && !reclaim) { - ret = nlm_lck_denied_grace_period; - goto out; - } - if (reclaim && !locks_in_grace()) { - ret = nlm_lck_denied_grace_period; - goto out; - } - - if (!wait) - lock->fl.fl_flags &= ~FL_SLEEP; - error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); - lock->fl.fl_flags &= ~FL_SLEEP; - - dprintk("lockd: vfs_lock_file returned %d\n", error); - switch (error) { - case 0: - ret = nlm_granted; - goto out; - case -EAGAIN: - /* - * If this is a blocking request for an - * already pending lock request then we need - * to put it back on lockd's block list - */ - if (wait) - break; - ret = nlm_lck_denied; - goto out; - case FILE_LOCK_DEFERRED: - if (wait) - break; - /* Filesystem lock operation is in progress - Add it to the queue waiting for callback */ - ret = nlmsvc_defer_lock_rqst(rqstp, block); - goto out; - case -EDEADLK: - ret = nlm_deadlock; - goto out; - default: /* includes ENOLCK */ - ret = nlm_lck_denied_nolocks; - goto out; - } - - ret = nlm_lck_blocked; - - /* Append to list of blocked */ - nlmsvc_insert_block(block, NLM_NEVER); -out: - mutex_unlock(&file->f_mutex); - nlmsvc_release_block(block); - dprintk("lockd: nlmsvc_lock returned %u\n", ret); - return ret; -} - -/* - * Test for presence of a conflicting lock. - */ -__be32 -nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, - struct nlm_host *host, struct nlm_lock *lock, - struct nlm_lock *conflock, struct nlm_cookie *cookie) -{ - struct nlm_block *block = NULL; - int error; - __be32 ret; - - dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", - file->f_file->f_path.dentry->d_inode->i_sb->s_id, - file->f_file->f_path.dentry->d_inode->i_ino, - lock->fl.fl_type, - (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end); - - /* Get existing block (in case client is busy-waiting) */ - block = nlmsvc_lookup_block(file, lock); - - if (block == NULL) { - struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL); - - if (conf == NULL) - return nlm_granted; - block = nlmsvc_create_block(rqstp, host, file, lock, cookie); - if (block == NULL) { - kfree(conf); - return nlm_granted; - } - block->b_fl = conf; - } - if (block->b_flags & B_QUEUED) { - dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n", - block, block->b_flags, block->b_fl); - if (block->b_flags & B_TIMED_OUT) { - nlmsvc_unlink_block(block); - ret = nlm_lck_denied; - goto out; - } - if (block->b_flags & B_GOT_CALLBACK) { - nlmsvc_unlink_block(block); - if (block->b_fl != NULL - && block->b_fl->fl_type != F_UNLCK) { - lock->fl = *block->b_fl; - goto conf_lock; - } else { - ret = nlm_granted; - goto out; - } - } - ret = nlm_drop_reply; - goto out; - } - - if (locks_in_grace()) { - ret = nlm_lck_denied_grace_period; - goto out; - } - error = vfs_test_lock(file->f_file, &lock->fl); - if (error == FILE_LOCK_DEFERRED) { - ret = nlmsvc_defer_lock_rqst(rqstp, block); - goto out; - } - if (error) { - ret = nlm_lck_denied_nolocks; - goto out; - } - if (lock->fl.fl_type == F_UNLCK) { - ret = nlm_granted; - goto out; - } - -conf_lock: - dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", - lock->fl.fl_type, (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end); - conflock->caller = "somehost"; /* FIXME */ - conflock->len = strlen(conflock->caller); - conflock->oh.len = 0; /* don't return OH info */ - conflock->svid = lock->fl.fl_pid; - conflock->fl.fl_type = lock->fl.fl_type; - conflock->fl.fl_start = lock->fl.fl_start; - conflock->fl.fl_end = lock->fl.fl_end; - ret = nlm_lck_denied; -out: - if (block) - nlmsvc_release_block(block); - return ret; -} - -/* - * Remove a lock. - * This implies a CANCEL call: We send a GRANT_MSG, the client replies - * with a GRANT_RES call which gets lost, and calls UNLOCK immediately - * afterwards. In this case the block will still be there, and hence - * must be removed. - */ -__be32 -nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) -{ - int error; - - dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", - file->f_file->f_path.dentry->d_inode->i_sb->s_id, - file->f_file->f_path.dentry->d_inode->i_ino, - lock->fl.fl_pid, - (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end); - - /* First, cancel any lock that might be there */ - nlmsvc_cancel_blocked(file, lock); - - lock->fl.fl_type = F_UNLCK; - error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); - - return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; -} - -/* - * Cancel a previously blocked request. - * - * A cancel request always overrides any grant that may currently - * be in progress. - * The calling procedure must check whether the file can be closed. - */ -__be32 -nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) -{ - struct nlm_block *block; - int status = 0; - - dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", - file->f_file->f_path.dentry->d_inode->i_sb->s_id, - file->f_file->f_path.dentry->d_inode->i_ino, - lock->fl.fl_pid, - (long long)lock->fl.fl_start, - (long long)lock->fl.fl_end); - - if (locks_in_grace()) - return nlm_lck_denied_grace_period; - - mutex_lock(&file->f_mutex); - block = nlmsvc_lookup_block(file, lock); - mutex_unlock(&file->f_mutex); - if (block != NULL) { - vfs_cancel_lock(block->b_file->f_file, - &block->b_call->a_args.lock.fl); - status = nlmsvc_unlink_block(block); - nlmsvc_release_block(block); - } - return status ? nlm_lck_denied : nlm_granted; -} - -/* - * This is a callback from the filesystem for VFS file lock requests. - * It will be used if lm_grant is defined and the filesystem can not - * respond to the request immediately. - * For GETLK request it will copy the reply to the nlm_block. - * For SETLK or SETLKW request it will get the local posix lock. - * In all cases it will move the block to the head of nlm_blocked q where - * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the - * deferred rpc for GETLK and SETLK. - */ -static void -nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf, - int result) -{ - block->b_flags |= B_GOT_CALLBACK; - if (result == 0) - block->b_granted = 1; - else - block->b_flags |= B_TIMED_OUT; - if (conf) { - if (block->b_fl) - __locks_copy_lock(block->b_fl, conf); - } -} - -static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf, - int result) -{ - struct nlm_block *block; - int rc = -ENOENT; - - spin_lock(&nlm_blocked_lock); - list_for_each_entry(block, &nlm_blocked, b_list) { - if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { - dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n", - block, block->b_flags); - if (block->b_flags & B_QUEUED) { - if (block->b_flags & B_TIMED_OUT) { - rc = -ENOLCK; - break; - } - nlmsvc_update_deferred_block(block, conf, result); - } else if (result == 0) - block->b_granted = 1; - - nlmsvc_insert_block_locked(block, 0); - svc_wake_up(block->b_daemon); - rc = 0; - break; - } - } - spin_unlock(&nlm_blocked_lock); - if (rc == -ENOENT) - printk(KERN_WARNING "lockd: grant for unknown block\n"); - return rc; -} - -/* - * Unblock a blocked lock request. This is a callback invoked from the - * VFS layer when a lock on which we blocked is removed. - * - * This function doesn't grant the blocked lock instantly, but rather moves - * the block to the head of nlm_blocked where it can be picked up by lockd. - */ -static void -nlmsvc_notify_blocked(struct file_lock *fl) -{ - struct nlm_block *block; - - dprintk("lockd: VFS unblock notification for block %p\n", fl); - spin_lock(&nlm_blocked_lock); - list_for_each_entry(block, &nlm_blocked, b_list) { - if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { - nlmsvc_insert_block_locked(block, 0); - spin_unlock(&nlm_blocked_lock); - svc_wake_up(block->b_daemon); - return; - } - } - spin_unlock(&nlm_blocked_lock); - printk(KERN_WARNING "lockd: notification for unknown block!\n"); -} - -static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) -{ - return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; -} - -const struct lock_manager_operations nlmsvc_lock_operations = { - .lm_compare_owner = nlmsvc_same_owner, - .lm_notify = nlmsvc_notify_blocked, - .lm_grant = nlmsvc_grant_deferred, -}; - -/* - * Try to claim a lock that was previously blocked. - * - * Note that we use both the RPC_GRANTED_MSG call _and_ an async - * RPC thread when notifying the client. This seems like overkill... - * Here's why: - * - we don't want to use a synchronous RPC thread, otherwise - * we might find ourselves hanging on a dead portmapper. - * - Some lockd implementations (e.g. HP) don't react to - * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. - */ -static void -nlmsvc_grant_blocked(struct nlm_block *block) -{ - struct nlm_file *file = block->b_file; - struct nlm_lock *lock = &block->b_call->a_args.lock; - int error; - - dprintk("lockd: grant blocked lock %p\n", block); - - kref_get(&block->b_count); - - /* Unlink block request from list */ - nlmsvc_unlink_block(block); - - /* If b_granted is true this means we've been here before. - * Just retry the grant callback, possibly refreshing the RPC - * binding */ - if (block->b_granted) { - nlm_rebind_host(block->b_host); - goto callback; - } - - /* Try the lock operation again */ - lock->fl.fl_flags |= FL_SLEEP; - error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); - lock->fl.fl_flags &= ~FL_SLEEP; - - switch (error) { - case 0: - break; - case FILE_LOCK_DEFERRED: - dprintk("lockd: lock still blocked error %d\n", error); - nlmsvc_insert_block(block, NLM_NEVER); - nlmsvc_release_block(block); - return; - default: - printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", - -error, __func__); - nlmsvc_insert_block(block, 10 * HZ); - nlmsvc_release_block(block); - return; - } - -callback: - /* Lock was granted by VFS. */ - dprintk("lockd: GRANTing blocked lock.\n"); - block->b_granted = 1; - - /* keep block on the list, but don't reattempt until the RPC - * completes or the submission fails - */ - nlmsvc_insert_block(block, NLM_NEVER); - - /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked - * will queue up a new one if this one times out - */ - error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, - &nlmsvc_grant_ops); - - /* RPC submission failed, wait a bit and retry */ - if (error < 0) - nlmsvc_insert_block(block, 10 * HZ); -} - -/* - * This is the callback from the RPC layer when the NLM_GRANTED_MSG - * RPC call has succeeded or timed out. - * Like all RPC callbacks, it is invoked by the rpciod process, so it - * better not sleep. Therefore, we put the blocked lock on the nlm_blocked - * chain once more in order to have it removed by lockd itself (which can - * then sleep on the file semaphore without disrupting e.g. the nfs client). - */ -static void nlmsvc_grant_callback(struct rpc_task *task, void *data) -{ - struct nlm_rqst *call = data; - struct nlm_block *block = call->a_block; - unsigned long timeout; - - dprintk("lockd: GRANT_MSG RPC callback\n"); - - spin_lock(&nlm_blocked_lock); - /* if the block is not on a list at this point then it has - * been invalidated. Don't try to requeue it. - * - * FIXME: it's possible that the block is removed from the list - * after this check but before the nlmsvc_insert_block. In that - * case it will be added back. Perhaps we need better locking - * for nlm_blocked? - */ - if (list_empty(&block->b_list)) - goto out; - - /* Technically, we should down the file semaphore here. Since we - * move the block towards the head of the queue only, no harm - * can be done, though. */ - if (task->tk_status < 0) { - /* RPC error: Re-insert for retransmission */ - timeout = 10 * HZ; - } else { - /* Call was successful, now wait for client callback */ - timeout = 60 * HZ; - } - nlmsvc_insert_block_locked(block, timeout); - svc_wake_up(block->b_daemon); -out: - spin_unlock(&nlm_blocked_lock); -} - -/* - * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an - * .rpc_release rpc_call_op - */ -static void nlmsvc_grant_release(void *data) -{ - struct nlm_rqst *call = data; - nlmsvc_release_block(call->a_block); -} - -static const struct rpc_call_ops nlmsvc_grant_ops = { - .rpc_call_done = nlmsvc_grant_callback, - .rpc_release = nlmsvc_grant_release, -}; - -/* - * We received a GRANT_RES callback. Try to find the corresponding - * block. - */ -void -nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status) -{ - struct nlm_block *block; - - dprintk("grant_reply: looking for cookie %x, s=%d \n", - *(unsigned int *)(cookie->data), status); - if (!(block = nlmsvc_find_block(cookie))) - return; - - if (block) { - if (status == nlm_lck_denied_grace_period) { - /* Try again in a couple of seconds */ - nlmsvc_insert_block(block, 10 * HZ); - } else { - /* Lock is now held by client, or has been rejected. - * In both cases, the block should be removed. */ - nlmsvc_unlink_block(block); - } - } - nlmsvc_release_block(block); -} - -/* Helper function to handle retry of a deferred block. - * If it is a blocking lock, call grant_blocked. - * For a non-blocking lock or test lock, revisit the request. - */ -static void -retry_deferred_block(struct nlm_block *block) -{ - if (!(block->b_flags & B_GOT_CALLBACK)) - block->b_flags |= B_TIMED_OUT; - nlmsvc_insert_block(block, NLM_TIMEOUT); - dprintk("revisit block %p flags %d\n", block, block->b_flags); - if (block->b_deferred_req) { - block->b_deferred_req->revisit(block->b_deferred_req, 0); - block->b_deferred_req = NULL; - } -} - -/* - * Retry all blocked locks that have been notified. This is where lockd - * picks up locks that can be granted, or grant notifications that must - * be retransmitted. - */ -unsigned long -nlmsvc_retry_blocked(void) -{ - unsigned long timeout = MAX_SCHEDULE_TIMEOUT; - struct nlm_block *block; - - while (!list_empty(&nlm_blocked) && !kthread_should_stop()) { - block = list_entry(nlm_blocked.next, struct nlm_block, b_list); - - if (block->b_when == NLM_NEVER) - break; - if (time_after(block->b_when, jiffies)) { - timeout = block->b_when - jiffies; - break; - } - - dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", - block, block->b_when); - if (block->b_flags & B_QUEUED) { - dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n", - block, block->b_granted, block->b_flags); - retry_deferred_block(block); - } else - nlmsvc_grant_blocked(block); - } - - return timeout; -} |