From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/afs/flock.c | 877 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 877 insertions(+) create mode 100644 fs/afs/flock.c (limited to 'fs/afs/flock.c') diff --git a/fs/afs/flock.c b/fs/afs/flock.c new file mode 100644 index 000000000..bbcc5afd1 --- /dev/null +++ b/fs/afs/flock.c @@ -0,0 +1,877 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS file locking support + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include "internal.h" + +#define AFS_LOCK_GRANTED 0 +#define AFS_LOCK_PENDING 1 +#define AFS_LOCK_YOUR_TRY 2 + +struct workqueue_struct *afs_lock_manager; + +static void afs_next_locker(struct afs_vnode *vnode, int error); +static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); +static void afs_fl_release_private(struct file_lock *fl); + +static const struct file_lock_operations afs_lock_ops = { + .fl_copy_lock = afs_fl_copy_lock, + .fl_release_private = afs_fl_release_private, +}; + +static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state) +{ + _debug("STATE %u -> %u", vnode->lock_state, state); + vnode->lock_state = state; +} + +static atomic_t afs_file_lock_debug_id; + +/* + * if the callback is broken on this vnode, then the lock may now be available + */ +void afs_lock_may_be_available(struct afs_vnode *vnode) +{ + _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); + + spin_lock(&vnode->lock); + if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) + afs_next_locker(vnode, 0); + trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0); + spin_unlock(&vnode->lock); +} + +/* + * the lock will time out in 5 minutes unless we extend it, so schedule + * extension in a bit less than that time + */ +static void afs_schedule_lock_extension(struct afs_vnode *vnode) +{ + ktime_t expires_at, now, duration; + u64 duration_j; + + expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2); + now = ktime_get_real(); + duration = ktime_sub(expires_at, now); + if (duration <= 0) + duration_j = 0; + else + duration_j = nsecs_to_jiffies(ktime_to_ns(duration)); + + queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j); +} + +/* + * In the case of successful completion of a lock operation, record the time + * the reply appeared and start the lock extension timer. + */ +void afs_lock_op_done(struct afs_call *call) +{ + struct afs_operation *op = call->op; + struct afs_vnode *vnode = op->file[0].vnode; + + if (call->error == 0) { + spin_lock(&vnode->lock); + trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0); + vnode->locked_at = call->issue_time; + afs_schedule_lock_extension(vnode); + spin_unlock(&vnode->lock); + } +} + +/* + * grant one or more locks (readlocks are allowed to jump the queue if the + * first lock in the queue is itself a readlock) + * - the caller must hold the vnode lock + */ +static void afs_grant_locks(struct afs_vnode *vnode) +{ + struct file_lock *p, *_p; + bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); + + list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { + if (!exclusive && p->fl_type == F_WRLCK) + continue; + + list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks); + p->fl_u.afs.state = AFS_LOCK_GRANTED; + trace_afs_flock_op(vnode, p, afs_flock_op_grant); + wake_up(&p->fl_wait); + } +} + +/* + * If an error is specified, reject every pending lock that matches the + * authentication and type of the lock we failed to get. If there are any + * remaining lockers, try to wake up one of them to have a go. + */ +static void afs_next_locker(struct afs_vnode *vnode, int error) +{ + struct file_lock *p, *_p, *next = NULL; + struct key *key = vnode->lock_key; + unsigned int fl_type = F_RDLCK; + + _enter(""); + + if (vnode->lock_type == AFS_LOCK_WRITE) + fl_type = F_WRLCK; + + list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { + if (error && + p->fl_type == fl_type && + afs_file_key(p->fl_file) == key) { + list_del_init(&p->fl_u.afs.link); + p->fl_u.afs.state = error; + wake_up(&p->fl_wait); + } + + /* Select the next locker to hand off to. */ + if (next && + (next->fl_type == F_WRLCK || p->fl_type == F_RDLCK)) + continue; + next = p; + } + + vnode->lock_key = NULL; + key_put(key); + + if (next) { + afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); + next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; + trace_afs_flock_op(vnode, next, afs_flock_op_wake); + wake_up(&next->fl_wait); + } else { + afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE); + trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0); + } + + _leave(""); +} + +/* + * Kill off all waiters in the the pending lock queue due to the vnode being + * deleted. + */ +static void afs_kill_lockers_enoent(struct afs_vnode *vnode) +{ + struct file_lock *p; + + afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED); + + while (!list_empty(&vnode->pending_locks)) { + p = list_entry(vnode->pending_locks.next, + struct file_lock, fl_u.afs.link); + list_del_init(&p->fl_u.afs.link); + p->fl_u.afs.state = -ENOENT; + wake_up(&p->fl_wait); + } + + key_put(vnode->lock_key); + vnode->lock_key = NULL; +} + +static void afs_lock_success(struct afs_operation *op) +{ + _enter("op=%08x", op->debug_id); + afs_vnode_commit_status(op, &op->file[0]); +} + +static const struct afs_operation_ops afs_set_lock_operation = { + .issue_afs_rpc = afs_fs_set_lock, + .issue_yfs_rpc = yfs_fs_set_lock, + .success = afs_lock_success, + .aborted = afs_check_for_remote_deletion, +}; + +/* + * Get a lock on a file + */ +static int afs_set_lock(struct afs_vnode *vnode, struct key *key, + afs_lock_type_t type) +{ + struct afs_operation *op; + + _enter("%s{%llx:%llu.%u},%x,%u", + vnode->volume->name, + vnode->fid.vid, + vnode->fid.vnode, + vnode->fid.unique, + key_serial(key), type); + + op = afs_alloc_operation(key, vnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + afs_op_set_vnode(op, 0, vnode); + + op->lock.type = type; + op->ops = &afs_set_lock_operation; + return afs_do_sync_operation(op); +} + +static const struct afs_operation_ops afs_extend_lock_operation = { + .issue_afs_rpc = afs_fs_extend_lock, + .issue_yfs_rpc = yfs_fs_extend_lock, + .success = afs_lock_success, +}; + +/* + * Extend a lock on a file + */ +static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) +{ + struct afs_operation *op; + + _enter("%s{%llx:%llu.%u},%x", + vnode->volume->name, + vnode->fid.vid, + vnode->fid.vnode, + vnode->fid.unique, + key_serial(key)); + + op = afs_alloc_operation(key, vnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + afs_op_set_vnode(op, 0, vnode); + + op->flags |= AFS_OPERATION_UNINTR; + op->ops = &afs_extend_lock_operation; + return afs_do_sync_operation(op); +} + +static const struct afs_operation_ops afs_release_lock_operation = { + .issue_afs_rpc = afs_fs_release_lock, + .issue_yfs_rpc = yfs_fs_release_lock, + .success = afs_lock_success, +}; + +/* + * Release a lock on a file + */ +static int afs_release_lock(struct afs_vnode *vnode, struct key *key) +{ + struct afs_operation *op; + + _enter("%s{%llx:%llu.%u},%x", + vnode->volume->name, + vnode->fid.vid, + vnode->fid.vnode, + vnode->fid.unique, + key_serial(key)); + + op = afs_alloc_operation(key, vnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + afs_op_set_vnode(op, 0, vnode); + + op->flags |= AFS_OPERATION_UNINTR; + op->ops = &afs_release_lock_operation; + return afs_do_sync_operation(op); +} + +/* + * do work for a lock, including: + * - probing for a lock we're waiting on but didn't get immediately + * - extending a lock that's close to timing out + */ +void afs_lock_work(struct work_struct *work) +{ + struct afs_vnode *vnode = + container_of(work, struct afs_vnode, lock_work.work); + struct key *key; + int ret; + + _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); + + spin_lock(&vnode->lock); + +again: + _debug("wstate %u for %p", vnode->lock_state, vnode); + switch (vnode->lock_state) { + case AFS_VNODE_LOCK_NEED_UNLOCK: + afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING); + trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0); + spin_unlock(&vnode->lock); + + /* attempt to release the server lock; if it fails, we just + * wait 5 minutes and it'll expire anyway */ + ret = afs_release_lock(vnode, vnode->lock_key); + if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { + trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail, + ret); + printk(KERN_WARNING "AFS:" + " Failed to release lock on {%llx:%llx} error %d\n", + vnode->fid.vid, vnode->fid.vnode, ret); + } + + spin_lock(&vnode->lock); + if (ret == -ENOENT) + afs_kill_lockers_enoent(vnode); + else + afs_next_locker(vnode, 0); + spin_unlock(&vnode->lock); + return; + + /* If we've already got a lock, then it must be time to extend that + * lock as AFS locks time out after 5 minutes. + */ + case AFS_VNODE_LOCK_GRANTED: + _debug("extend"); + + ASSERT(!list_empty(&vnode->granted_locks)); + + key = key_get(vnode->lock_key); + afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING); + trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0); + spin_unlock(&vnode->lock); + + ret = afs_extend_lock(vnode, key); /* RPC */ + key_put(key); + + if (ret < 0) { + trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail, + ret); + pr_warn("AFS: Failed to extend lock on {%llx:%llx} error %d\n", + vnode->fid.vid, vnode->fid.vnode, ret); + } + + spin_lock(&vnode->lock); + + if (ret == -ENOENT) { + afs_kill_lockers_enoent(vnode); + spin_unlock(&vnode->lock); + return; + } + + if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) + goto again; + afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); + + if (ret != 0) + queue_delayed_work(afs_lock_manager, &vnode->lock_work, + HZ * 10); + spin_unlock(&vnode->lock); + _leave(" [ext]"); + return; + + /* If we're waiting for a callback to indicate lock release, we can't + * actually rely on this, so need to recheck at regular intervals. The + * problem is that the server might not notify us if the lock just + * expires (say because a client died) rather than being explicitly + * released. + */ + case AFS_VNODE_LOCK_WAITING_FOR_CB: + _debug("retry"); + afs_next_locker(vnode, 0); + spin_unlock(&vnode->lock); + return; + + case AFS_VNODE_LOCK_DELETED: + afs_kill_lockers_enoent(vnode); + spin_unlock(&vnode->lock); + return; + + default: + /* Looks like a lock request was withdrawn. */ + spin_unlock(&vnode->lock); + _leave(" [no]"); + return; + } +} + +/* + * pass responsibility for the unlocking of a vnode on the server to the + * manager thread, lest a pending signal in the calling thread interrupt + * AF_RXRPC + * - the caller must hold the vnode lock + */ +static void afs_defer_unlock(struct afs_vnode *vnode) +{ + _enter("%u", vnode->lock_state); + + if (list_empty(&vnode->granted_locks) && + (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || + vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { + cancel_delayed_work(&vnode->lock_work); + + afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK); + trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0); + queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); + } +} + +/* + * Check that our view of the file metadata is up to date and check to see + * whether we think that we have a locking permit. + */ +static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, + enum afs_flock_mode mode, afs_lock_type_t type) +{ + afs_access_t access; + int ret; + + /* Make sure we've got a callback on this file and that our view of the + * data version is up to date. + */ + ret = afs_validate(vnode, key); + if (ret < 0) + return ret; + + /* Check the permission set to see if we're actually going to be + * allowed to get a lock on this file. + */ + ret = afs_check_permit(vnode, key, &access); + if (ret < 0) + return ret; + + /* At a rough estimation, you need LOCK, WRITE or INSERT perm to + * read-lock a file and WRITE or INSERT perm to write-lock a file. + * + * We can't rely on the server to do this for us since if we want to + * share a read lock that we already have, we won't go the server. + */ + if (type == AFS_LOCK_READ) { + if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) + return -EACCES; + } else { + if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) + return -EACCES; + } + + return 0; +} + +/* + * request a lock on a file on the server + */ +static int afs_do_setlk(struct file *file, struct file_lock *fl) +{ + struct inode *inode = locks_inode(file); + struct afs_vnode *vnode = AFS_FS_I(inode); + enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode; + afs_lock_type_t type; + struct key *key = afs_file_key(file); + bool partial, no_server_lock = false; + int ret; + + if (mode == afs_flock_mode_unset) + mode = afs_flock_mode_openafs; + + _enter("{%llx:%llu},%llu-%llu,%u,%u", + vnode->fid.vid, vnode->fid.vnode, + fl->fl_start, fl->fl_end, fl->fl_type, mode); + + fl->fl_ops = &afs_lock_ops; + INIT_LIST_HEAD(&fl->fl_u.afs.link); + fl->fl_u.afs.state = AFS_LOCK_PENDING; + + partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); + type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; + if (mode == afs_flock_mode_write && partial) + type = AFS_LOCK_WRITE; + + ret = afs_do_setlk_check(vnode, key, mode, type); + if (ret < 0) + return ret; + + trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock); + + /* AFS3 protocol only supports full-file locks and doesn't provide any + * method of upgrade/downgrade, so we need to emulate for partial-file + * locks. + * + * The OpenAFS client only gets a server lock for a full-file lock and + * keeps partial-file locks local. Allow this behaviour to be emulated + * (as the default). + */ + if (mode == afs_flock_mode_local || + (partial && mode == afs_flock_mode_openafs)) { + no_server_lock = true; + goto skip_server_lock; + } + + spin_lock(&vnode->lock); + list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); + + ret = -ENOENT; + if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) + goto error_unlock; + + /* If we've already got a lock on the server then try to move to having + * the VFS grant the requested lock. Note that this means that other + * clients may get starved out. + */ + _debug("try %u", vnode->lock_state); + if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { + if (type == AFS_LOCK_READ) { + _debug("instant readlock"); + list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); + fl->fl_u.afs.state = AFS_LOCK_GRANTED; + goto vnode_is_locked_u; + } + + if (vnode->lock_type == AFS_LOCK_WRITE) { + _debug("instant writelock"); + list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); + fl->fl_u.afs.state = AFS_LOCK_GRANTED; + goto vnode_is_locked_u; + } + } + + if (vnode->lock_state == AFS_VNODE_LOCK_NONE && + !(fl->fl_flags & FL_SLEEP)) { + ret = -EAGAIN; + if (type == AFS_LOCK_READ) { + if (vnode->status.lock_count == -1) + goto lock_is_contended; /* Write locked */ + } else { + if (vnode->status.lock_count != 0) + goto lock_is_contended; /* Locked */ + } + } + + if (vnode->lock_state != AFS_VNODE_LOCK_NONE) + goto need_to_wait; + +try_to_lock: + /* We don't have a lock on this vnode and we aren't currently waiting + * for one either, so ask the server for a lock. + * + * Note that we need to be careful if we get interrupted by a signal + * after dispatching the request as we may still get the lock, even + * though we don't wait for the reply (it's not too bad a problem - the + * lock will expire in 5 mins anyway). + */ + trace_afs_flock_ev(vnode, fl, afs_flock_try_to_lock, 0); + vnode->lock_key = key_get(key); + vnode->lock_type = type; + afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); + spin_unlock(&vnode->lock); + + ret = afs_set_lock(vnode, key, type); /* RPC */ + + spin_lock(&vnode->lock); + switch (ret) { + case -EKEYREJECTED: + case -EKEYEXPIRED: + case -EKEYREVOKED: + case -EPERM: + case -EACCES: + fl->fl_u.afs.state = ret; + trace_afs_flock_ev(vnode, fl, afs_flock_fail_perm, ret); + list_del_init(&fl->fl_u.afs.link); + afs_next_locker(vnode, ret); + goto error_unlock; + + case -ENOENT: + fl->fl_u.afs.state = ret; + trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); + list_del_init(&fl->fl_u.afs.link); + afs_kill_lockers_enoent(vnode); + goto error_unlock; + + default: + fl->fl_u.afs.state = ret; + trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); + list_del_init(&fl->fl_u.afs.link); + afs_next_locker(vnode, 0); + goto error_unlock; + + case -EWOULDBLOCK: + /* The server doesn't have a lock-waiting queue, so the client + * will have to retry. The server will break the outstanding + * callbacks on a file when a lock is released. + */ + ASSERT(list_empty(&vnode->granted_locks)); + ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); + goto lock_is_contended; + + case 0: + afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); + trace_afs_flock_ev(vnode, fl, afs_flock_acquired, type); + afs_grant_locks(vnode); + goto vnode_is_locked_u; + } + +vnode_is_locked_u: + spin_unlock(&vnode->lock); +vnode_is_locked: + /* the lock has been granted by the server... */ + ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED); + +skip_server_lock: + /* ... but the VFS still needs to distribute access on this client. */ + trace_afs_flock_ev(vnode, fl, afs_flock_vfs_locking, 0); + ret = locks_lock_file_wait(file, fl); + trace_afs_flock_ev(vnode, fl, afs_flock_vfs_lock, ret); + if (ret < 0) + goto vfs_rejected_lock; + + /* Again, make sure we've got a callback on this file and, again, make + * sure that our view of the data version is up to date (we ignore + * errors incurred here and deal with the consequences elsewhere). + */ + afs_validate(vnode, key); + _leave(" = 0"); + return 0; + +lock_is_contended: + if (!(fl->fl_flags & FL_SLEEP)) { + list_del_init(&fl->fl_u.afs.link); + afs_next_locker(vnode, 0); + ret = -EAGAIN; + goto error_unlock; + } + + afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB); + trace_afs_flock_ev(vnode, fl, afs_flock_would_block, ret); + queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5); + +need_to_wait: + /* We're going to have to wait. Either this client doesn't have a lock + * on the server yet and we need to wait for a callback to occur, or + * the client does have a lock on the server, but it's shared and we + * need an exclusive lock. + */ + spin_unlock(&vnode->lock); + + trace_afs_flock_ev(vnode, fl, afs_flock_waiting, 0); + ret = wait_event_interruptible(fl->fl_wait, + fl->fl_u.afs.state != AFS_LOCK_PENDING); + trace_afs_flock_ev(vnode, fl, afs_flock_waited, ret); + + if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) { + spin_lock(&vnode->lock); + + switch (fl->fl_u.afs.state) { + case AFS_LOCK_YOUR_TRY: + fl->fl_u.afs.state = AFS_LOCK_PENDING; + goto try_to_lock; + case AFS_LOCK_PENDING: + if (ret > 0) { + /* We need to retry the lock. We may not be + * notified by the server if it just expired + * rather than being released. + */ + ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB); + afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); + fl->fl_u.afs.state = AFS_LOCK_PENDING; + goto try_to_lock; + } + goto error_unlock; + case AFS_LOCK_GRANTED: + default: + break; + } + + spin_unlock(&vnode->lock); + } + + if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) + goto vnode_is_locked; + ret = fl->fl_u.afs.state; + goto error; + +vfs_rejected_lock: + /* The VFS rejected the lock we just obtained, so we have to discard + * what we just got. We defer this to the lock manager work item to + * deal with. + */ + _debug("vfs refused %d", ret); + if (no_server_lock) + goto error; + spin_lock(&vnode->lock); + list_del_init(&fl->fl_u.afs.link); + afs_defer_unlock(vnode); + +error_unlock: + spin_unlock(&vnode->lock); +error: + _leave(" = %d", ret); + return ret; +} + +/* + * unlock on a file on the server + */ +static int afs_do_unlk(struct file *file, struct file_lock *fl) +{ + struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); + int ret; + + _enter("{%llx:%llu},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); + + trace_afs_flock_op(vnode, fl, afs_flock_op_unlock); + + /* Flush all pending writes before doing anything with locks. */ + vfs_fsync(file, 0); + + ret = locks_lock_file_wait(file, fl); + _leave(" = %d [%u]", ret, vnode->lock_state); + return ret; +} + +/* + * return information about a lock we currently hold, if indeed we hold one + */ +static int afs_do_getlk(struct file *file, struct file_lock *fl) +{ + struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); + struct key *key = afs_file_key(file); + int ret, lock_count; + + _enter(""); + + if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) + return -ENOENT; + + fl->fl_type = F_UNLCK; + + /* check local lock records first */ + posix_test_lock(file, fl); + if (fl->fl_type == F_UNLCK) { + /* no local locks; consult the server */ + ret = afs_fetch_status(vnode, key, false, NULL); + if (ret < 0) + goto error; + + lock_count = READ_ONCE(vnode->status.lock_count); + if (lock_count != 0) { + if (lock_count > 0) + fl->fl_type = F_RDLCK; + else + fl->fl_type = F_WRLCK; + fl->fl_start = 0; + fl->fl_end = OFFSET_MAX; + fl->fl_pid = 0; + } + } + + ret = 0; +error: + _leave(" = %d [%hd]", ret, fl->fl_type); + return ret; +} + +/* + * manage POSIX locks on a file + */ +int afs_lock(struct file *file, int cmd, struct file_lock *fl) +{ + struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); + enum afs_flock_operation op; + int ret; + + _enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}", + vnode->fid.vid, vnode->fid.vnode, cmd, + fl->fl_type, fl->fl_flags, + (long long) fl->fl_start, (long long) fl->fl_end); + + if (IS_GETLK(cmd)) + return afs_do_getlk(file, fl); + + fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); + trace_afs_flock_op(vnode, fl, afs_flock_op_lock); + + if (fl->fl_type == F_UNLCK) + ret = afs_do_unlk(file, fl); + else + ret = afs_do_setlk(file, fl); + + switch (ret) { + case 0: op = afs_flock_op_return_ok; break; + case -EAGAIN: op = afs_flock_op_return_eagain; break; + case -EDEADLK: op = afs_flock_op_return_edeadlk; break; + default: op = afs_flock_op_return_error; break; + } + trace_afs_flock_op(vnode, fl, op); + return ret; +} + +/* + * manage FLOCK locks on a file + */ +int afs_flock(struct file *file, int cmd, struct file_lock *fl) +{ + struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); + enum afs_flock_operation op; + int ret; + + _enter("{%llx:%llu},%d,{t=%x,fl=%x}", + vnode->fid.vid, vnode->fid.vnode, cmd, + fl->fl_type, fl->fl_flags); + + /* + * No BSD flocks over NFS allowed. + * Note: we could try to fake a POSIX lock request here by + * using ((u32) filp | 0x80000000) or some such as the pid. + * Not sure whether that would be unique, though, or whether + * that would break in other places. + */ + if (!(fl->fl_flags & FL_FLOCK)) + return -ENOLCK; + + fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); + trace_afs_flock_op(vnode, fl, afs_flock_op_flock); + + /* we're simulating flock() locks using posix locks on the server */ + if (fl->fl_type == F_UNLCK) + ret = afs_do_unlk(file, fl); + else + ret = afs_do_setlk(file, fl); + + switch (ret) { + case 0: op = afs_flock_op_return_ok; break; + case -EAGAIN: op = afs_flock_op_return_eagain; break; + case -EDEADLK: op = afs_flock_op_return_edeadlk; break; + default: op = afs_flock_op_return_error; break; + } + trace_afs_flock_op(vnode, fl, op); + return ret; +} + +/* + * the POSIX lock management core VFS code copies the lock record and adds the + * copy into its own list, so we need to add that copy to the vnode's lock + * queue in the same place as the original (which will be deleted shortly + * after) + */ +static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) +{ + struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); + + _enter(""); + + new->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); + + spin_lock(&vnode->lock); + trace_afs_flock_op(vnode, new, afs_flock_op_copy_lock); + list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); + spin_unlock(&vnode->lock); +} + +/* + * need to remove this lock from the vnode queue when it's removed from the + * VFS's list + */ +static void afs_fl_release_private(struct file_lock *fl) +{ + struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); + + _enter(""); + + spin_lock(&vnode->lock); + + trace_afs_flock_op(vnode, fl, afs_flock_op_release_lock); + list_del_init(&fl->fl_u.afs.link); + if (list_empty(&vnode->granted_locks)) + afs_defer_unlock(vnode); + + _debug("state %u for %p", vnode->lock_state, vnode); + spin_unlock(&vnode->lock); +} -- cgit v1.2.3