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-rw-r--r--fs/afs/flock.c881
1 files changed, 881 insertions, 0 deletions
diff --git a/fs/afs/flock.c b/fs/afs/flock.c
new file mode 100644
index 000000000..466ad609f
--- /dev/null
+++ b/fs/afs/flock.c
@@ -0,0 +1,881 @@
+// 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);
+
+ /* AFS doesn't support mandatory locks */
+ if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
+ return -ENOLCK;
+
+ 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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 16:17:52 +0000