[PATCH] AFS: Implement file locking

David Howells
2007-05-24T16:56:22Z

Implement file locking for AFS.

Signed-off-by: David Howells <dhowells@redhat.com>
---

fs/afs/Makefile | 1
fs/afs/afs.h | 8 +
fs/afs/afs_fs.h | 3
fs/afs/callback.c | 3
fs/afs/dir.c | 1
fs/afs/file.c | 2
fs/afs/flock.c | 558 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/afs/fsclient.c | 155 ++++++++++++++
fs/afs/internal.h | 30 +++
fs/afs/main.c | 1
fs/afs/misc.c | 1
fs/afs/super.c | 3
fs/afs/vnode.c | 130 +++++++++++-
include/linux/fs.h | 4
14 files changed, 885 insertions(+), 15 deletions(-)

diff --git a/fs/afs/Makefile b/fs/afs/Makefile
index 73ce561..a666710 100644
--- a/fs/afs/Makefile
+++ b/fs/afs/Makefile
@@ -8,6 +8,7 @@ kafs-objs := \
cmservice.o \
dir.o \
file.o \
+ flock.o \
fsclient.o \
inode.o \
main.o \
diff --git a/fs/afs/afs.h b/fs/afs/afs.h
index 2452579..c548aa3 100644
--- a/fs/afs/afs.h
+++ b/fs/afs/afs.h
@@ -37,6 +37,13 @@ typedef enum {
AFS_FTYPE_SYMLINK = 3,
} afs_file_type_t;

+typedef enum {
+ AFS_LOCK_READ = 0, /* read lock request */
+ AFS_LOCK_WRITE = 1, /* write lock request */
+} afs_lock_type_t;
+
+#define AFS_LOCKWAIT (5 * 60) /* time until a lock times out (seconds) */
+
/*
* AFS file identifier
*/
@@ -120,6 +127,7 @@ struct afs_file_status {
struct afs_fid parent; /* parent dir ID for non-dirs only */
time_t mtime_client; /* last time client changed data */
time_t mtime_server; /* last time server changed data */
+ s32 lock_count; /* file lock count (0=UNLK -1=WRLCK +ve=#RDLCK */
};

/*
diff --git a/fs/afs/afs_fs.h b/fs/afs/afs_fs.h
index a18c374..eb64732 100644
--- a/fs/afs/afs_fs.h
+++ b/fs/afs/afs_fs.h
@@ -31,6 +31,9 @@ enum AFS_FS_Operations {
FSGETVOLUMEINFO = 148, /* AFS Get information about a volume */
FSGETVOLUMESTATUS = 149, /* AFS Get volume status information */
FSGETROOTVOLUME = 151, /* AFS Get root volume name */
+ FSSETLOCK = 156, /* AFS Request a file lock */
+ FSEXTENDLOCK = 157, /* AFS Extend a file lock */
+ FSRELEASELOCK = 158, /* AFS Release a file lock */
FSLOOKUP = 161, /* AFS lookup file in directory */
FSFETCHDATA64 = 65537, /* AFS Fetch file data */
FSSTOREDATA64 = 65538, /* AFS Store file data */
diff --git a/fs/afs/callback.c b/fs/afs/callback.c
index bacf518..b824394 100644
--- a/fs/afs/callback.c
+++ b/fs/afs/callback.c
@@ -125,6 +125,9 @@ static void afs_break_callback(struct afs_server *server,
spin_unlock(&server->cb_lock);

queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
+ if (list_empty(&vnode->granted_locks) &&
+ !list_empty(&vnode->pending_locks))
+ afs_lock_may_be_available(vnode);
spin_unlock(&vnode->lock);
}
}
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 546c595..33fe39a 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -44,6 +44,7 @@ const struct file_operations afs_dir_file_operations = {
.open = afs_dir_open,
.release = afs_release,
.readdir = afs_readdir,
+ .lock = afs_lock,
};

const struct inode_operations afs_dir_inode_operations = {
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 1547500..8aaa233 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -35,6 +35,8 @@ const struct file_operations afs_file_operations = {
.mmap = afs_mmap,
.sendfile = generic_file_sendfile,
.fsync = afs_fsync,
+ .lock = afs_lock,
+ .flock = afs_flock,
};

const struct inode_operations afs_file_inode_operations = {
diff --git a/fs/afs/flock.c b/fs/afs/flock.c
new file mode 100644
index 0000000..8f07f8d
--- /dev/null
+++ b/fs/afs/flock.c
@@ -0,0 +1,558 @@
+/* AFS file locking support
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/smp_lock.h>
+#include "internal.h"
+
+#define AFS_LOCK_GRANTED 0
+#define AFS_LOCK_PENDING 1
+
+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 struct workqueue_struct *afs_lock_manager;
+
+static struct file_lock_operations afs_lock_ops = {
+ .fl_copy_lock = afs_fl_copy_lock,
+ .fl_release_private = afs_fl_release_private,
+};
+
+/*
+ * initialise the lock manager thread if it isn't already running
+ */
+static int afs_init_lock_manager(void)
+{
+ if (!afs_lock_manager) {
+ afs_lock_manager = create_singlethread_workqueue("kafs_lockd");
+ if (!afs_lock_manager)
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+/*
+ * destroy the lock manager thread if it's running
+ */
+void __exit afs_kill_lock_manager(void)
+{
+ if (afs_lock_manager)
+ destroy_workqueue(afs_lock_manager);
+}
+
+/*
+ * 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("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
+
+ queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
+}
+
+/*
+ * 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)
+{
+ queue_delayed_work(afs_lock_manager, &vnode->lock_work,
+ AFS_LOCKWAIT * HZ / 2);
+}
+
+/*
+ * 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 file_lock *fl;
+ afs_lock_type_t type;
+ struct key *key;
+ int ret;
+
+ _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
+
+ spin_lock(&vnode->lock);
+
+ if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) {
+ _debug("unlock");
+ spin_unlock(&vnode->lock);
+
+ /* attempt to release the server lock; if it fails, we just
+ * wait 5 minutes and it'll time out anyway */
+ ret = afs_vnode_release_lock(vnode, vnode->unlock_key);
+ if (ret < 0)
+ printk(KERN_WARNING "AFS:"
+ " Failed to release lock on {%x:%x} error %d\n",
+ vnode->fid.vid, vnode->fid.vnode, ret);
+
+ spin_lock(&vnode->lock);
+ key_put(vnode->unlock_key);
+ vnode->unlock_key = NULL;
+ clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags);
+ }
+
+ /* if we've got a lock, then it must be time to extend that lock as AFS
+ * locks time out after 5 minutes */
+ if (!list_empty(&vnode->granted_locks)) {
+ _debug("extend");
+
+ if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
+ BUG();
+ fl = list_entry(vnode->granted_locks.next,
+ struct file_lock, fl_u.afs.link);
+ key = key_get(fl->fl_file->private_data);
+ spin_unlock(&vnode->lock);
+
+ ret = afs_vnode_extend_lock(vnode, key);
+ clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
+ key_put(key);
+ switch (ret) {
+ case 0:
+ afs_schedule_lock_extension(vnode);
+ break;
+ default:
+ /* ummm... we failed to extend the lock - retry
+ * extension shortly */
+ printk(KERN_WARNING "AFS:"
+ " Failed to extend lock on {%x:%x} error %d\n",
+ vnode->fid.vid, vnode->fid.vnode, ret);
+ queue_delayed_work(afs_lock_manager, &vnode->lock_work,
+ HZ * 10);
+ break;
+ }
+ _leave(" [extend]");
+ return;
+ }
+
+ /* if we don't have a granted lock, then we must've been called back by
+ * the server, and so if might be possible to get a lock we're
+ * currently waiting for */
+ if (!list_empty(&vnode->pending_locks)) {
+ _debug("get");
+
+ if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
+ BUG();
+ fl = list_entry(vnode->pending_locks.next,
+ struct file_lock, fl_u.afs.link);
+ key = key_get(fl->fl_file->private_data);
+ type = (fl->fl_type == F_RDLCK) ?
+ AFS_LOCK_READ : AFS_LOCK_WRITE;
+ spin_unlock(&vnode->lock);
+
+ ret = afs_vnode_set_lock(vnode, key, type);
+ clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
+ switch (ret) {
+ case -EWOULDBLOCK:
+ _debug("blocked");
+ break;
+ case 0:
+ _debug("acquired");
+ if (type == AFS_LOCK_READ)
+ set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
+ else
+ set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
+ ret = AFS_LOCK_GRANTED;
+ default:
+ spin_lock(&vnode->lock);
+ /* the pending lock may have been withdrawn due to a
+ * signal */
+ if (list_entry(vnode->pending_locks.next,
+ struct file_lock, fl_u.afs.link) == fl) {
+ fl->fl_u.afs.state = ret;
+ if (ret == AFS_LOCK_GRANTED)
+ list_move_tail(&fl->fl_u.afs.link,
+ &vnode->granted_locks);
+ else
+ list_del_init(&fl->fl_u.afs.link);
+ wake_up(&fl->fl_wait);
+ spin_unlock(&vnode->lock);
+ } else {
+ _debug("withdrawn");
+ clear_bit(AFS_VNODE_READLOCKED, &vnode->flags);
+ clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
+ spin_unlock(&vnode->lock);
+ afs_vnode_release_lock(vnode, key);
+ if (!list_empty(&vnode->pending_locks))
+ afs_lock_may_be_available(vnode);
+ }
+ break;
+ }
+ key_put(key);
+ _leave(" [pend]");
+ return;
+ }
+
+ /* looks like the lock request was withdrawn on a signal */
+ spin_unlock(&vnode->lock);
+ _leave(" [no locks]");
+}
+
+/*
+ * 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, struct key *key)
+{
+ cancel_delayed_work(&vnode->lock_work);
+ if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) &&
+ !test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags))
+ BUG();
+ if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags))
+ BUG();
+ vnode->unlock_key = key_get(key);
+ afs_lock_may_be_available(vnode);
+}
+
+/*
+ * request a lock on a file on the server
+ */
+static int afs_do_setlk(struct file *file, struct file_lock *fl)
+{
+ struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
+ afs_lock_type_t type;
+ struct key *key = file->private_data;
+ int ret;
+
+ _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
+
+ /* only whole-file locks are supported */
+ if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
+ return -EINVAL;
+
+ ret = afs_init_lock_manager();
+ if (ret < 0)
+ return ret;
+
+ fl->fl_ops = &afs_lock_ops;
+ INIT_LIST_HEAD(&fl->fl_u.afs.link);
+ fl->fl_u.afs.state = AFS_LOCK_PENDING;
+
+ type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
+
+ lock_kernel();
+
+ /* make sure we've got a callback on this file and that our view of the
+ * data version is up to date */
+ ret = afs_vnode_fetch_status(vnode, NULL, key);
+ if (ret < 0)
+ goto error;
+
+ if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) {
+ ret = -EAGAIN;
+ goto error;
+ }
+
+ spin_lock(&vnode->lock);
+
+ if (list_empty(&vnode->pending_locks)) {
+ /* if there's no-one else with a lock on this vnode, then we
+ * need to ask the server for a lock */
+ if (list_empty(&vnode->granted_locks)) {
+ _debug("not locked");
+ ASSERTCMP(vnode->flags &
+ ((1 << AFS_VNODE_LOCKING) |
+ (1 << AFS_VNODE_READLOCKED) |
+ (1 << AFS_VNODE_WRITELOCKED)), ==, 0);
+ list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
+ set_bit(AFS_VNODE_LOCKING, &vnode->flags);
+ spin_unlock(&vnode->lock);
+
+ ret = afs_vnode_set_lock(vnode, key, type);
+ clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
+ switch (ret) {
+ case 0:
+ goto acquired_server_lock;
+ case -EWOULDBLOCK:
+ spin_lock(&vnode->lock);
+ ASSERT(list_empty(&vnode->granted_locks));
+ ASSERTCMP(vnode->pending_locks.next, ==,
+ &fl->fl_u.afs.link);
+ goto wait;
+ default:
+ spin_lock(&vnode->lock);
+ list_del_init(&fl->fl_u.afs.link);
+ spin_unlock(&vnode->lock);
+ goto error;
+ }
+ }
+
+ /* if we've already got a readlock on the server and no waiting
+ * writelocks, then we might be able to instantly grant another
+ * readlock */
+ if (type == AFS_LOCK_READ &&
+ vnode->flags & (1 << AFS_VNODE_READLOCKED)) {
+ _debug("instant readlock");
+ ASSERTCMP(vnode->flags &
+ ((1 << AFS_VNODE_LOCKING) |
+ (1 << AFS_VNODE_WRITELOCKED)), ==, 0);
+ ASSERT(!list_empty(&vnode->granted_locks));
+ goto sharing_existing_lock;
+ }
+ }
+
+ /* otherwise, we need to wait for a local lock to become available */
+ _debug("wait local");
+ list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
+wait:
+ if (!(fl->fl_flags & FL_SLEEP)) {
+ _debug("noblock");
+ ret = -EAGAIN;
+ goto abort_attempt;
+ }
+ spin_unlock(&vnode->lock);
+
+ /* now we need to sleep and wait for the lock manager thread to get the
+ * lock from the server */
+ _debug("sleep");
+ ret = wait_event_interruptible(fl->fl_wait,
+ fl->fl_u.afs.state <= AFS_LOCK_GRANTED);
+ if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
+ ret = fl->fl_u.afs.state;
+ if (ret < 0)
+ goto error;
+ spin_lock(&vnode->lock);
+ goto given_lock;
+ }
+
+ /* we were interrupted, but someone may still be in the throes of
+ * giving us the lock */
+ _debug("intr");
+ ASSERTCMP(ret, ==, -ERESTARTSYS);
+
+ spin_lock(&vnode->lock);
+ if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
+ ret = fl->fl_u.afs.state;
+ if (ret < 0) {
+ spin_unlock(&vnode->lock);
+ goto error;
+ }
+ goto given_lock;
+ }
+
+abort_attempt:
+ /* we aren't going to get the lock, either because we're unwilling to
+ * wait, or because some signal happened */
+ _debug("abort");
+ if (list_empty(&vnode->granted_locks) &&
+ vnode->pending_locks.next == &fl->fl_u.afs.link) {
+ if (vnode->pending_locks.prev != &fl->fl_u.afs.link) {
+ /* kick the next pending lock into having a go */
+ list_del_init(&fl->fl_u.afs.link);
+ afs_lock_may_be_available(vnode);
+ }
+ } else {
+ list_del_init(&fl->fl_u.afs.link);
+ }
+ spin_unlock(&vnode->lock);
+ goto error;
+
+acquired_server_lock:
+ /* we've acquired a server lock, but it needs to be renewed after 5
+ * mins */
+ spin_lock(&vnode->lock);
+ afs_schedule_lock_extension(vnode);
+ if (type == AFS_LOCK_READ)
+ set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
+ else
+ set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
+sharing_existing_lock:
+ /* the lock has been granted as far as we're concerned... */
+ fl->fl_u.afs.state = AFS_LOCK_GRANTED;
+ list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
+given_lock:
+ /* ... but we do still need to get the VFS's blessing */
+ ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING)));
+ ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) |
+ (1 << AFS_VNODE_WRITELOCKED))) != 0);
+ ret = posix_lock_file(file, fl, NULL);
+ if (ret < 0)
+ goto vfs_rejected_lock;
+ spin_unlock(&vnode->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_vnode_fetch_status(vnode, NULL, key);
+
+error:
+ unlock_kernel();
+ _leave(" = %d", ret);
+ return ret;
+
+vfs_rejected_lock:
+ /* the VFS rejected the lock we just obtained, so we have to discard
+ * what we just got */
+ _debug("vfs refused %d", ret);
+ list_del_init(&fl->fl_u.afs.link);
+ if (list_empty(&vnode->granted_locks))
+ afs_defer_unlock(vnode, key);
+ spin_unlock(&vnode->lock);
+ goto abort_attempt;
+}
+
+/*
+ * 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(file->f_mapping->host);
+ struct key *key = file->private_data;
+ int ret;
+
+ _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
+
+ /* only whole-file unlocks are supported */
+ if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
+ return -EINVAL;
+
+ fl->fl_ops = &afs_lock_ops;
+ INIT_LIST_HEAD(&fl->fl_u.afs.link);
+ fl->fl_u.afs.state = AFS_LOCK_PENDING;
+
+ spin_lock(&vnode->lock);
+ ret = posix_lock_file(file, fl, NULL);
+ if (ret < 0) {
+ spin_unlock(&vnode->lock);
+ _leave(" = %d [vfs]", ret);
+ return ret;
+ }
+
+ /* discard the server lock only if all granted locks are gone */
+ if (list_empty(&vnode->granted_locks))
+ afs_defer_unlock(vnode, key);
+ spin_unlock(&vnode->lock);
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * 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(file->f_mapping->host);
+ struct key *key = file->private_data;
+ int ret, lock_count;
+
+ _enter("");
+
+ fl->fl_type = F_UNLCK;
+
+ mutex_lock(&vnode->vfs_inode.i_mutex);
+
+ /* check local lock records first */
+ ret = 0;
+ if (posix_test_lock(file, fl) == 0) {
+ /* no local locks; consult the server */
+ ret = afs_vnode_fetch_status(vnode, NULL, key);
+ if (ret < 0)
+ goto error;
+ lock_count = vnode->status.lock_count;
+ if (lock_count) {
+ if (lock_count > 0)
+ fl->fl_type = F_RDLCK;
+ else
+ fl->fl_type = F_WRLCK;
+ fl->fl_start = 0;
+ fl->fl_end = OFFSET_MAX;
+ }
+ }
+
+error:
+ mutex_unlock(&vnode->vfs_inode.i_mutex);
+ _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(file->f_dentry->d_inode);
+
+ _enter("{%x:%u},%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 ((vnode->vfs_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
+ fl->fl_type != F_UNLCK)
+ return -ENOLCK;
+
+ if (IS_GETLK(cmd))
+ return afs_do_getlk(file, fl);
+ if (fl->fl_type == F_UNLCK)
+ return afs_do_unlk(file, fl);
+ return afs_do_setlk(file, fl);
+}
+
+/*
+ * 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(file->f_dentry->d_inode);
+
+ _enter("{%x:%u},%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;
+
+ /* we're simulating flock() locks using posix locks on the server */
+ fl->fl_owner = (fl_owner_t) file;
+ fl->fl_start = 0;
+ fl->fl_end = OFFSET_MAX;
+
+ if (fl->fl_type == F_UNLCK)
+ return afs_do_unlk(file, fl);
+ return afs_do_setlk(file, fl);
+}
+
+/*
+ * 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)
+{
+ _enter("");
+
+ list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
+}
+
+/*
+ * 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)
+{
+ _enter("");
+
+ list_del_init(&fl->fl_u.afs.link);
+}
diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 60f9500..04584c0 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -67,7 +67,7 @@ static void xdr_decode_AFSFetchStatus(const __be32 **_bp,
EXTRACT(status->group);
bp++; /* sync counter */
data_version |= (u64) ntohl(*bp++) << 32;
- bp++; /* lock count */
+ EXTRACT(status->lock_count);
size |= (u64) ntohl(*bp++) << 32;
bp++; /* spare 4 */
*_bp = bp;
@@ -1750,3 +1750,156 @@ int afs_fs_get_volume_status(struct afs_server *server,

return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
}
+
+/*
+ * deliver reply data to an FS.SetLock, FS.ExtendLock or FS.ReleaseLock
+ */
+static int afs_deliver_fs_xxxx_lock(struct afs_call *call,
+ struct sk_buff *skb, bool last)
+{
+ const __be32 *bp;
+
+ _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+
+ afs_transfer_reply(call, skb);
+ if (!last)
+ return 0;
+
+ if (call->reply_size != call->reply_max)
+ return -EBADMSG;
+
+ /* unmarshall the reply once we've received all of it */
+ bp = call->buffer;
+ /* xdr_decode_AFSVolSync(&bp, call->replyX); */
+
+ _leave(" = 0 [done]");
+ return 0;
+}
+
+/*
+ * FS.SetLock operation type
+ */
+static const struct afs_call_type afs_RXFSSetLock = {
+ .name = "FS.SetLock",
+ .deliver = afs_deliver_fs_xxxx_lock,
+ .abort_to_error = afs_abort_to_error,
+ .destructor = afs_flat_call_destructor,
+};
+
+/*
+ * FS.ExtendLock operation type
+ */
+static const struct afs_call_type afs_RXFSExtendLock = {
+ .name = "FS.ExtendLock",
+ .deliver = afs_deliver_fs_xxxx_lock,
+ .abort_to_error = afs_abort_to_error,
+ .destructor = afs_flat_call_destructor,
+};
+
+/*
+ * FS.ReleaseLock operation type
+ */
+static const struct afs_call_type afs_RXFSReleaseLock = {
+ .name = "FS.ReleaseLock",
+ .deliver = afs_deliver_fs_xxxx_lock,
+ .abort_to_error = afs_abort_to_error,
+ .destructor = afs_flat_call_destructor,
+};
+
+/*
+ * get a lock on a file
+ */
+int afs_fs_set_lock(struct afs_server *server,
+ struct key *key,
+ struct afs_vnode *vnode,
+ afs_lock_type_t type,
+ const struct afs_wait_mode *wait_mode)
+{
+ struct afs_call *call;
+ __be32 *bp;
+
+ _enter("");
+
+ call = afs_alloc_flat_call(&afs_RXFSSetLock, 5 * 4, 6 * 4);
+ if (!call)
+ return -ENOMEM;
+
+ call->key = key;
+ call->reply = vnode;
+ call->service_id = FS_SERVICE;
+ call->port = htons(AFS_FS_PORT);
+
+ /* marshall the parameters */
+ bp = call->request;
+ *bp++ = htonl(FSSETLOCK);
+ *bp++ = htonl(vnode->fid.vid);
+ *bp++ = htonl(vnode->fid.vnode);
+ *bp++ = htonl(vnode->fid.unique);
+ *bp++ = htonl(type);
+
+ return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
+}
+
+/*
+ * extend a lock on a file
+ */
+int afs_fs_extend_lock(struct afs_server *server,
+ struct key *key,
+ struct afs_vnode *vnode,
+ const struct afs_wait_mode *wait_mode)
+{
+ struct afs_call *call;
+ __be32 *bp;
+
+ _enter("");
+
+ call = afs_alloc_flat_call(&afs_RXFSExtendLock, 4 * 4, 6 * 4);
+ if (!call)
+ return -ENOMEM;
+
+ call->key = key;
+ call->reply = vnode;
+ call->service_id = FS_SERVICE;
+ call->port = htons(AFS_FS_PORT);
+
+ /* marshall the parameters */
+ bp = call->request;
+ *bp++ = htonl(FSEXTENDLOCK);
+ *bp++ = htonl(vnode->fid.vid);
+ *bp++ = htonl(vnode->fid.vnode);
+ *bp++ = htonl(vnode->fid.unique);
+
+ return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
+}
+
+/*
+ * release a lock on a file
+ */
+int afs_fs_release_lock(struct afs_server *server,
+ struct key *key,
+ struct afs_vnode *vnode,
+ const struct afs_wait_mode *wait_mode)
+{
+ struct afs_call *call;
+ __be32 *bp;
+
+ _enter("");
+
+ call = afs_alloc_flat_call(&afs_RXFSReleaseLock, 4 * 4, 6 * 4);
+ if (!call)
+ return -ENOMEM;
+
+ call->key = key;
+ call->reply = vnode;
+ call->service_id = FS_SERVICE;
+ call->port = htons(AFS_FS_PORT);
+
+ /* marshall the parameters */
+ bp = call->request;
+ *bp++ = htonl(FSRELEASELOCK);
+ *bp++ = htonl(vnode->fid.vid);
+ *bp++ = htonl(vnode->fid.vnode);
+ *bp++ = htonl(vnode->fid.unique);
+
+ return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
+}
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index bc39eba..f8a41bd 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -350,10 +350,18 @@ struct afs_vnode {
#define AFS_VNODE_ZAP_DATA 3 /* set if vnode's data should be invalidated */
#define AFS_VNODE_DELETED 4 /* set if vnode deleted on server */
#define AFS_VNODE_MOUNTPOINT 5 /* set if vnode is a mountpoint symlink */
+#define AFS_VNODE_LOCKING 6 /* set if waiting for lock on vnode */
+#define AFS_VNODE_READLOCKED 7 /* set if vnode is read-locked on the server */
+#define AFS_VNODE_WRITELOCKED 8 /* set if vnode is write-locked on the server */
+#define AFS_VNODE_UNLOCKING 9 /* set if vnode is being unlocked on the server */

long acl_order; /* ACL check count (callback break count) */

struct list_head writebacks; /* alterations in pagecache that need writing */
+ struct list_head pending_locks; /* locks waiting to be granted */
+ struct list_head granted_locks; /* locks granted on this file */
+ struct delayed_work lock_work; /* work to be done in locking */
+ struct key *unlock_key; /* key to be used in unlocking */

/* outstanding callback notification on this file */
struct rb_node server_rb; /* link in server->fs_vnodes */
@@ -473,6 +481,15 @@ extern int afs_open(struct inode *, struct file *);
extern int afs_release(struct inode *, struct file *);

/*
+ * flock.c
+ */
+extern void __exit afs_kill_lock_manager(void);
+extern void afs_lock_work(struct work_struct *);
+extern void afs_lock_may_be_available(struct afs_vnode *);
+extern int afs_lock(struct file *, int, struct file_lock *);
+extern int afs_flock(struct file *, int, struct file_lock *);
+
+/*
* fsclient.c
*/
extern int afs_fs_fetch_file_status(struct afs_server *, struct key *,
@@ -512,6 +529,15 @@ extern int afs_fs_get_volume_status(struct afs_server *, struct key *,
struct afs_vnode *,
struct afs_volume_status *,
const struct afs_wait_mode *);
+extern int afs_fs_set_lock(struct afs_server *, struct key *,
+ struct afs_vnode *, afs_lock_type_t,
+ const struct afs_wait_mode *);
+extern int afs_fs_extend_lock(struct afs_server *, struct key *,
+ struct afs_vnode *,
+ const struct afs_wait_mode *);
+extern int afs_fs_release_lock(struct afs_server *, struct key *,
+ struct afs_vnode *,
+ const struct afs_wait_mode *);

/*
* inode.c
@@ -680,6 +706,10 @@ extern int afs_vnode_store_data(struct afs_writeback *, pgoff_t, pgoff_t,
extern int afs_vnode_setattr(struct afs_vnode *, struct key *, struct iattr *);
extern int afs_vnode_get_volume_status(struct afs_vnode *, struct key *,
struct afs_volume_status *);
+extern int afs_vnode_set_lock(struct afs_vnode *, struct key *,
+ afs_lock_type_t);
+extern int afs_vnode_extend_lock(struct afs_vnode *, struct key *);
+extern int afs_vnode_release_lock(struct afs_vnode *, struct key *);

/*
* volume.c
diff --git a/fs/afs/main.c b/fs/afs/main.c
index cd21195..0f60f6b 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -168,6 +168,7 @@ static void __exit afs_exit(void)
printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 unregistering.\n");

afs_fs_exit();
+ afs_kill_lock_manager();
afs_close_socket();
afs_purge_servers();
afs_callback_update_kill();
diff --git a/fs/afs/misc.c b/fs/afs/misc.c
index d1a889c..2d33a5f 100644
--- a/fs/afs/misc.c
+++ b/fs/afs/misc.c
@@ -35,6 +35,7 @@ int afs_abort_to_error(u32 abort_code)
case VOVERQUOTA: return -EDQUOT;
case VBUSY: return -EBUSY;
case VMOVED: return -ENXIO;
+ case 0x2f6df0a: return -EWOULDBLOCK;
case 0x2f6df0c: return -EACCES;
case 0x2f6df0f: return -EBUSY;
case 0x2f6df10: return -EEXIST;
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 2e8496b..993cdf1 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -460,6 +460,9 @@ static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep,
spin_lock_init(&vnode->writeback_lock);
spin_lock_init(&vnode->lock);
INIT_LIST_HEAD(&vnode->writebacks);
+ INIT_LIST_HEAD(&vnode->pending_locks);
+ INIT_LIST_HEAD(&vnode->granted_locks);
+ INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
}

diff --git a/fs/afs/vnode.c b/fs/afs/vnode.c
index 232c55d..ac811e4 100644
--- a/fs/afs/vnode.c
+++ b/fs/afs/vnode.c
@@ -887,11 +887,6 @@ int afs_vnode_get_volume_status(struct afs_vnode *vnode, struct key *key,
vnode->fid.unique,
key_serial(key));

- /* this op will fetch the status */
- spin_lock(&vnode->lock);
- vnode->update_cnt++;
- spin_unlock(&vnode->lock);
-
do {
/* pick a server to query */
server = afs_volume_pick_fileserver(vnode);
@@ -905,20 +900,127 @@ int afs_vnode_get_volume_status(struct afs_vnode *vnode, struct key *key,
} while (!afs_volume_release_fileserver(vnode, server, ret));

/* adjust the flags */
- if (ret == 0) {
- afs_vnode_finalise_status_update(vnode, server);
+ if (ret == 0)
+ afs_put_server(server);
+
+ _leave(" = %d", ret);
+ return ret;
+
+no_server:
+ return PTR_ERR(server);
+}
+
+/*
+ * get a lock on a file
+ */
+int afs_vnode_set_lock(struct afs_vnode *vnode, struct key *key,
+ afs_lock_type_t type)
+{
+ struct afs_server *server;
+ int ret;
+
+ _enter("%s{%x:%u.%u},%x,%u",
+ vnode->volume->vlocation->vldb.name,
+ vnode->fid.vid,
+ vnode->fid.vnode,
+ vnode->fid.unique,
+ key_serial(key), type);
+
+ do {
+ /* pick a server to query */
+ server = afs_volume_pick_fileserver(vnode);
+ if (IS_ERR(server))
+ goto no_server;
+
+ _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
+
+ ret = afs_fs_set_lock(server, key, vnode, type, &afs_sync_call);
+
+ } while (!afs_volume_release_fileserver(vnode, server, ret));
+
+ /* adjust the flags */
+ if (ret == 0)
+ afs_put_server(server);
+
+ _leave(" = %d", ret);
+ return ret;
+
+no_server:
+ return PTR_ERR(server);
+}
+
+/*
+ * extend a lock on a file
+ */
+int afs_vnode_extend_lock(struct afs_vnode *vnode, struct key *key)
+{
+ struct afs_server *server;
+ int ret;
+
+ _enter("%s{%x:%u.%u},%x",
+ vnode->volume->vlocation->vldb.name,
+ vnode->fid.vid,
+ vnode->fid.vnode,
+ vnode->fid.unique,
+ key_serial(key));
+
+ do {
+ /* pick a server to query */
+ server = afs_volume_pick_fileserver(vnode);
+ if (IS_ERR(server))
+ goto no_server;
+
+ _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
+
+ ret = afs_fs_extend_lock(server, key, vnode, &afs_sync_call);
+
+ } while (!afs_volume_release_fileserver(vnode, server, ret));
+
+ /* adjust the flags */
+ if (ret == 0)
+ afs_put_server(server);
+
+ _leave(" = %d", ret);
+ return ret;
+
+no_server:
+ return PTR_ERR(server);
+}
+
+/*
+ * release a lock on a file
+ */
+int afs_vnode_release_lock(struct afs_vnode *vnode, struct key *key)
+{
+ struct afs_server *server;
+ int ret;
+
+ _enter("%s{%x:%u.%u},%x",
+ vnode->volume->vlocation->vldb.name,
+ vnode->fid.vid,
+ vnode->fid.vnode,
+ vnode->fid.unique,
+ key_serial(key));
+
+ do {
+ /* pick a server to query */
+ server = afs_volume_pick_fileserver(vnode);
+ if (IS_ERR(server))
+ goto no_server;
+
+ _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
+
+ ret = afs_fs_release_lock(server, key, vnode, &afs_sync_call);
+
+ } while (!afs_volume_release_fileserver(vnode, server, ret));
+
+ /* adjust the flags */
+ if (ret == 0)
afs_put_server(server);
- } else {
- afs_vnode_status_update_failed(vnode, ret);
- }

_leave(" = %d", ret);
return ret;

no_server:
- spin_lock(&vnode->lock);
- vnode->update_cnt--;
- ASSERTCMP(vnode->update_cnt, >=, 0);
- spin_unlock(&vnode->lock);
return PTR_ERR(server);
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7cf0c54..c81fb3b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -820,6 +820,10 @@ struct file_lock {
union {
struct nfs_lock_info nfs_fl;
struct nfs4_lock_info nfs4_fl;
+ struct {
+ struct list_head link; /* link in AFS vnode's pending_locks list */
+ int state; /* state of grant or error if -ve */
+ } afs;
} fl_u;
};