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![Yan, Zheng](/assets/img/avatar_default.png)
When a process exits, kernel closes its files. locks_remove_file() is called to remove file locks on these files. locks_remove_file() tries unlocking files even there is no file lock. Signed-off-by: "Yan, Zheng" <zyan@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
497 lines
13 KiB
C
497 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/ceph/ceph_debug.h>
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#include <linux/file.h>
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#include <linux/namei.h>
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#include <linux/random.h>
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#include "super.h"
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#include "mds_client.h"
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#include <linux/ceph/pagelist.h>
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static u64 lock_secret;
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static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
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struct ceph_mds_request *req);
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static inline u64 secure_addr(void *addr)
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{
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u64 v = lock_secret ^ (u64)(unsigned long)addr;
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/*
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* Set the most significant bit, so that MDS knows the 'owner'
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* is sufficient to identify the owner of lock. (old code uses
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* both 'owner' and 'pid')
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*/
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v |= (1ULL << 63);
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return v;
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}
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void __init ceph_flock_init(void)
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{
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get_random_bytes(&lock_secret, sizeof(lock_secret));
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}
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static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
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{
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struct ceph_file_info *fi = dst->fl_file->private_data;
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struct inode *inode = file_inode(dst->fl_file);
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atomic_inc(&ceph_inode(inode)->i_filelock_ref);
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atomic_inc(&fi->num_locks);
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}
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static void ceph_fl_release_lock(struct file_lock *fl)
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{
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struct ceph_file_info *fi = fl->fl_file->private_data;
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struct inode *inode = file_inode(fl->fl_file);
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struct ceph_inode_info *ci = ceph_inode(inode);
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atomic_dec(&fi->num_locks);
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if (atomic_dec_and_test(&ci->i_filelock_ref)) {
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/* clear error when all locks are released */
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spin_lock(&ci->i_ceph_lock);
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ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK;
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spin_unlock(&ci->i_ceph_lock);
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}
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}
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static const struct file_lock_operations ceph_fl_lock_ops = {
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.fl_copy_lock = ceph_fl_copy_lock,
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.fl_release_private = ceph_fl_release_lock,
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};
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/**
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* Implement fcntl and flock locking functions.
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*/
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static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode,
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int cmd, u8 wait, struct file_lock *fl)
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{
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struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
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struct ceph_mds_request *req;
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int err;
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u64 length = 0;
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u64 owner;
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if (operation == CEPH_MDS_OP_SETFILELOCK) {
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/*
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* increasing i_filelock_ref closes race window between
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* handling request reply and adding file_lock struct to
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* inode. Otherwise, auth caps may get trimmed in the
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* window. Caller function will decrease the counter.
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*/
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fl->fl_ops = &ceph_fl_lock_ops;
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fl->fl_ops->fl_copy_lock(fl, NULL);
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}
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if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK)
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wait = 0;
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req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
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if (IS_ERR(req))
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return PTR_ERR(req);
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req->r_inode = inode;
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ihold(inode);
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req->r_num_caps = 1;
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/* mds requires start and length rather than start and end */
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if (LLONG_MAX == fl->fl_end)
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length = 0;
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else
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length = fl->fl_end - fl->fl_start + 1;
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owner = secure_addr(fl->fl_owner);
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dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, pid: %llu, "
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"start: %llu, length: %llu, wait: %d, type: %d\n", (int)lock_type,
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(int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length,
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wait, fl->fl_type);
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req->r_args.filelock_change.rule = lock_type;
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req->r_args.filelock_change.type = cmd;
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req->r_args.filelock_change.owner = cpu_to_le64(owner);
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req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);
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req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
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req->r_args.filelock_change.length = cpu_to_le64(length);
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req->r_args.filelock_change.wait = wait;
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if (wait)
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req->r_wait_for_completion = ceph_lock_wait_for_completion;
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err = ceph_mdsc_do_request(mdsc, inode, req);
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if (!err && operation == CEPH_MDS_OP_GETFILELOCK) {
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fl->fl_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid);
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if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
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fl->fl_type = F_RDLCK;
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else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
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fl->fl_type = F_WRLCK;
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else
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fl->fl_type = F_UNLCK;
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fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
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length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
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le64_to_cpu(req->r_reply_info.filelock_reply->length);
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if (length >= 1)
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fl->fl_end = length -1;
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else
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fl->fl_end = 0;
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}
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ceph_mdsc_put_request(req);
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dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
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"length: %llu, wait: %d, type: %d, err code %d\n", (int)lock_type,
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(int)operation, (u64)fl->fl_pid, fl->fl_start,
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length, wait, fl->fl_type, err);
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return err;
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}
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static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
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struct ceph_mds_request *req)
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{
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struct ceph_mds_request *intr_req;
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struct inode *inode = req->r_inode;
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int err, lock_type;
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BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK);
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if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL)
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lock_type = CEPH_LOCK_FCNTL_INTR;
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else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK)
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lock_type = CEPH_LOCK_FLOCK_INTR;
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else
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BUG_ON(1);
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BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK);
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err = wait_for_completion_interruptible(&req->r_completion);
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if (!err)
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return 0;
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dout("ceph_lock_wait_for_completion: request %llu was interrupted\n",
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req->r_tid);
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mutex_lock(&mdsc->mutex);
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if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
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err = 0;
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} else {
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/*
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* ensure we aren't running concurrently with
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* ceph_fill_trace or ceph_readdir_prepopulate, which
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* rely on locks (dir mutex) held by our caller.
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*/
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mutex_lock(&req->r_fill_mutex);
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req->r_err = err;
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set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
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mutex_unlock(&req->r_fill_mutex);
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if (!req->r_session) {
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// haven't sent the request
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err = 0;
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}
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}
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mutex_unlock(&mdsc->mutex);
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if (!err)
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return 0;
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intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK,
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USE_AUTH_MDS);
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if (IS_ERR(intr_req))
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return PTR_ERR(intr_req);
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intr_req->r_inode = inode;
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ihold(inode);
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intr_req->r_num_caps = 1;
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intr_req->r_args.filelock_change = req->r_args.filelock_change;
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intr_req->r_args.filelock_change.rule = lock_type;
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intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK;
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err = ceph_mdsc_do_request(mdsc, inode, intr_req);
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ceph_mdsc_put_request(intr_req);
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if (err && err != -ERESTARTSYS)
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return err;
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wait_for_completion_killable(&req->r_safe_completion);
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return 0;
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}
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static int try_unlock_file(struct file *file, struct file_lock *fl)
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{
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int err;
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unsigned int orig_flags = fl->fl_flags;
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fl->fl_flags |= FL_EXISTS;
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err = locks_lock_file_wait(file, fl);
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fl->fl_flags = orig_flags;
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if (err == -ENOENT) {
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if (!(orig_flags & FL_EXISTS))
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err = 0;
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return err;
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}
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return 1;
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}
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/**
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* Attempt to set an fcntl lock.
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* For now, this just goes away to the server. Later it may be more awesome.
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*/
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int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
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{
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struct inode *inode = file_inode(file);
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struct ceph_inode_info *ci = ceph_inode(inode);
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int err = 0;
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u16 op = CEPH_MDS_OP_SETFILELOCK;
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u8 wait = 0;
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u8 lock_cmd;
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if (!(fl->fl_flags & FL_POSIX))
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return -ENOLCK;
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/* No mandatory locks */
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if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
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return -ENOLCK;
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dout("ceph_lock, fl_owner: %p\n", fl->fl_owner);
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/* set wait bit as appropriate, then make command as Ceph expects it*/
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if (IS_GETLK(cmd))
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op = CEPH_MDS_OP_GETFILELOCK;
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else if (IS_SETLKW(cmd))
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wait = 1;
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spin_lock(&ci->i_ceph_lock);
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if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) {
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err = -EIO;
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}
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spin_unlock(&ci->i_ceph_lock);
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if (err < 0) {
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if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK == fl->fl_type)
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posix_lock_file(file, fl, NULL);
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return err;
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}
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if (F_RDLCK == fl->fl_type)
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lock_cmd = CEPH_LOCK_SHARED;
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else if (F_WRLCK == fl->fl_type)
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lock_cmd = CEPH_LOCK_EXCL;
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else
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lock_cmd = CEPH_LOCK_UNLOCK;
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if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK == fl->fl_type) {
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err = try_unlock_file(file, fl);
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if (err <= 0)
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return err;
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}
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err = ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, lock_cmd, wait, fl);
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if (!err) {
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if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK != fl->fl_type) {
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dout("mds locked, locking locally\n");
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err = posix_lock_file(file, fl, NULL);
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if (err) {
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/* undo! This should only happen if
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* the kernel detects local
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* deadlock. */
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ceph_lock_message(CEPH_LOCK_FCNTL, op, inode,
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CEPH_LOCK_UNLOCK, 0, fl);
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dout("got %d on posix_lock_file, undid lock\n",
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err);
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}
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}
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}
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return err;
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}
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int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
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{
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struct inode *inode = file_inode(file);
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struct ceph_inode_info *ci = ceph_inode(inode);
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int err = 0;
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u8 wait = 0;
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u8 lock_cmd;
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if (!(fl->fl_flags & FL_FLOCK))
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return -ENOLCK;
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/* No mandatory locks */
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if (fl->fl_type & LOCK_MAND)
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return -EOPNOTSUPP;
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dout("ceph_flock, fl_file: %p\n", fl->fl_file);
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spin_lock(&ci->i_ceph_lock);
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if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) {
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err = -EIO;
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}
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spin_unlock(&ci->i_ceph_lock);
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if (err < 0) {
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if (F_UNLCK == fl->fl_type)
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locks_lock_file_wait(file, fl);
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return err;
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}
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if (IS_SETLKW(cmd))
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wait = 1;
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if (F_RDLCK == fl->fl_type)
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lock_cmd = CEPH_LOCK_SHARED;
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else if (F_WRLCK == fl->fl_type)
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lock_cmd = CEPH_LOCK_EXCL;
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else
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lock_cmd = CEPH_LOCK_UNLOCK;
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if (F_UNLCK == fl->fl_type) {
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err = try_unlock_file(file, fl);
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if (err <= 0)
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return err;
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}
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err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
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inode, lock_cmd, wait, fl);
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if (!err && F_UNLCK != fl->fl_type) {
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err = locks_lock_file_wait(file, fl);
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if (err) {
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ceph_lock_message(CEPH_LOCK_FLOCK,
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CEPH_MDS_OP_SETFILELOCK,
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inode, CEPH_LOCK_UNLOCK, 0, fl);
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dout("got %d on locks_lock_file_wait, undid lock\n", err);
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}
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}
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return err;
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}
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/*
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* Fills in the passed counter variables, so you can prepare pagelist metadata
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* before calling ceph_encode_locks.
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*/
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void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
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{
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struct file_lock *lock;
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struct file_lock_context *ctx;
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*fcntl_count = 0;
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*flock_count = 0;
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ctx = inode->i_flctx;
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if (ctx) {
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spin_lock(&ctx->flc_lock);
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list_for_each_entry(lock, &ctx->flc_posix, fl_list)
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++(*fcntl_count);
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list_for_each_entry(lock, &ctx->flc_flock, fl_list)
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++(*flock_count);
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spin_unlock(&ctx->flc_lock);
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}
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dout("counted %d flock locks and %d fcntl locks\n",
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*flock_count, *fcntl_count);
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}
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/*
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* Given a pointer to a lock, convert it to a ceph filelock
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*/
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static int lock_to_ceph_filelock(struct file_lock *lock,
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struct ceph_filelock *cephlock)
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{
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int err = 0;
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cephlock->start = cpu_to_le64(lock->fl_start);
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cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
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cephlock->client = cpu_to_le64(0);
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cephlock->pid = cpu_to_le64((u64)lock->fl_pid);
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cephlock->owner = cpu_to_le64(secure_addr(lock->fl_owner));
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switch (lock->fl_type) {
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case F_RDLCK:
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cephlock->type = CEPH_LOCK_SHARED;
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break;
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case F_WRLCK:
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cephlock->type = CEPH_LOCK_EXCL;
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break;
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case F_UNLCK:
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cephlock->type = CEPH_LOCK_UNLOCK;
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break;
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default:
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dout("Have unknown lock type %d\n", lock->fl_type);
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err = -EINVAL;
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}
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return err;
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}
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/**
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* Encode the flock and fcntl locks for the given inode into the ceph_filelock
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* array. Must be called with inode->i_lock already held.
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* If we encounter more of a specific lock type than expected, return -ENOSPC.
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*/
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int ceph_encode_locks_to_buffer(struct inode *inode,
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struct ceph_filelock *flocks,
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int num_fcntl_locks, int num_flock_locks)
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{
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struct file_lock *lock;
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struct file_lock_context *ctx = inode->i_flctx;
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int err = 0;
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int seen_fcntl = 0;
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int seen_flock = 0;
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int l = 0;
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dout("encoding %d flock and %d fcntl locks\n", num_flock_locks,
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num_fcntl_locks);
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if (!ctx)
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return 0;
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spin_lock(&ctx->flc_lock);
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list_for_each_entry(lock, &ctx->flc_posix, fl_list) {
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++seen_fcntl;
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if (seen_fcntl > num_fcntl_locks) {
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err = -ENOSPC;
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goto fail;
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}
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err = lock_to_ceph_filelock(lock, &flocks[l]);
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if (err)
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goto fail;
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++l;
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}
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list_for_each_entry(lock, &ctx->flc_flock, fl_list) {
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++seen_flock;
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if (seen_flock > num_flock_locks) {
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err = -ENOSPC;
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goto fail;
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}
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err = lock_to_ceph_filelock(lock, &flocks[l]);
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if (err)
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goto fail;
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++l;
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}
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fail:
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spin_unlock(&ctx->flc_lock);
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return err;
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}
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/**
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* Copy the encoded flock and fcntl locks into the pagelist.
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* Format is: #fcntl locks, sequential fcntl locks, #flock locks,
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* sequential flock locks.
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* Returns zero on success.
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*/
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int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
|
|
struct ceph_pagelist *pagelist,
|
|
int num_fcntl_locks, int num_flock_locks)
|
|
{
|
|
int err = 0;
|
|
__le32 nlocks;
|
|
|
|
nlocks = cpu_to_le32(num_fcntl_locks);
|
|
err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
|
|
if (err)
|
|
goto out_fail;
|
|
|
|
if (num_fcntl_locks > 0) {
|
|
err = ceph_pagelist_append(pagelist, flocks,
|
|
num_fcntl_locks * sizeof(*flocks));
|
|
if (err)
|
|
goto out_fail;
|
|
}
|
|
|
|
nlocks = cpu_to_le32(num_flock_locks);
|
|
err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
|
|
if (err)
|
|
goto out_fail;
|
|
|
|
if (num_flock_locks > 0) {
|
|
err = ceph_pagelist_append(pagelist, &flocks[num_fcntl_locks],
|
|
num_flock_locks * sizeof(*flocks));
|
|
}
|
|
out_fail:
|
|
return err;
|
|
}
|