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![Sage Weil](/assets/img/avatar_default.png)
If we request a lock and then abort (e.g., ^C), we need to send a matching unlock request to the MDS to unwind our lock attempt to avoid indefinitely blocking other clients. Reported-by: Brian Chrisman <brchrisman@gmail.com> Signed-off-by: Sage Weil <sage@newdream.net>
286 lines
7.7 KiB
C
286 lines
7.7 KiB
C
#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 "super.h"
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#include "mds_client.h"
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#include <linux/ceph/pagelist.h>
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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 file *file,
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int cmd, u8 wait, struct file_lock *fl)
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{
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struct inode *inode = file->f_dentry->d_inode;
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struct ceph_mds_client *mdsc =
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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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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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/* 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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dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
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"length: %llu, wait: %d, type: %d", (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);
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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.pid = cpu_to_le64((u64)fl->fl_pid);
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/* This should be adjusted, but I'm not sure if
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namespaces actually get id numbers*/
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req->r_args.filelock_change.pid_namespace =
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cpu_to_le64((u64)(unsigned long)fl->fl_nspid);
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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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err = ceph_mdsc_do_request(mdsc, inode, req);
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if ( 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", (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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/**
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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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u8 lock_cmd;
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int err;
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u8 wait = 0;
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u16 op = CEPH_MDS_OP_SETFILELOCK;
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fl->fl_nspid = get_pid(task_tgid(current));
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dout("ceph_lock, fl_pid:%d", fl->fl_pid);
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/* set wait bit as appropriate, then make command as Ceph expects it*/
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if (F_SETLKW == cmd)
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wait = 1;
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if (F_GETLK == cmd)
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op = CEPH_MDS_OP_GETFILELOCK;
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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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err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
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if (!err) {
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if ( op != CEPH_MDS_OP_GETFILELOCK ){
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dout("mds locked, locking locally");
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err = posix_lock_file(file, fl, NULL);
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if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
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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, file,
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CEPH_LOCK_UNLOCK, 0, fl);
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dout("got %d on posix_lock_file, undid lock",
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err);
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}
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}
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} else if (err == -ERESTARTSYS) {
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dout("undoing lock\n");
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ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
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CEPH_LOCK_UNLOCK, 0, fl);
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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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u8 lock_cmd;
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int err;
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u8 wait = 1;
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fl->fl_nspid = get_pid(task_tgid(current));
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dout("ceph_flock, fl_pid:%d", fl->fl_pid);
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/* set wait bit, then clear it out of cmd*/
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if (cmd & LOCK_NB)
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wait = 0;
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cmd = cmd & (LOCK_SH | LOCK_EX | LOCK_UN);
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/* set command sequence that Ceph wants to see:
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shared lock, exclusive lock, or unlock */
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if (LOCK_SH == cmd)
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lock_cmd = CEPH_LOCK_SHARED;
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else if (LOCK_EX == cmd)
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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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err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
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file, lock_cmd, wait, fl);
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if (!err) {
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err = flock_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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file, CEPH_LOCK_UNLOCK, 0, fl);
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dout("got %d on flock_lock_file_wait, undid lock", err);
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}
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} else if (err == -ERESTARTSYS) {
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dout("undoing lock\n");
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ceph_lock_message(CEPH_LOCK_FLOCK,
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CEPH_MDS_OP_SETFILELOCK,
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file, CEPH_LOCK_UNLOCK, 0, fl);
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}
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return err;
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}
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/**
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* Must be called with BKL already held. Fills in the passed
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* counter variables, so you can prepare pagelist metadata before calling
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* 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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*fcntl_count = 0;
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*flock_count = 0;
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for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
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if (lock->fl_flags & FL_POSIX)
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++(*fcntl_count);
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else if (lock->fl_flags & FL_FLOCK)
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++(*flock_count);
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}
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dout("counted %d flock locks and %d fcntl locks",
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*flock_count, *fcntl_count);
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}
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/**
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* Encode the flock and fcntl locks for the given inode 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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* Must be called with lock_flocks() already held.
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* If we encounter more of a specific lock type than expected,
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* we return the value 1.
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*/
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int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist,
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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 ceph_filelock cephlock;
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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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dout("encoding %d flock and %d fcntl locks", num_flock_locks,
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num_fcntl_locks);
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err = ceph_pagelist_append(pagelist, &num_fcntl_locks, sizeof(u32));
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if (err)
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goto fail;
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for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
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if (lock->fl_flags & FL_POSIX) {
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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, &cephlock);
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if (err)
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goto fail;
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err = ceph_pagelist_append(pagelist, &cephlock,
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sizeof(struct ceph_filelock));
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}
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if (err)
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goto fail;
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}
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err = ceph_pagelist_append(pagelist, &num_flock_locks, sizeof(u32));
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if (err)
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goto fail;
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for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
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if (lock->fl_flags & FL_FLOCK) {
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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, &cephlock);
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if (err)
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goto fail;
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err = ceph_pagelist_append(pagelist, &cephlock,
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sizeof(struct ceph_filelock));
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}
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if (err)
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goto fail;
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}
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fail:
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return err;
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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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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(lock->fl_pid);
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cephlock->pid_namespace =
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cpu_to_le64((u64)(unsigned long)lock->fl_nspid);
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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", 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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