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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | // SPDX-License-Identifier: GPL-2.0-or-later /* -*- mode: c; c-basic-offset: 8; -*- * vim: noexpandtab sw=8 ts=8 sts=0: * * locks.c * * Userspace file locking support * * Copyright (C) 2007 Oracle. All rights reserved. */ #include <linux/fs.h> #include <linux/fcntl.h> #include <cluster/masklog.h> #include "ocfs2.h" #include "dlmglue.h" #include "file.h" #include "inode.h" #include "locks.h" static int ocfs2_do_flock(struct file *file, struct inode *inode, int cmd, struct file_lock *fl) { int ret = 0, level = 0, trylock = 0; struct ocfs2_file_private *fp = file->private_data; struct ocfs2_lock_res *lockres = &fp->fp_flock; if (fl->fl_type == F_WRLCK) level = 1; if (!IS_SETLKW(cmd)) trylock = 1; mutex_lock(&fp->fp_mutex); if (lockres->l_flags & OCFS2_LOCK_ATTACHED && lockres->l_level > LKM_NLMODE) { int old_level = 0; struct file_lock request; if (lockres->l_level == LKM_EXMODE) old_level = 1; if (level == old_level) goto out; /* * Converting an existing lock is not guaranteed to be * atomic, so we can get away with simply unlocking * here and allowing the lock code to try at the new * level. */ locks_init_lock(&request); request.fl_type = F_UNLCK; request.fl_flags = FL_FLOCK; locks_lock_file_wait(file, &request); ocfs2_file_unlock(file); } ret = ocfs2_file_lock(file, level, trylock); if (ret) { if (ret == -EAGAIN && trylock) ret = -EWOULDBLOCK; else mlog_errno(ret); goto out; } ret = locks_lock_file_wait(file, fl); if (ret) ocfs2_file_unlock(file); out: mutex_unlock(&fp->fp_mutex); return ret; } static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) { int ret; struct ocfs2_file_private *fp = file->private_data; mutex_lock(&fp->fp_mutex); ocfs2_file_unlock(file); ret = locks_lock_file_wait(file, fl); mutex_unlock(&fp->fp_mutex); return ret; } /* * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). */ int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file->f_mapping->host; struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); if (!(fl->fl_flags & FL_FLOCK)) return -ENOLCK; if (__mandatory_lock(inode)) return -ENOLCK; if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || ocfs2_mount_local(osb)) return locks_lock_file_wait(file, fl); if (fl->fl_type == F_UNLCK) return ocfs2_do_funlock(file, cmd, fl); else return ocfs2_do_flock(file, inode, cmd, fl); } int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file->f_mapping->host; struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); if (!(fl->fl_flags & FL_POSIX)) return -ENOLCK; if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) return -ENOLCK; return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); } |