Loading...
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 | // SPDX-License-Identifier: GPL-2.0-or-later /* * locks.c * * Userspace file locking support * * Copyright (C) 2007 Oracle. All rights reserved. */ #include <linux/fs.h> #include <linux/filelock.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 ((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; return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); } |