1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * Portions of this source code were derived from Berkeley 4.3 BSD 32 * under license from the Regents of the University of California. 33 */ 34 35 #include <sys/param.h> 36 #include <sys/isa_defs.h> 37 #include <sys/types.h> 38 #include <sys/sysmacros.h> 39 #include <sys/cred.h> 40 #include <sys/systm.h> 41 #include <sys/errno.h> 42 #include <sys/pathname.h> 43 #include <sys/vnode.h> 44 #include <sys/vfs.h> 45 #include <sys/file.h> 46 #include <sys/uio.h> 47 #include <sys/debug.h> 48 #include <fs/fs_subr.h> 49 50 /* 51 * Common code for pathconf(), fpathconf() system calls 52 */ 53 static long 54 cpathconf(register vnode_t *vp, int cmd, struct cred *cr) 55 { 56 struct statvfs64 sb; 57 int error; 58 ulong_t val; 59 60 switch (cmd) { 61 case _PC_2_SYMLINKS: 62 if (error = VOP_PATHCONF(vp, _PC_SYMLINK_MAX, &val, cr, NULL)) 63 return ((long)set_errno(error)); 64 return ((long)(val > 0)); 65 66 case _PC_ALLOC_SIZE_MIN: 67 case _PC_REC_INCR_XFER_SIZE: 68 case _PC_REC_MAX_XFER_SIZE: 69 case _PC_REC_MIN_XFER_SIZE: 70 case _PC_REC_XFER_ALIGN: 71 if ((error = VFS_STATVFS(vp->v_vfsp, &sb)) != 0) 72 return ((long)set_errno(error)); 73 74 /* 75 * There is generally no harm in doing larger transfers, but 76 * there's a point of diminishing returns. With 1MB transfers, 77 * even if they're random, you get very close to platter speed. 78 * Se we return 1MB as the maximum transfer size. 79 */ 80 if (cmd == _PC_REC_MAX_XFER_SIZE) 81 return ((long)MAX(sb.f_bsize, 1UL << 20)); 82 83 /* 84 * By definition, f_frsize is the smallest filesystem block. 85 * However, _PC_ALLOC_SIZE_MIN is intended to define the 86 * threshold for direct I/O. This implies two requirements: 87 * the VM and I/O subsystems must be able to create mappings 88 * for DMA, which requires at least page alignment; and the 89 * filesystem must avoid read/modify/write, which generally 90 * requires multiples of its 'preferred' blocksize, f_bsize. 91 * 92 * PAGESIZE alignment is sufficient for DMA and block copy. 93 * Rounding up to the filesystem 'preferred' blocksize 94 * works just as well. 95 * 96 * All together, this means that the remaining parameters 97 * map into the same value. 98 */ 99 return ((long)MAX(sb.f_bsize, PAGESIZE)); 100 101 case _PC_ASYNC_IO: 102 return (1l); 103 104 case _PC_PRIO_IO: 105 return ((long)set_errno(EINVAL)); 106 107 case _PC_SYNC_IO: 108 if (!(error = VOP_FSYNC(vp, FSYNC, cr, NULL))) 109 return (1l); 110 return ((long)set_errno(error)); 111 112 case _PC_XATTR_ENABLED: 113 return ((vp->v_vfsp->vfs_flag & VFS_XATTR) ? 1 : 0); 114 115 default: 116 if (error = VOP_PATHCONF(vp, cmd, &val, cr, NULL)) 117 return ((long)set_errno(error)); 118 return (val); 119 } 120 /* NOTREACHED */ 121 } 122 123 /* fpathconf/pathconf interfaces */ 124 125 long 126 fpathconf(int fdes, int name) 127 { 128 file_t *fp; 129 long retval; 130 131 if ((fp = getf(fdes)) == NULL) 132 return (set_errno(EBADF)); 133 retval = cpathconf(fp->f_vnode, name, fp->f_cred); 134 releasef(fdes); 135 return (retval); 136 } 137 138 long 139 pathconf(char *fname, int name) 140 { 141 vnode_t *vp; 142 long retval; 143 int error; 144 int estale_retry = 0; 145 146 lookup: 147 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 148 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 149 goto lookup; 150 return ((long)set_errno(error)); 151 } 152 153 retval = cpathconf(vp, name, CRED()); 154 VN_RELE(vp); 155 return (retval); 156 } 157