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 #pragma ident "%Z%%M% %I% %E% SMI" 36 37 #include <sys/param.h> 38 #include <sys/isa_defs.h> 39 #include <sys/types.h> 40 #include <sys/sysmacros.h> 41 #include <sys/cred.h> 42 #include <sys/systm.h> 43 #include <sys/errno.h> 44 #include <sys/pathname.h> 45 #include <sys/vnode.h> 46 #include <sys/vfs.h> 47 #include <sys/file.h> 48 #include <sys/uio.h> 49 #include <sys/debug.h> 50 #include <fs/fs_subr.h> 51 52 /* 53 * Common code for pathconf(), fpathconf() system calls 54 */ 55 static long 56 cpathconf(register vnode_t *vp, int cmd, struct cred *cr) 57 { 58 struct statvfs64 sb; 59 int error; 60 ulong_t val; 61 62 switch (cmd) { 63 case _PC_2_SYMLINKS: 64 if (error = VOP_PATHCONF(vp, _PC_SYMLINK_MAX, &val, cr, NULL)) 65 return ((long)set_errno(error)); 66 return ((long)(val > 0)); 67 68 case _PC_ALLOC_SIZE_MIN: 69 case _PC_REC_INCR_XFER_SIZE: 70 case _PC_REC_MAX_XFER_SIZE: 71 case _PC_REC_MIN_XFER_SIZE: 72 case _PC_REC_XFER_ALIGN: 73 if ((error = VFS_STATVFS(vp->v_vfsp, &sb)) != 0) 74 return ((long)set_errno(error)); 75 76 /* 77 * There is generally no harm in doing larger transfers, but 78 * there's a point of diminishing returns. With 1MB transfers, 79 * even if they're random, you get very close to platter speed. 80 * Se we return 1MB as the maximum transfer size. 81 */ 82 if (cmd == _PC_REC_MAX_XFER_SIZE) 83 return ((long)MAX(sb.f_bsize, 1UL << 20)); 84 85 /* 86 * By definition, f_frsize is the smallest filesystem block. 87 * However, _PC_ALLOC_SIZE_MIN is intended to define the 88 * threshold for direct I/O. This implies two requirements: 89 * the VM and I/O subsystems must be able to create mappings 90 * for DMA, which requires at least page alignment; and the 91 * filesystem must avoid read/modify/write, which generally 92 * requires multiples of its 'preferred' blocksize, f_bsize. 93 * 94 * PAGESIZE alignment is sufficient for DMA and block copy. 95 * Rounding up to the filesystem 'preferred' blocksize 96 * works just as well. 97 * 98 * All together, this means that the remaining parameters 99 * map into the same value. 100 */ 101 return ((long)MAX(sb.f_bsize, PAGESIZE)); 102 103 case _PC_ASYNC_IO: 104 return (1l); 105 106 case _PC_PRIO_IO: 107 return ((long)set_errno(EINVAL)); 108 109 case _PC_SYNC_IO: 110 if (!(error = VOP_FSYNC(vp, FSYNC, cr, NULL))) 111 return (1l); 112 return ((long)set_errno(error)); 113 114 case _PC_XATTR_ENABLED: 115 return ((vp->v_vfsp->vfs_flag & VFS_XATTR) ? 1 : 0); 116 117 default: 118 if (error = VOP_PATHCONF(vp, cmd, &val, cr, NULL)) 119 return ((long)set_errno(error)); 120 return (val); 121 } 122 /* NOTREACHED */ 123 } 124 125 /* fpathconf/pathconf interfaces */ 126 127 long 128 fpathconf(int fdes, int name) 129 { 130 file_t *fp; 131 long retval; 132 133 if ((fp = getf(fdes)) == NULL) 134 return (set_errno(EBADF)); 135 retval = cpathconf(fp->f_vnode, name, fp->f_cred); 136 releasef(fdes); 137 return (retval); 138 } 139 140 long 141 pathconf(char *fname, int name) 142 { 143 vnode_t *vp; 144 long retval; 145 int error; 146 int estale_retry = 0; 147 148 lookup: 149 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 150 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 151 goto lookup; 152 return ((long)set_errno(error)); 153 } 154 155 retval = cpathconf(vp, name, CRED()); 156 VN_RELE(vp); 157 return (retval); 158 } 159