Annotation of sys/ufs/ext2fs/ext2fs_readwrite.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: ext2fs_readwrite.c,v 1.22 2007/06/17 20:15:25 jasper Exp $ */
2: /* $NetBSD: ext2fs_readwrite.c,v 1.16 2001/02/27 04:37:47 chs Exp $ */
3:
4: /*-
5: * Copyright (c) 1997 Manuel Bouyer.
6: * Copyright (c) 1993
7: * The Regents of the University of California. All rights reserved.
8: *
9: * Redistribution and use in source and binary forms, with or without
10: * modification, are permitted provided that the following conditions
11: * are met:
12: * 1. Redistributions of source code must retain the above copyright
13: * notice, this list of conditions and the following disclaimer.
14: * 2. Redistributions in binary form must reproduce the above copyright
15: * notice, this list of conditions and the following disclaimer in the
16: * documentation and/or other materials provided with the distribution.
17: * 3. Neither the name of the University nor the names of its contributors
18: * may be used to endorse or promote products derived from this software
19: * without specific prior written permission.
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31: * SUCH DAMAGE.
32: *
33: * @(#)ufs_readwrite.c 8.8 (Berkeley) 8/4/94
34: * Modified for ext2fs by Manuel Bouyer.
35: */
36:
37: #include <sys/param.h>
38: #include <sys/systm.h>
39: #include <sys/resourcevar.h>
40: #include <sys/kernel.h>
41: #include <sys/file.h>
42: #include <sys/stat.h>
43: #include <sys/buf.h>
44: #include <sys/proc.h>
45: #include <sys/conf.h>
46: #include <sys/mount.h>
47: #include <sys/vnode.h>
48: #include <sys/malloc.h>
49: #include <sys/signalvar.h>
50:
51: #include <ufs/ufs/quota.h>
52: #include <ufs/ufs/inode.h>
53: #include <ufs/ext2fs/ext2fs.h>
54: #include <ufs/ext2fs/ext2fs_extern.h>
55:
56:
57: #define doclusterread 0 /* XXX underway */
58: #define doclusterwrite 0
59:
60: /*
61: * Vnode op for reading.
62: */
63: /* ARGSUSED */
64: int
65: ext2fs_read(void *v)
66: {
67: struct vop_read_args *ap = v;
68: struct vnode *vp;
69: struct inode *ip;
70: struct uio *uio;
71: struct m_ext2fs *fs;
72: struct buf *bp;
73: daddr64_t lbn, nextlbn;
74: off_t bytesinfile;
75: long size, xfersize, blkoffset;
76: int error;
77:
78: vp = ap->a_vp;
79: ip = VTOI(vp);
80: uio = ap->a_uio;
81:
82: #ifdef DIAGNOSTIC
83: if (uio->uio_rw != UIO_READ)
84: panic("%s: mode", "ext2fs_read");
85:
86: if (vp->v_type == VLNK) {
87: if ((int)ext2fs_size(ip) < vp->v_mount->mnt_maxsymlinklen ||
88: (vp->v_mount->mnt_maxsymlinklen == 0 &&
89: ip->i_e2fs_nblock == 0))
90: panic("%s: short symlink", "ext2fs_read");
91: } else if (vp->v_type != VREG && vp->v_type != VDIR)
92: panic("%s: type %d", "ext2fs_read", vp->v_type);
93: #endif
94: fs = ip->i_e2fs;
95: if ((u_int64_t)uio->uio_offset >
96: ((u_int64_t)0x80000000 * fs->e2fs_bsize - 1))
97: return (EFBIG);
98: if (uio->uio_resid == 0)
99: return (0);
100:
101: for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
102: if ((bytesinfile = ext2fs_size(ip) - uio->uio_offset) <= 0)
103: break;
104: lbn = lblkno(fs, uio->uio_offset);
105: nextlbn = lbn + 1;
106: size = fs->e2fs_bsize;
107: blkoffset = blkoff(fs, uio->uio_offset);
108: xfersize = fs->e2fs_bsize - blkoffset;
109: if (uio->uio_resid < xfersize)
110: xfersize = uio->uio_resid;
111: if (bytesinfile < xfersize)
112: xfersize = bytesinfile;
113:
114: if (lblktosize(fs, nextlbn) >= ext2fs_size(ip))
115: error = bread(vp, lbn, size, NOCRED, &bp);
116: else if (lbn - 1 == ip->i_ci.ci_lastr) {
117: int nextsize = fs->e2fs_bsize;
118: error = breadn(vp, lbn,
119: size, &nextlbn, &nextsize, 1, NOCRED, &bp);
120: } else
121: error = bread(vp, lbn, size, NOCRED, &bp);
122: if (error)
123: break;
124: ip->i_ci.ci_lastr = lbn;
125:
126: /*
127: * We should only get non-zero b_resid when an I/O error
128: * has occurred, which should cause us to break above.
129: * However, if the short read did not cause an error,
130: * then we want to ensure that we do not uiomove bad
131: * or uninitialized data.
132: */
133: size -= bp->b_resid;
134: if (size < xfersize) {
135: if (size == 0)
136: break;
137: xfersize = size;
138: }
139: error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio);
140: if (error)
141: break;
142: brelse(bp);
143: }
144: if (bp != NULL)
145: brelse(bp);
146:
147: if (!(vp->v_mount->mnt_flag & MNT_NOATIME)) {
148: ip->i_flag |= IN_ACCESS;
149: }
150: return (error);
151: }
152:
153: /*
154: * Vnode op for writing.
155: */
156: int
157: ext2fs_write(void *v)
158: {
159: struct vop_write_args *ap = v;
160: struct vnode *vp;
161: struct uio *uio;
162: struct inode *ip;
163: struct m_ext2fs *fs;
164: struct buf *bp;
165: struct proc *p;
166: int32_t lbn;
167: off_t osize;
168: int blkoffset, error, flags, ioflag, resid, size, xfersize;
169:
170: ioflag = ap->a_ioflag;
171: uio = ap->a_uio;
172: vp = ap->a_vp;
173: ip = VTOI(vp);
174:
175: #ifdef DIAGNOSTIC
176: if (uio->uio_rw != UIO_WRITE)
177: panic("%s: mode", "ext2fs_write");
178: #endif
179:
180: /*
181: * If writing 0 bytes, succeed and do not change
182: * update time or file offset (standards compliance)
183: */
184: if (uio->uio_resid == 0)
185: return (0);
186:
187: switch (vp->v_type) {
188: case VREG:
189: if (ioflag & IO_APPEND)
190: uio->uio_offset = ext2fs_size(ip);
191: if ((ip->i_e2fs_flags & EXT2_APPEND) &&
192: uio->uio_offset != ext2fs_size(ip))
193: return (EPERM);
194: /* FALLTHROUGH */
195: case VLNK:
196: break;
197: case VDIR:
198: if ((ioflag & IO_SYNC) == 0)
199: panic("%s: nonsync dir write", "ext2fs_write");
200: break;
201: default:
202: panic("%s: type", "ext2fs_write");
203: }
204:
205: fs = ip->i_e2fs;
206: if (uio->uio_offset < 0 ||
207: (u_int64_t)uio->uio_offset + uio->uio_resid >
208: ((u_int64_t)0x80000000 * fs->e2fs_bsize - 1))
209: return (EFBIG);
210: /*
211: * Maybe this should be above the vnode op call, but so long as
212: * file servers have no limits, I don't think it matters.
213: */
214: p = uio->uio_procp;
215: if (vp->v_type == VREG && p &&
216: uio->uio_offset + uio->uio_resid >
217: p->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
218: psignal(p, SIGXFSZ);
219: return (EFBIG);
220: }
221:
222: resid = uio->uio_resid;
223: osize = ext2fs_size(ip);
224: flags = ioflag & IO_SYNC ? B_SYNC : 0;
225:
226: for (error = 0; uio->uio_resid > 0;) {
227: lbn = lblkno(fs, uio->uio_offset);
228: blkoffset = blkoff(fs, uio->uio_offset);
229: xfersize = fs->e2fs_bsize - blkoffset;
230: if (uio->uio_resid < xfersize)
231: xfersize = uio->uio_resid;
232: if (fs->e2fs_bsize > xfersize)
233: flags |= B_CLRBUF;
234: else
235: flags &= ~B_CLRBUF;
236:
237: error = ext2fs_buf_alloc(ip,
238: lbn, blkoffset + xfersize, ap->a_cred, &bp, flags);
239: if (error)
240: break;
241: if (uio->uio_offset + xfersize > ext2fs_size(ip)) {
242: error = ext2fs_setsize(ip, uio->uio_offset + xfersize);
243: if (error)
244: break;
245: uvm_vnp_setsize(vp, ip->i_e2fs_size);
246: }
247: uvm_vnp_uncache(vp);
248:
249: size = fs->e2fs_bsize - bp->b_resid;
250: if (size < xfersize)
251: xfersize = size;
252:
253: error =
254: uiomove((char *)bp->b_data + blkoffset, (int)xfersize, uio);
255: if (ioflag & IO_SYNC)
256: (void)bwrite(bp);
257: else if (xfersize + blkoffset == fs->e2fs_bsize) {
258: if (doclusterwrite)
259: cluster_write(bp, &ip->i_ci, ext2fs_size(ip));
260: else
261: bawrite(bp);
262: } else
263: bdwrite(bp);
264: if (error || xfersize == 0)
265: break;
266: ip->i_flag |= IN_CHANGE | IN_UPDATE;
267: }
268: /*
269: * If we successfully wrote any data, and we are not the superuser
270: * we clear the setuid and setgid bits as a precaution against
271: * tampering.
272: */
273: if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0)
274: ip->i_e2fs_mode &= ~(ISUID | ISGID);
275: if (error) {
276: if (ioflag & IO_UNIT) {
277: (void)ext2fs_truncate(ip, osize,
278: ioflag & IO_SYNC, ap->a_cred);
279: uio->uio_offset -= resid - uio->uio_resid;
280: uio->uio_resid = resid;
281: }
282: } else if (resid > uio->uio_resid && (ioflag & IO_SYNC)) {
283: error = ext2fs_update(ip, NULL, NULL, 1);
284: }
285: return (error);
286: }
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