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29 * @(#)ufs_readwrite.c 8.11 (Berkeley) 5/8/95
30 * $FreeBSD: src/sys/ufs/ufs/ufs_readwrite.c,v 1.65.2.14 2003/04/04 22:21:29 tegge Exp $
33 #define BLKSIZE(a, b, c) blksize(a, b, c)
38 #include <vm/vm_object.h>
39 #include <vm/vm_pager.h>
40 #include <vm/vm_map.h>
41 #include <vm/vnode_pager.h>
42 #include <sys/event.h>
43 #include <sys/vmmeter.h>
44 #include <sys/sysctl.h>
45 #include <vm/vm_page2.h>
47 #define VN_KNOTE(vp, b) KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, (b))
49 SYSCTL_DECL(_vfs_ffs);
52 * Vnode op for reading.
54 * ffs_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
55 * struct ucred *a_cred)
59 ffs_read(struct vop_read_args *ap)
67 int xfersize, blkoffset;
68 int error, orig_resid;
73 seqcount = ap->a_ioflag >> 16;
76 ioflag = ap->a_ioflag;
78 if (uio->uio_rw != UIO_READ)
79 panic("ffs_read: mode");
81 if (vp->v_type == VLNK) {
82 if ((int)ip->i_size < vp->v_mount->mnt_maxsymlinklen)
83 panic("ffs_read: short symlink");
84 } else if (vp->v_type != VREG && vp->v_type != VDIR)
85 panic("ffs_read: type %d", vp->v_type);
88 if ((uint64_t)uio->uio_offset > fs->fs_maxfilesize)
91 orig_resid = uio->uio_resid;
95 bytesinfile = ip->i_size - uio->uio_offset;
96 if (bytesinfile <= 0) {
97 if ((vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
98 ip->i_flag |= IN_ACCESS;
103 * Ok so we couldn't do it all in one vm trick...
104 * so cycle around trying smaller bites..
106 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
107 if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0)
110 error = ffs_blkatoff_ra(vp, uio->uio_offset, NULL,
116 * If IO_DIRECT then set B_DIRECT for the buffer. This
117 * will cause us to attempt to release the buffer later on
118 * and will cause the buffer cache to attempt to free the
121 if (ioflag & IO_DIRECT)
122 bp->b_flags |= B_DIRECT;
125 * We should only get non-zero b_resid when an I/O error
126 * has occurred, which should cause us to break above.
127 * However, if the short read did not cause an error,
128 * then we want to ensure that we do not uiomove bad
129 * or uninitialized data.
131 * XXX b_resid is only valid when an actual I/O has occured
132 * and may be incorrect if the buffer is B_CACHE or if the
133 * last op on the buffer was a failed write. This KASSERT
134 * is a precursor to removing it from the UFS code.
136 KASSERT(bp->b_resid == 0, ("bp->b_resid != 0"));
139 * Calculate how much data we can copy
141 blkoffset = blkoff(fs, uio->uio_offset);
142 xfersize = bp->b_bufsize - blkoffset;
143 if (xfersize > uio->uio_resid)
144 xfersize = uio->uio_resid;
145 if (xfersize > bytesinfile)
146 xfersize = bytesinfile;
148 panic("ufs_readwrite: impossible xfersize: %d",
153 * otherwise use the general form
155 error = uiomovebp(bp, bp->b_data + blkoffset, xfersize, uio);
160 if ((ioflag & (IO_VMIO|IO_DIRECT)) &&
161 (LIST_FIRST(&bp->b_dep) == NULL)) {
163 * If there are no dependencies, and it's VMIO,
164 * then we don't need the buf, mark it available
165 * for freeing. The VM has the data.
167 bp->b_flags |= B_RELBUF;
171 * Otherwise let whoever
172 * made the request take care of
173 * freeing it. We just queue
174 * it onto another list.
181 * This can only happen in the case of an error
182 * because the loop above resets bp to NULL on each iteration
183 * and on normal completion has not set a new value into it.
184 * so it must have come from a 'break' statement
187 if ((ioflag & (IO_VMIO|IO_DIRECT)) &&
188 (LIST_FIRST(&bp->b_dep) == NULL)) {
189 bp->b_flags |= B_RELBUF;
196 if ((error == 0 || uio->uio_resid != orig_resid) &&
197 (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
198 ip->i_flag |= IN_ACCESS;
203 * Vnode op for writing.
205 * ffs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
206 * struct ucred *a_cred)
209 ffs_write(struct vop_write_args *ap)
220 int blkoffset, error, extended, flags, ioflag, resid, size, xfersize;
224 seqcount = ap->a_ioflag >> 16;
225 ioflag = ap->a_ioflag;
231 if (uio->uio_rw != UIO_WRITE)
232 panic("ffs_write: mode");
235 switch (vp->v_type) {
237 if (ioflag & IO_APPEND)
238 uio->uio_offset = ip->i_size;
239 if ((ip->i_flags & APPEND) && uio->uio_offset != ip->i_size)
245 panic("ffs_write: dir write");
248 panic("ffs_write: type %p %d (%d,%d)", vp, (int)vp->v_type,
249 (int)uio->uio_offset,
255 if (uio->uio_offset < 0 ||
256 (uint64_t)uio->uio_offset + uio->uio_resid > fs->fs_maxfilesize) {
260 * Maybe this should be above the vnode op call, but so long as
261 * file servers have no limits, I don't think it matters.
264 if (vp->v_type == VREG && td && td->td_proc &&
265 uio->uio_offset + uio->uio_resid >
266 td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
267 lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ);
271 resid = uio->uio_resid;
275 * NOTE! These B_ flags are actually balloc-only flags, not buffer
276 * flags. They are similar to the BA_ flags in fbsd.
278 if (seqcount > B_SEQMAX)
279 flags = B_SEQMAX << B_SEQSHIFT;
281 flags = seqcount << B_SEQSHIFT;
282 if ((ioflag & IO_SYNC) && !DOINGASYNC(vp))
285 ip->i_flag |= IN_WRITING;
287 for (error = 0; uio->uio_resid > 0;) {
288 lbn = lblkno(fs, uio->uio_offset);
289 blkoffset = blkoff(fs, uio->uio_offset);
290 xfersize = fs->fs_bsize - blkoffset;
291 if (uio->uio_resid < xfersize)
292 xfersize = uio->uio_resid;
294 if (uio->uio_offset + xfersize > ip->i_size) {
295 nsize = uio->uio_offset + xfersize;
296 nvnode_pager_setsize(vp, nsize,
297 blkoffresize(fs, nsize), blkoff(fs, nsize));
302 * If doing a dummy write to flush the buffer for a
303 * putpages we must perform a read-before-write to
304 * fill in any missing spots and clear any invalid
305 * areas. Otherwise a multi-page buffer may not properly
308 * We must clear any invalid areas
310 if (uio->uio_segflg == UIO_NOCOPY) {
311 error = ffs_blkatoff(vp, uio->uio_offset, NULL, &bp);
319 * We must clear invalid areas.
321 if (xfersize < fs->fs_bsize || uio->uio_segflg == UIO_NOCOPY)
325 /* XXX is uio->uio_offset the right thing here? */
326 error = VOP_BALLOC(vp, uio->uio_offset, xfersize,
327 ap->a_cred, flags, &bp);
331 * If the buffer is not valid and we did not clear garbage
332 * out above, we have to do so here even though the write
333 * covers the entire buffer in order to avoid a mmap()/write
334 * race where another process may see the garbage prior to
335 * the uiomove() for a write replacing it.
337 if ((bp->b_flags & B_CACHE) == 0 && (flags & B_CLRBUF) == 0)
339 if (ioflag & IO_DIRECT)
340 bp->b_flags |= B_DIRECT;
341 if ((ioflag & (IO_SYNC|IO_INVAL)) == (IO_SYNC|IO_INVAL))
342 bp->b_flags |= B_NOCACHE;
344 if (uio->uio_offset + xfersize > ip->i_size) {
345 ip->i_size = uio->uio_offset + xfersize;
349 size = BLKSIZE(fs, ip, lbn) - bp->b_resid;
353 error = uiomovebp(bp, bp->b_data + blkoffset, xfersize, uio);
354 if ((ioflag & (IO_VMIO|IO_DIRECT)) &&
355 (LIST_FIRST(&bp->b_dep) == NULL)) {
356 bp->b_flags |= B_RELBUF;
360 * If IO_SYNC each buffer is written synchronously. Otherwise
361 * if we have a severe page deficiency write the buffer
362 * asynchronously. Otherwise try to cluster, and if that
363 * doesn't do it then either do an async write (if O_DIRECT),
364 * or a delayed write (if not).
367 if (ioflag & IO_SYNC) {
369 } else if (vm_page_count_severe() ||
370 buf_dirty_count_severe() ||
371 (ioflag & IO_ASYNC)) {
372 bp->b_flags |= B_CLUSTEROK;
374 } else if (xfersize + blkoffset == fs->fs_bsize) {
375 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) {
376 bp->b_flags |= B_CLUSTEROK;
377 cluster_write(bp, (off_t)ip->i_size, fs->fs_bsize, seqcount);
381 } else if (ioflag & IO_DIRECT) {
382 bp->b_flags |= B_CLUSTEROK;
385 bp->b_flags |= B_CLUSTEROK;
388 if (error || xfersize == 0)
390 ip->i_flag |= IN_CHANGE | IN_UPDATE;
393 * If we successfully wrote any data, and we are not the superuser
394 * we clear the setuid and setgid bits as a precaution against
397 if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0)
398 ip->i_mode &= ~(ISUID | ISGID);
399 if (resid > uio->uio_resid)
400 VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0));
402 if (ioflag & IO_UNIT) {
403 (void)ffs_truncate(vp, osize, ioflag & IO_SYNC,
405 uio->uio_offset -= resid - uio->uio_resid;
406 uio->uio_resid = resid;
408 } else if (resid > uio->uio_resid && (ioflag & IO_SYNC)) {
409 error = ffs_update(vp, 1);
413 ip->i_flag &= ~IN_WRITING;