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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 if (uio
->uio_segflg
== UIO_NOCOPY
)
286 ip
->i_flag
|= IN_NOCOPYWRITE
;
288 vclrflags(vp
, VLASTWRITETS
);
290 for (error
= 0; uio
->uio_resid
> 0;) {
291 lbn
= lblkno(fs
, uio
->uio_offset
);
292 blkoffset
= blkoff(fs
, uio
->uio_offset
);
293 xfersize
= fs
->fs_bsize
- blkoffset
;
294 if (uio
->uio_resid
< xfersize
)
295 xfersize
= uio
->uio_resid
;
297 if (uio
->uio_offset
+ xfersize
> ip
->i_size
) {
298 nsize
= uio
->uio_offset
+ xfersize
;
299 nvnode_pager_setsize(vp
, nsize
,
300 blkoffresize(fs
, nsize
), blkoff(fs
, nsize
));
305 * If doing a dummy write to flush the buffer for a
306 * putpages we must perform a read-before-write to
307 * fill in any missing spots and clear any invalid
308 * areas. Otherwise a multi-page buffer may not properly
311 * We must clear any invalid areas
313 if (uio
->uio_segflg
== UIO_NOCOPY
) {
314 error
= ffs_blkatoff(vp
, uio
->uio_offset
, NULL
, &bp
);
322 * We must clear invalid areas.
324 if (xfersize
< fs
->fs_bsize
|| uio
->uio_segflg
== UIO_NOCOPY
)
328 /* XXX is uio->uio_offset the right thing here? */
329 error
= VOP_BALLOC(vp
, uio
->uio_offset
, xfersize
,
330 ap
->a_cred
, flags
, &bp
);
334 * If the buffer is not valid and we did not clear garbage
335 * out above, we have to do so here even though the write
336 * covers the entire buffer in order to avoid a mmap()/write
337 * race where another process may see the garbage prior to
338 * the uiomove() for a write replacing it.
340 if ((bp
->b_flags
& B_CACHE
) == 0 && (flags
& B_CLRBUF
) == 0)
342 if (ioflag
& IO_DIRECT
)
343 bp
->b_flags
|= B_DIRECT
;
344 if ((ioflag
& (IO_SYNC
|IO_INVAL
)) == (IO_SYNC
|IO_INVAL
))
345 bp
->b_flags
|= B_NOCACHE
;
347 if (uio
->uio_offset
+ xfersize
> ip
->i_size
) {
348 ip
->i_size
= uio
->uio_offset
+ xfersize
;
352 size
= BLKSIZE(fs
, ip
, lbn
) - bp
->b_resid
;
356 error
= uiomovebp(bp
, bp
->b_data
+ blkoffset
, xfersize
, uio
);
357 if ((ioflag
& (IO_VMIO
|IO_DIRECT
)) &&
358 (LIST_FIRST(&bp
->b_dep
) == NULL
)) {
359 bp
->b_flags
|= B_RELBUF
;
363 * If IO_SYNC each buffer is written synchronously. Otherwise
364 * if we have a severe page deficiency write the buffer
365 * asynchronously. Otherwise try to cluster, and if that
366 * doesn't do it then either do an async write (if O_DIRECT),
367 * or a delayed write (if not).
370 if (ioflag
& IO_SYNC
) {
372 } else if (vm_page_count_severe() ||
373 buf_dirty_count_severe() ||
374 (ioflag
& IO_ASYNC
)) {
375 bp
->b_flags
|= B_CLUSTEROK
;
377 } else if (xfersize
+ blkoffset
== fs
->fs_bsize
) {
378 if ((vp
->v_mount
->mnt_flag
& MNT_NOCLUSTERW
) == 0) {
379 bp
->b_flags
|= B_CLUSTEROK
;
380 cluster_write(bp
, (off_t
)ip
->i_size
, fs
->fs_bsize
, seqcount
);
384 } else if (ioflag
& IO_DIRECT
) {
385 bp
->b_flags
|= B_CLUSTEROK
;
388 bp
->b_flags
|= B_CLUSTEROK
;
391 if (error
|| xfersize
== 0)
393 ip
->i_flag
|= IN_CHANGE
| IN_UPDATE
;
396 * If we successfully wrote any data, and we are not the superuser
397 * we clear the setuid and setgid bits as a precaution against
400 if (resid
> uio
->uio_resid
&& ap
->a_cred
&& ap
->a_cred
->cr_uid
!= 0)
401 ip
->i_mode
&= ~(ISUID
| ISGID
);
402 if (resid
> uio
->uio_resid
)
403 VN_KNOTE(vp
, NOTE_WRITE
| (extended
? NOTE_EXTEND
: 0));
405 if (ioflag
& IO_UNIT
) {
406 (void)ffs_truncate(vp
, osize
, ioflag
& IO_SYNC
,
408 uio
->uio_offset
-= resid
- uio
->uio_resid
;
409 uio
->uio_resid
= resid
;
411 } else if (resid
> uio
->uio_resid
&& (ioflag
& IO_SYNC
)) {
412 error
= ffs_update(vp
, 1);
416 if (uio
->uio_segflg
== UIO_NOCOPY
)
417 ip
->i_flag
&= ~IN_NOCOPYWRITE
;