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33 * @(#)ufs_readwrite.c 8.11 (Berkeley) 5/8/95
34 * $FreeBSD: src/sys/ufs/ufs/ufs_readwrite.c,v 1.65.2.14 2003/04/04 22:21:29 tegge Exp $
35 * $DragonFly: src/sys/vfs/ufs/ufs_readwrite.c,v 1.26 2008/06/19 23:27:39 dillon Exp $
38 #define BLKSIZE(a, b, c) blksize(a, b, c)
43 #include <vm/vm_object.h>
44 #include <vm/vm_pager.h>
45 #include <vm/vm_map.h>
46 #include <vm/vnode_pager.h>
47 #include <sys/event.h>
48 #include <sys/vmmeter.h>
49 #include <sys/sysctl.h>
50 #include <vm/vm_page2.h>
52 #include "opt_directio.h"
54 #define VN_KNOTE(vp, b) \
55 KNOTE((struct klist *)&vp->v_pollinfo.vpi_selinfo.si_note, (b))
58 extern int ffs_rawread(struct vnode
*vp
, struct uio
*uio
, int *workdone
);
61 SYSCTL_DECL(_vfs_ffs
);
64 * Vnode op for reading.
66 * ffs_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
67 * struct ucred *a_cred)
71 ffs_read(struct vop_read_args
*ap
)
79 int xfersize
, blkoffset
;
80 int error
, orig_resid
;
86 seqcount
= ap
->a_ioflag
>> 16;
90 ioflag
= ap
->a_ioflag
;
92 if ((ioflag
& IO_DIRECT
) != 0) {
95 error
= ffs_rawread(vp
, uio
, &workdone
);
96 if (error
|| workdone
)
102 if (uio
->uio_rw
!= UIO_READ
)
103 panic("ffs_read: mode");
105 if (vp
->v_type
== VLNK
) {
106 if ((int)ip
->i_size
< vp
->v_mount
->mnt_maxsymlinklen
)
107 panic("ffs_read: short symlink");
108 } else if (vp
->v_type
!= VREG
&& vp
->v_type
!= VDIR
)
109 panic("ffs_read: type %d", vp
->v_type
);
112 if ((uint64_t)uio
->uio_offset
> fs
->fs_maxfilesize
)
115 orig_resid
= uio
->uio_resid
;
119 bytesinfile
= ip
->i_size
- uio
->uio_offset
;
120 if (bytesinfile
<= 0) {
121 if ((vp
->v_mount
->mnt_flag
& MNT_NOATIME
) == 0)
122 ip
->i_flag
|= IN_ACCESS
;
127 * Ok so we couldn't do it all in one vm trick...
128 * so cycle around trying smaller bites..
130 for (error
= 0, bp
= NULL
; uio
->uio_resid
> 0; bp
= NULL
) {
131 if ((bytesinfile
= ip
->i_size
- uio
->uio_offset
) <= 0)
134 error
= ffs_blkatoff_ra(vp
, uio
->uio_offset
, NULL
,
140 * If IO_DIRECT then set B_DIRECT for the buffer. This
141 * will cause us to attempt to release the buffer later on
142 * and will cause the buffer cache to attempt to free the
145 if (ioflag
& IO_DIRECT
)
146 bp
->b_flags
|= B_DIRECT
;
149 * We should only get non-zero b_resid when an I/O error
150 * has occurred, which should cause us to break above.
151 * However, if the short read did not cause an error,
152 * then we want to ensure that we do not uiomove bad
153 * or uninitialized data.
155 * XXX b_resid is only valid when an actual I/O has occured
156 * and may be incorrect if the buffer is B_CACHE or if the
157 * last op on the buffer was a failed write. This KASSERT
158 * is a precursor to removing it from the UFS code.
160 KASSERT(bp
->b_resid
== 0, ("bp->b_resid != 0"));
163 * Calculate how much data we can copy
165 blkoffset
= blkoff(fs
, uio
->uio_offset
);
166 xfersize
= bp
->b_bufsize
- blkoffset
;
167 if (xfersize
> uio
->uio_resid
)
168 xfersize
= uio
->uio_resid
;
169 if (xfersize
> bytesinfile
)
170 xfersize
= bytesinfile
;
172 panic("ufs_readwrite: impossible xfersize: %d",
177 * otherwise use the general form
179 error
= uiomove(bp
->b_data
+ blkoffset
, (int)xfersize
, uio
);
184 if ((ioflag
& (IO_VMIO
|IO_DIRECT
)) &&
185 (LIST_FIRST(&bp
->b_dep
) == NULL
)) {
187 * If there are no dependencies, and it's VMIO,
188 * then we don't need the buf, mark it available
189 * for freeing. The VM has the data.
191 bp
->b_flags
|= B_RELBUF
;
195 * Otherwise let whoever
196 * made the request take care of
197 * freeing it. We just queue
198 * it onto another list.
205 * This can only happen in the case of an error
206 * because the loop above resets bp to NULL on each iteration
207 * and on normal completion has not set a new value into it.
208 * so it must have come from a 'break' statement
211 if ((ioflag
& (IO_VMIO
|IO_DIRECT
)) &&
212 (LIST_FIRST(&bp
->b_dep
) == NULL
)) {
213 bp
->b_flags
|= B_RELBUF
;
220 if ((error
== 0 || uio
->uio_resid
!= orig_resid
) &&
221 (vp
->v_mount
->mnt_flag
& MNT_NOATIME
) == 0)
222 ip
->i_flag
|= IN_ACCESS
;
227 * Vnode op for writing.
229 * ffs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
230 * struct ucred *a_cred)
233 ffs_write(struct vop_write_args
*ap
)
244 int blkoffset
, error
, extended
, flags
, ioflag
, resid
, size
, xfersize
;
248 seqcount
= ap
->a_ioflag
>> 16;
249 ioflag
= ap
->a_ioflag
;
255 if (uio
->uio_rw
!= UIO_WRITE
)
256 panic("ffs_write: mode");
259 switch (vp
->v_type
) {
261 if (ioflag
& IO_APPEND
)
262 uio
->uio_offset
= ip
->i_size
;
263 if ((ip
->i_flags
& APPEND
) && uio
->uio_offset
!= ip
->i_size
)
269 panic("ffs_write: dir write");
272 panic("ffs_write: type %p %d (%d,%d)", vp
, (int)vp
->v_type
,
273 (int)uio
->uio_offset
,
279 if (uio
->uio_offset
< 0 ||
280 (uint64_t)uio
->uio_offset
+ uio
->uio_resid
> fs
->fs_maxfilesize
) {
284 * Maybe this should be above the vnode op call, but so long as
285 * file servers have no limits, I don't think it matters.
288 if (vp
->v_type
== VREG
&& td
&& td
->td_proc
&&
289 uio
->uio_offset
+ uio
->uio_resid
>
290 td
->td_proc
->p_rlimit
[RLIMIT_FSIZE
].rlim_cur
) {
291 lwpsignal(td
->td_proc
, td
->td_lwp
, SIGXFSZ
);
295 resid
= uio
->uio_resid
;
299 * NOTE! These B_ flags are actually balloc-only flags, not buffer
300 * flags. They are similar to the BA_ flags in fbsd.
302 if (seqcount
> B_SEQMAX
)
303 flags
= B_SEQMAX
<< B_SEQSHIFT
;
305 flags
= seqcount
<< B_SEQSHIFT
;
306 if ((ioflag
& IO_SYNC
) && !DOINGASYNC(vp
))
309 for (error
= 0; uio
->uio_resid
> 0;) {
310 lbn
= lblkno(fs
, uio
->uio_offset
);
311 blkoffset
= blkoff(fs
, uio
->uio_offset
);
312 xfersize
= fs
->fs_bsize
- blkoffset
;
313 if (uio
->uio_resid
< xfersize
)
314 xfersize
= uio
->uio_resid
;
316 if (uio
->uio_offset
+ xfersize
> ip
->i_size
) {
317 nsize
= uio
->uio_offset
+ xfersize
;
318 nvnode_pager_setsize(vp
, nsize
,
319 blkoffresize(fs
, nsize
), blkoff(fs
, nsize
));
324 * If doing a dummy write to flush the buffer for a
325 * putpages we must perform a read-before-write to
326 * fill in any missing spots and clear any invalid
327 * areas. Otherwise a multi-page buffer may not properly
330 * We must clear any invalid areas
332 if (uio
->uio_segflg
== UIO_NOCOPY
) {
333 error
= ffs_blkatoff(vp
, uio
->uio_offset
, NULL
, &bp
);
341 * We must clear invalid areas.
343 if (xfersize
< fs
->fs_bsize
|| uio
->uio_segflg
== UIO_NOCOPY
)
347 /* XXX is uio->uio_offset the right thing here? */
348 error
= VOP_BALLOC(vp
, uio
->uio_offset
, xfersize
,
349 ap
->a_cred
, flags
, &bp
);
353 * If the buffer is not valid and we did not clear garbage
354 * out above, we have to do so here even though the write
355 * covers the entire buffer in order to avoid a mmap()/write
356 * race where another process may see the garbage prior to
357 * the uiomove() for a write replacing it.
359 if ((bp
->b_flags
& B_CACHE
) == 0 && (flags
& B_CLRBUF
) == 0)
361 if (ioflag
& IO_DIRECT
)
362 bp
->b_flags
|= B_DIRECT
;
363 if ((ioflag
& (IO_SYNC
|IO_INVAL
)) == (IO_SYNC
|IO_INVAL
))
364 bp
->b_flags
|= B_NOCACHE
;
366 if (uio
->uio_offset
+ xfersize
> ip
->i_size
) {
367 ip
->i_size
= uio
->uio_offset
+ xfersize
;
371 size
= BLKSIZE(fs
, ip
, lbn
) - bp
->b_resid
;
375 error
= uiomove(bp
->b_data
+ blkoffset
, (int)xfersize
, uio
);
376 if ((ioflag
& (IO_VMIO
|IO_DIRECT
)) &&
377 (LIST_FIRST(&bp
->b_dep
) == NULL
)) {
378 bp
->b_flags
|= B_RELBUF
;
382 * If IO_SYNC each buffer is written synchronously. Otherwise
383 * if we have a severe page deficiency write the buffer
384 * asynchronously. Otherwise try to cluster, and if that
385 * doesn't do it then either do an async write (if O_DIRECT),
386 * or a delayed write (if not).
389 if (ioflag
& IO_SYNC
) {
391 } else if (vm_page_count_severe() ||
392 buf_dirty_count_severe() ||
393 (ioflag
& IO_ASYNC
)) {
394 bp
->b_flags
|= B_CLUSTEROK
;
396 } else if (xfersize
+ blkoffset
== fs
->fs_bsize
) {
397 if ((vp
->v_mount
->mnt_flag
& MNT_NOCLUSTERW
) == 0) {
398 bp
->b_flags
|= B_CLUSTEROK
;
399 cluster_write(bp
, (off_t
)ip
->i_size
, fs
->fs_bsize
, seqcount
);
403 } else if (ioflag
& IO_DIRECT
) {
404 bp
->b_flags
|= B_CLUSTEROK
;
407 bp
->b_flags
|= B_CLUSTEROK
;
410 if (error
|| xfersize
== 0)
412 ip
->i_flag
|= IN_CHANGE
| IN_UPDATE
;
415 * If we successfully wrote any data, and we are not the superuser
416 * we clear the setuid and setgid bits as a precaution against
419 if (resid
> uio
->uio_resid
&& ap
->a_cred
&& ap
->a_cred
->cr_uid
!= 0)
420 ip
->i_mode
&= ~(ISUID
| ISGID
);
421 if (resid
> uio
->uio_resid
)
422 VN_KNOTE(vp
, NOTE_WRITE
| (extended
? NOTE_EXTEND
: 0));
424 if (ioflag
& IO_UNIT
) {
425 (void)ffs_truncate(vp
, osize
, ioflag
& IO_SYNC
,
427 uio
->uio_offset
-= resid
- uio
->uio_resid
;
428 uio
->uio_resid
= resid
;
430 } else if (resid
> uio
->uio_resid
&& (ioflag
& IO_SYNC
)) {
431 error
= ffs_update(vp
, 1);