xref: /openbmc/qemu/hw/9pfs/9p.c (revision e09484ef)
1 /*
2  * Virtio 9p backend
3  *
4  * Copyright IBM, Corp. 2010
5  *
6  * Authors:
7  *  Anthony Liguori   <aliguori@us.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 #include "hw/virtio/virtio.h"
16 #include "qapi/error.h"
17 #include "qemu/error-report.h"
18 #include "qemu/iov.h"
19 #include "qemu/sockets.h"
20 #include "virtio-9p.h"
21 #include "fsdev/qemu-fsdev.h"
22 #include "9p-xattr.h"
23 #include "coth.h"
24 #include "trace.h"
25 #include "migration/migration.h"
26 
27 int open_fd_hw;
28 int total_open_fd;
29 static int open_fd_rc;
30 
31 enum {
32     Oread   = 0x00,
33     Owrite  = 0x01,
34     Ordwr   = 0x02,
35     Oexec   = 0x03,
36     Oexcl   = 0x04,
37     Otrunc  = 0x10,
38     Orexec  = 0x20,
39     Orclose = 0x40,
40     Oappend = 0x80,
41 };
42 
43 ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
44 {
45     ssize_t ret;
46     va_list ap;
47 
48     va_start(ap, fmt);
49     ret = virtio_pdu_vmarshal(pdu, offset, fmt, ap);
50     va_end(ap);
51 
52     return ret;
53 }
54 
55 ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
56 {
57     ssize_t ret;
58     va_list ap;
59 
60     va_start(ap, fmt);
61     ret = virtio_pdu_vunmarshal(pdu, offset, fmt, ap);
62     va_end(ap);
63 
64     return ret;
65 }
66 
67 static void pdu_push_and_notify(V9fsPDU *pdu)
68 {
69     virtio_9p_push_and_notify(pdu);
70 }
71 
72 static int omode_to_uflags(int8_t mode)
73 {
74     int ret = 0;
75 
76     switch (mode & 3) {
77     case Oread:
78         ret = O_RDONLY;
79         break;
80     case Ordwr:
81         ret = O_RDWR;
82         break;
83     case Owrite:
84         ret = O_WRONLY;
85         break;
86     case Oexec:
87         ret = O_RDONLY;
88         break;
89     }
90 
91     if (mode & Otrunc) {
92         ret |= O_TRUNC;
93     }
94 
95     if (mode & Oappend) {
96         ret |= O_APPEND;
97     }
98 
99     if (mode & Oexcl) {
100         ret |= O_EXCL;
101     }
102 
103     return ret;
104 }
105 
106 struct dotl_openflag_map {
107     int dotl_flag;
108     int open_flag;
109 };
110 
111 static int dotl_to_open_flags(int flags)
112 {
113     int i;
114     /*
115      * We have same bits for P9_DOTL_READONLY, P9_DOTL_WRONLY
116      * and P9_DOTL_NOACCESS
117      */
118     int oflags = flags & O_ACCMODE;
119 
120     struct dotl_openflag_map dotl_oflag_map[] = {
121         { P9_DOTL_CREATE, O_CREAT },
122         { P9_DOTL_EXCL, O_EXCL },
123         { P9_DOTL_NOCTTY , O_NOCTTY },
124         { P9_DOTL_TRUNC, O_TRUNC },
125         { P9_DOTL_APPEND, O_APPEND },
126         { P9_DOTL_NONBLOCK, O_NONBLOCK } ,
127         { P9_DOTL_DSYNC, O_DSYNC },
128         { P9_DOTL_FASYNC, FASYNC },
129         { P9_DOTL_DIRECT, O_DIRECT },
130         { P9_DOTL_LARGEFILE, O_LARGEFILE },
131         { P9_DOTL_DIRECTORY, O_DIRECTORY },
132         { P9_DOTL_NOFOLLOW, O_NOFOLLOW },
133         { P9_DOTL_NOATIME, O_NOATIME },
134         { P9_DOTL_SYNC, O_SYNC },
135     };
136 
137     for (i = 0; i < ARRAY_SIZE(dotl_oflag_map); i++) {
138         if (flags & dotl_oflag_map[i].dotl_flag) {
139             oflags |= dotl_oflag_map[i].open_flag;
140         }
141     }
142 
143     return oflags;
144 }
145 
146 void cred_init(FsCred *credp)
147 {
148     credp->fc_uid = -1;
149     credp->fc_gid = -1;
150     credp->fc_mode = -1;
151     credp->fc_rdev = -1;
152 }
153 
154 static int get_dotl_openflags(V9fsState *s, int oflags)
155 {
156     int flags;
157     /*
158      * Filter the client open flags
159      */
160     flags = dotl_to_open_flags(oflags);
161     flags &= ~(O_NOCTTY | O_ASYNC | O_CREAT);
162     /*
163      * Ignore direct disk access hint until the server supports it.
164      */
165     flags &= ~O_DIRECT;
166     return flags;
167 }
168 
169 void v9fs_path_init(V9fsPath *path)
170 {
171     path->data = NULL;
172     path->size = 0;
173 }
174 
175 void v9fs_path_free(V9fsPath *path)
176 {
177     g_free(path->data);
178     path->data = NULL;
179     path->size = 0;
180 }
181 
182 void v9fs_path_copy(V9fsPath *lhs, V9fsPath *rhs)
183 {
184     v9fs_path_free(lhs);
185     lhs->data = g_malloc(rhs->size);
186     memcpy(lhs->data, rhs->data, rhs->size);
187     lhs->size = rhs->size;
188 }
189 
190 int v9fs_name_to_path(V9fsState *s, V9fsPath *dirpath,
191                       const char *name, V9fsPath *path)
192 {
193     int err;
194     err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
195     if (err < 0) {
196         err = -errno;
197     }
198     return err;
199 }
200 
201 /*
202  * Return TRUE if s1 is an ancestor of s2.
203  *
204  * E.g. "a/b" is an ancestor of "a/b/c" but not of "a/bc/d".
205  * As a special case, We treat s1 as ancestor of s2 if they are same!
206  */
207 static int v9fs_path_is_ancestor(V9fsPath *s1, V9fsPath *s2)
208 {
209     if (!strncmp(s1->data, s2->data, s1->size - 1)) {
210         if (s2->data[s1->size - 1] == '\0' || s2->data[s1->size - 1] == '/') {
211             return 1;
212         }
213     }
214     return 0;
215 }
216 
217 static size_t v9fs_string_size(V9fsString *str)
218 {
219     return str->size;
220 }
221 
222 /*
223  * returns 0 if fid got re-opened, 1 if not, < 0 on error */
224 static int v9fs_reopen_fid(V9fsPDU *pdu, V9fsFidState *f)
225 {
226     int err = 1;
227     if (f->fid_type == P9_FID_FILE) {
228         if (f->fs.fd == -1) {
229             do {
230                 err = v9fs_co_open(pdu, f, f->open_flags);
231             } while (err == -EINTR && !pdu->cancelled);
232         }
233     } else if (f->fid_type == P9_FID_DIR) {
234         if (f->fs.dir.stream == NULL) {
235             do {
236                 err = v9fs_co_opendir(pdu, f);
237             } while (err == -EINTR && !pdu->cancelled);
238         }
239     }
240     return err;
241 }
242 
243 static V9fsFidState *get_fid(V9fsPDU *pdu, int32_t fid)
244 {
245     int err;
246     V9fsFidState *f;
247     V9fsState *s = pdu->s;
248 
249     for (f = s->fid_list; f; f = f->next) {
250         BUG_ON(f->clunked);
251         if (f->fid == fid) {
252             /*
253              * Update the fid ref upfront so that
254              * we don't get reclaimed when we yield
255              * in open later.
256              */
257             f->ref++;
258             /*
259              * check whether we need to reopen the
260              * file. We might have closed the fd
261              * while trying to free up some file
262              * descriptors.
263              */
264             err = v9fs_reopen_fid(pdu, f);
265             if (err < 0) {
266                 f->ref--;
267                 return NULL;
268             }
269             /*
270              * Mark the fid as referenced so that the LRU
271              * reclaim won't close the file descriptor
272              */
273             f->flags |= FID_REFERENCED;
274             return f;
275         }
276     }
277     return NULL;
278 }
279 
280 static V9fsFidState *alloc_fid(V9fsState *s, int32_t fid)
281 {
282     V9fsFidState *f;
283 
284     for (f = s->fid_list; f; f = f->next) {
285         /* If fid is already there return NULL */
286         BUG_ON(f->clunked);
287         if (f->fid == fid) {
288             return NULL;
289         }
290     }
291     f = g_malloc0(sizeof(V9fsFidState));
292     f->fid = fid;
293     f->fid_type = P9_FID_NONE;
294     f->ref = 1;
295     /*
296      * Mark the fid as referenced so that the LRU
297      * reclaim won't close the file descriptor
298      */
299     f->flags |= FID_REFERENCED;
300     f->next = s->fid_list;
301     s->fid_list = f;
302 
303     v9fs_readdir_init(&f->fs.dir);
304     v9fs_readdir_init(&f->fs_reclaim.dir);
305 
306     return f;
307 }
308 
309 static int v9fs_xattr_fid_clunk(V9fsPDU *pdu, V9fsFidState *fidp)
310 {
311     int retval = 0;
312 
313     if (fidp->fs.xattr.copied_len == -1) {
314         /* getxattr/listxattr fid */
315         goto free_value;
316     }
317     /*
318      * if this is fid for setxattr. clunk should
319      * result in setxattr localcall
320      */
321     if (fidp->fs.xattr.len != fidp->fs.xattr.copied_len) {
322         /* clunk after partial write */
323         retval = -EINVAL;
324         goto free_out;
325     }
326     if (fidp->fs.xattr.len) {
327         retval = v9fs_co_lsetxattr(pdu, &fidp->path, &fidp->fs.xattr.name,
328                                    fidp->fs.xattr.value,
329                                    fidp->fs.xattr.len,
330                                    fidp->fs.xattr.flags);
331     } else {
332         retval = v9fs_co_lremovexattr(pdu, &fidp->path, &fidp->fs.xattr.name);
333     }
334 free_out:
335     v9fs_string_free(&fidp->fs.xattr.name);
336 free_value:
337     g_free(fidp->fs.xattr.value);
338     return retval;
339 }
340 
341 static int free_fid(V9fsPDU *pdu, V9fsFidState *fidp)
342 {
343     int retval = 0;
344 
345     if (fidp->fid_type == P9_FID_FILE) {
346         /* If we reclaimed the fd no need to close */
347         if (fidp->fs.fd != -1) {
348             retval = v9fs_co_close(pdu, &fidp->fs);
349         }
350     } else if (fidp->fid_type == P9_FID_DIR) {
351         if (fidp->fs.dir.stream != NULL) {
352             retval = v9fs_co_closedir(pdu, &fidp->fs);
353         }
354     } else if (fidp->fid_type == P9_FID_XATTR) {
355         retval = v9fs_xattr_fid_clunk(pdu, fidp);
356     }
357     v9fs_path_free(&fidp->path);
358     g_free(fidp);
359     return retval;
360 }
361 
362 static int put_fid(V9fsPDU *pdu, V9fsFidState *fidp)
363 {
364     BUG_ON(!fidp->ref);
365     fidp->ref--;
366     /*
367      * Don't free the fid if it is in reclaim list
368      */
369     if (!fidp->ref && fidp->clunked) {
370         if (fidp->fid == pdu->s->root_fid) {
371             /*
372              * if the clunked fid is root fid then we
373              * have unmounted the fs on the client side.
374              * delete the migration blocker. Ideally, this
375              * should be hooked to transport close notification
376              */
377             if (pdu->s->migration_blocker) {
378                 migrate_del_blocker(pdu->s->migration_blocker);
379                 error_free(pdu->s->migration_blocker);
380                 pdu->s->migration_blocker = NULL;
381             }
382         }
383         return free_fid(pdu, fidp);
384     }
385     return 0;
386 }
387 
388 static V9fsFidState *clunk_fid(V9fsState *s, int32_t fid)
389 {
390     V9fsFidState **fidpp, *fidp;
391 
392     for (fidpp = &s->fid_list; *fidpp; fidpp = &(*fidpp)->next) {
393         if ((*fidpp)->fid == fid) {
394             break;
395         }
396     }
397     if (*fidpp == NULL) {
398         return NULL;
399     }
400     fidp = *fidpp;
401     *fidpp = fidp->next;
402     fidp->clunked = 1;
403     return fidp;
404 }
405 
406 void v9fs_reclaim_fd(V9fsPDU *pdu)
407 {
408     int reclaim_count = 0;
409     V9fsState *s = pdu->s;
410     V9fsFidState *f, *reclaim_list = NULL;
411 
412     for (f = s->fid_list; f; f = f->next) {
413         /*
414          * Unlink fids cannot be reclaimed. Check
415          * for them and skip them. Also skip fids
416          * currently being operated on.
417          */
418         if (f->ref || f->flags & FID_NON_RECLAIMABLE) {
419             continue;
420         }
421         /*
422          * if it is a recently referenced fid
423          * we leave the fid untouched and clear the
424          * reference bit. We come back to it later
425          * in the next iteration. (a simple LRU without
426          * moving list elements around)
427          */
428         if (f->flags & FID_REFERENCED) {
429             f->flags &= ~FID_REFERENCED;
430             continue;
431         }
432         /*
433          * Add fids to reclaim list.
434          */
435         if (f->fid_type == P9_FID_FILE) {
436             if (f->fs.fd != -1) {
437                 /*
438                  * Up the reference count so that
439                  * a clunk request won't free this fid
440                  */
441                 f->ref++;
442                 f->rclm_lst = reclaim_list;
443                 reclaim_list = f;
444                 f->fs_reclaim.fd = f->fs.fd;
445                 f->fs.fd = -1;
446                 reclaim_count++;
447             }
448         } else if (f->fid_type == P9_FID_DIR) {
449             if (f->fs.dir.stream != NULL) {
450                 /*
451                  * Up the reference count so that
452                  * a clunk request won't free this fid
453                  */
454                 f->ref++;
455                 f->rclm_lst = reclaim_list;
456                 reclaim_list = f;
457                 f->fs_reclaim.dir.stream = f->fs.dir.stream;
458                 f->fs.dir.stream = NULL;
459                 reclaim_count++;
460             }
461         }
462         if (reclaim_count >= open_fd_rc) {
463             break;
464         }
465     }
466     /*
467      * Now close the fid in reclaim list. Free them if they
468      * are already clunked.
469      */
470     while (reclaim_list) {
471         f = reclaim_list;
472         reclaim_list = f->rclm_lst;
473         if (f->fid_type == P9_FID_FILE) {
474             v9fs_co_close(pdu, &f->fs_reclaim);
475         } else if (f->fid_type == P9_FID_DIR) {
476             v9fs_co_closedir(pdu, &f->fs_reclaim);
477         }
478         f->rclm_lst = NULL;
479         /*
480          * Now drop the fid reference, free it
481          * if clunked.
482          */
483         put_fid(pdu, f);
484     }
485 }
486 
487 static int v9fs_mark_fids_unreclaim(V9fsPDU *pdu, V9fsPath *path)
488 {
489     int err;
490     V9fsState *s = pdu->s;
491     V9fsFidState *fidp, head_fid;
492 
493     head_fid.next = s->fid_list;
494     for (fidp = s->fid_list; fidp; fidp = fidp->next) {
495         if (fidp->path.size != path->size) {
496             continue;
497         }
498         if (!memcmp(fidp->path.data, path->data, path->size)) {
499             /* Mark the fid non reclaimable. */
500             fidp->flags |= FID_NON_RECLAIMABLE;
501 
502             /* reopen the file/dir if already closed */
503             err = v9fs_reopen_fid(pdu, fidp);
504             if (err < 0) {
505                 return -1;
506             }
507             /*
508              * Go back to head of fid list because
509              * the list could have got updated when
510              * switched to the worker thread
511              */
512             if (err == 0) {
513                 fidp = &head_fid;
514             }
515         }
516     }
517     return 0;
518 }
519 
520 static void virtfs_reset(V9fsPDU *pdu)
521 {
522     V9fsState *s = pdu->s;
523     V9fsFidState *fidp = NULL;
524 
525     /* Free all fids */
526     while (s->fid_list) {
527         fidp = s->fid_list;
528         s->fid_list = fidp->next;
529 
530         if (fidp->ref) {
531             fidp->clunked = 1;
532         } else {
533             free_fid(pdu, fidp);
534         }
535     }
536     if (fidp) {
537         /* One or more unclunked fids found... */
538         error_report("9pfs:%s: One or more uncluncked fids "
539                      "found during reset", __func__);
540     }
541 }
542 
543 #define P9_QID_TYPE_DIR         0x80
544 #define P9_QID_TYPE_SYMLINK     0x02
545 
546 #define P9_STAT_MODE_DIR        0x80000000
547 #define P9_STAT_MODE_APPEND     0x40000000
548 #define P9_STAT_MODE_EXCL       0x20000000
549 #define P9_STAT_MODE_MOUNT      0x10000000
550 #define P9_STAT_MODE_AUTH       0x08000000
551 #define P9_STAT_MODE_TMP        0x04000000
552 #define P9_STAT_MODE_SYMLINK    0x02000000
553 #define P9_STAT_MODE_LINK       0x01000000
554 #define P9_STAT_MODE_DEVICE     0x00800000
555 #define P9_STAT_MODE_NAMED_PIPE 0x00200000
556 #define P9_STAT_MODE_SOCKET     0x00100000
557 #define P9_STAT_MODE_SETUID     0x00080000
558 #define P9_STAT_MODE_SETGID     0x00040000
559 #define P9_STAT_MODE_SETVTX     0x00010000
560 
561 #define P9_STAT_MODE_TYPE_BITS (P9_STAT_MODE_DIR |          \
562                                 P9_STAT_MODE_SYMLINK |      \
563                                 P9_STAT_MODE_LINK |         \
564                                 P9_STAT_MODE_DEVICE |       \
565                                 P9_STAT_MODE_NAMED_PIPE |   \
566                                 P9_STAT_MODE_SOCKET)
567 
568 /* This is the algorithm from ufs in spfs */
569 static void stat_to_qid(const struct stat *stbuf, V9fsQID *qidp)
570 {
571     size_t size;
572 
573     memset(&qidp->path, 0, sizeof(qidp->path));
574     size = MIN(sizeof(stbuf->st_ino), sizeof(qidp->path));
575     memcpy(&qidp->path, &stbuf->st_ino, size);
576     qidp->version = stbuf->st_mtime ^ (stbuf->st_size << 8);
577     qidp->type = 0;
578     if (S_ISDIR(stbuf->st_mode)) {
579         qidp->type |= P9_QID_TYPE_DIR;
580     }
581     if (S_ISLNK(stbuf->st_mode)) {
582         qidp->type |= P9_QID_TYPE_SYMLINK;
583     }
584 }
585 
586 static int fid_to_qid(V9fsPDU *pdu, V9fsFidState *fidp, V9fsQID *qidp)
587 {
588     struct stat stbuf;
589     int err;
590 
591     err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
592     if (err < 0) {
593         return err;
594     }
595     stat_to_qid(&stbuf, qidp);
596     return 0;
597 }
598 
599 V9fsPDU *pdu_alloc(V9fsState *s)
600 {
601     V9fsPDU *pdu = NULL;
602 
603     if (!QLIST_EMPTY(&s->free_list)) {
604         pdu = QLIST_FIRST(&s->free_list);
605         QLIST_REMOVE(pdu, next);
606         QLIST_INSERT_HEAD(&s->active_list, pdu, next);
607     }
608     return pdu;
609 }
610 
611 void pdu_free(V9fsPDU *pdu)
612 {
613     if (pdu) {
614         V9fsState *s = pdu->s;
615         /*
616          * Cancelled pdu are added back to the freelist
617          * by flush request .
618          */
619         if (!pdu->cancelled) {
620             QLIST_REMOVE(pdu, next);
621             QLIST_INSERT_HEAD(&s->free_list, pdu, next);
622         }
623     }
624 }
625 
626 /*
627  * We don't do error checking for pdu_marshal/unmarshal here
628  * because we always expect to have enough space to encode
629  * error details
630  */
631 static void pdu_complete(V9fsPDU *pdu, ssize_t len)
632 {
633     int8_t id = pdu->id + 1; /* Response */
634     V9fsState *s = pdu->s;
635 
636     if (len < 0) {
637         int err = -len;
638         len = 7;
639 
640         if (s->proto_version != V9FS_PROTO_2000L) {
641             V9fsString str;
642 
643             str.data = strerror(err);
644             str.size = strlen(str.data);
645 
646             len += pdu_marshal(pdu, len, "s", &str);
647             id = P9_RERROR;
648         }
649 
650         len += pdu_marshal(pdu, len, "d", err);
651 
652         if (s->proto_version == V9FS_PROTO_2000L) {
653             id = P9_RLERROR;
654         }
655         trace_v9fs_rerror(pdu->tag, pdu->id, err); /* Trace ERROR */
656     }
657 
658     /* fill out the header */
659     pdu_marshal(pdu, 0, "dbw", (int32_t)len, id, pdu->tag);
660 
661     /* keep these in sync */
662     pdu->size = len;
663     pdu->id = id;
664 
665     pdu_push_and_notify(pdu);
666 
667     /* Now wakeup anybody waiting in flush for this request */
668     qemu_co_queue_next(&pdu->complete);
669 
670     pdu_free(pdu);
671 }
672 
673 static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)
674 {
675     mode_t ret;
676 
677     ret = mode & 0777;
678     if (mode & P9_STAT_MODE_DIR) {
679         ret |= S_IFDIR;
680     }
681 
682     if (mode & P9_STAT_MODE_SYMLINK) {
683         ret |= S_IFLNK;
684     }
685     if (mode & P9_STAT_MODE_SOCKET) {
686         ret |= S_IFSOCK;
687     }
688     if (mode & P9_STAT_MODE_NAMED_PIPE) {
689         ret |= S_IFIFO;
690     }
691     if (mode & P9_STAT_MODE_DEVICE) {
692         if (extension->size && extension->data[0] == 'c') {
693             ret |= S_IFCHR;
694         } else {
695             ret |= S_IFBLK;
696         }
697     }
698 
699     if (!(ret&~0777)) {
700         ret |= S_IFREG;
701     }
702 
703     if (mode & P9_STAT_MODE_SETUID) {
704         ret |= S_ISUID;
705     }
706     if (mode & P9_STAT_MODE_SETGID) {
707         ret |= S_ISGID;
708     }
709     if (mode & P9_STAT_MODE_SETVTX) {
710         ret |= S_ISVTX;
711     }
712 
713     return ret;
714 }
715 
716 static int donttouch_stat(V9fsStat *stat)
717 {
718     if (stat->type == -1 &&
719         stat->dev == -1 &&
720         stat->qid.type == -1 &&
721         stat->qid.version == -1 &&
722         stat->qid.path == -1 &&
723         stat->mode == -1 &&
724         stat->atime == -1 &&
725         stat->mtime == -1 &&
726         stat->length == -1 &&
727         !stat->name.size &&
728         !stat->uid.size &&
729         !stat->gid.size &&
730         !stat->muid.size &&
731         stat->n_uid == -1 &&
732         stat->n_gid == -1 &&
733         stat->n_muid == -1) {
734         return 1;
735     }
736 
737     return 0;
738 }
739 
740 static void v9fs_stat_init(V9fsStat *stat)
741 {
742     v9fs_string_init(&stat->name);
743     v9fs_string_init(&stat->uid);
744     v9fs_string_init(&stat->gid);
745     v9fs_string_init(&stat->muid);
746     v9fs_string_init(&stat->extension);
747 }
748 
749 static void v9fs_stat_free(V9fsStat *stat)
750 {
751     v9fs_string_free(&stat->name);
752     v9fs_string_free(&stat->uid);
753     v9fs_string_free(&stat->gid);
754     v9fs_string_free(&stat->muid);
755     v9fs_string_free(&stat->extension);
756 }
757 
758 static uint32_t stat_to_v9mode(const struct stat *stbuf)
759 {
760     uint32_t mode;
761 
762     mode = stbuf->st_mode & 0777;
763     if (S_ISDIR(stbuf->st_mode)) {
764         mode |= P9_STAT_MODE_DIR;
765     }
766 
767     if (S_ISLNK(stbuf->st_mode)) {
768         mode |= P9_STAT_MODE_SYMLINK;
769     }
770 
771     if (S_ISSOCK(stbuf->st_mode)) {
772         mode |= P9_STAT_MODE_SOCKET;
773     }
774 
775     if (S_ISFIFO(stbuf->st_mode)) {
776         mode |= P9_STAT_MODE_NAMED_PIPE;
777     }
778 
779     if (S_ISBLK(stbuf->st_mode) || S_ISCHR(stbuf->st_mode)) {
780         mode |= P9_STAT_MODE_DEVICE;
781     }
782 
783     if (stbuf->st_mode & S_ISUID) {
784         mode |= P9_STAT_MODE_SETUID;
785     }
786 
787     if (stbuf->st_mode & S_ISGID) {
788         mode |= P9_STAT_MODE_SETGID;
789     }
790 
791     if (stbuf->st_mode & S_ISVTX) {
792         mode |= P9_STAT_MODE_SETVTX;
793     }
794 
795     return mode;
796 }
797 
798 static int stat_to_v9stat(V9fsPDU *pdu, V9fsPath *name,
799                             const struct stat *stbuf,
800                             V9fsStat *v9stat)
801 {
802     int err;
803     const char *str;
804 
805     memset(v9stat, 0, sizeof(*v9stat));
806 
807     stat_to_qid(stbuf, &v9stat->qid);
808     v9stat->mode = stat_to_v9mode(stbuf);
809     v9stat->atime = stbuf->st_atime;
810     v9stat->mtime = stbuf->st_mtime;
811     v9stat->length = stbuf->st_size;
812 
813     v9fs_string_null(&v9stat->uid);
814     v9fs_string_null(&v9stat->gid);
815     v9fs_string_null(&v9stat->muid);
816 
817     v9stat->n_uid = stbuf->st_uid;
818     v9stat->n_gid = stbuf->st_gid;
819     v9stat->n_muid = 0;
820 
821     v9fs_string_null(&v9stat->extension);
822 
823     if (v9stat->mode & P9_STAT_MODE_SYMLINK) {
824         err = v9fs_co_readlink(pdu, name, &v9stat->extension);
825         if (err < 0) {
826             return err;
827         }
828     } else if (v9stat->mode & P9_STAT_MODE_DEVICE) {
829         v9fs_string_sprintf(&v9stat->extension, "%c %u %u",
830                 S_ISCHR(stbuf->st_mode) ? 'c' : 'b',
831                 major(stbuf->st_rdev), minor(stbuf->st_rdev));
832     } else if (S_ISDIR(stbuf->st_mode) || S_ISREG(stbuf->st_mode)) {
833         v9fs_string_sprintf(&v9stat->extension, "%s %lu",
834                 "HARDLINKCOUNT", (unsigned long)stbuf->st_nlink);
835     }
836 
837     str = strrchr(name->data, '/');
838     if (str) {
839         str += 1;
840     } else {
841         str = name->data;
842     }
843 
844     v9fs_string_sprintf(&v9stat->name, "%s", str);
845 
846     v9stat->size = 61 +
847         v9fs_string_size(&v9stat->name) +
848         v9fs_string_size(&v9stat->uid) +
849         v9fs_string_size(&v9stat->gid) +
850         v9fs_string_size(&v9stat->muid) +
851         v9fs_string_size(&v9stat->extension);
852     return 0;
853 }
854 
855 #define P9_STATS_MODE          0x00000001ULL
856 #define P9_STATS_NLINK         0x00000002ULL
857 #define P9_STATS_UID           0x00000004ULL
858 #define P9_STATS_GID           0x00000008ULL
859 #define P9_STATS_RDEV          0x00000010ULL
860 #define P9_STATS_ATIME         0x00000020ULL
861 #define P9_STATS_MTIME         0x00000040ULL
862 #define P9_STATS_CTIME         0x00000080ULL
863 #define P9_STATS_INO           0x00000100ULL
864 #define P9_STATS_SIZE          0x00000200ULL
865 #define P9_STATS_BLOCKS        0x00000400ULL
866 
867 #define P9_STATS_BTIME         0x00000800ULL
868 #define P9_STATS_GEN           0x00001000ULL
869 #define P9_STATS_DATA_VERSION  0x00002000ULL
870 
871 #define P9_STATS_BASIC         0x000007ffULL /* Mask for fields up to BLOCKS */
872 #define P9_STATS_ALL           0x00003fffULL /* Mask for All fields above */
873 
874 
875 static void stat_to_v9stat_dotl(V9fsState *s, const struct stat *stbuf,
876                                 V9fsStatDotl *v9lstat)
877 {
878     memset(v9lstat, 0, sizeof(*v9lstat));
879 
880     v9lstat->st_mode = stbuf->st_mode;
881     v9lstat->st_nlink = stbuf->st_nlink;
882     v9lstat->st_uid = stbuf->st_uid;
883     v9lstat->st_gid = stbuf->st_gid;
884     v9lstat->st_rdev = stbuf->st_rdev;
885     v9lstat->st_size = stbuf->st_size;
886     v9lstat->st_blksize = stbuf->st_blksize;
887     v9lstat->st_blocks = stbuf->st_blocks;
888     v9lstat->st_atime_sec = stbuf->st_atime;
889     v9lstat->st_atime_nsec = stbuf->st_atim.tv_nsec;
890     v9lstat->st_mtime_sec = stbuf->st_mtime;
891     v9lstat->st_mtime_nsec = stbuf->st_mtim.tv_nsec;
892     v9lstat->st_ctime_sec = stbuf->st_ctime;
893     v9lstat->st_ctime_nsec = stbuf->st_ctim.tv_nsec;
894     /* Currently we only support BASIC fields in stat */
895     v9lstat->st_result_mask = P9_STATS_BASIC;
896 
897     stat_to_qid(stbuf, &v9lstat->qid);
898 }
899 
900 static void print_sg(struct iovec *sg, int cnt)
901 {
902     int i;
903 
904     printf("sg[%d]: {", cnt);
905     for (i = 0; i < cnt; i++) {
906         if (i) {
907             printf(", ");
908         }
909         printf("(%p, %zd)", sg[i].iov_base, sg[i].iov_len);
910     }
911     printf("}\n");
912 }
913 
914 /* Will call this only for path name based fid */
915 static void v9fs_fix_path(V9fsPath *dst, V9fsPath *src, int len)
916 {
917     V9fsPath str;
918     v9fs_path_init(&str);
919     v9fs_path_copy(&str, dst);
920     v9fs_string_sprintf((V9fsString *)dst, "%s%s", src->data, str.data+len);
921     v9fs_path_free(&str);
922     /* +1 to include terminating NULL */
923     dst->size++;
924 }
925 
926 static inline bool is_ro_export(FsContext *ctx)
927 {
928     return ctx->export_flags & V9FS_RDONLY;
929 }
930 
931 static void v9fs_version(void *opaque)
932 {
933     ssize_t err;
934     V9fsPDU *pdu = opaque;
935     V9fsState *s = pdu->s;
936     V9fsString version;
937     size_t offset = 7;
938 
939     v9fs_string_init(&version);
940     err = pdu_unmarshal(pdu, offset, "ds", &s->msize, &version);
941     if (err < 0) {
942         offset = err;
943         goto out;
944     }
945     trace_v9fs_version(pdu->tag, pdu->id, s->msize, version.data);
946 
947     virtfs_reset(pdu);
948 
949     if (!strcmp(version.data, "9P2000.u")) {
950         s->proto_version = V9FS_PROTO_2000U;
951     } else if (!strcmp(version.data, "9P2000.L")) {
952         s->proto_version = V9FS_PROTO_2000L;
953     } else {
954         v9fs_string_sprintf(&version, "unknown");
955     }
956 
957     err = pdu_marshal(pdu, offset, "ds", s->msize, &version);
958     if (err < 0) {
959         offset = err;
960         goto out;
961     }
962     offset += err;
963     trace_v9fs_version_return(pdu->tag, pdu->id, s->msize, version.data);
964 out:
965     pdu_complete(pdu, offset);
966     v9fs_string_free(&version);
967 }
968 
969 static void v9fs_attach(void *opaque)
970 {
971     V9fsPDU *pdu = opaque;
972     V9fsState *s = pdu->s;
973     int32_t fid, afid, n_uname;
974     V9fsString uname, aname;
975     V9fsFidState *fidp;
976     size_t offset = 7;
977     V9fsQID qid;
978     ssize_t err;
979 
980     v9fs_string_init(&uname);
981     v9fs_string_init(&aname);
982     err = pdu_unmarshal(pdu, offset, "ddssd", &fid,
983                         &afid, &uname, &aname, &n_uname);
984     if (err < 0) {
985         goto out_nofid;
986     }
987     trace_v9fs_attach(pdu->tag, pdu->id, fid, afid, uname.data, aname.data);
988 
989     fidp = alloc_fid(s, fid);
990     if (fidp == NULL) {
991         err = -EINVAL;
992         goto out_nofid;
993     }
994     fidp->uid = n_uname;
995     err = v9fs_co_name_to_path(pdu, NULL, "/", &fidp->path);
996     if (err < 0) {
997         err = -EINVAL;
998         clunk_fid(s, fid);
999         goto out;
1000     }
1001     err = fid_to_qid(pdu, fidp, &qid);
1002     if (err < 0) {
1003         err = -EINVAL;
1004         clunk_fid(s, fid);
1005         goto out;
1006     }
1007     err = pdu_marshal(pdu, offset, "Q", &qid);
1008     if (err < 0) {
1009         clunk_fid(s, fid);
1010         goto out;
1011     }
1012     err += offset;
1013     memcpy(&s->root_qid, &qid, sizeof(qid));
1014     trace_v9fs_attach_return(pdu->tag, pdu->id,
1015                              qid.type, qid.version, qid.path);
1016     /*
1017      * disable migration if we haven't done already.
1018      * attach could get called multiple times for the same export.
1019      */
1020     if (!s->migration_blocker) {
1021         s->root_fid = fid;
1022         error_setg(&s->migration_blocker,
1023                    "Migration is disabled when VirtFS export path '%s' is mounted in the guest using mount_tag '%s'",
1024                    s->ctx.fs_root ? s->ctx.fs_root : "NULL", s->tag);
1025         migrate_add_blocker(s->migration_blocker);
1026     }
1027 out:
1028     put_fid(pdu, fidp);
1029 out_nofid:
1030     pdu_complete(pdu, err);
1031     v9fs_string_free(&uname);
1032     v9fs_string_free(&aname);
1033 }
1034 
1035 static void v9fs_stat(void *opaque)
1036 {
1037     int32_t fid;
1038     V9fsStat v9stat;
1039     ssize_t err = 0;
1040     size_t offset = 7;
1041     struct stat stbuf;
1042     V9fsFidState *fidp;
1043     V9fsPDU *pdu = opaque;
1044 
1045     err = pdu_unmarshal(pdu, offset, "d", &fid);
1046     if (err < 0) {
1047         goto out_nofid;
1048     }
1049     trace_v9fs_stat(pdu->tag, pdu->id, fid);
1050 
1051     fidp = get_fid(pdu, fid);
1052     if (fidp == NULL) {
1053         err = -ENOENT;
1054         goto out_nofid;
1055     }
1056     err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
1057     if (err < 0) {
1058         goto out;
1059     }
1060     err = stat_to_v9stat(pdu, &fidp->path, &stbuf, &v9stat);
1061     if (err < 0) {
1062         goto out;
1063     }
1064     err = pdu_marshal(pdu, offset, "wS", 0, &v9stat);
1065     if (err < 0) {
1066         v9fs_stat_free(&v9stat);
1067         goto out;
1068     }
1069     trace_v9fs_stat_return(pdu->tag, pdu->id, v9stat.mode,
1070                            v9stat.atime, v9stat.mtime, v9stat.length);
1071     err += offset;
1072     v9fs_stat_free(&v9stat);
1073 out:
1074     put_fid(pdu, fidp);
1075 out_nofid:
1076     pdu_complete(pdu, err);
1077 }
1078 
1079 static void v9fs_getattr(void *opaque)
1080 {
1081     int32_t fid;
1082     size_t offset = 7;
1083     ssize_t retval = 0;
1084     struct stat stbuf;
1085     V9fsFidState *fidp;
1086     uint64_t request_mask;
1087     V9fsStatDotl v9stat_dotl;
1088     V9fsPDU *pdu = opaque;
1089     V9fsState *s = pdu->s;
1090 
1091     retval = pdu_unmarshal(pdu, offset, "dq", &fid, &request_mask);
1092     if (retval < 0) {
1093         goto out_nofid;
1094     }
1095     trace_v9fs_getattr(pdu->tag, pdu->id, fid, request_mask);
1096 
1097     fidp = get_fid(pdu, fid);
1098     if (fidp == NULL) {
1099         retval = -ENOENT;
1100         goto out_nofid;
1101     }
1102     /*
1103      * Currently we only support BASIC fields in stat, so there is no
1104      * need to look at request_mask.
1105      */
1106     retval = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
1107     if (retval < 0) {
1108         goto out;
1109     }
1110     stat_to_v9stat_dotl(s, &stbuf, &v9stat_dotl);
1111 
1112     /*  fill st_gen if requested and supported by underlying fs */
1113     if (request_mask & P9_STATS_GEN) {
1114         retval = v9fs_co_st_gen(pdu, &fidp->path, stbuf.st_mode, &v9stat_dotl);
1115         switch (retval) {
1116         case 0:
1117             /* we have valid st_gen: update result mask */
1118             v9stat_dotl.st_result_mask |= P9_STATS_GEN;
1119             break;
1120         case -EINTR:
1121             /* request cancelled, e.g. by Tflush */
1122             goto out;
1123         default:
1124             /* failed to get st_gen: not fatal, ignore */
1125             break;
1126         }
1127     }
1128     retval = pdu_marshal(pdu, offset, "A", &v9stat_dotl);
1129     if (retval < 0) {
1130         goto out;
1131     }
1132     retval += offset;
1133     trace_v9fs_getattr_return(pdu->tag, pdu->id, v9stat_dotl.st_result_mask,
1134                               v9stat_dotl.st_mode, v9stat_dotl.st_uid,
1135                               v9stat_dotl.st_gid);
1136 out:
1137     put_fid(pdu, fidp);
1138 out_nofid:
1139     pdu_complete(pdu, retval);
1140 }
1141 
1142 /* Attribute flags */
1143 #define P9_ATTR_MODE       (1 << 0)
1144 #define P9_ATTR_UID        (1 << 1)
1145 #define P9_ATTR_GID        (1 << 2)
1146 #define P9_ATTR_SIZE       (1 << 3)
1147 #define P9_ATTR_ATIME      (1 << 4)
1148 #define P9_ATTR_MTIME      (1 << 5)
1149 #define P9_ATTR_CTIME      (1 << 6)
1150 #define P9_ATTR_ATIME_SET  (1 << 7)
1151 #define P9_ATTR_MTIME_SET  (1 << 8)
1152 
1153 #define P9_ATTR_MASK    127
1154 
1155 static void v9fs_setattr(void *opaque)
1156 {
1157     int err = 0;
1158     int32_t fid;
1159     V9fsFidState *fidp;
1160     size_t offset = 7;
1161     V9fsIattr v9iattr;
1162     V9fsPDU *pdu = opaque;
1163 
1164     err = pdu_unmarshal(pdu, offset, "dI", &fid, &v9iattr);
1165     if (err < 0) {
1166         goto out_nofid;
1167     }
1168 
1169     fidp = get_fid(pdu, fid);
1170     if (fidp == NULL) {
1171         err = -EINVAL;
1172         goto out_nofid;
1173     }
1174     if (v9iattr.valid & P9_ATTR_MODE) {
1175         err = v9fs_co_chmod(pdu, &fidp->path, v9iattr.mode);
1176         if (err < 0) {
1177             goto out;
1178         }
1179     }
1180     if (v9iattr.valid & (P9_ATTR_ATIME | P9_ATTR_MTIME)) {
1181         struct timespec times[2];
1182         if (v9iattr.valid & P9_ATTR_ATIME) {
1183             if (v9iattr.valid & P9_ATTR_ATIME_SET) {
1184                 times[0].tv_sec = v9iattr.atime_sec;
1185                 times[0].tv_nsec = v9iattr.atime_nsec;
1186             } else {
1187                 times[0].tv_nsec = UTIME_NOW;
1188             }
1189         } else {
1190             times[0].tv_nsec = UTIME_OMIT;
1191         }
1192         if (v9iattr.valid & P9_ATTR_MTIME) {
1193             if (v9iattr.valid & P9_ATTR_MTIME_SET) {
1194                 times[1].tv_sec = v9iattr.mtime_sec;
1195                 times[1].tv_nsec = v9iattr.mtime_nsec;
1196             } else {
1197                 times[1].tv_nsec = UTIME_NOW;
1198             }
1199         } else {
1200             times[1].tv_nsec = UTIME_OMIT;
1201         }
1202         err = v9fs_co_utimensat(pdu, &fidp->path, times);
1203         if (err < 0) {
1204             goto out;
1205         }
1206     }
1207     /*
1208      * If the only valid entry in iattr is ctime we can call
1209      * chown(-1,-1) to update the ctime of the file
1210      */
1211     if ((v9iattr.valid & (P9_ATTR_UID | P9_ATTR_GID)) ||
1212         ((v9iattr.valid & P9_ATTR_CTIME)
1213          && !((v9iattr.valid & P9_ATTR_MASK) & ~P9_ATTR_CTIME))) {
1214         if (!(v9iattr.valid & P9_ATTR_UID)) {
1215             v9iattr.uid = -1;
1216         }
1217         if (!(v9iattr.valid & P9_ATTR_GID)) {
1218             v9iattr.gid = -1;
1219         }
1220         err = v9fs_co_chown(pdu, &fidp->path, v9iattr.uid,
1221                             v9iattr.gid);
1222         if (err < 0) {
1223             goto out;
1224         }
1225     }
1226     if (v9iattr.valid & (P9_ATTR_SIZE)) {
1227         err = v9fs_co_truncate(pdu, &fidp->path, v9iattr.size);
1228         if (err < 0) {
1229             goto out;
1230         }
1231     }
1232     err = offset;
1233 out:
1234     put_fid(pdu, fidp);
1235 out_nofid:
1236     pdu_complete(pdu, err);
1237 }
1238 
1239 static int v9fs_walk_marshal(V9fsPDU *pdu, uint16_t nwnames, V9fsQID *qids)
1240 {
1241     int i;
1242     ssize_t err;
1243     size_t offset = 7;
1244 
1245     err = pdu_marshal(pdu, offset, "w", nwnames);
1246     if (err < 0) {
1247         return err;
1248     }
1249     offset += err;
1250     for (i = 0; i < nwnames; i++) {
1251         err = pdu_marshal(pdu, offset, "Q", &qids[i]);
1252         if (err < 0) {
1253             return err;
1254         }
1255         offset += err;
1256     }
1257     return offset;
1258 }
1259 
1260 static bool name_is_illegal(const char *name)
1261 {
1262     return !*name || strchr(name, '/') != NULL;
1263 }
1264 
1265 static bool not_same_qid(const V9fsQID *qid1, const V9fsQID *qid2)
1266 {
1267     return
1268         qid1->type != qid2->type ||
1269         qid1->version != qid2->version ||
1270         qid1->path != qid2->path;
1271 }
1272 
1273 static void v9fs_walk(void *opaque)
1274 {
1275     int name_idx;
1276     V9fsQID *qids = NULL;
1277     int i, err = 0;
1278     V9fsPath dpath, path;
1279     uint16_t nwnames;
1280     struct stat stbuf;
1281     size_t offset = 7;
1282     int32_t fid, newfid;
1283     V9fsString *wnames = NULL;
1284     V9fsFidState *fidp;
1285     V9fsFidState *newfidp = NULL;
1286     V9fsPDU *pdu = opaque;
1287     V9fsState *s = pdu->s;
1288     V9fsQID qid;
1289 
1290     err = pdu_unmarshal(pdu, offset, "ddw", &fid, &newfid, &nwnames);
1291     if (err < 0) {
1292         pdu_complete(pdu, err);
1293         return ;
1294     }
1295     offset += err;
1296 
1297     trace_v9fs_walk(pdu->tag, pdu->id, fid, newfid, nwnames);
1298 
1299     if (nwnames && nwnames <= P9_MAXWELEM) {
1300         wnames = g_malloc0(sizeof(wnames[0]) * nwnames);
1301         qids   = g_malloc0(sizeof(qids[0]) * nwnames);
1302         for (i = 0; i < nwnames; i++) {
1303             err = pdu_unmarshal(pdu, offset, "s", &wnames[i]);
1304             if (err < 0) {
1305                 goto out_nofid;
1306             }
1307             if (name_is_illegal(wnames[i].data)) {
1308                 err = -ENOENT;
1309                 goto out_nofid;
1310             }
1311             offset += err;
1312         }
1313     } else if (nwnames > P9_MAXWELEM) {
1314         err = -EINVAL;
1315         goto out_nofid;
1316     }
1317     fidp = get_fid(pdu, fid);
1318     if (fidp == NULL) {
1319         err = -ENOENT;
1320         goto out_nofid;
1321     }
1322 
1323     err = fid_to_qid(pdu, fidp, &qid);
1324     if (err < 0) {
1325         goto out;
1326     }
1327 
1328     v9fs_path_init(&dpath);
1329     v9fs_path_init(&path);
1330     /*
1331      * Both dpath and path initially poin to fidp.
1332      * Needed to handle request with nwnames == 0
1333      */
1334     v9fs_path_copy(&dpath, &fidp->path);
1335     v9fs_path_copy(&path, &fidp->path);
1336     for (name_idx = 0; name_idx < nwnames; name_idx++) {
1337         if (not_same_qid(&pdu->s->root_qid, &qid) ||
1338             strcmp("..", wnames[name_idx].data)) {
1339             err = v9fs_co_name_to_path(pdu, &dpath, wnames[name_idx].data,
1340                                        &path);
1341             if (err < 0) {
1342                 goto out;
1343             }
1344 
1345             err = v9fs_co_lstat(pdu, &path, &stbuf);
1346             if (err < 0) {
1347                 goto out;
1348             }
1349             stat_to_qid(&stbuf, &qid);
1350             v9fs_path_copy(&dpath, &path);
1351         }
1352         memcpy(&qids[name_idx], &qid, sizeof(qid));
1353     }
1354     if (fid == newfid) {
1355         BUG_ON(fidp->fid_type != P9_FID_NONE);
1356         v9fs_path_copy(&fidp->path, &path);
1357     } else {
1358         newfidp = alloc_fid(s, newfid);
1359         if (newfidp == NULL) {
1360             err = -EINVAL;
1361             goto out;
1362         }
1363         newfidp->uid = fidp->uid;
1364         v9fs_path_copy(&newfidp->path, &path);
1365     }
1366     err = v9fs_walk_marshal(pdu, nwnames, qids);
1367     trace_v9fs_walk_return(pdu->tag, pdu->id, nwnames, qids);
1368 out:
1369     put_fid(pdu, fidp);
1370     if (newfidp) {
1371         put_fid(pdu, newfidp);
1372     }
1373     v9fs_path_free(&dpath);
1374     v9fs_path_free(&path);
1375 out_nofid:
1376     pdu_complete(pdu, err);
1377     if (nwnames && nwnames <= P9_MAXWELEM) {
1378         for (name_idx = 0; name_idx < nwnames; name_idx++) {
1379             v9fs_string_free(&wnames[name_idx]);
1380         }
1381         g_free(wnames);
1382         g_free(qids);
1383     }
1384 }
1385 
1386 static int32_t get_iounit(V9fsPDU *pdu, V9fsPath *path)
1387 {
1388     struct statfs stbuf;
1389     int32_t iounit = 0;
1390     V9fsState *s = pdu->s;
1391 
1392     /*
1393      * iounit should be multiples of f_bsize (host filesystem block size
1394      * and as well as less than (client msize - P9_IOHDRSZ))
1395      */
1396     if (!v9fs_co_statfs(pdu, path, &stbuf)) {
1397         iounit = stbuf.f_bsize;
1398         iounit *= (s->msize - P9_IOHDRSZ)/stbuf.f_bsize;
1399     }
1400     if (!iounit) {
1401         iounit = s->msize - P9_IOHDRSZ;
1402     }
1403     return iounit;
1404 }
1405 
1406 static void v9fs_open(void *opaque)
1407 {
1408     int flags;
1409     int32_t fid;
1410     int32_t mode;
1411     V9fsQID qid;
1412     int iounit = 0;
1413     ssize_t err = 0;
1414     size_t offset = 7;
1415     struct stat stbuf;
1416     V9fsFidState *fidp;
1417     V9fsPDU *pdu = opaque;
1418     V9fsState *s = pdu->s;
1419 
1420     if (s->proto_version == V9FS_PROTO_2000L) {
1421         err = pdu_unmarshal(pdu, offset, "dd", &fid, &mode);
1422     } else {
1423         uint8_t modebyte;
1424         err = pdu_unmarshal(pdu, offset, "db", &fid, &modebyte);
1425         mode = modebyte;
1426     }
1427     if (err < 0) {
1428         goto out_nofid;
1429     }
1430     trace_v9fs_open(pdu->tag, pdu->id, fid, mode);
1431 
1432     fidp = get_fid(pdu, fid);
1433     if (fidp == NULL) {
1434         err = -ENOENT;
1435         goto out_nofid;
1436     }
1437     BUG_ON(fidp->fid_type != P9_FID_NONE);
1438 
1439     err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
1440     if (err < 0) {
1441         goto out;
1442     }
1443     stat_to_qid(&stbuf, &qid);
1444     if (S_ISDIR(stbuf.st_mode)) {
1445         err = v9fs_co_opendir(pdu, fidp);
1446         if (err < 0) {
1447             goto out;
1448         }
1449         fidp->fid_type = P9_FID_DIR;
1450         err = pdu_marshal(pdu, offset, "Qd", &qid, 0);
1451         if (err < 0) {
1452             goto out;
1453         }
1454         err += offset;
1455     } else {
1456         if (s->proto_version == V9FS_PROTO_2000L) {
1457             flags = get_dotl_openflags(s, mode);
1458         } else {
1459             flags = omode_to_uflags(mode);
1460         }
1461         if (is_ro_export(&s->ctx)) {
1462             if (mode & O_WRONLY || mode & O_RDWR ||
1463                 mode & O_APPEND || mode & O_TRUNC) {
1464                 err = -EROFS;
1465                 goto out;
1466             }
1467         }
1468         err = v9fs_co_open(pdu, fidp, flags);
1469         if (err < 0) {
1470             goto out;
1471         }
1472         fidp->fid_type = P9_FID_FILE;
1473         fidp->open_flags = flags;
1474         if (flags & O_EXCL) {
1475             /*
1476              * We let the host file system do O_EXCL check
1477              * We should not reclaim such fd
1478              */
1479             fidp->flags |= FID_NON_RECLAIMABLE;
1480         }
1481         iounit = get_iounit(pdu, &fidp->path);
1482         err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
1483         if (err < 0) {
1484             goto out;
1485         }
1486         err += offset;
1487     }
1488     trace_v9fs_open_return(pdu->tag, pdu->id,
1489                            qid.type, qid.version, qid.path, iounit);
1490 out:
1491     put_fid(pdu, fidp);
1492 out_nofid:
1493     pdu_complete(pdu, err);
1494 }
1495 
1496 static void v9fs_lcreate(void *opaque)
1497 {
1498     int32_t dfid, flags, mode;
1499     gid_t gid;
1500     ssize_t err = 0;
1501     ssize_t offset = 7;
1502     V9fsString name;
1503     V9fsFidState *fidp;
1504     struct stat stbuf;
1505     V9fsQID qid;
1506     int32_t iounit;
1507     V9fsPDU *pdu = opaque;
1508 
1509     v9fs_string_init(&name);
1510     err = pdu_unmarshal(pdu, offset, "dsddd", &dfid,
1511                         &name, &flags, &mode, &gid);
1512     if (err < 0) {
1513         goto out_nofid;
1514     }
1515     trace_v9fs_lcreate(pdu->tag, pdu->id, dfid, flags, mode, gid);
1516 
1517     if (name_is_illegal(name.data)) {
1518         err = -ENOENT;
1519         goto out_nofid;
1520     }
1521 
1522     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
1523         err = -EEXIST;
1524         goto out_nofid;
1525     }
1526 
1527     fidp = get_fid(pdu, dfid);
1528     if (fidp == NULL) {
1529         err = -ENOENT;
1530         goto out_nofid;
1531     }
1532 
1533     flags = get_dotl_openflags(pdu->s, flags);
1534     err = v9fs_co_open2(pdu, fidp, &name, gid,
1535                         flags | O_CREAT, mode, &stbuf);
1536     if (err < 0) {
1537         goto out;
1538     }
1539     fidp->fid_type = P9_FID_FILE;
1540     fidp->open_flags = flags;
1541     if (flags & O_EXCL) {
1542         /*
1543          * We let the host file system do O_EXCL check
1544          * We should not reclaim such fd
1545          */
1546         fidp->flags |= FID_NON_RECLAIMABLE;
1547     }
1548     iounit =  get_iounit(pdu, &fidp->path);
1549     stat_to_qid(&stbuf, &qid);
1550     err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
1551     if (err < 0) {
1552         goto out;
1553     }
1554     err += offset;
1555     trace_v9fs_lcreate_return(pdu->tag, pdu->id,
1556                               qid.type, qid.version, qid.path, iounit);
1557 out:
1558     put_fid(pdu, fidp);
1559 out_nofid:
1560     pdu_complete(pdu, err);
1561     v9fs_string_free(&name);
1562 }
1563 
1564 static void v9fs_fsync(void *opaque)
1565 {
1566     int err;
1567     int32_t fid;
1568     int datasync;
1569     size_t offset = 7;
1570     V9fsFidState *fidp;
1571     V9fsPDU *pdu = opaque;
1572 
1573     err = pdu_unmarshal(pdu, offset, "dd", &fid, &datasync);
1574     if (err < 0) {
1575         goto out_nofid;
1576     }
1577     trace_v9fs_fsync(pdu->tag, pdu->id, fid, datasync);
1578 
1579     fidp = get_fid(pdu, fid);
1580     if (fidp == NULL) {
1581         err = -ENOENT;
1582         goto out_nofid;
1583     }
1584     err = v9fs_co_fsync(pdu, fidp, datasync);
1585     if (!err) {
1586         err = offset;
1587     }
1588     put_fid(pdu, fidp);
1589 out_nofid:
1590     pdu_complete(pdu, err);
1591 }
1592 
1593 static void v9fs_clunk(void *opaque)
1594 {
1595     int err;
1596     int32_t fid;
1597     size_t offset = 7;
1598     V9fsFidState *fidp;
1599     V9fsPDU *pdu = opaque;
1600     V9fsState *s = pdu->s;
1601 
1602     err = pdu_unmarshal(pdu, offset, "d", &fid);
1603     if (err < 0) {
1604         goto out_nofid;
1605     }
1606     trace_v9fs_clunk(pdu->tag, pdu->id, fid);
1607 
1608     fidp = clunk_fid(s, fid);
1609     if (fidp == NULL) {
1610         err = -ENOENT;
1611         goto out_nofid;
1612     }
1613     /*
1614      * Bump the ref so that put_fid will
1615      * free the fid.
1616      */
1617     fidp->ref++;
1618     err = put_fid(pdu, fidp);
1619     if (!err) {
1620         err = offset;
1621     }
1622 out_nofid:
1623     pdu_complete(pdu, err);
1624 }
1625 
1626 static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
1627                            uint64_t off, uint32_t max_count)
1628 {
1629     ssize_t err;
1630     size_t offset = 7;
1631     int read_count;
1632     int64_t xattr_len;
1633     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
1634     VirtQueueElement *elem = v->elems[pdu->idx];
1635 
1636     xattr_len = fidp->fs.xattr.len;
1637     read_count = xattr_len - off;
1638     if (read_count > max_count) {
1639         read_count = max_count;
1640     } else if (read_count < 0) {
1641         /*
1642          * read beyond XATTR value
1643          */
1644         read_count = 0;
1645     }
1646     err = pdu_marshal(pdu, offset, "d", read_count);
1647     if (err < 0) {
1648         return err;
1649     }
1650     offset += err;
1651 
1652     err = v9fs_pack(elem->in_sg, elem->in_num, offset,
1653                     ((char *)fidp->fs.xattr.value) + off,
1654                     read_count);
1655     if (err < 0) {
1656         return err;
1657     }
1658     offset += err;
1659     return offset;
1660 }
1661 
1662 static int v9fs_do_readdir_with_stat(V9fsPDU *pdu,
1663                                      V9fsFidState *fidp, uint32_t max_count)
1664 {
1665     V9fsPath path;
1666     V9fsStat v9stat;
1667     int len, err = 0;
1668     int32_t count = 0;
1669     struct stat stbuf;
1670     off_t saved_dir_pos;
1671     struct dirent *dent;
1672 
1673     /* save the directory position */
1674     saved_dir_pos = v9fs_co_telldir(pdu, fidp);
1675     if (saved_dir_pos < 0) {
1676         return saved_dir_pos;
1677     }
1678 
1679     while (1) {
1680         v9fs_path_init(&path);
1681 
1682         v9fs_readdir_lock(&fidp->fs.dir);
1683 
1684         err = v9fs_co_readdir(pdu, fidp, &dent);
1685         if (err || !dent) {
1686             break;
1687         }
1688         err = v9fs_co_name_to_path(pdu, &fidp->path, dent->d_name, &path);
1689         if (err < 0) {
1690             break;
1691         }
1692         err = v9fs_co_lstat(pdu, &path, &stbuf);
1693         if (err < 0) {
1694             break;
1695         }
1696         err = stat_to_v9stat(pdu, &path, &stbuf, &v9stat);
1697         if (err < 0) {
1698             break;
1699         }
1700         /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */
1701         len = pdu_marshal(pdu, 11 + count, "S", &v9stat);
1702 
1703         v9fs_readdir_unlock(&fidp->fs.dir);
1704 
1705         if ((len != (v9stat.size + 2)) || ((count + len) > max_count)) {
1706             /* Ran out of buffer. Set dir back to old position and return */
1707             v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
1708             v9fs_stat_free(&v9stat);
1709             v9fs_path_free(&path);
1710             return count;
1711         }
1712         count += len;
1713         v9fs_stat_free(&v9stat);
1714         v9fs_path_free(&path);
1715         saved_dir_pos = dent->d_off;
1716     }
1717 
1718     v9fs_readdir_unlock(&fidp->fs.dir);
1719 
1720     v9fs_path_free(&path);
1721     if (err < 0) {
1722         return err;
1723     }
1724     return count;
1725 }
1726 
1727 /*
1728  * Create a QEMUIOVector for a sub-region of PDU iovecs
1729  *
1730  * @qiov:       uninitialized QEMUIOVector
1731  * @skip:       number of bytes to skip from beginning of PDU
1732  * @size:       number of bytes to include
1733  * @is_write:   true - write, false - read
1734  *
1735  * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
1736  * with qemu_iovec_destroy().
1737  */
1738 static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
1739                                     size_t skip, size_t size,
1740                                     bool is_write)
1741 {
1742     QEMUIOVector elem;
1743     struct iovec *iov;
1744     unsigned int niov;
1745 
1746     virtio_init_iov_from_pdu(pdu, &iov, &niov, is_write);
1747 
1748     qemu_iovec_init_external(&elem, iov, niov);
1749     qemu_iovec_init(qiov, niov);
1750     qemu_iovec_concat(qiov, &elem, skip, size);
1751 }
1752 
1753 static void v9fs_read(void *opaque)
1754 {
1755     int32_t fid;
1756     uint64_t off;
1757     ssize_t err = 0;
1758     int32_t count = 0;
1759     size_t offset = 7;
1760     uint32_t max_count;
1761     V9fsFidState *fidp;
1762     V9fsPDU *pdu = opaque;
1763     V9fsState *s = pdu->s;
1764 
1765     err = pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &max_count);
1766     if (err < 0) {
1767         goto out_nofid;
1768     }
1769     trace_v9fs_read(pdu->tag, pdu->id, fid, off, max_count);
1770 
1771     fidp = get_fid(pdu, fid);
1772     if (fidp == NULL) {
1773         err = -EINVAL;
1774         goto out_nofid;
1775     }
1776     if (fidp->fid_type == P9_FID_DIR) {
1777 
1778         if (off == 0) {
1779             v9fs_co_rewinddir(pdu, fidp);
1780         }
1781         count = v9fs_do_readdir_with_stat(pdu, fidp, max_count);
1782         if (count < 0) {
1783             err = count;
1784             goto out;
1785         }
1786         err = pdu_marshal(pdu, offset, "d", count);
1787         if (err < 0) {
1788             goto out;
1789         }
1790         err += offset + count;
1791     } else if (fidp->fid_type == P9_FID_FILE) {
1792         QEMUIOVector qiov_full;
1793         QEMUIOVector qiov;
1794         int32_t len;
1795 
1796         v9fs_init_qiov_from_pdu(&qiov_full, pdu, offset + 4, max_count, false);
1797         qemu_iovec_init(&qiov, qiov_full.niov);
1798         do {
1799             qemu_iovec_reset(&qiov);
1800             qemu_iovec_concat(&qiov, &qiov_full, count, qiov_full.size - count);
1801             if (0) {
1802                 print_sg(qiov.iov, qiov.niov);
1803             }
1804             /* Loop in case of EINTR */
1805             do {
1806                 len = v9fs_co_preadv(pdu, fidp, qiov.iov, qiov.niov, off);
1807                 if (len >= 0) {
1808                     off   += len;
1809                     count += len;
1810                 }
1811             } while (len == -EINTR && !pdu->cancelled);
1812             if (len < 0) {
1813                 /* IO error return the error */
1814                 err = len;
1815                 goto out;
1816             }
1817         } while (count < max_count && len > 0);
1818         err = pdu_marshal(pdu, offset, "d", count);
1819         if (err < 0) {
1820             goto out;
1821         }
1822         err += offset + count;
1823         qemu_iovec_destroy(&qiov);
1824         qemu_iovec_destroy(&qiov_full);
1825     } else if (fidp->fid_type == P9_FID_XATTR) {
1826         err = v9fs_xattr_read(s, pdu, fidp, off, max_count);
1827     } else {
1828         err = -EINVAL;
1829     }
1830     trace_v9fs_read_return(pdu->tag, pdu->id, count, err);
1831 out:
1832     put_fid(pdu, fidp);
1833 out_nofid:
1834     pdu_complete(pdu, err);
1835 }
1836 
1837 static size_t v9fs_readdir_data_size(V9fsString *name)
1838 {
1839     /*
1840      * Size of each dirent on the wire: size of qid (13) + size of offset (8)
1841      * size of type (1) + size of name.size (2) + strlen(name.data)
1842      */
1843     return 24 + v9fs_string_size(name);
1844 }
1845 
1846 static int v9fs_do_readdir(V9fsPDU *pdu,
1847                            V9fsFidState *fidp, int32_t max_count)
1848 {
1849     size_t size;
1850     V9fsQID qid;
1851     V9fsString name;
1852     int len, err = 0;
1853     int32_t count = 0;
1854     off_t saved_dir_pos;
1855     struct dirent *dent;
1856 
1857     /* save the directory position */
1858     saved_dir_pos = v9fs_co_telldir(pdu, fidp);
1859     if (saved_dir_pos < 0) {
1860         return saved_dir_pos;
1861     }
1862 
1863     while (1) {
1864         v9fs_readdir_lock(&fidp->fs.dir);
1865 
1866         err = v9fs_co_readdir(pdu, fidp, &dent);
1867         if (err || !dent) {
1868             break;
1869         }
1870         v9fs_string_init(&name);
1871         v9fs_string_sprintf(&name, "%s", dent->d_name);
1872         if ((count + v9fs_readdir_data_size(&name)) > max_count) {
1873             v9fs_readdir_unlock(&fidp->fs.dir);
1874 
1875             /* Ran out of buffer. Set dir back to old position and return */
1876             v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
1877             v9fs_string_free(&name);
1878             return count;
1879         }
1880         /*
1881          * Fill up just the path field of qid because the client uses
1882          * only that. To fill the entire qid structure we will have
1883          * to stat each dirent found, which is expensive
1884          */
1885         size = MIN(sizeof(dent->d_ino), sizeof(qid.path));
1886         memcpy(&qid.path, &dent->d_ino, size);
1887         /* Fill the other fields with dummy values */
1888         qid.type = 0;
1889         qid.version = 0;
1890 
1891         /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */
1892         len = pdu_marshal(pdu, 11 + count, "Qqbs",
1893                           &qid, dent->d_off,
1894                           dent->d_type, &name);
1895 
1896         v9fs_readdir_unlock(&fidp->fs.dir);
1897 
1898         if (len < 0) {
1899             v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
1900             v9fs_string_free(&name);
1901             return len;
1902         }
1903         count += len;
1904         v9fs_string_free(&name);
1905         saved_dir_pos = dent->d_off;
1906     }
1907 
1908     v9fs_readdir_unlock(&fidp->fs.dir);
1909 
1910     if (err < 0) {
1911         return err;
1912     }
1913     return count;
1914 }
1915 
1916 static void v9fs_readdir(void *opaque)
1917 {
1918     int32_t fid;
1919     V9fsFidState *fidp;
1920     ssize_t retval = 0;
1921     size_t offset = 7;
1922     uint64_t initial_offset;
1923     int32_t count;
1924     uint32_t max_count;
1925     V9fsPDU *pdu = opaque;
1926 
1927     retval = pdu_unmarshal(pdu, offset, "dqd", &fid,
1928                            &initial_offset, &max_count);
1929     if (retval < 0) {
1930         goto out_nofid;
1931     }
1932     trace_v9fs_readdir(pdu->tag, pdu->id, fid, initial_offset, max_count);
1933 
1934     fidp = get_fid(pdu, fid);
1935     if (fidp == NULL) {
1936         retval = -EINVAL;
1937         goto out_nofid;
1938     }
1939     if (!fidp->fs.dir.stream) {
1940         retval = -EINVAL;
1941         goto out;
1942     }
1943     if (initial_offset == 0) {
1944         v9fs_co_rewinddir(pdu, fidp);
1945     } else {
1946         v9fs_co_seekdir(pdu, fidp, initial_offset);
1947     }
1948     count = v9fs_do_readdir(pdu, fidp, max_count);
1949     if (count < 0) {
1950         retval = count;
1951         goto out;
1952     }
1953     retval = pdu_marshal(pdu, offset, "d", count);
1954     if (retval < 0) {
1955         goto out;
1956     }
1957     retval += count + offset;
1958     trace_v9fs_readdir_return(pdu->tag, pdu->id, count, retval);
1959 out:
1960     put_fid(pdu, fidp);
1961 out_nofid:
1962     pdu_complete(pdu, retval);
1963 }
1964 
1965 static int v9fs_xattr_write(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
1966                             uint64_t off, uint32_t count,
1967                             struct iovec *sg, int cnt)
1968 {
1969     int i, to_copy;
1970     ssize_t err = 0;
1971     int write_count;
1972     int64_t xattr_len;
1973     size_t offset = 7;
1974 
1975 
1976     xattr_len = fidp->fs.xattr.len;
1977     write_count = xattr_len - off;
1978     if (write_count > count) {
1979         write_count = count;
1980     } else if (write_count < 0) {
1981         /*
1982          * write beyond XATTR value len specified in
1983          * xattrcreate
1984          */
1985         err = -ENOSPC;
1986         goto out;
1987     }
1988     err = pdu_marshal(pdu, offset, "d", write_count);
1989     if (err < 0) {
1990         return err;
1991     }
1992     err += offset;
1993     fidp->fs.xattr.copied_len += write_count;
1994     /*
1995      * Now copy the content from sg list
1996      */
1997     for (i = 0; i < cnt; i++) {
1998         if (write_count > sg[i].iov_len) {
1999             to_copy = sg[i].iov_len;
2000         } else {
2001             to_copy = write_count;
2002         }
2003         memcpy((char *)fidp->fs.xattr.value + off, sg[i].iov_base, to_copy);
2004         /* updating vs->off since we are not using below */
2005         off += to_copy;
2006         write_count -= to_copy;
2007     }
2008 out:
2009     return err;
2010 }
2011 
2012 static void v9fs_write(void *opaque)
2013 {
2014     ssize_t err;
2015     int32_t fid;
2016     uint64_t off;
2017     uint32_t count;
2018     int32_t len = 0;
2019     int32_t total = 0;
2020     size_t offset = 7;
2021     V9fsFidState *fidp;
2022     V9fsPDU *pdu = opaque;
2023     V9fsState *s = pdu->s;
2024     QEMUIOVector qiov_full;
2025     QEMUIOVector qiov;
2026 
2027     err = pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &count);
2028     if (err < 0) {
2029         pdu_complete(pdu, err);
2030         return;
2031     }
2032     offset += err;
2033     v9fs_init_qiov_from_pdu(&qiov_full, pdu, offset, count, true);
2034     trace_v9fs_write(pdu->tag, pdu->id, fid, off, count, qiov_full.niov);
2035 
2036     fidp = get_fid(pdu, fid);
2037     if (fidp == NULL) {
2038         err = -EINVAL;
2039         goto out_nofid;
2040     }
2041     if (fidp->fid_type == P9_FID_FILE) {
2042         if (fidp->fs.fd == -1) {
2043             err = -EINVAL;
2044             goto out;
2045         }
2046     } else if (fidp->fid_type == P9_FID_XATTR) {
2047         /*
2048          * setxattr operation
2049          */
2050         err = v9fs_xattr_write(s, pdu, fidp, off, count,
2051                                qiov_full.iov, qiov_full.niov);
2052         goto out;
2053     } else {
2054         err = -EINVAL;
2055         goto out;
2056     }
2057     qemu_iovec_init(&qiov, qiov_full.niov);
2058     do {
2059         qemu_iovec_reset(&qiov);
2060         qemu_iovec_concat(&qiov, &qiov_full, total, qiov_full.size - total);
2061         if (0) {
2062             print_sg(qiov.iov, qiov.niov);
2063         }
2064         /* Loop in case of EINTR */
2065         do {
2066             len = v9fs_co_pwritev(pdu, fidp, qiov.iov, qiov.niov, off);
2067             if (len >= 0) {
2068                 off   += len;
2069                 total += len;
2070             }
2071         } while (len == -EINTR && !pdu->cancelled);
2072         if (len < 0) {
2073             /* IO error return the error */
2074             err = len;
2075             goto out_qiov;
2076         }
2077     } while (total < count && len > 0);
2078 
2079     offset = 7;
2080     err = pdu_marshal(pdu, offset, "d", total);
2081     if (err < 0) {
2082         goto out;
2083     }
2084     err += offset;
2085     trace_v9fs_write_return(pdu->tag, pdu->id, total, err);
2086 out_qiov:
2087     qemu_iovec_destroy(&qiov);
2088 out:
2089     put_fid(pdu, fidp);
2090 out_nofid:
2091     qemu_iovec_destroy(&qiov_full);
2092     pdu_complete(pdu, err);
2093 }
2094 
2095 static void v9fs_create(void *opaque)
2096 {
2097     int32_t fid;
2098     int err = 0;
2099     size_t offset = 7;
2100     V9fsFidState *fidp;
2101     V9fsQID qid;
2102     int32_t perm;
2103     int8_t mode;
2104     V9fsPath path;
2105     struct stat stbuf;
2106     V9fsString name;
2107     V9fsString extension;
2108     int iounit;
2109     V9fsPDU *pdu = opaque;
2110 
2111     v9fs_path_init(&path);
2112     v9fs_string_init(&name);
2113     v9fs_string_init(&extension);
2114     err = pdu_unmarshal(pdu, offset, "dsdbs", &fid, &name,
2115                         &perm, &mode, &extension);
2116     if (err < 0) {
2117         goto out_nofid;
2118     }
2119     trace_v9fs_create(pdu->tag, pdu->id, fid, name.data, perm, mode);
2120 
2121     if (name_is_illegal(name.data)) {
2122         err = -ENOENT;
2123         goto out_nofid;
2124     }
2125 
2126     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
2127         err = -EEXIST;
2128         goto out_nofid;
2129     }
2130 
2131     fidp = get_fid(pdu, fid);
2132     if (fidp == NULL) {
2133         err = -EINVAL;
2134         goto out_nofid;
2135     }
2136     if (perm & P9_STAT_MODE_DIR) {
2137         err = v9fs_co_mkdir(pdu, fidp, &name, perm & 0777,
2138                             fidp->uid, -1, &stbuf);
2139         if (err < 0) {
2140             goto out;
2141         }
2142         err = v9fs_co_name_to_path(pdu, &fidp->path, name.data, &path);
2143         if (err < 0) {
2144             goto out;
2145         }
2146         v9fs_path_copy(&fidp->path, &path);
2147         err = v9fs_co_opendir(pdu, fidp);
2148         if (err < 0) {
2149             goto out;
2150         }
2151         fidp->fid_type = P9_FID_DIR;
2152     } else if (perm & P9_STAT_MODE_SYMLINK) {
2153         err = v9fs_co_symlink(pdu, fidp, &name,
2154                               extension.data, -1 , &stbuf);
2155         if (err < 0) {
2156             goto out;
2157         }
2158         err = v9fs_co_name_to_path(pdu, &fidp->path, name.data, &path);
2159         if (err < 0) {
2160             goto out;
2161         }
2162         v9fs_path_copy(&fidp->path, &path);
2163     } else if (perm & P9_STAT_MODE_LINK) {
2164         int32_t ofid = atoi(extension.data);
2165         V9fsFidState *ofidp = get_fid(pdu, ofid);
2166         if (ofidp == NULL) {
2167             err = -EINVAL;
2168             goto out;
2169         }
2170         err = v9fs_co_link(pdu, ofidp, fidp, &name);
2171         put_fid(pdu, ofidp);
2172         if (err < 0) {
2173             goto out;
2174         }
2175         err = v9fs_co_name_to_path(pdu, &fidp->path, name.data, &path);
2176         if (err < 0) {
2177             fidp->fid_type = P9_FID_NONE;
2178             goto out;
2179         }
2180         v9fs_path_copy(&fidp->path, &path);
2181         err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
2182         if (err < 0) {
2183             fidp->fid_type = P9_FID_NONE;
2184             goto out;
2185         }
2186     } else if (perm & P9_STAT_MODE_DEVICE) {
2187         char ctype;
2188         uint32_t major, minor;
2189         mode_t nmode = 0;
2190 
2191         if (sscanf(extension.data, "%c %u %u", &ctype, &major, &minor) != 3) {
2192             err = -errno;
2193             goto out;
2194         }
2195 
2196         switch (ctype) {
2197         case 'c':
2198             nmode = S_IFCHR;
2199             break;
2200         case 'b':
2201             nmode = S_IFBLK;
2202             break;
2203         default:
2204             err = -EIO;
2205             goto out;
2206         }
2207 
2208         nmode |= perm & 0777;
2209         err = v9fs_co_mknod(pdu, fidp, &name, fidp->uid, -1,
2210                             makedev(major, minor), nmode, &stbuf);
2211         if (err < 0) {
2212             goto out;
2213         }
2214         err = v9fs_co_name_to_path(pdu, &fidp->path, name.data, &path);
2215         if (err < 0) {
2216             goto out;
2217         }
2218         v9fs_path_copy(&fidp->path, &path);
2219     } else if (perm & P9_STAT_MODE_NAMED_PIPE) {
2220         err = v9fs_co_mknod(pdu, fidp, &name, fidp->uid, -1,
2221                             0, S_IFIFO | (perm & 0777), &stbuf);
2222         if (err < 0) {
2223             goto out;
2224         }
2225         err = v9fs_co_name_to_path(pdu, &fidp->path, name.data, &path);
2226         if (err < 0) {
2227             goto out;
2228         }
2229         v9fs_path_copy(&fidp->path, &path);
2230     } else if (perm & P9_STAT_MODE_SOCKET) {
2231         err = v9fs_co_mknod(pdu, fidp, &name, fidp->uid, -1,
2232                             0, S_IFSOCK | (perm & 0777), &stbuf);
2233         if (err < 0) {
2234             goto out;
2235         }
2236         err = v9fs_co_name_to_path(pdu, &fidp->path, name.data, &path);
2237         if (err < 0) {
2238             goto out;
2239         }
2240         v9fs_path_copy(&fidp->path, &path);
2241     } else {
2242         err = v9fs_co_open2(pdu, fidp, &name, -1,
2243                             omode_to_uflags(mode)|O_CREAT, perm, &stbuf);
2244         if (err < 0) {
2245             goto out;
2246         }
2247         fidp->fid_type = P9_FID_FILE;
2248         fidp->open_flags = omode_to_uflags(mode);
2249         if (fidp->open_flags & O_EXCL) {
2250             /*
2251              * We let the host file system do O_EXCL check
2252              * We should not reclaim such fd
2253              */
2254             fidp->flags |= FID_NON_RECLAIMABLE;
2255         }
2256     }
2257     iounit = get_iounit(pdu, &fidp->path);
2258     stat_to_qid(&stbuf, &qid);
2259     err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
2260     if (err < 0) {
2261         goto out;
2262     }
2263     err += offset;
2264     trace_v9fs_create_return(pdu->tag, pdu->id,
2265                              qid.type, qid.version, qid.path, iounit);
2266 out:
2267     put_fid(pdu, fidp);
2268 out_nofid:
2269    pdu_complete(pdu, err);
2270    v9fs_string_free(&name);
2271    v9fs_string_free(&extension);
2272    v9fs_path_free(&path);
2273 }
2274 
2275 static void v9fs_symlink(void *opaque)
2276 {
2277     V9fsPDU *pdu = opaque;
2278     V9fsString name;
2279     V9fsString symname;
2280     V9fsFidState *dfidp;
2281     V9fsQID qid;
2282     struct stat stbuf;
2283     int32_t dfid;
2284     int err = 0;
2285     gid_t gid;
2286     size_t offset = 7;
2287 
2288     v9fs_string_init(&name);
2289     v9fs_string_init(&symname);
2290     err = pdu_unmarshal(pdu, offset, "dssd", &dfid, &name, &symname, &gid);
2291     if (err < 0) {
2292         goto out_nofid;
2293     }
2294     trace_v9fs_symlink(pdu->tag, pdu->id, dfid, name.data, symname.data, gid);
2295 
2296     if (name_is_illegal(name.data)) {
2297         err = -ENOENT;
2298         goto out_nofid;
2299     }
2300 
2301     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
2302         err = -EEXIST;
2303         goto out_nofid;
2304     }
2305 
2306     dfidp = get_fid(pdu, dfid);
2307     if (dfidp == NULL) {
2308         err = -EINVAL;
2309         goto out_nofid;
2310     }
2311     err = v9fs_co_symlink(pdu, dfidp, &name, symname.data, gid, &stbuf);
2312     if (err < 0) {
2313         goto out;
2314     }
2315     stat_to_qid(&stbuf, &qid);
2316     err =  pdu_marshal(pdu, offset, "Q", &qid);
2317     if (err < 0) {
2318         goto out;
2319     }
2320     err += offset;
2321     trace_v9fs_symlink_return(pdu->tag, pdu->id,
2322                               qid.type, qid.version, qid.path);
2323 out:
2324     put_fid(pdu, dfidp);
2325 out_nofid:
2326     pdu_complete(pdu, err);
2327     v9fs_string_free(&name);
2328     v9fs_string_free(&symname);
2329 }
2330 
2331 static void v9fs_flush(void *opaque)
2332 {
2333     ssize_t err;
2334     int16_t tag;
2335     size_t offset = 7;
2336     V9fsPDU *cancel_pdu;
2337     V9fsPDU *pdu = opaque;
2338     V9fsState *s = pdu->s;
2339 
2340     err = pdu_unmarshal(pdu, offset, "w", &tag);
2341     if (err < 0) {
2342         pdu_complete(pdu, err);
2343         return;
2344     }
2345     trace_v9fs_flush(pdu->tag, pdu->id, tag);
2346 
2347     QLIST_FOREACH(cancel_pdu, &s->active_list, next) {
2348         if (cancel_pdu->tag == tag) {
2349             break;
2350         }
2351     }
2352     if (cancel_pdu) {
2353         cancel_pdu->cancelled = 1;
2354         /*
2355          * Wait for pdu to complete.
2356          */
2357         qemu_co_queue_wait(&cancel_pdu->complete);
2358         cancel_pdu->cancelled = 0;
2359         pdu_free(cancel_pdu);
2360     }
2361     pdu_complete(pdu, 7);
2362 }
2363 
2364 static void v9fs_link(void *opaque)
2365 {
2366     V9fsPDU *pdu = opaque;
2367     int32_t dfid, oldfid;
2368     V9fsFidState *dfidp, *oldfidp;
2369     V9fsString name;
2370     size_t offset = 7;
2371     int err = 0;
2372 
2373     v9fs_string_init(&name);
2374     err = pdu_unmarshal(pdu, offset, "dds", &dfid, &oldfid, &name);
2375     if (err < 0) {
2376         goto out_nofid;
2377     }
2378     trace_v9fs_link(pdu->tag, pdu->id, dfid, oldfid, name.data);
2379 
2380     if (name_is_illegal(name.data)) {
2381         err = -ENOENT;
2382         goto out_nofid;
2383     }
2384 
2385     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
2386         err = -EEXIST;
2387         goto out_nofid;
2388     }
2389 
2390     dfidp = get_fid(pdu, dfid);
2391     if (dfidp == NULL) {
2392         err = -ENOENT;
2393         goto out_nofid;
2394     }
2395 
2396     oldfidp = get_fid(pdu, oldfid);
2397     if (oldfidp == NULL) {
2398         err = -ENOENT;
2399         goto out;
2400     }
2401     err = v9fs_co_link(pdu, oldfidp, dfidp, &name);
2402     if (!err) {
2403         err = offset;
2404     }
2405 out:
2406     put_fid(pdu, dfidp);
2407 out_nofid:
2408     v9fs_string_free(&name);
2409     pdu_complete(pdu, err);
2410 }
2411 
2412 /* Only works with path name based fid */
2413 static void v9fs_remove(void *opaque)
2414 {
2415     int32_t fid;
2416     int err = 0;
2417     size_t offset = 7;
2418     V9fsFidState *fidp;
2419     V9fsPDU *pdu = opaque;
2420 
2421     err = pdu_unmarshal(pdu, offset, "d", &fid);
2422     if (err < 0) {
2423         goto out_nofid;
2424     }
2425     trace_v9fs_remove(pdu->tag, pdu->id, fid);
2426 
2427     fidp = get_fid(pdu, fid);
2428     if (fidp == NULL) {
2429         err = -EINVAL;
2430         goto out_nofid;
2431     }
2432     /* if fs driver is not path based, return EOPNOTSUPP */
2433     if (!(pdu->s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT)) {
2434         err = -EOPNOTSUPP;
2435         goto out_err;
2436     }
2437     /*
2438      * IF the file is unlinked, we cannot reopen
2439      * the file later. So don't reclaim fd
2440      */
2441     err = v9fs_mark_fids_unreclaim(pdu, &fidp->path);
2442     if (err < 0) {
2443         goto out_err;
2444     }
2445     err = v9fs_co_remove(pdu, &fidp->path);
2446     if (!err) {
2447         err = offset;
2448     }
2449 out_err:
2450     /* For TREMOVE we need to clunk the fid even on failed remove */
2451     clunk_fid(pdu->s, fidp->fid);
2452     put_fid(pdu, fidp);
2453 out_nofid:
2454     pdu_complete(pdu, err);
2455 }
2456 
2457 static void v9fs_unlinkat(void *opaque)
2458 {
2459     int err = 0;
2460     V9fsString name;
2461     int32_t dfid, flags;
2462     size_t offset = 7;
2463     V9fsPath path;
2464     V9fsFidState *dfidp;
2465     V9fsPDU *pdu = opaque;
2466 
2467     v9fs_string_init(&name);
2468     err = pdu_unmarshal(pdu, offset, "dsd", &dfid, &name, &flags);
2469     if (err < 0) {
2470         goto out_nofid;
2471     }
2472 
2473     if (name_is_illegal(name.data)) {
2474         err = -ENOENT;
2475         goto out_nofid;
2476     }
2477 
2478     if (!strcmp(".", name.data)) {
2479         err = -EINVAL;
2480         goto out_nofid;
2481     }
2482 
2483     if (!strcmp("..", name.data)) {
2484         err = -ENOTEMPTY;
2485         goto out_nofid;
2486     }
2487 
2488     dfidp = get_fid(pdu, dfid);
2489     if (dfidp == NULL) {
2490         err = -EINVAL;
2491         goto out_nofid;
2492     }
2493     /*
2494      * IF the file is unlinked, we cannot reopen
2495      * the file later. So don't reclaim fd
2496      */
2497     v9fs_path_init(&path);
2498     err = v9fs_co_name_to_path(pdu, &dfidp->path, name.data, &path);
2499     if (err < 0) {
2500         goto out_err;
2501     }
2502     err = v9fs_mark_fids_unreclaim(pdu, &path);
2503     if (err < 0) {
2504         goto out_err;
2505     }
2506     err = v9fs_co_unlinkat(pdu, &dfidp->path, &name, flags);
2507     if (!err) {
2508         err = offset;
2509     }
2510 out_err:
2511     put_fid(pdu, dfidp);
2512     v9fs_path_free(&path);
2513 out_nofid:
2514     pdu_complete(pdu, err);
2515     v9fs_string_free(&name);
2516 }
2517 
2518 
2519 /* Only works with path name based fid */
2520 static int v9fs_complete_rename(V9fsPDU *pdu, V9fsFidState *fidp,
2521                                 int32_t newdirfid, V9fsString *name)
2522 {
2523     char *end;
2524     int err = 0;
2525     V9fsPath new_path;
2526     V9fsFidState *tfidp;
2527     V9fsState *s = pdu->s;
2528     V9fsFidState *dirfidp = NULL;
2529     char *old_name, *new_name;
2530 
2531     v9fs_path_init(&new_path);
2532     if (newdirfid != -1) {
2533         dirfidp = get_fid(pdu, newdirfid);
2534         if (dirfidp == NULL) {
2535             err = -ENOENT;
2536             goto out_nofid;
2537         }
2538         BUG_ON(dirfidp->fid_type != P9_FID_NONE);
2539         v9fs_co_name_to_path(pdu, &dirfidp->path, name->data, &new_path);
2540     } else {
2541         old_name = fidp->path.data;
2542         end = strrchr(old_name, '/');
2543         if (end) {
2544             end++;
2545         } else {
2546             end = old_name;
2547         }
2548         new_name = g_malloc0(end - old_name + name->size + 1);
2549         strncat(new_name, old_name, end - old_name);
2550         strncat(new_name + (end - old_name), name->data, name->size);
2551         v9fs_co_name_to_path(pdu, NULL, new_name, &new_path);
2552         g_free(new_name);
2553     }
2554     err = v9fs_co_rename(pdu, &fidp->path, &new_path);
2555     if (err < 0) {
2556         goto out;
2557     }
2558     /*
2559      * Fixup fid's pointing to the old name to
2560      * start pointing to the new name
2561      */
2562     for (tfidp = s->fid_list; tfidp; tfidp = tfidp->next) {
2563         if (v9fs_path_is_ancestor(&fidp->path, &tfidp->path)) {
2564             /* replace the name */
2565             v9fs_fix_path(&tfidp->path, &new_path, strlen(fidp->path.data));
2566         }
2567     }
2568 out:
2569     if (dirfidp) {
2570         put_fid(pdu, dirfidp);
2571     }
2572     v9fs_path_free(&new_path);
2573 out_nofid:
2574     return err;
2575 }
2576 
2577 /* Only works with path name based fid */
2578 static void v9fs_rename(void *opaque)
2579 {
2580     int32_t fid;
2581     ssize_t err = 0;
2582     size_t offset = 7;
2583     V9fsString name;
2584     int32_t newdirfid;
2585     V9fsFidState *fidp;
2586     V9fsPDU *pdu = opaque;
2587     V9fsState *s = pdu->s;
2588 
2589     v9fs_string_init(&name);
2590     err = pdu_unmarshal(pdu, offset, "dds", &fid, &newdirfid, &name);
2591     if (err < 0) {
2592         goto out_nofid;
2593     }
2594 
2595     if (name_is_illegal(name.data)) {
2596         err = -ENOENT;
2597         goto out_nofid;
2598     }
2599 
2600     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
2601         err = -EISDIR;
2602         goto out_nofid;
2603     }
2604 
2605     fidp = get_fid(pdu, fid);
2606     if (fidp == NULL) {
2607         err = -ENOENT;
2608         goto out_nofid;
2609     }
2610     BUG_ON(fidp->fid_type != P9_FID_NONE);
2611     /* if fs driver is not path based, return EOPNOTSUPP */
2612     if (!(pdu->s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT)) {
2613         err = -EOPNOTSUPP;
2614         goto out;
2615     }
2616     v9fs_path_write_lock(s);
2617     err = v9fs_complete_rename(pdu, fidp, newdirfid, &name);
2618     v9fs_path_unlock(s);
2619     if (!err) {
2620         err = offset;
2621     }
2622 out:
2623     put_fid(pdu, fidp);
2624 out_nofid:
2625     pdu_complete(pdu, err);
2626     v9fs_string_free(&name);
2627 }
2628 
2629 static void v9fs_fix_fid_paths(V9fsPDU *pdu, V9fsPath *olddir,
2630                                V9fsString *old_name, V9fsPath *newdir,
2631                                V9fsString *new_name)
2632 {
2633     V9fsFidState *tfidp;
2634     V9fsPath oldpath, newpath;
2635     V9fsState *s = pdu->s;
2636 
2637 
2638     v9fs_path_init(&oldpath);
2639     v9fs_path_init(&newpath);
2640     v9fs_co_name_to_path(pdu, olddir, old_name->data, &oldpath);
2641     v9fs_co_name_to_path(pdu, newdir, new_name->data, &newpath);
2642 
2643     /*
2644      * Fixup fid's pointing to the old name to
2645      * start pointing to the new name
2646      */
2647     for (tfidp = s->fid_list; tfidp; tfidp = tfidp->next) {
2648         if (v9fs_path_is_ancestor(&oldpath, &tfidp->path)) {
2649             /* replace the name */
2650             v9fs_fix_path(&tfidp->path, &newpath, strlen(oldpath.data));
2651         }
2652     }
2653     v9fs_path_free(&oldpath);
2654     v9fs_path_free(&newpath);
2655 }
2656 
2657 static int v9fs_complete_renameat(V9fsPDU *pdu, int32_t olddirfid,
2658                                   V9fsString *old_name, int32_t newdirfid,
2659                                   V9fsString *new_name)
2660 {
2661     int err = 0;
2662     V9fsState *s = pdu->s;
2663     V9fsFidState *newdirfidp = NULL, *olddirfidp = NULL;
2664 
2665     olddirfidp = get_fid(pdu, olddirfid);
2666     if (olddirfidp == NULL) {
2667         err = -ENOENT;
2668         goto out;
2669     }
2670     if (newdirfid != -1) {
2671         newdirfidp = get_fid(pdu, newdirfid);
2672         if (newdirfidp == NULL) {
2673             err = -ENOENT;
2674             goto out;
2675         }
2676     } else {
2677         newdirfidp = get_fid(pdu, olddirfid);
2678     }
2679 
2680     err = v9fs_co_renameat(pdu, &olddirfidp->path, old_name,
2681                            &newdirfidp->path, new_name);
2682     if (err < 0) {
2683         goto out;
2684     }
2685     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
2686         /* Only for path based fid  we need to do the below fixup */
2687         v9fs_fix_fid_paths(pdu, &olddirfidp->path, old_name,
2688                            &newdirfidp->path, new_name);
2689     }
2690 out:
2691     if (olddirfidp) {
2692         put_fid(pdu, olddirfidp);
2693     }
2694     if (newdirfidp) {
2695         put_fid(pdu, newdirfidp);
2696     }
2697     return err;
2698 }
2699 
2700 static void v9fs_renameat(void *opaque)
2701 {
2702     ssize_t err = 0;
2703     size_t offset = 7;
2704     V9fsPDU *pdu = opaque;
2705     V9fsState *s = pdu->s;
2706     int32_t olddirfid, newdirfid;
2707     V9fsString old_name, new_name;
2708 
2709     v9fs_string_init(&old_name);
2710     v9fs_string_init(&new_name);
2711     err = pdu_unmarshal(pdu, offset, "dsds", &olddirfid,
2712                         &old_name, &newdirfid, &new_name);
2713     if (err < 0) {
2714         goto out_err;
2715     }
2716 
2717     if (name_is_illegal(old_name.data) || name_is_illegal(new_name.data)) {
2718         err = -ENOENT;
2719         goto out_err;
2720     }
2721 
2722     if (!strcmp(".", old_name.data) || !strcmp("..", old_name.data) ||
2723         !strcmp(".", new_name.data) || !strcmp("..", new_name.data)) {
2724         err = -EISDIR;
2725         goto out_err;
2726     }
2727 
2728     v9fs_path_write_lock(s);
2729     err = v9fs_complete_renameat(pdu, olddirfid,
2730                                  &old_name, newdirfid, &new_name);
2731     v9fs_path_unlock(s);
2732     if (!err) {
2733         err = offset;
2734     }
2735 
2736 out_err:
2737     pdu_complete(pdu, err);
2738     v9fs_string_free(&old_name);
2739     v9fs_string_free(&new_name);
2740 }
2741 
2742 static void v9fs_wstat(void *opaque)
2743 {
2744     int32_t fid;
2745     int err = 0;
2746     int16_t unused;
2747     V9fsStat v9stat;
2748     size_t offset = 7;
2749     struct stat stbuf;
2750     V9fsFidState *fidp;
2751     V9fsPDU *pdu = opaque;
2752 
2753     v9fs_stat_init(&v9stat);
2754     err = pdu_unmarshal(pdu, offset, "dwS", &fid, &unused, &v9stat);
2755     if (err < 0) {
2756         goto out_nofid;
2757     }
2758     trace_v9fs_wstat(pdu->tag, pdu->id, fid,
2759                      v9stat.mode, v9stat.atime, v9stat.mtime);
2760 
2761     fidp = get_fid(pdu, fid);
2762     if (fidp == NULL) {
2763         err = -EINVAL;
2764         goto out_nofid;
2765     }
2766     /* do we need to sync the file? */
2767     if (donttouch_stat(&v9stat)) {
2768         err = v9fs_co_fsync(pdu, fidp, 0);
2769         goto out;
2770     }
2771     if (v9stat.mode != -1) {
2772         uint32_t v9_mode;
2773         err = v9fs_co_lstat(pdu, &fidp->path, &stbuf);
2774         if (err < 0) {
2775             goto out;
2776         }
2777         v9_mode = stat_to_v9mode(&stbuf);
2778         if ((v9stat.mode & P9_STAT_MODE_TYPE_BITS) !=
2779             (v9_mode & P9_STAT_MODE_TYPE_BITS)) {
2780             /* Attempting to change the type */
2781             err = -EIO;
2782             goto out;
2783         }
2784         err = v9fs_co_chmod(pdu, &fidp->path,
2785                             v9mode_to_mode(v9stat.mode,
2786                                            &v9stat.extension));
2787         if (err < 0) {
2788             goto out;
2789         }
2790     }
2791     if (v9stat.mtime != -1 || v9stat.atime != -1) {
2792         struct timespec times[2];
2793         if (v9stat.atime != -1) {
2794             times[0].tv_sec = v9stat.atime;
2795             times[0].tv_nsec = 0;
2796         } else {
2797             times[0].tv_nsec = UTIME_OMIT;
2798         }
2799         if (v9stat.mtime != -1) {
2800             times[1].tv_sec = v9stat.mtime;
2801             times[1].tv_nsec = 0;
2802         } else {
2803             times[1].tv_nsec = UTIME_OMIT;
2804         }
2805         err = v9fs_co_utimensat(pdu, &fidp->path, times);
2806         if (err < 0) {
2807             goto out;
2808         }
2809     }
2810     if (v9stat.n_gid != -1 || v9stat.n_uid != -1) {
2811         err = v9fs_co_chown(pdu, &fidp->path, v9stat.n_uid, v9stat.n_gid);
2812         if (err < 0) {
2813             goto out;
2814         }
2815     }
2816     if (v9stat.name.size != 0) {
2817         err = v9fs_complete_rename(pdu, fidp, -1, &v9stat.name);
2818         if (err < 0) {
2819             goto out;
2820         }
2821     }
2822     if (v9stat.length != -1) {
2823         err = v9fs_co_truncate(pdu, &fidp->path, v9stat.length);
2824         if (err < 0) {
2825             goto out;
2826         }
2827     }
2828     err = offset;
2829 out:
2830     put_fid(pdu, fidp);
2831 out_nofid:
2832     v9fs_stat_free(&v9stat);
2833     pdu_complete(pdu, err);
2834 }
2835 
2836 static int v9fs_fill_statfs(V9fsState *s, V9fsPDU *pdu, struct statfs *stbuf)
2837 {
2838     uint32_t f_type;
2839     uint32_t f_bsize;
2840     uint64_t f_blocks;
2841     uint64_t f_bfree;
2842     uint64_t f_bavail;
2843     uint64_t f_files;
2844     uint64_t f_ffree;
2845     uint64_t fsid_val;
2846     uint32_t f_namelen;
2847     size_t offset = 7;
2848     int32_t bsize_factor;
2849 
2850     /*
2851      * compute bsize factor based on host file system block size
2852      * and client msize
2853      */
2854     bsize_factor = (s->msize - P9_IOHDRSZ)/stbuf->f_bsize;
2855     if (!bsize_factor) {
2856         bsize_factor = 1;
2857     }
2858     f_type  = stbuf->f_type;
2859     f_bsize = stbuf->f_bsize;
2860     f_bsize *= bsize_factor;
2861     /*
2862      * f_bsize is adjusted(multiplied) by bsize factor, so we need to
2863      * adjust(divide) the number of blocks, free blocks and available
2864      * blocks by bsize factor
2865      */
2866     f_blocks = stbuf->f_blocks/bsize_factor;
2867     f_bfree  = stbuf->f_bfree/bsize_factor;
2868     f_bavail = stbuf->f_bavail/bsize_factor;
2869     f_files  = stbuf->f_files;
2870     f_ffree  = stbuf->f_ffree;
2871     fsid_val = (unsigned int) stbuf->f_fsid.__val[0] |
2872                (unsigned long long)stbuf->f_fsid.__val[1] << 32;
2873     f_namelen = stbuf->f_namelen;
2874 
2875     return pdu_marshal(pdu, offset, "ddqqqqqqd",
2876                        f_type, f_bsize, f_blocks, f_bfree,
2877                        f_bavail, f_files, f_ffree,
2878                        fsid_val, f_namelen);
2879 }
2880 
2881 static void v9fs_statfs(void *opaque)
2882 {
2883     int32_t fid;
2884     ssize_t retval = 0;
2885     size_t offset = 7;
2886     V9fsFidState *fidp;
2887     struct statfs stbuf;
2888     V9fsPDU *pdu = opaque;
2889     V9fsState *s = pdu->s;
2890 
2891     retval = pdu_unmarshal(pdu, offset, "d", &fid);
2892     if (retval < 0) {
2893         goto out_nofid;
2894     }
2895     fidp = get_fid(pdu, fid);
2896     if (fidp == NULL) {
2897         retval = -ENOENT;
2898         goto out_nofid;
2899     }
2900     retval = v9fs_co_statfs(pdu, &fidp->path, &stbuf);
2901     if (retval < 0) {
2902         goto out;
2903     }
2904     retval = v9fs_fill_statfs(s, pdu, &stbuf);
2905     if (retval < 0) {
2906         goto out;
2907     }
2908     retval += offset;
2909 out:
2910     put_fid(pdu, fidp);
2911 out_nofid:
2912     pdu_complete(pdu, retval);
2913 }
2914 
2915 static void v9fs_mknod(void *opaque)
2916 {
2917 
2918     int mode;
2919     gid_t gid;
2920     int32_t fid;
2921     V9fsQID qid;
2922     int err = 0;
2923     int major, minor;
2924     size_t offset = 7;
2925     V9fsString name;
2926     struct stat stbuf;
2927     V9fsFidState *fidp;
2928     V9fsPDU *pdu = opaque;
2929 
2930     v9fs_string_init(&name);
2931     err = pdu_unmarshal(pdu, offset, "dsdddd", &fid, &name, &mode,
2932                         &major, &minor, &gid);
2933     if (err < 0) {
2934         goto out_nofid;
2935     }
2936     trace_v9fs_mknod(pdu->tag, pdu->id, fid, mode, major, minor);
2937 
2938     if (name_is_illegal(name.data)) {
2939         err = -ENOENT;
2940         goto out_nofid;
2941     }
2942 
2943     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
2944         err = -EEXIST;
2945         goto out_nofid;
2946     }
2947 
2948     fidp = get_fid(pdu, fid);
2949     if (fidp == NULL) {
2950         err = -ENOENT;
2951         goto out_nofid;
2952     }
2953     err = v9fs_co_mknod(pdu, fidp, &name, fidp->uid, gid,
2954                         makedev(major, minor), mode, &stbuf);
2955     if (err < 0) {
2956         goto out;
2957     }
2958     stat_to_qid(&stbuf, &qid);
2959     err = pdu_marshal(pdu, offset, "Q", &qid);
2960     if (err < 0) {
2961         goto out;
2962     }
2963     err += offset;
2964     trace_v9fs_mknod_return(pdu->tag, pdu->id,
2965                             qid.type, qid.version, qid.path);
2966 out:
2967     put_fid(pdu, fidp);
2968 out_nofid:
2969     pdu_complete(pdu, err);
2970     v9fs_string_free(&name);
2971 }
2972 
2973 /*
2974  * Implement posix byte range locking code
2975  * Server side handling of locking code is very simple, because 9p server in
2976  * QEMU can handle only one client. And most of the lock handling
2977  * (like conflict, merging) etc is done by the VFS layer itself, so no need to
2978  * do any thing in * qemu 9p server side lock code path.
2979  * So when a TLOCK request comes, always return success
2980  */
2981 static void v9fs_lock(void *opaque)
2982 {
2983     int8_t status;
2984     V9fsFlock flock;
2985     size_t offset = 7;
2986     struct stat stbuf;
2987     V9fsFidState *fidp;
2988     int32_t fid, err = 0;
2989     V9fsPDU *pdu = opaque;
2990 
2991     status = P9_LOCK_ERROR;
2992     v9fs_string_init(&flock.client_id);
2993     err = pdu_unmarshal(pdu, offset, "dbdqqds", &fid, &flock.type,
2994                         &flock.flags, &flock.start, &flock.length,
2995                         &flock.proc_id, &flock.client_id);
2996     if (err < 0) {
2997         goto out_nofid;
2998     }
2999     trace_v9fs_lock(pdu->tag, pdu->id, fid,
3000                     flock.type, flock.start, flock.length);
3001 
3002 
3003     /* We support only block flag now (that too ignored currently) */
3004     if (flock.flags & ~P9_LOCK_FLAGS_BLOCK) {
3005         err = -EINVAL;
3006         goto out_nofid;
3007     }
3008     fidp = get_fid(pdu, fid);
3009     if (fidp == NULL) {
3010         err = -ENOENT;
3011         goto out_nofid;
3012     }
3013     err = v9fs_co_fstat(pdu, fidp, &stbuf);
3014     if (err < 0) {
3015         goto out;
3016     }
3017     status = P9_LOCK_SUCCESS;
3018 out:
3019     put_fid(pdu, fidp);
3020 out_nofid:
3021     err = pdu_marshal(pdu, offset, "b", status);
3022     if (err > 0) {
3023         err += offset;
3024     }
3025     trace_v9fs_lock_return(pdu->tag, pdu->id, status);
3026     pdu_complete(pdu, err);
3027     v9fs_string_free(&flock.client_id);
3028 }
3029 
3030 /*
3031  * When a TGETLOCK request comes, always return success because all lock
3032  * handling is done by client's VFS layer.
3033  */
3034 static void v9fs_getlock(void *opaque)
3035 {
3036     size_t offset = 7;
3037     struct stat stbuf;
3038     V9fsFidState *fidp;
3039     V9fsGetlock glock;
3040     int32_t fid, err = 0;
3041     V9fsPDU *pdu = opaque;
3042 
3043     v9fs_string_init(&glock.client_id);
3044     err = pdu_unmarshal(pdu, offset, "dbqqds", &fid, &glock.type,
3045                         &glock.start, &glock.length, &glock.proc_id,
3046                         &glock.client_id);
3047     if (err < 0) {
3048         goto out_nofid;
3049     }
3050     trace_v9fs_getlock(pdu->tag, pdu->id, fid,
3051                        glock.type, glock.start, glock.length);
3052 
3053     fidp = get_fid(pdu, fid);
3054     if (fidp == NULL) {
3055         err = -ENOENT;
3056         goto out_nofid;
3057     }
3058     err = v9fs_co_fstat(pdu, fidp, &stbuf);
3059     if (err < 0) {
3060         goto out;
3061     }
3062     glock.type = P9_LOCK_TYPE_UNLCK;
3063     err = pdu_marshal(pdu, offset, "bqqds", glock.type,
3064                           glock.start, glock.length, glock.proc_id,
3065                           &glock.client_id);
3066     if (err < 0) {
3067         goto out;
3068     }
3069     err += offset;
3070     trace_v9fs_getlock_return(pdu->tag, pdu->id, glock.type, glock.start,
3071                               glock.length, glock.proc_id);
3072 out:
3073     put_fid(pdu, fidp);
3074 out_nofid:
3075     pdu_complete(pdu, err);
3076     v9fs_string_free(&glock.client_id);
3077 }
3078 
3079 static void v9fs_mkdir(void *opaque)
3080 {
3081     V9fsPDU *pdu = opaque;
3082     size_t offset = 7;
3083     int32_t fid;
3084     struct stat stbuf;
3085     V9fsQID qid;
3086     V9fsString name;
3087     V9fsFidState *fidp;
3088     gid_t gid;
3089     int mode;
3090     int err = 0;
3091 
3092     v9fs_string_init(&name);
3093     err = pdu_unmarshal(pdu, offset, "dsdd", &fid, &name, &mode, &gid);
3094     if (err < 0) {
3095         goto out_nofid;
3096     }
3097     trace_v9fs_mkdir(pdu->tag, pdu->id, fid, name.data, mode, gid);
3098 
3099     if (name_is_illegal(name.data)) {
3100         err = -ENOENT;
3101         goto out_nofid;
3102     }
3103 
3104     if (!strcmp(".", name.data) || !strcmp("..", name.data)) {
3105         err = -EEXIST;
3106         goto out_nofid;
3107     }
3108 
3109     fidp = get_fid(pdu, fid);
3110     if (fidp == NULL) {
3111         err = -ENOENT;
3112         goto out_nofid;
3113     }
3114     err = v9fs_co_mkdir(pdu, fidp, &name, mode, fidp->uid, gid, &stbuf);
3115     if (err < 0) {
3116         goto out;
3117     }
3118     stat_to_qid(&stbuf, &qid);
3119     err = pdu_marshal(pdu, offset, "Q", &qid);
3120     if (err < 0) {
3121         goto out;
3122     }
3123     err += offset;
3124     trace_v9fs_mkdir_return(pdu->tag, pdu->id,
3125                             qid.type, qid.version, qid.path, err);
3126 out:
3127     put_fid(pdu, fidp);
3128 out_nofid:
3129     pdu_complete(pdu, err);
3130     v9fs_string_free(&name);
3131 }
3132 
3133 static void v9fs_xattrwalk(void *opaque)
3134 {
3135     int64_t size;
3136     V9fsString name;
3137     ssize_t err = 0;
3138     size_t offset = 7;
3139     int32_t fid, newfid;
3140     V9fsFidState *file_fidp;
3141     V9fsFidState *xattr_fidp = NULL;
3142     V9fsPDU *pdu = opaque;
3143     V9fsState *s = pdu->s;
3144 
3145     v9fs_string_init(&name);
3146     err = pdu_unmarshal(pdu, offset, "dds", &fid, &newfid, &name);
3147     if (err < 0) {
3148         goto out_nofid;
3149     }
3150     trace_v9fs_xattrwalk(pdu->tag, pdu->id, fid, newfid, name.data);
3151 
3152     file_fidp = get_fid(pdu, fid);
3153     if (file_fidp == NULL) {
3154         err = -ENOENT;
3155         goto out_nofid;
3156     }
3157     xattr_fidp = alloc_fid(s, newfid);
3158     if (xattr_fidp == NULL) {
3159         err = -EINVAL;
3160         goto out;
3161     }
3162     v9fs_path_copy(&xattr_fidp->path, &file_fidp->path);
3163     if (name.data == NULL) {
3164         /*
3165          * listxattr request. Get the size first
3166          */
3167         size = v9fs_co_llistxattr(pdu, &xattr_fidp->path, NULL, 0);
3168         if (size < 0) {
3169             err = size;
3170             clunk_fid(s, xattr_fidp->fid);
3171             goto out;
3172         }
3173         /*
3174          * Read the xattr value
3175          */
3176         xattr_fidp->fs.xattr.len = size;
3177         xattr_fidp->fid_type = P9_FID_XATTR;
3178         xattr_fidp->fs.xattr.copied_len = -1;
3179         if (size) {
3180             xattr_fidp->fs.xattr.value = g_malloc(size);
3181             err = v9fs_co_llistxattr(pdu, &xattr_fidp->path,
3182                                      xattr_fidp->fs.xattr.value,
3183                                      xattr_fidp->fs.xattr.len);
3184             if (err < 0) {
3185                 clunk_fid(s, xattr_fidp->fid);
3186                 goto out;
3187             }
3188         }
3189         err = pdu_marshal(pdu, offset, "q", size);
3190         if (err < 0) {
3191             goto out;
3192         }
3193         err += offset;
3194     } else {
3195         /*
3196          * specific xattr fid. We check for xattr
3197          * presence also collect the xattr size
3198          */
3199         size = v9fs_co_lgetxattr(pdu, &xattr_fidp->path,
3200                                  &name, NULL, 0);
3201         if (size < 0) {
3202             err = size;
3203             clunk_fid(s, xattr_fidp->fid);
3204             goto out;
3205         }
3206         /*
3207          * Read the xattr value
3208          */
3209         xattr_fidp->fs.xattr.len = size;
3210         xattr_fidp->fid_type = P9_FID_XATTR;
3211         xattr_fidp->fs.xattr.copied_len = -1;
3212         if (size) {
3213             xattr_fidp->fs.xattr.value = g_malloc(size);
3214             err = v9fs_co_lgetxattr(pdu, &xattr_fidp->path,
3215                                     &name, xattr_fidp->fs.xattr.value,
3216                                     xattr_fidp->fs.xattr.len);
3217             if (err < 0) {
3218                 clunk_fid(s, xattr_fidp->fid);
3219                 goto out;
3220             }
3221         }
3222         err = pdu_marshal(pdu, offset, "q", size);
3223         if (err < 0) {
3224             goto out;
3225         }
3226         err += offset;
3227     }
3228     trace_v9fs_xattrwalk_return(pdu->tag, pdu->id, size);
3229 out:
3230     put_fid(pdu, file_fidp);
3231     if (xattr_fidp) {
3232         put_fid(pdu, xattr_fidp);
3233     }
3234 out_nofid:
3235     pdu_complete(pdu, err);
3236     v9fs_string_free(&name);
3237 }
3238 
3239 static void v9fs_xattrcreate(void *opaque)
3240 {
3241     int flags;
3242     int32_t fid;
3243     int64_t size;
3244     ssize_t err = 0;
3245     V9fsString name;
3246     size_t offset = 7;
3247     V9fsFidState *file_fidp;
3248     V9fsFidState *xattr_fidp;
3249     V9fsPDU *pdu = opaque;
3250 
3251     v9fs_string_init(&name);
3252     err = pdu_unmarshal(pdu, offset, "dsqd", &fid, &name, &size, &flags);
3253     if (err < 0) {
3254         goto out_nofid;
3255     }
3256     trace_v9fs_xattrcreate(pdu->tag, pdu->id, fid, name.data, size, flags);
3257 
3258     file_fidp = get_fid(pdu, fid);
3259     if (file_fidp == NULL) {
3260         err = -EINVAL;
3261         goto out_nofid;
3262     }
3263     /* Make the file fid point to xattr */
3264     xattr_fidp = file_fidp;
3265     xattr_fidp->fid_type = P9_FID_XATTR;
3266     xattr_fidp->fs.xattr.copied_len = 0;
3267     xattr_fidp->fs.xattr.len = size;
3268     xattr_fidp->fs.xattr.flags = flags;
3269     v9fs_string_init(&xattr_fidp->fs.xattr.name);
3270     v9fs_string_copy(&xattr_fidp->fs.xattr.name, &name);
3271     xattr_fidp->fs.xattr.value = g_malloc(size);
3272     err = offset;
3273     put_fid(pdu, file_fidp);
3274 out_nofid:
3275     pdu_complete(pdu, err);
3276     v9fs_string_free(&name);
3277 }
3278 
3279 static void v9fs_readlink(void *opaque)
3280 {
3281     V9fsPDU *pdu = opaque;
3282     size_t offset = 7;
3283     V9fsString target;
3284     int32_t fid;
3285     int err = 0;
3286     V9fsFidState *fidp;
3287 
3288     err = pdu_unmarshal(pdu, offset, "d", &fid);
3289     if (err < 0) {
3290         goto out_nofid;
3291     }
3292     trace_v9fs_readlink(pdu->tag, pdu->id, fid);
3293     fidp = get_fid(pdu, fid);
3294     if (fidp == NULL) {
3295         err = -ENOENT;
3296         goto out_nofid;
3297     }
3298 
3299     v9fs_string_init(&target);
3300     err = v9fs_co_readlink(pdu, &fidp->path, &target);
3301     if (err < 0) {
3302         goto out;
3303     }
3304     err = pdu_marshal(pdu, offset, "s", &target);
3305     if (err < 0) {
3306         v9fs_string_free(&target);
3307         goto out;
3308     }
3309     err += offset;
3310     trace_v9fs_readlink_return(pdu->tag, pdu->id, target.data);
3311     v9fs_string_free(&target);
3312 out:
3313     put_fid(pdu, fidp);
3314 out_nofid:
3315     pdu_complete(pdu, err);
3316 }
3317 
3318 static CoroutineEntry *pdu_co_handlers[] = {
3319     [P9_TREADDIR] = v9fs_readdir,
3320     [P9_TSTATFS] = v9fs_statfs,
3321     [P9_TGETATTR] = v9fs_getattr,
3322     [P9_TSETATTR] = v9fs_setattr,
3323     [P9_TXATTRWALK] = v9fs_xattrwalk,
3324     [P9_TXATTRCREATE] = v9fs_xattrcreate,
3325     [P9_TMKNOD] = v9fs_mknod,
3326     [P9_TRENAME] = v9fs_rename,
3327     [P9_TLOCK] = v9fs_lock,
3328     [P9_TGETLOCK] = v9fs_getlock,
3329     [P9_TRENAMEAT] = v9fs_renameat,
3330     [P9_TREADLINK] = v9fs_readlink,
3331     [P9_TUNLINKAT] = v9fs_unlinkat,
3332     [P9_TMKDIR] = v9fs_mkdir,
3333     [P9_TVERSION] = v9fs_version,
3334     [P9_TLOPEN] = v9fs_open,
3335     [P9_TATTACH] = v9fs_attach,
3336     [P9_TSTAT] = v9fs_stat,
3337     [P9_TWALK] = v9fs_walk,
3338     [P9_TCLUNK] = v9fs_clunk,
3339     [P9_TFSYNC] = v9fs_fsync,
3340     [P9_TOPEN] = v9fs_open,
3341     [P9_TREAD] = v9fs_read,
3342 #if 0
3343     [P9_TAUTH] = v9fs_auth,
3344 #endif
3345     [P9_TFLUSH] = v9fs_flush,
3346     [P9_TLINK] = v9fs_link,
3347     [P9_TSYMLINK] = v9fs_symlink,
3348     [P9_TCREATE] = v9fs_create,
3349     [P9_TLCREATE] = v9fs_lcreate,
3350     [P9_TWRITE] = v9fs_write,
3351     [P9_TWSTAT] = v9fs_wstat,
3352     [P9_TREMOVE] = v9fs_remove,
3353 };
3354 
3355 static void v9fs_op_not_supp(void *opaque)
3356 {
3357     V9fsPDU *pdu = opaque;
3358     pdu_complete(pdu, -EOPNOTSUPP);
3359 }
3360 
3361 static void v9fs_fs_ro(void *opaque)
3362 {
3363     V9fsPDU *pdu = opaque;
3364     pdu_complete(pdu, -EROFS);
3365 }
3366 
3367 static inline bool is_read_only_op(V9fsPDU *pdu)
3368 {
3369     switch (pdu->id) {
3370     case P9_TREADDIR:
3371     case P9_TSTATFS:
3372     case P9_TGETATTR:
3373     case P9_TXATTRWALK:
3374     case P9_TLOCK:
3375     case P9_TGETLOCK:
3376     case P9_TREADLINK:
3377     case P9_TVERSION:
3378     case P9_TLOPEN:
3379     case P9_TATTACH:
3380     case P9_TSTAT:
3381     case P9_TWALK:
3382     case P9_TCLUNK:
3383     case P9_TFSYNC:
3384     case P9_TOPEN:
3385     case P9_TREAD:
3386     case P9_TAUTH:
3387     case P9_TFLUSH:
3388         return 1;
3389     default:
3390         return 0;
3391     }
3392 }
3393 
3394 void pdu_submit(V9fsPDU *pdu)
3395 {
3396     Coroutine *co;
3397     CoroutineEntry *handler;
3398     V9fsState *s = pdu->s;
3399 
3400     if (pdu->id >= ARRAY_SIZE(pdu_co_handlers) ||
3401         (pdu_co_handlers[pdu->id] == NULL)) {
3402         handler = v9fs_op_not_supp;
3403     } else {
3404         handler = pdu_co_handlers[pdu->id];
3405     }
3406 
3407     if (is_ro_export(&s->ctx) && !is_read_only_op(pdu)) {
3408         handler = v9fs_fs_ro;
3409     }
3410     co = qemu_coroutine_create(handler, pdu);
3411     qemu_coroutine_enter(co);
3412 }
3413 
3414 /* Returns 0 on success, 1 on failure. */
3415 int v9fs_device_realize_common(V9fsState *s, Error **errp)
3416 {
3417     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
3418     int i, len;
3419     struct stat stat;
3420     FsDriverEntry *fse;
3421     V9fsPath path;
3422     int rc = 1;
3423 
3424     /* initialize pdu allocator */
3425     QLIST_INIT(&s->free_list);
3426     QLIST_INIT(&s->active_list);
3427     for (i = 0; i < (MAX_REQ - 1); i++) {
3428         QLIST_INSERT_HEAD(&s->free_list, &v->pdus[i], next);
3429         v->pdus[i].s = s;
3430         v->pdus[i].idx = i;
3431     }
3432 
3433     v9fs_path_init(&path);
3434 
3435     fse = get_fsdev_fsentry(s->fsconf.fsdev_id);
3436 
3437     if (!fse) {
3438         /* We don't have a fsdev identified by fsdev_id */
3439         error_setg(errp, "9pfs device couldn't find fsdev with the "
3440                    "id = %s",
3441                    s->fsconf.fsdev_id ? s->fsconf.fsdev_id : "NULL");
3442         goto out;
3443     }
3444 
3445     if (!s->fsconf.tag) {
3446         /* we haven't specified a mount_tag */
3447         error_setg(errp, "fsdev with id %s needs mount_tag arguments",
3448                    s->fsconf.fsdev_id);
3449         goto out;
3450     }
3451 
3452     s->ctx.export_flags = fse->export_flags;
3453     s->ctx.fs_root = g_strdup(fse->path);
3454     s->ctx.exops.get_st_gen = NULL;
3455     len = strlen(s->fsconf.tag);
3456     if (len > MAX_TAG_LEN - 1) {
3457         error_setg(errp, "mount tag '%s' (%d bytes) is longer than "
3458                    "maximum (%d bytes)", s->fsconf.tag, len, MAX_TAG_LEN - 1);
3459         goto out;
3460     }
3461 
3462     s->tag = g_strdup(s->fsconf.tag);
3463     s->ctx.uid = -1;
3464 
3465     s->ops = fse->ops;
3466 
3467     s->fid_list = NULL;
3468     qemu_co_rwlock_init(&s->rename_lock);
3469 
3470     if (s->ops->init(&s->ctx) < 0) {
3471         error_setg(errp, "9pfs Failed to initialize fs-driver with id:%s"
3472                    " and export path:%s", s->fsconf.fsdev_id, s->ctx.fs_root);
3473         goto out;
3474     }
3475 
3476     /*
3477      * Check details of export path, We need to use fs driver
3478      * call back to do that. Since we are in the init path, we don't
3479      * use co-routines here.
3480      */
3481     if (s->ops->name_to_path(&s->ctx, NULL, "/", &path) < 0) {
3482         error_setg(errp,
3483                    "error in converting name to path %s", strerror(errno));
3484         goto out;
3485     }
3486     if (s->ops->lstat(&s->ctx, &path, &stat)) {
3487         error_setg(errp, "share path %s does not exist", fse->path);
3488         goto out;
3489     } else if (!S_ISDIR(stat.st_mode)) {
3490         error_setg(errp, "share path %s is not a directory", fse->path);
3491         goto out;
3492     }
3493     v9fs_path_free(&path);
3494 
3495     rc = 0;
3496 out:
3497     if (rc) {
3498         g_free(s->ctx.fs_root);
3499         g_free(s->tag);
3500         v9fs_path_free(&path);
3501     }
3502     return rc;
3503 }
3504 
3505 void v9fs_device_unrealize_common(V9fsState *s, Error **errp)
3506 {
3507     g_free(s->ctx.fs_root);
3508     g_free(s->tag);
3509 }
3510 
3511 static void __attribute__((__constructor__)) v9fs_set_fd_limit(void)
3512 {
3513     struct rlimit rlim;
3514     if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
3515         error_report("Failed to get the resource limit");
3516         exit(1);
3517     }
3518     open_fd_hw = rlim.rlim_cur - MIN(400, rlim.rlim_cur/3);
3519     open_fd_rc = rlim.rlim_cur/2;
3520 }
3521