hw/9pfs/cofile.c

   1 /*
   2  * 9p backend
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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 /*
  15  * Not so fast! You might want to read the 9p developer docs first:
  16  * https://wiki.qemu.org/Documentation/9p
  17  */
  18
  19 #include "qemu/osdep.h"
  20 #include "fsdev/qemu-fsdev.h"
  21 #include "qemu/thread.h"
  22 #include "qemu/coroutine.h"
  23 #include "qemu/main-loop.h"
  24 #include "coth.h"
  25
  26 int coroutine_fn v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t st_mode,
  27                                 V9fsStatDotl *v9stat)
  28 {
  29     int err = 0;
  30     V9fsState *s = pdu->s;
  31
  32     if (v9fs_request_cancelled(pdu)) {
  33         return -EINTR;
  34     }
  35     if (s->ctx.exops.get_st_gen) {
  36         v9fs_path_read_lock(s);
  37         v9fs_co_run_in_worker(
  38             {
  39                 err = s->ctx.exops.get_st_gen(&s->ctx, path, st_mode,
  40                                               &v9stat->st_gen);
  41                 if (err < 0) {
  42                     err = -errno;
  43                 }
  44             });
  45         v9fs_path_unlock(s);
  46     }
  47     return err;
  48 }
  49
  50 int coroutine_fn v9fs_co_lstat(V9fsPDU *pdu, V9fsPath *path, struct stat *stbuf)
  51 {
  52     int err;
  53     V9fsState *s = pdu->s;
  54
  55     if (v9fs_request_cancelled(pdu)) {
  56         return -EINTR;
  57     }
  58     v9fs_path_read_lock(s);
  59     v9fs_co_run_in_worker(
  60         {
  61             err = s->ops->lstat(&s->ctx, path, stbuf);
  62             if (err < 0) {
  63                 err = -errno;
  64             }
  65         });
  66     v9fs_path_unlock(s);
  67     return err;
  68 }
  69
  70 int coroutine_fn v9fs_co_fstat(V9fsPDU *pdu, V9fsFidState *fidp,
  71                                struct stat *stbuf)
  72 {
  73     int err;
  74     V9fsState *s = pdu->s;
  75
  76     if (v9fs_request_cancelled(pdu)) {
  77         return -EINTR;
  78     }
  79     v9fs_co_run_in_worker(
  80         {
  81             err = s->ops->fstat(&s->ctx, fidp->fid_type, &fidp->fs, stbuf);
  82             if (err < 0) {
  83                 err = -errno;
  84             }
  85         });
  86     /*
  87      * Some FS driver (local:mapped-file) can't support fetching attributes
  88      * using file descriptor. Use Path name in that case.
  89      */
  90     if (err == -EOPNOTSUPP) {
  91         err = v9fs_co_lstat(pdu, &fidp->path, stbuf);
  92         if (err == -ENOENT) {
  93             /*
  94              * fstat on an unlinked file. Work with partial results
  95              * returned from s->ops->fstat
  96              */
  97             err = 0;
  98         }
  99     }
 100     return err;
 101 }
 102
 103 int coroutine_fn v9fs_co_open(V9fsPDU *pdu, V9fsFidState *fidp, int flags)
 104 {
 105     int err;
 106     V9fsState *s = pdu->s;
 107
 108     if (v9fs_request_cancelled(pdu)) {
 109         return -EINTR;
 110     }
 111     v9fs_path_read_lock(s);
 112     v9fs_co_run_in_worker(
 113         {
 114             err = s->ops->open(&s->ctx, &fidp->path, flags, &fidp->fs);
 115             if (err == -1) {
 116                 err = -errno;
 117             } else {
 118                 err = 0;
 119             }
 120         });
 121     v9fs_path_unlock(s);
 122     if (!err) {
 123         total_open_fd++;
 124         if (total_open_fd > open_fd_hw) {
 125             v9fs_reclaim_fd(pdu);
 126         }
 127     }
 128     return err;
 129 }
 130
 131 int coroutine_fn v9fs_co_open2(V9fsPDU *pdu, V9fsFidState *fidp,
 132                                V9fsString *name, gid_t gid, int flags, int mode,
 133                                struct stat *stbuf)
 134 {
 135     int err;
 136     FsCred cred;
 137     V9fsPath path;
 138     V9fsState *s = pdu->s;
 139
 140     if (v9fs_request_cancelled(pdu)) {
 141         return -EINTR;
 142     }
 143     cred_init(&cred);
 144     cred.fc_mode = mode & 07777;
 145     cred.fc_uid = fidp->uid;
 146     cred.fc_gid = gid;
 147     /*
 148      * Hold the directory fid lock so that directory path name
 149      * don't change. Take the write lock to be sure this fid
 150      * cannot be used by another operation.
 151      */
 152     v9fs_path_write_lock(s);
 153     v9fs_co_run_in_worker(
 154         {
 155             err = s->ops->open2(&s->ctx, &fidp->path,
 156                                 name->data, flags, &cred, &fidp->fs);
 157             if (err < 0) {
 158                 err = -errno;
 159             } else {
 160                 v9fs_path_init(&path);
 161                 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
 162                 if (!err) {
 163                     err = s->ops->lstat(&s->ctx, &path, stbuf);
 164                     if (err < 0) {
 165                         err = -errno;
 166                         s->ops->close(&s->ctx, &fidp->fs);
 167                     } else {
 168                         v9fs_path_copy(&fidp->path, &path);
 169                     }
 170                 } else {
 171                     s->ops->close(&s->ctx, &fidp->fs);
 172                 }
 173                 v9fs_path_free(&path);
 174             }
 175         });
 176     v9fs_path_unlock(s);
 177     if (!err) {
 178         total_open_fd++;
 179         if (total_open_fd > open_fd_hw) {
 180             v9fs_reclaim_fd(pdu);
 181         }
 182     }
 183     return err;
 184 }
 185
 186 int coroutine_fn v9fs_co_close(V9fsPDU *pdu, V9fsFidOpenState *fs)
 187 {
 188     int err;
 189     V9fsState *s = pdu->s;
 190
 191     if (v9fs_request_cancelled(pdu)) {
 192         return -EINTR;
 193     }
 194     v9fs_co_run_in_worker(
 195         {
 196             err = s->ops->close(&s->ctx, fs);
 197             if (err < 0) {
 198                 err = -errno;
 199             }
 200         });
 201     if (!err) {
 202         total_open_fd--;
 203     }
 204     return err;
 205 }
 206
 207 int coroutine_fn v9fs_co_fsync(V9fsPDU *pdu, V9fsFidState *fidp, int datasync)
 208 {
 209     int err;
 210     V9fsState *s = pdu->s;
 211
 212     if (v9fs_request_cancelled(pdu)) {
 213         return -EINTR;
 214     }
 215     v9fs_co_run_in_worker(
 216         {
 217             err = s->ops->fsync(&s->ctx, fidp->fid_type, &fidp->fs, datasync);
 218             if (err < 0) {
 219                 err = -errno;
 220             }
 221         });
 222     return err;
 223 }
 224
 225 int coroutine_fn v9fs_co_link(V9fsPDU *pdu, V9fsFidState *oldfid,
 226                               V9fsFidState *newdirfid, V9fsString *name)
 227 {
 228     int err;
 229     V9fsState *s = pdu->s;
 230
 231     if (v9fs_request_cancelled(pdu)) {
 232         return -EINTR;
 233     }
 234     v9fs_path_read_lock(s);
 235     v9fs_co_run_in_worker(
 236         {
 237             err = s->ops->link(&s->ctx, &oldfid->path,
 238                                &newdirfid->path, name->data);
 239             if (err < 0) {
 240                 err = -errno;
 241             }
 242         });
 243     v9fs_path_unlock(s);
 244     return err;
 245 }
 246
 247 int coroutine_fn v9fs_co_pwritev(V9fsPDU *pdu, V9fsFidState *fidp,
 248                                  struct iovec *iov, int iovcnt, int64_t offset)
 249 {
 250     int err;
 251     V9fsState *s = pdu->s;
 252
 253     if (v9fs_request_cancelled(pdu)) {
 254         return -EINTR;
 255     }
 256     fsdev_co_throttle_request(s->ctx.fst, true, iov, iovcnt);
 257     v9fs_co_run_in_worker(
 258         {
 259             err = s->ops->pwritev(&s->ctx, &fidp->fs, iov, iovcnt, offset);
 260             if (err < 0) {
 261                 err = -errno;
 262             }
 263         });
 264     return err;
 265 }
 266
 267 int coroutine_fn v9fs_co_preadv(V9fsPDU *pdu, V9fsFidState *fidp,
 268                                 struct iovec *iov, int iovcnt, int64_t offset)
 269 {
 270     int err;
 271     V9fsState *s = pdu->s;
 272
 273     if (v9fs_request_cancelled(pdu)) {
 274         return -EINTR;
 275     }
 276     fsdev_co_throttle_request(s->ctx.fst, false, iov, iovcnt);
 277     v9fs_co_run_in_worker(
 278         {
 279             err = s->ops->preadv(&s->ctx, &fidp->fs, iov, iovcnt, offset);
 280             if (err < 0) {
 281                 err = -errno;
 282             }
 283         });
 284     return err;
 285 }