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