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