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