qemu/hw/9pfs/cofile.c
Kirill A. Shutemov f8b7ee38b3 hw/9pfs: fix P9_STATS_GEN handling
Currently we fail getattr request altogether if we can't read
P9_STATS_GEN for some reason. It breaks valid use cases:

E.g let's assume we have non-readable directory with execution bit set
on host and we export it to client over 9p On host we can chdir into
directory, but not open directory on read and list content.

But if client will try to call getattr (as part of chdir(2)) for the
directory it will fail with -EACCES. It happens because we try to open
the directory on read to call ioctl(FS_IOC_GETVERSION), it fails and we
return the error code to client.

It's excessive. The solution is to make P9_STATS_GEN failure non-fatal
for getattr request. Just don't set P9_STATS_GEN flag in result mask on
failure.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2014-02-02 22:09:16 +05:30

276 lines
6.6 KiB
C

/*
* Virtio 9p backend
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "fsdev/qemu-fsdev.h"
#include "qemu/thread.h"
#include "block/coroutine.h"
#include "virtio-9p-coth.h"
int v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t st_mode,
V9fsStatDotl *v9stat)
{
int err = 0;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
if (s->ctx.exops.get_st_gen) {
v9fs_path_read_lock(s);
v9fs_co_run_in_worker(
{
err = s->ctx.exops.get_st_gen(&s->ctx, path, st_mode,
&v9stat->st_gen);
if (err < 0) {
err = -errno;
}
});
v9fs_path_unlock(s);
}
return err;
}
int v9fs_co_lstat(V9fsPDU *pdu, V9fsPath *path, struct stat *stbuf)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_path_read_lock(s);
v9fs_co_run_in_worker(
{
err = s->ops->lstat(&s->ctx, path, stbuf);
if (err < 0) {
err = -errno;
}
});
v9fs_path_unlock(s);
return err;
}
int v9fs_co_fstat(V9fsPDU *pdu, V9fsFidState *fidp, struct stat *stbuf)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_co_run_in_worker(
{
err = s->ops->fstat(&s->ctx, fidp->fid_type, &fidp->fs, stbuf);
if (err < 0) {
err = -errno;
}
});
/*
* Some FS driver (local:mapped-file) can't support fetching attributes
* using file descriptor. Use Path name in that case.
*/
if (err == -EOPNOTSUPP) {
err = v9fs_co_lstat(pdu, &fidp->path, stbuf);
if (err == -ENOENT) {
/*
* fstat on an unlinked file. Work with partial results
* returned from s->ops->fstat
*/
err = 0;
}
}
return err;
}
int v9fs_co_open(V9fsPDU *pdu, V9fsFidState *fidp, int flags)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_path_read_lock(s);
v9fs_co_run_in_worker(
{
err = s->ops->open(&s->ctx, &fidp->path, flags, &fidp->fs);
if (err == -1) {
err = -errno;
} else {
err = 0;
}
});
v9fs_path_unlock(s);
if (!err) {
total_open_fd++;
if (total_open_fd > open_fd_hw) {
v9fs_reclaim_fd(pdu);
}
}
return err;
}
int v9fs_co_open2(V9fsPDU *pdu, V9fsFidState *fidp, V9fsString *name, gid_t gid,
int flags, int mode, struct stat *stbuf)
{
int err;
FsCred cred;
V9fsPath path;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
cred_init(&cred);
cred.fc_mode = mode & 07777;
cred.fc_uid = fidp->uid;
cred.fc_gid = gid;
/*
* Hold the directory fid lock so that directory path name
* don't change. Read lock is fine because this fid cannot
* be used by any other operation.
*/
v9fs_path_read_lock(s);
v9fs_co_run_in_worker(
{
err = s->ops->open2(&s->ctx, &fidp->path,
name->data, flags, &cred, &fidp->fs);
if (err < 0) {
err = -errno;
} else {
v9fs_path_init(&path);
err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
if (!err) {
err = s->ops->lstat(&s->ctx, &path, stbuf);
if (err < 0) {
err = -errno;
s->ops->close(&s->ctx, &fidp->fs);
} else {
v9fs_path_copy(&fidp->path, &path);
}
} else {
s->ops->close(&s->ctx, &fidp->fs);
}
v9fs_path_free(&path);
}
});
v9fs_path_unlock(s);
if (!err) {
total_open_fd++;
if (total_open_fd > open_fd_hw) {
v9fs_reclaim_fd(pdu);
}
}
return err;
}
int v9fs_co_close(V9fsPDU *pdu, V9fsFidOpenState *fs)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_co_run_in_worker(
{
err = s->ops->close(&s->ctx, fs);
if (err < 0) {
err = -errno;
}
});
if (!err) {
total_open_fd--;
}
return err;
}
int v9fs_co_fsync(V9fsPDU *pdu, V9fsFidState *fidp, int datasync)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_co_run_in_worker(
{
err = s->ops->fsync(&s->ctx, fidp->fid_type, &fidp->fs, datasync);
if (err < 0) {
err = -errno;
}
});
return err;
}
int v9fs_co_link(V9fsPDU *pdu, V9fsFidState *oldfid,
V9fsFidState *newdirfid, V9fsString *name)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_path_read_lock(s);
v9fs_co_run_in_worker(
{
err = s->ops->link(&s->ctx, &oldfid->path,
&newdirfid->path, name->data);
if (err < 0) {
err = -errno;
}
});
v9fs_path_unlock(s);
return err;
}
int v9fs_co_pwritev(V9fsPDU *pdu, V9fsFidState *fidp,
struct iovec *iov, int iovcnt, int64_t offset)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_co_run_in_worker(
{
err = s->ops->pwritev(&s->ctx, &fidp->fs, iov, iovcnt, offset);
if (err < 0) {
err = -errno;
}
});
return err;
}
int v9fs_co_preadv(V9fsPDU *pdu, V9fsFidState *fidp,
struct iovec *iov, int iovcnt, int64_t offset)
{
int err;
V9fsState *s = pdu->s;
if (v9fs_request_cancelled(pdu)) {
return -EINTR;
}
v9fs_co_run_in_worker(
{
err = s->ops->preadv(&s->ctx, &fidp->fs, iov, iovcnt, offset);
if (err < 0) {
err = -errno;
}
});
return err;
}