hw/9pfs: Use read-write lock for protecting fid path.

On rename we take the write lock and this ensure path
doesn't change as we operate on them.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

1 files changed, 45 insertions, 7 deletions

diff --git a/hw/9pfs/cofs.c b/hw/9pfs/cofs.c
index a78fccbe23..98860f9189 100644
--- a/hw/9pfs/cofs.c
+++ b/hw/9pfs/cofs.c
@@ -23,6 +23,8 @@ int v9fs_co_readlink(V9fsState *s, V9fsString *path, V9fsString *buf)
     ssize_t len;
 
     buf->data = g_malloc(PATH_MAX);
+    qemu_co_rwlock_rdlock(&s->rename_lock);
+
     v9fs_co_run_in_worker(
         {
             len = s->ops->readlink(&s->ctx, path->data,
@@ -35,6 +37,7 @@ int v9fs_co_readlink(V9fsState *s, V9fsString *path, V9fsString *buf)
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     if (err) {
         g_free(buf->data);
         buf->data = NULL;
@@ -47,6 +50,7 @@ int v9fs_co_statfs(V9fsState *s, V9fsString *path, struct statfs *stbuf)
 {
     int err;
 
+    qemu_co_rwlock_rdlock(&s->rename_lock);
     v9fs_co_run_in_worker(
         {
             err = s->ops->statfs(&s->ctx, path->data, stbuf);
@@ -54,6 +58,7 @@ int v9fs_co_statfs(V9fsState *s, V9fsString *path, struct statfs *stbuf)
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     return err;
 }
 
@@ -64,6 +69,7 @@ int v9fs_co_chmod(V9fsState *s, V9fsString *path, mode_t mode)
 
     cred_init(&cred);
     cred.fc_mode = mode;
+    qemu_co_rwlock_rdlock(&s->rename_lock);
     v9fs_co_run_in_worker(
         {
             err = s->ops->chmod(&s->ctx, path->data, &cred);
@@ -71,6 +77,7 @@ int v9fs_co_chmod(V9fsState *s, V9fsString *path, mode_t mode)
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     return err;
 }
 
@@ -79,6 +86,7 @@ int v9fs_co_utimensat(V9fsState *s, V9fsString *path,
 {
     int err;
 
+    qemu_co_rwlock_rdlock(&s->rename_lock);
     v9fs_co_run_in_worker(
         {
             err = s->ops->utimensat(&s->ctx, path->data, times);
@@ -86,6 +94,7 @@ int v9fs_co_utimensat(V9fsState *s, V9fsString *path,
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     return err;
 }
 
@@ -97,6 +106,7 @@ int v9fs_co_chown(V9fsState *s, V9fsString *path, uid_t uid, gid_t gid)
     cred_init(&cred);
     cred.fc_uid = uid;
     cred.fc_gid = gid;
+    qemu_co_rwlock_rdlock(&s->rename_lock);
     v9fs_co_run_in_worker(
         {
             err = s->ops->chown(&s->ctx, path->data, &cred);
@@ -104,6 +114,7 @@ int v9fs_co_chown(V9fsState *s, V9fsString *path, uid_t uid, gid_t gid)
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     return err;
 }
 
@@ -111,6 +122,7 @@ int v9fs_co_truncate(V9fsState *s, V9fsString *path, off_t size)
 {
     int err;
 
+    qemu_co_rwlock_rdlock(&s->rename_lock);
     v9fs_co_run_in_worker(
         {
             err = s->ops->truncate(&s->ctx, path->data, size);
@@ -118,27 +130,39 @@ int v9fs_co_truncate(V9fsState *s, V9fsString *path, off_t size)
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     return err;
 }
 
-int v9fs_co_mknod(V9fsState *s, V9fsString *path, uid_t uid,
-                  gid_t gid, dev_t dev, mode_t mode)
+int v9fs_co_mknod(V9fsState *s, V9fsFidState *fidp, V9fsString *name, uid_t uid,
+                  gid_t gid, dev_t dev, mode_t mode, struct stat *stbuf)
 {
     int err;
     FsCred cred;
+    V9fsString fullname;
 
     cred_init(&cred);
     cred.fc_uid  = uid;
     cred.fc_gid  = gid;
     cred.fc_mode = mode;
     cred.fc_rdev = dev;
+    v9fs_string_init(&fullname);
+    qemu_co_rwlock_rdlock(&s->rename_lock);
+    v9fs_string_sprintf(&fullname, "%s/%s", fidp->path.data, name->data);
     v9fs_co_run_in_worker(
         {
-            err = s->ops->mknod(&s->ctx, path->data, &cred);
+            err = s->ops->mknod(&s->ctx, fullname.data, &cred);
             if (err < 0) {
                 err = -errno;
+            } else {
+                err = s->ops->lstat(&s->ctx, fullname.data, stbuf);
+                if (err < 0) {
+                    err = -errno;
+                }
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
+    v9fs_string_free(&fullname);
     return err;
 }
 
@@ -146,6 +170,7 @@ int v9fs_co_remove(V9fsState *s, V9fsString *path)
 {
     int err;
 
+    qemu_co_rwlock_rdlock(&s->rename_lock);
     v9fs_co_run_in_worker(
         {
             err = s->ops->remove(&s->ctx, path->data);
@@ -153,6 +178,7 @@ int v9fs_co_remove(V9fsState *s, V9fsString *path)
                 err = -errno;
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
     return err;
 }
 
@@ -170,22 +196,34 @@ int v9fs_co_rename(V9fsState *s, V9fsString *oldpath, V9fsString *newpath)
     return err;
 }
 
-int v9fs_co_symlink(V9fsState *s, V9fsFidState *fidp,
-                    const char *oldpath, const char *newpath, gid_t gid)
+int v9fs_co_symlink(V9fsState *s, V9fsFidState *dfidp, V9fsString *name,
+                    const char *oldpath, gid_t gid, struct stat *stbuf)
 {
     int err;
     FsCred cred;
+    V9fsString fullname;
+
 
     cred_init(&cred);
-    cred.fc_uid = fidp->uid;
+    cred.fc_uid = dfidp->uid;
     cred.fc_gid = gid;
     cred.fc_mode = 0777;
+    v9fs_string_init(&fullname);
+    qemu_co_rwlock_rdlock(&s->rename_lock);
+    v9fs_string_sprintf(&fullname, "%s/%s", dfidp->path.data, name->data);
     v9fs_co_run_in_worker(
         {
-            err = s->ops->symlink(&s->ctx, oldpath, newpath, &cred);
+            err = s->ops->symlink(&s->ctx, oldpath, fullname.data, &cred);
             if (err < 0) {
                 err = -errno;
+            } else {
+                err = s->ops->lstat(&s->ctx, fullname.data, stbuf);
+                if (err < 0) {
+                    err = -errno;
+                }
             }
         });
+    qemu_co_rwlock_unlock(&s->rename_lock);
+    v9fs_string_free(&fullname);
     return err;
 }