[LibOS] Move chroot specific truncate to generic FS operations

`generic_truncate` can be used for other file system types.

Signed-off-by: Li, Xun <xun.li@intel.com>

libos/include/libos_fs.h

@@ -943,6 +943,7 @@ int generic_emulated_mmap(struct libos_handle* hdl, void* addr, size_t size, int
                           uint64_t offset);
 int generic_emulated_msync(struct libos_handle* hdl, void* addr, size_t size, int prot, int flags,
                            uint64_t offset);
+int generic_truncate(struct libos_handle* hdl, file_off_t size);
 
 int synthetic_setup_dentry(struct libos_dentry* dent, mode_t type, mode_t perm);
 

libos/src/fs/chroot/fs.c

@@ -338,22 +338,6 @@ static int chroot_mmap(struct libos_handle* hdl, void* addr, size_t size, int pr
     return 0;
 }
 
-static int chroot_truncate(struct libos_handle* hdl, file_off_t size) {
-    assert(hdl->type == TYPE_CHROOT);
-
-    int ret;
-
-    lock(&hdl->inode->lock);
-    ret = PalStreamSetLength(hdl->pal_handle, size);
-    if (ret == 0) {
-        hdl->inode->size = size;
-    } else {
-        ret = pal_to_unix_errno(ret);
-    }
-    unlock(&hdl->inode->lock);
-    return ret;
-}
-
 int chroot_readdir(struct libos_dentry* dent, readdir_callback_t callback, void* arg) {
     int ret;
     PAL_HANDLE palhdl;
@@ -503,7 +487,7 @@ struct libos_fs_ops chroot_fs_ops = {
      * breaks for such device-specific cases */
     .seek       = &generic_inode_seek,
     .hstat      = &generic_inode_hstat,
-    .truncate   = &chroot_truncate,
+    .truncate   = &generic_truncate,
     .poll       = &generic_inode_poll,
 };
 

libos/src/fs/libos_fs_util.c

@@ -234,3 +234,15 @@ int generic_emulated_msync(struct libos_handle* hdl, void* addr, size_t size, in
     }
     return ret;
 }
+
+int generic_truncate(struct libos_handle* hdl, file_off_t size) {
+    lock(&hdl->inode->lock);
+    int ret = PalStreamSetLength(hdl->pal_handle, size);
+    if (ret == 0) {
+        hdl->inode->size = size;
+    } else {
+        ret = pal_to_unix_errno(ret);
+    }
+    unlock(&hdl->inode->lock);
+    return ret;
+}