fuse2fs: implement O_TRUNC correctly

Actually truncate files on open with O_TRUNC.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/174786677783.1383760.5736479713431403960.stgit@frogsfrogsfrogs
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index 9f3093c8595cbe83748c32ea80a9ee875701a880..3fd42821170d1744591ed63e36d37ca667d61e94 100644 (file)
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -1971,6 +1971,29 @@ out:
        return ret;
 }
 
+static int truncate_helper(ext2_filsys fs, ext2_ino_t ino, off_t new_size)
+{
+       ext2_file_t file;
+       errcode_t err;
+       int ret = 0;
+
+       err = ext2fs_file_open(fs, ino, EXT2_FILE_WRITE, &file);
+       if (err)
+               return translate_error(fs, ino, err);
+
+       err = ext2fs_file_set_size2(file, new_size);
+       if (err)
+               ret = translate_error(fs, ino, err);
+
+       err = ext2fs_file_close(file);
+       if (ret)
+               return ret;
+       if (err)
+               return translate_error(fs, ino, err);
+
+       return update_mtime(fs, ino, NULL);
+}
+
 static int op_truncate(const char *path, off_t len
 #if FUSE_VERSION >= FUSE_MAKE_VERSION(3, 0)
                        , struct fuse_file_info *fi EXT2FS_ATTR((unused))
@@ -1980,9 +2003,8 @@ static int op_truncate(const char *path, off_t len
        struct fuse_context *ctxt = fuse_get_context();
        struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
        ext2_filsys fs;
-       errcode_t err;
        ext2_ino_t ino;
-       ext2_file_t file;
+       errcode_t err;
        int ret = 0;
 
        FUSE2FS_CHECK_CONTEXT(ff);
@@ -2003,28 +2025,9 @@ static int op_truncate(const char *path, off_t len
        if (ret)
                goto out;
 
-       err = ext2fs_file_open(fs, ino, EXT2_FILE_WRITE, &file);
-       if (err) {
-               ret = translate_error(fs, ino, err);
-               goto out;
-       }
-
-       err = ext2fs_file_set_size2(file, len);
-       if (err) {
-               ret = translate_error(fs, ino, err);
-               goto out2;
-       }
-
-out2:
-       err = ext2fs_file_close(file);
+       ret = truncate_helper(fs, ino, len);
        if (ret)
                goto out;
-       if (err) {
-               ret = translate_error(fs, ino, err);
-               goto out;
-       }
-
-       ret = update_mtime(fs, ino, NULL);
 
 out:
        pthread_mutex_unlock(&ff->bfl);
@@ -2060,7 +2063,7 @@ static int __op_open(struct fuse2fs *ff, const char *path,
        struct fuse2fs_file_handle *file;
        int check = 0, ret = 0;
 
-       dbg_printf(ff, "%s: path=%s\n", __func__, path);
+       dbg_printf(ff, "%s: path=%s oflags=0o%o\n", __func__, path, fp->flags);
        err = ext2fs_get_mem(sizeof(*file), &file);
        if (err)
                return translate_error(fs, 0, err);
@@ -2111,6 +2114,13 @@ static int __op_open(struct fuse2fs *ff, const char *path,
                } else
                        goto out;
        }
+
+       if (fp->flags & O_TRUNC) {
+               ret = truncate_helper(fs, file->ino, 0);
+               if (ret)
+                       goto out;
+       }
+
        fp->fh = (uintptr_t)file;
 
 out: