erofs-utils: fix overriding of i_rdev for special device

In tarerofs index mode, tarerofs_write_chunk_indexes() is still called
even for files with i_size 0, and inode->u.chunkformat is initialized
accordingly.  This will make the previously set inode->u.i_rdev be
overridden as u.chunkformat and u.i_rdev are reused in one union.

To tidy up the code of writing file, extract two helpers for index and
non-index modes.  Also fix the missing erofs_iput() when
tarerofs_write_chunkes() fails.

Fixes: 95d315fd7958 ("erofs-utils: introduce tarerofs")
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230816021347.126886-2-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/lib/tar.c b/lib/tar.c
index 54ee33fd24237b6ca33a26890ea0cd53b3691012..42590d2d218a48f17ecd7e872333b395623a3882 100644 (file)
--- a/lib/tar.c
+++ b/lib/tar.c
@@ -359,6 +359,44 @@ void tarerofs_remove_inode(struct erofs_inode *inode)
        --inode->i_parent->i_nlink;
 }
 
+static int tarerofs_write_file_data(struct erofs_inode *inode,
+                                   struct erofs_tarfile *tar)
+{
+       unsigned int j, rem;
+       char buf[65536];
+
+       if (!inode->i_tmpfile) {
+               inode->i_tmpfile = tmpfile();
+               if (!inode->i_tmpfile)
+                       return -ENOSPC;
+       }
+
+       for (j = inode->i_size; j; ) {
+               rem = min_t(unsigned int, sizeof(buf), j);
+
+               if (erofs_read_from_fd(tar->fd, buf, rem) != rem ||
+                   fwrite(buf, rem, 1, inode->i_tmpfile) != 1)
+                       return -EIO;
+               j -= rem;
+       }
+       fseek(inode->i_tmpfile, 0, SEEK_SET);
+       inode->with_tmpfile = true;
+       return 0;
+}
+
+static int tarerofs_write_file_index(struct erofs_inode *inode,
+               struct erofs_tarfile *tar, erofs_off_t data_offset)
+{
+       int ret;
+
+       ret = tarerofs_write_chunkes(inode, data_offset);
+       if (ret)
+               return ret;
+       if (erofs_lskip(tar->fd, inode->i_size))
+               return -EIO;
+       return 0;
+}
+
 int tarerofs_parse_tar(struct erofs_inode *root, struct erofs_tarfile *tar)
 {
        char path[PATH_MAX];
@@ -672,41 +710,16 @@ new_inode:
                        inode->i_size = strlen(eh.link);
                        inode->i_link = malloc(inode->i_size + 1);
                        memcpy(inode->i_link, eh.link, inode->i_size + 1);
-               } else if (tar->index_mode) {
-                       ret = tarerofs_write_chunkes(inode, data_offset);
-                       if (ret)
-                               goto out;
-                       if (erofs_lskip(tar->fd, inode->i_size)) {
+               } else if (inode->i_size) {
+                       if (tar->index_mode)
+                               ret = tarerofs_write_file_index(inode, tar,
+                                                               data_offset);
+                       else
+                               ret = tarerofs_write_file_data(inode, tar);
+                       if (ret) {
                                erofs_iput(inode);
-                               ret = -EIO;
                                goto out;
                        }
-               } else {
-                       char buf[65536];
-
-                       if (!inode->i_tmpfile) {
-                               inode->i_tmpfile = tmpfile();
-
-                               if (!inode->i_tmpfile) {
-                                       erofs_iput(inode);
-                                       ret = -ENOSPC;
-                                       goto out;
-                               }
-                       }
-
-                       for (j = inode->i_size; j; ) {
-                               rem = min_t(int, sizeof(buf), j);
-
-                               if (erofs_read_from_fd(tar->fd, buf, rem) != rem ||
-                                   fwrite(buf, rem, 1, inode->i_tmpfile) != 1) {
-                                       erofs_iput(inode);
-                                       ret = -EIO;
-                                       goto out;
-                               }
-                               j -= rem;
-                       }
-                       fseek(inode->i_tmpfile, 0, SEEK_SET);
-                       inode->with_tmpfile = true;
                }
                inode->i_nlink++;
                ret = 0;