+ switch (origin) {
+ case SEEK_END:
+ offset += eof;
+ break;
+ case SEEK_CUR:
+ /*
+ * Here we special-case the lseek(fd, 0, SEEK_CUR)
+ * position-querying operation. Avoid rewriting the "same"
+ * f_pos value back to the file because a concurrent read(),
+ * write() or lseek() might have altered it
+ */
+ if (offset == 0)
+ return file->f_pos;
+ /*
+ * f_lock protects against read/modify/write race with other
+ * SEEK_CURs. Note that parallel writes and reads behave
+ * like SEEK_SET.
+ */
+ mutex_lock(&inode->i_mutex);
+ offset = llseek_execute(file, file->f_pos + offset, maxsize);
+ mutex_unlock(&inode->i_mutex);
+ return offset;
+ case SEEK_DATA:
+ /*
+ * In the generic case the entire file is data, so as long as
+ * offset isn't at the end of the file then the offset is data.
+ */
+ if (offset >= eof)
+ return -ENXIO;
+ break;
+ case SEEK_HOLE:
+ /*
+ * There is a virtual hole at the end of the file, so as long as
+ * offset isn't i_size or larger, return i_size.
+ */
+ if (offset >= eof)
+ return -ENXIO;
+ offset = eof;
+ break;
+ }