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1 /*
2  * valid_blk.c --- does the inode have valid blocks?
3  *
4  * Copyright 1997 by Theodore Ts'o
5  *
6  * %Begin-Header%
7  * This file may be redistributed under the terms of the GNU Public
8  * License.
9  * %End-Header%
10  *
11  */
12 
13 #include <stdio.h>
14 #if HAVE_UNISTD_H
15 #include <unistd.h>
16 #endif
17 #include <string.h>
18 #include <time.h>
19 
20 #include "ext2_fs.h"
21 #include "ext2fs.h"
22 
23 /*
24  * This function returns 1 if the inode's block entries actually
25  * contain block entries.
26  */
ext2fs_inode_has_valid_blocks(struct ext2_inode * inode)27 int ext2fs_inode_has_valid_blocks(struct ext2_inode *inode)
28 {
29 	/*
30 	 * Only directories, regular files, and some symbolic links
31 	 * have valid block entries.
32 	 */
33 	if (!LINUX_S_ISDIR(inode->i_mode) && !LINUX_S_ISREG(inode->i_mode) &&
34 	    !LINUX_S_ISLNK(inode->i_mode))
35 		return 0;
36 
37 	/*
38 	 * If the symbolic link is a "fast symlink", then the symlink
39 	 * target is stored in the block entries.
40 	 */
41 	if (LINUX_S_ISLNK (inode->i_mode)) {
42 		if (inode->i_file_acl == 0) {
43 			/* With no EA block, we can rely on i_blocks */
44 			if (inode->i_blocks == 0)
45 				return 0;
46 		} else {
47 			/* With an EA block, life gets more tricky */
48 			if (inode->i_size >= EXT2_N_BLOCKS*4)
49 				return 1; /* definitely using i_block[] */
50 			if (inode->i_size > 4 && inode->i_block[1] == 0)
51 				return 1; /* definitely using i_block[] */
52 			return 0; /* Probably a fast symlink */
53 		}
54 	}
55 	return 1;
56 }
57