1 /*
2  * pass4.c -- pass #4 of e2fsck: Check reference counts
3  *
4  * Copyright (C) 1993, 1994, 1995, 1996, 1997 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  * Pass 4 frees the following data structures:
12  * 	- A bitmap of which inodes are in bad blocks.	(inode_bb_map)
13  * 	- A bitmap of which inodes are imagic inodes.	(inode_imagic_map)
14  */
15 
16 #include "e2fsck.h"
17 #include "problem.h"
18 #include <ext2fs/ext2_ext_attr.h>
19 
20 /*
21  * This routine is called when an inode is not connected to the
22  * directory tree.
23  *
24  * This subroutine returns 1 then the caller shouldn't bother with the
25  * rest of the pass 4 tests.
26  */
disconnect_inode(e2fsck_t ctx,ext2_ino_t i,struct ext2_inode * inode)27 static int disconnect_inode(e2fsck_t ctx, ext2_ino_t i,
28 			    struct ext2_inode *inode)
29 {
30 	ext2_filsys fs = ctx->fs;
31 	struct problem_context	pctx;
32 	__u32 eamagic = 0;
33 	int extra_size = 0;
34 
35 	if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE) {
36 		e2fsck_read_inode_full(ctx, i, inode,EXT2_INODE_SIZE(fs->super),
37 				       "pass4: disconnect_inode");
38 		extra_size = ((struct ext2_inode_large *)inode)->i_extra_isize;
39 	} else {
40 		e2fsck_read_inode(ctx, i, inode, "pass4: disconnect_inode");
41 	}
42 	clear_problem_context(&pctx);
43 	pctx.ino = i;
44 	pctx.inode = inode;
45 
46 	if (EXT2_INODE_SIZE(fs->super) -EXT2_GOOD_OLD_INODE_SIZE -extra_size >0)
47 		eamagic = *(__u32 *)(((char *)inode) +EXT2_GOOD_OLD_INODE_SIZE +
48 				     extra_size);
49 	/*
50 	 * Offer to delete any zero-length files that does not have
51 	 * blocks.  If there is an EA block, it might have useful
52 	 * information, so we won't prompt to delete it, but let it be
53 	 * reconnected to lost+found.
54 	 */
55 	if (!inode->i_blocks && eamagic != EXT2_EXT_ATTR_MAGIC &&
56 	    (LINUX_S_ISREG(inode->i_mode) || LINUX_S_ISDIR(inode->i_mode))) {
57 		if (fix_problem(ctx, PR_4_ZERO_LEN_INODE, &pctx)) {
58 			e2fsck_clear_inode(ctx, i, inode, 0,
59 					   "disconnect_inode");
60 			/*
61 			 * Fix up the bitmaps...
62 			 */
63 			e2fsck_read_bitmaps(ctx);
64 			ext2fs_inode_alloc_stats2(fs, i, -1,
65 						  LINUX_S_ISDIR(inode->i_mode));
66 			quota_data_inodes(ctx->qctx, inode, i, -1);
67 			return 0;
68 		}
69 	}
70 
71 	/*
72 	 * Prompt to reconnect.
73 	 */
74 	if (fix_problem(ctx, PR_4_UNATTACHED_INODE, &pctx)) {
75 		if (e2fsck_reconnect_file(ctx, i))
76 			ext2fs_unmark_valid(fs);
77 	} else {
78 		/*
79 		 * If we don't attach the inode, then skip the
80 		 * i_links_test since there's no point in trying to
81 		 * force i_links_count to zero.
82 		 */
83 		ext2fs_unmark_valid(fs);
84 		return 1;
85 	}
86 	return 0;
87 }
88 
89 
e2fsck_pass4(e2fsck_t ctx)90 void e2fsck_pass4(e2fsck_t ctx)
91 {
92 	ext2_filsys fs = ctx->fs;
93 	ext2_ino_t	i;
94 	struct ext2_inode	*inode;
95 #ifdef RESOURCE_TRACK
96 	struct resource_track	rtrack;
97 #endif
98 	struct problem_context	pctx;
99 	__u16	link_count, link_counted;
100 	char	*buf = 0;
101 	dgrp_t	group, maxgroup;
102 
103 	init_resource_track(&rtrack, ctx->fs->io);
104 
105 #ifdef MTRACE
106 	mtrace_print("Pass 4");
107 #endif
108 
109 	clear_problem_context(&pctx);
110 
111 	if (!(ctx->options & E2F_OPT_PREEN))
112 		fix_problem(ctx, PR_4_PASS_HEADER, &pctx);
113 
114 	group = 0;
115 	maxgroup = fs->group_desc_count;
116 	if (ctx->progress)
117 		if ((ctx->progress)(ctx, 4, 0, maxgroup))
118 			return;
119 
120 	inode = e2fsck_allocate_memory(ctx, EXT2_INODE_SIZE(fs->super),
121 				       "scratch inode");
122 
123 	/* Protect loop from wrap-around if s_inodes_count maxed */
124 	for (i=1; i <= fs->super->s_inodes_count && i > 0; i++) {
125 		int isdir;
126 
127 		if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
128 			goto errout;
129 		if ((i % fs->super->s_inodes_per_group) == 0) {
130 			group++;
131 			if (ctx->progress)
132 				if ((ctx->progress)(ctx, 4, group, maxgroup))
133 					goto errout;
134 		}
135 		if (i == EXT2_BAD_INO ||
136 		    (i > EXT2_ROOT_INO && i < EXT2_FIRST_INODE(fs->super)))
137 			continue;
138 		if (!(ext2fs_test_inode_bitmap2(ctx->inode_used_map, i)) ||
139 		    (ctx->inode_imagic_map &&
140 		     ext2fs_test_inode_bitmap2(ctx->inode_imagic_map, i)) ||
141 		    (ctx->inode_bb_map &&
142 		     ext2fs_test_inode_bitmap2(ctx->inode_bb_map, i)))
143 			continue;
144 		ext2fs_icount_fetch(ctx->inode_link_info, i, &link_count);
145 		ext2fs_icount_fetch(ctx->inode_count, i, &link_counted);
146 		if (link_counted == 0) {
147 			if (!buf)
148 				buf = e2fsck_allocate_memory(ctx,
149 				     fs->blocksize, "bad_inode buffer");
150 			if (e2fsck_process_bad_inode(ctx, 0, i, buf))
151 				continue;
152 			if (disconnect_inode(ctx, i, inode))
153 				continue;
154 			ext2fs_icount_fetch(ctx->inode_link_info, i,
155 					    &link_count);
156 			ext2fs_icount_fetch(ctx->inode_count, i,
157 					    &link_counted);
158 		}
159 		isdir = ext2fs_test_inode_bitmap2(ctx->inode_dir_map, i);
160 		if (isdir && (link_counted > EXT2_LINK_MAX))
161 			link_counted = 1;
162 		if (link_counted != link_count) {
163 			e2fsck_read_inode(ctx, i, inode, "pass4");
164 			pctx.ino = i;
165 			pctx.inode = inode;
166 			if ((link_count != inode->i_links_count) && !isdir &&
167 			    (inode->i_links_count <= EXT2_LINK_MAX)) {
168 				pctx.num = link_count;
169 				fix_problem(ctx,
170 					    PR_4_INCONSISTENT_COUNT, &pctx);
171 			}
172 			pctx.num = link_counted;
173 			/* i_link_count was previously exceeded, but no longer
174 			 * is, fix this but don't consider it an error */
175 			if ((isdir && link_counted > 1 &&
176 			     (inode->i_flags & EXT2_INDEX_FL) &&
177 			     link_count == 1 && !(ctx->options & E2F_OPT_NO)) ||
178 			    fix_problem(ctx, PR_4_BAD_REF_COUNT, &pctx)) {
179 				inode->i_links_count = link_counted;
180 				e2fsck_write_inode(ctx, i, inode, "pass4");
181 			}
182 		}
183 	}
184 	ext2fs_free_icount(ctx->inode_link_info); ctx->inode_link_info = 0;
185 	ext2fs_free_icount(ctx->inode_count); ctx->inode_count = 0;
186 	ext2fs_free_inode_bitmap(ctx->inode_bb_map);
187 	ctx->inode_bb_map = 0;
188 	ext2fs_free_inode_bitmap(ctx->inode_imagic_map);
189 	ctx->inode_imagic_map = 0;
190 errout:
191 	if (buf)
192 		ext2fs_free_mem(&buf);
193 
194 	ext2fs_free_mem(&inode);
195 	print_resource_track(ctx, _("Pass 4"), &rtrack, ctx->fs->io);
196 }
197 
198