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      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 "config.h"
     17 #include "e2fsck.h"
     18 #include "problem.h"
     19 #include <ext2fs/ext2_ext_attr.h>
     20 
     21 /*
     22  * This routine is called when an inode is not connected to the
     23  * directory tree.
     24  *
     25  * This subroutine returns 1 then the caller shouldn't bother with the
     26  * rest of the pass 4 tests.
     27  */
     28 static int disconnect_inode(e2fsck_t ctx, ext2_ino_t i,
     29 			    struct ext2_inode_large *inode)
     30 {
     31 	ext2_filsys fs = ctx->fs;
     32 	struct problem_context	pctx;
     33 	__u32 eamagic = 0;
     34 	int extra_size = 0;
     35 
     36 	e2fsck_read_inode_full(ctx, i, EXT2_INODE(inode),
     37 			       EXT2_INODE_SIZE(fs->super),
     38 			       "pass4: disconnect_inode");
     39 	if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE)
     40 		extra_size = inode->i_extra_isize;
     41 	clear_problem_context(&pctx);
     42 	pctx.ino = i;
     43 	pctx.inode = EXT2_INODE(inode);
     44 
     45 	if (EXT2_INODE_SIZE(fs->super) -EXT2_GOOD_OLD_INODE_SIZE -extra_size >0)
     46 		eamagic = *(__u32 *)(((char *)inode) +EXT2_GOOD_OLD_INODE_SIZE +
     47 				     extra_size);
     48 	/*
     49 	 * Offer to delete any zero-length files that does not have
     50 	 * blocks.  If there is an EA block, it might have useful
     51 	 * information, so we won't prompt to delete it, but let it be
     52 	 * reconnected to lost+found.
     53 	 */
     54 	if (!inode->i_blocks && eamagic != EXT2_EXT_ATTR_MAGIC &&
     55 	    (LINUX_S_ISREG(inode->i_mode) || LINUX_S_ISDIR(inode->i_mode))) {
     56 		if (fix_problem(ctx, PR_4_ZERO_LEN_INODE, &pctx)) {
     57 			e2fsck_clear_inode(ctx, i, EXT2_INODE(inode), 0,
     58 					   "disconnect_inode");
     59 			/*
     60 			 * Fix up the bitmaps...
     61 			 */
     62 			e2fsck_read_bitmaps(ctx);
     63 			ext2fs_inode_alloc_stats2(fs, i, -1,
     64 						  LINUX_S_ISDIR(inode->i_mode));
     65 			quota_data_inodes(ctx->qctx, inode, i, -1);
     66 			return 0;
     67 		}
     68 	}
     69 
     70 	/*
     71 	 * Prompt to reconnect.
     72 	 */
     73 	if (fix_problem(ctx, PR_4_UNATTACHED_INODE, &pctx)) {
     74 		if (e2fsck_reconnect_file(ctx, i))
     75 			ext2fs_unmark_valid(fs);
     76 	} else {
     77 		/*
     78 		 * If we don't attach the inode, then skip the
     79 		 * i_links_test since there's no point in trying to
     80 		 * force i_links_count to zero.
     81 		 */
     82 		ext2fs_unmark_valid(fs);
     83 		return 1;
     84 	}
     85 	return 0;
     86 }
     87 
     88 
     89 void e2fsck_pass4(e2fsck_t ctx)
     90 {
     91 	ext2_filsys fs = ctx->fs;
     92 	ext2_ino_t	i;
     93 	struct ext2_inode_large	*inode;
     94 	int inode_size = EXT2_INODE_SIZE(fs->super);
     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 	 * Since pass4 is mostly CPU bound, start readahead of bitmaps
    110 	 * ahead of pass 5 if we haven't already loaded them.
    111 	 */
    112 	if (ctx->readahead_kb &&
    113 	    (fs->block_map == NULL || fs->inode_map == NULL))
    114 		e2fsck_readahead(fs, E2FSCK_READA_BBITMAP |
    115 				     E2FSCK_READA_IBITMAP,
    116 				 0, fs->group_desc_count);
    117 
    118 	clear_problem_context(&pctx);
    119 
    120 	if (!(ctx->options & E2F_OPT_PREEN))
    121 		fix_problem(ctx, PR_4_PASS_HEADER, &pctx);
    122 
    123 	group = 0;
    124 	maxgroup = fs->group_desc_count;
    125 	if (ctx->progress)
    126 		if ((ctx->progress)(ctx, 4, 0, maxgroup))
    127 			return;
    128 
    129 	inode = e2fsck_allocate_memory(ctx, inode_size, "scratch inode");
    130 
    131 	/* Protect loop from wrap-around if s_inodes_count maxed */
    132 	for (i=1; i <= fs->super->s_inodes_count && i > 0; i++) {
    133 		int isdir;
    134 
    135 		if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
    136 			goto errout;
    137 		if ((i % fs->super->s_inodes_per_group) == 0) {
    138 			group++;
    139 			if (ctx->progress)
    140 				if ((ctx->progress)(ctx, 4, group, maxgroup))
    141 					goto errout;
    142 		}
    143 		if (i == quota_type2inum(PRJQUOTA, ctx->fs->super) ||
    144 		    i == EXT2_BAD_INO ||
    145 		    (i > EXT2_ROOT_INO && i < EXT2_FIRST_INODE(fs->super)))
    146 			continue;
    147 		if (!(ext2fs_test_inode_bitmap2(ctx->inode_used_map, i)) ||
    148 		    (ctx->inode_imagic_map &&
    149 		     ext2fs_test_inode_bitmap2(ctx->inode_imagic_map, i)) ||
    150 		    (ctx->inode_bb_map &&
    151 		     ext2fs_test_inode_bitmap2(ctx->inode_bb_map, i)))
    152 			continue;
    153 		ext2fs_icount_fetch(ctx->inode_link_info, i, &link_count);
    154 		ext2fs_icount_fetch(ctx->inode_count, i, &link_counted);
    155 		if (link_counted == 0) {
    156 			if (!buf)
    157 				buf = e2fsck_allocate_memory(ctx,
    158 				     fs->blocksize, "bad_inode buffer");
    159 			if (e2fsck_process_bad_inode(ctx, 0, i, buf))
    160 				continue;
    161 			if (disconnect_inode(ctx, i, inode))
    162 				continue;
    163 			ext2fs_icount_fetch(ctx->inode_link_info, i,
    164 					    &link_count);
    165 			ext2fs_icount_fetch(ctx->inode_count, i,
    166 					    &link_counted);
    167 		}
    168 		isdir = ext2fs_test_inode_bitmap2(ctx->inode_dir_map, i);
    169 		if (isdir && (link_counted > EXT2_LINK_MAX))
    170 			link_counted = 1;
    171 		if (link_counted != link_count) {
    172 			e2fsck_read_inode_full(ctx, i, EXT2_INODE(inode),
    173 					       inode_size, "pass4");
    174 			pctx.ino = i;
    175 			pctx.inode = EXT2_INODE(inode);
    176 			if ((link_count != inode->i_links_count) && !isdir &&
    177 			    (inode->i_links_count <= EXT2_LINK_MAX)) {
    178 				pctx.num = link_count;
    179 				fix_problem(ctx,
    180 					    PR_4_INCONSISTENT_COUNT, &pctx);
    181 			}
    182 			pctx.num = link_counted;
    183 			/* i_link_count was previously exceeded, but no longer
    184 			 * is, fix this but don't consider it an error */
    185 			if ((isdir && link_counted > 1 &&
    186 			     (inode->i_flags & EXT2_INDEX_FL) &&
    187 			     link_count == 1 && !(ctx->options & E2F_OPT_NO)) ||
    188 			    fix_problem(ctx, PR_4_BAD_REF_COUNT, &pctx)) {
    189 				inode->i_links_count = link_counted;
    190 				e2fsck_write_inode_full(ctx, i,
    191 							EXT2_INODE(inode),
    192 							inode_size, "pass4");
    193 			}
    194 		}
    195 	}
    196 	ext2fs_free_icount(ctx->inode_link_info); ctx->inode_link_info = 0;
    197 	ext2fs_free_icount(ctx->inode_count); ctx->inode_count = 0;
    198 	ext2fs_free_inode_bitmap(ctx->inode_bb_map);
    199 	ctx->inode_bb_map = 0;
    200 	ext2fs_free_inode_bitmap(ctx->inode_imagic_map);
    201 	ctx->inode_imagic_map = 0;
    202 errout:
    203 	if (buf)
    204 		ext2fs_free_mem(&buf);
    205 
    206 	ext2fs_free_mem(&inode);
    207 	print_resource_track(ctx, _("Pass 4"), &rtrack, ctx->fs->io);
    208 }
    209 
    210