Many files:

[thirdparty/e2fsprogs.git] / e2fsck / pass3.c

/*
 * pass3.c -- pass #3 of e2fsck: Check for directory connectivity
 *
 * Copyright (C) 1993, 1994, 1995, 1996, 1997 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 * 
 * Pass #3 assures that all directories are connected to the
 * filesystem tree, using the following algorithm:
 *
 * First, the root directory is checked to make sure it exists; if
 * not, e2fsck will offer to create a new one.  It is then marked as
 * "done".
 * 
 * Then, pass3 interates over all directory inodes; for each directory
 * it attempts to trace up the filesystem tree, using dirinfo.parent
 * until it reaches a directory which has been marked "done".  If it
 * can not do so, then the directory must be disconnected, and e2fsck
 * will offer to reconnect it to /lost+found.  While it is chasing
 * parent pointers up the filesystem tree, if pass3 sees a directory
 * twice, then it has detected a filesystem loop, and it will again
 * offer to reconnect the directory to /lost+found in to break the
 * filesystem loop.
 * 
 * Pass 3 also contains the subroutine, reconnect_file() to reconnect
 * inodes to /lost+found; this subroutine is also used by pass 4.
 * reconnect_file() calls get_lost_and_found(), which is responsible
 * for creating /lost+found if it does not exist.
 *
 * Pass 3 frees the following data structures:
 *      - The dirinfo directory information cache.
 */

#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

#include "e2fsck.h"
#include "problem.h"

static void check_root(e2fsck_t ctx);
static void check_directory(e2fsck_t ctx, struct dir_info *dir,
                            struct problem_context *pctx);
static ino_t get_lost_and_found(e2fsck_t ctx);
static void fix_dotdot(e2fsck_t ctx, struct dir_info *dir, ino_t parent);
static errcode_t adjust_inode_count(e2fsck_t ctx, ino_t ino, int adj);
static errcode_t expand_directory(e2fsck_t ctx, ino_t dir);

static ino_t lost_and_found = 0;
static int bad_lost_and_found = 0;

static ext2fs_inode_bitmap inode_loop_detect;
static ext2fs_inode_bitmap inode_done_map;
        
void pass3(e2fsck_t ctx)
{
        ext2_filsys fs = ctx->fs;
        int             i;
        struct resource_track   rtrack;
        struct problem_context  pctx;
        struct dir_info *dir;
        
        init_resource_track(&rtrack);

        clear_problem_context(&pctx);

#ifdef MTRACE
        mtrace_print("Pass 3");
#endif

        if (!(ctx->options & E2F_OPT_PREEN))
                fix_problem(ctx, PR_3_PASS_HEADER, &pctx);

        /*
         * Allocate some bitmaps to do loop detection.
         */
        pctx.errcode = ext2fs_allocate_inode_bitmap(fs,
                    "inode loop detection bitmap", &inode_loop_detect);
        if (pctx.errcode) {
                pctx.num = 1;
                fix_problem(ctx, PR_3_ALLOCATE_IBITMAP_ERROR, &pctx);
                fatal_error(0);
        }
        pctx.errcode = ext2fs_allocate_inode_bitmap(fs, "inode done bitmap",
                                                    &inode_done_map);
        if (pctx.errcode) {
                pctx.num = 2;
                fix_problem(ctx, PR_3_ALLOCATE_IBITMAP_ERROR, &pctx);
                fatal_error(0);
        }
        if (ctx->options & E2F_OPT_TIME)
                print_resource_track("Peak memory", &ctx->global_rtrack);

        check_root(ctx);
        ext2fs_mark_inode_bitmap(inode_done_map, EXT2_ROOT_INO);

        for (i=0; (dir = dir_info_iter(&i)) != 0;) {
                if (ext2fs_test_inode_bitmap(ctx->inode_dir_map, dir->ino))
                        check_directory(ctx, dir, &pctx);
        }
        
        
        free_dir_info(fs);
        ext2fs_free_inode_bitmap(inode_loop_detect);
        ext2fs_free_inode_bitmap(inode_done_map);
        if (ctx->options & E2F_OPT_TIME2)
                print_resource_track("Pass 3", &rtrack);
}

/*
 * This makes sure the root inode is present; if not, we ask if the
 * user wants us to create it.  Not creating it is a fatal error.
 */
static void check_root(e2fsck_t ctx)
{
        ext2_filsys fs = ctx->fs;
        blk_t                   blk;
        struct ext2_inode       inode;
        char *                  block;
        struct problem_context  pctx;
        
        clear_problem_context(&pctx);
        
        if (ext2fs_test_inode_bitmap(ctx->inode_used_map, EXT2_ROOT_INO)) {
                /*
                 * If the root inode is a directory, die here.  The
                 * user must have answered 'no' in pass1 when we
                 * offered to clear it.
                 */
                if (!(ext2fs_test_inode_bitmap(ctx->inode_dir_map,
                                               EXT2_ROOT_INO)))
                        fatal_error("Root inode not directory");
                return;
        }

        if (!fix_problem(ctx, PR_3_NO_ROOT_INODE, &pctx))
                fatal_error("Cannot proceed without a root inode.");

        read_bitmaps(ctx);
        
        /*
         * First, find a free block
         */
        pctx.errcode = ext2fs_new_block(fs, 0, ctx->block_found_map, &blk);
        if (pctx.errcode) {
                pctx.str = "ext2fs_new_block";
                fix_problem(ctx, PR_3_CREATE_ROOT_ERROR, &pctx);
                fatal_error(0);
        }
        ext2fs_mark_block_bitmap(ctx->block_found_map, blk);
        ext2fs_mark_block_bitmap(fs->block_map, blk);
        ext2fs_mark_bb_dirty(fs);

        /*
         * Now let's create the actual data block for the inode
         */
        pctx.errcode = ext2fs_new_dir_block(fs, EXT2_ROOT_INO, EXT2_ROOT_INO,
                                            &block);
        if (pctx.errcode) {
                pctx.str = "ext2fs_new_dir_block";
                fix_problem(ctx, PR_3_CREATE_ROOT_ERROR, &pctx);
                fatal_error(0);
        }

        pctx.errcode = ext2fs_write_dir_block(fs, blk, block);
        if (pctx.errcode) {
                pctx.str = "ext2fs_write_dir_block";
                fix_problem(ctx, PR_3_CREATE_ROOT_ERROR, &pctx);
                fatal_error(0);
        }
        free(block);

        /*
         * Set up the inode structure
         */
        memset(&inode, 0, sizeof(inode));
        inode.i_mode = 040755;
        inode.i_size = fs->blocksize;
        inode.i_atime = inode.i_ctime = inode.i_mtime = time(0);
        inode.i_links_count = 2;
        inode.i_blocks = fs->blocksize / 512;
        inode.i_block[0] = blk;

        /*
         * Write out the inode.
         */
        pctx.errcode = ext2fs_write_inode(fs, EXT2_ROOT_INO, &inode);
        if (pctx.errcode) {
                pctx.str = "ext2fs_write_inode";
                fix_problem(ctx, PR_3_CREATE_ROOT_ERROR, &pctx);
                fatal_error(0);
        }
        
        /*
         * Miscellaneous bookkeeping...
         */
        add_dir_info(fs, EXT2_ROOT_INO, EXT2_ROOT_INO);
        ext2fs_icount_store(ctx->inode_count, EXT2_ROOT_INO, 2);
        ext2fs_icount_store(ctx->inode_link_info, EXT2_ROOT_INO, 2);

        ext2fs_mark_inode_bitmap(ctx->inode_used_map, EXT2_ROOT_INO);
        ext2fs_mark_inode_bitmap(ctx->inode_dir_map, EXT2_ROOT_INO);
        ext2fs_mark_inode_bitmap(fs->inode_map, EXT2_ROOT_INO);
        ext2fs_mark_ib_dirty(fs);
}

/*
 * This subroutine is responsible for making sure that a particular
 * directory is connected to the root; if it isn't we trace it up as
 * far as we can go, and then offer to connect the resulting parent to
 * the lost+found.  We have to do loop detection; if we ever discover
 * a loop, we treat that as a disconnected directory and offer to
 * reparent it to lost+found.
 */
static void check_directory(e2fsck_t ctx, struct dir_info *dir,
                            struct problem_context *pctx)
{
        ext2_filsys fs = ctx->fs;
        struct dir_info *p = dir;

        ext2fs_clear_inode_bitmap(inode_loop_detect);
        while (p) {
                /*
                 * If we find a parent which we've already checked,
                 * then stop; we know it's either already connected to
                 * the directory tree, or it isn't but the user has
                 * already told us he doesn't want us to reconnect the
                 * disconnected subtree.
                 */
                if (ext2fs_test_inode_bitmap(inode_done_map, p->ino))
                        goto check_dot_dot;
                /*
                 * Mark this inode as being "done"; by the time we
                 * return from this function, the inode we either be
                 * verified as being connected to the directory tree,
                 * or we will have offered to reconnect this to
                 * lost+found.
                 */
                ext2fs_mark_inode_bitmap(inode_done_map, p->ino);
                /*
                 * If this directory doesn't have a parent, or we've
                 * seen the parent once already, then offer to
                 * reparent it to lost+found
                 */
                if (!p->parent ||
                    (ext2fs_test_inode_bitmap(inode_loop_detect,
                                              p->parent)))
                        break;
                ext2fs_mark_inode_bitmap(inode_loop_detect,
                                         p->parent);
                p = get_dir_info(p->parent);
        }
        /*
         * If we've reached here, we've hit a detached directory
         * inode; offer to reconnect it to lost+found.
         */
        pctx->ino = p->ino;
        if (fix_problem(ctx, PR_3_UNCONNECTED_DIR, pctx)) {
                if (reconnect_file(ctx, p->ino))
                        ext2fs_unmark_valid(fs);
                else {
                        p->parent = lost_and_found;
                        fix_dotdot(ctx, p, lost_and_found);
                }
        }

        /*
         * Make sure that .. and the parent directory are the same;
         * offer to fix it if not.
         */
check_dot_dot:
        if (dir->parent != dir->dotdot) {
                pctx->ino = dir->ino;
                pctx->ino2 = dir->dotdot;
                pctx->dir = dir->parent;
                if (fix_problem(ctx, PR_3_BAD_DOT_DOT, pctx))
                        fix_dotdot(ctx, dir, dir->parent);
        }
}       

/*
 * This routine gets the lost_and_found inode, making it a directory
 * if necessary
 */
ino_t get_lost_and_found(e2fsck_t ctx)
{
        ext2_filsys fs = ctx->fs;
        ino_t                   ino;
        blk_t                   blk;
        errcode_t               retval;
        struct ext2_inode       inode;
        char *                  block;
        const char              name[] = "lost+found";
        struct  problem_context pctx;

        clear_problem_context(&pctx);
        
        retval = ext2fs_lookup(fs, EXT2_ROOT_INO, name,
                               sizeof(name)-1, 0, &ino);
        if (!retval)
                return ino;
        if (retval != ENOENT) {
                pctx.errcode = retval;
                fix_problem(ctx, PR_3_ERR_FIND_LPF, &pctx);
        }
        if (!fix_problem(ctx, PR_3_NO_LF_DIR, 0))
                return 0;

        /*
         * Read the inode and block bitmaps in; we'll be messing with
         * them.
         */
        read_bitmaps(ctx);
        
        /*
         * First, find a free block
         */
        retval = ext2fs_new_block(fs, 0, ctx->block_found_map, &blk);
        if (retval) {
                pctx.errcode = retval;
                fix_problem(ctx, PR_3_ERR_LPF_NEW_BLOCK, &pctx);
                return 0;
        }
        ext2fs_mark_block_bitmap(ctx->block_found_map, blk);
        ext2fs_mark_block_bitmap(fs->block_map, blk);
        ext2fs_mark_bb_dirty(fs);

        /*
         * Next find a free inode.
         */
        retval = ext2fs_new_inode(fs, EXT2_ROOT_INO, 040755,
                                  ctx->inode_used_map, &ino);
        if (retval) {
                pctx.errcode = retval;
                fix_problem(ctx, PR_3_ERR_LPF_NEW_INODE, &pctx);
                return 0;
        }
        ext2fs_mark_inode_bitmap(ctx->inode_used_map, ino);
        ext2fs_mark_inode_bitmap(ctx->inode_dir_map, ino);
        ext2fs_mark_inode_bitmap(fs->inode_map, ino);
        ext2fs_mark_ib_dirty(fs);

        /*
         * Now let's create the actual data block for the inode
         */
        retval = ext2fs_new_dir_block(fs, ino, EXT2_ROOT_INO, &block);
        if (retval) {
                pctx.errcode = retval;
                fix_problem(ctx, PR_3_ERR_LPF_NEW_DIR_BLOCK, &pctx);
                return 0;
        }

        retval = ext2fs_write_dir_block(fs, blk, block);
        free(block);
        if (retval) {
                pctx.errcode = retval;
                fix_problem(ctx, PR_3_ERR_LPF_WRITE_BLOCK, &pctx);
                return 0;
        }

        /*
         * Set up the inode structure
         */
        memset(&inode, 0, sizeof(inode));
        inode.i_mode = 040755;
        inode.i_size = fs->blocksize;
        inode.i_atime = inode.i_ctime = inode.i_mtime = time(0);
        inode.i_links_count = 2;
        inode.i_blocks = fs->blocksize / 512;
        inode.i_block[0] = blk;

        /*
         * Next, write out the inode.
         */
        pctx.errcode = ext2fs_write_inode(fs, ino, &inode);
        if (pctx.errcode) {
                pctx.str = "ext2fs_write_inode";
                fix_problem(ctx, PR_3_CREATE_LPF_ERROR, &pctx);
                return 0;
        }
        /*
         * Finally, create the directory link
         */
        pctx.errcode = ext2fs_link(fs, EXT2_ROOT_INO, name, ino, 0);
        if (pctx.errcode) {
                pctx.str = "ext2fs_link";
                fix_problem(ctx, PR_3_CREATE_LPF_ERROR, &pctx);
                return 0;
        }

        /*
         * Miscellaneous bookkeeping that needs to be kept straight.
         */
        add_dir_info(fs, ino, EXT2_ROOT_INO);
        adjust_inode_count(ctx, EXT2_ROOT_INO, +1);
        ext2fs_icount_store(ctx->inode_count, ino, 2);
        ext2fs_icount_store(ctx->inode_link_info, ino, 2);
#if 0
        printf("/lost+found created; inode #%lu\n", ino);
#endif
        return ino;
}

/*
 * This routine will connect a file to lost+found
 */
int reconnect_file(e2fsck_t ctx, ino_t inode)
{
        ext2_filsys fs = ctx->fs;
        errcode_t       retval;
        char            name[80];
        struct problem_context  pctx;

        clear_problem_context(&pctx);
        pctx.ino = inode;

        if (!bad_lost_and_found && !lost_and_found) {
                lost_and_found = get_lost_and_found(ctx);
                if (!lost_and_found)
                        bad_lost_and_found++;
        }
        if (bad_lost_and_found) {
                fix_problem(ctx, PR_3_NO_LPF, &pctx);
                return 1;
        }
        
        sprintf(name, "#%lu", inode);
        retval = ext2fs_link(fs, lost_and_found, name, inode, 0);
        if (retval == EXT2_ET_DIR_NO_SPACE) {
                if (!fix_problem(ctx, PR_3_EXPAND_LF_DIR, &pctx))
                        return 1;
                retval = expand_directory(ctx, lost_and_found);
                if (retval) {
                        pctx.errcode = retval;
                        fix_problem(ctx, PR_3_CANT_EXPAND_LPF, &pctx);
                        return 1;
                }
                retval = ext2fs_link(fs, lost_and_found, name, inode, 0);
        }
        if (retval) {
                pctx.errcode = retval;
                fix_problem(ctx, PR_3_CANT_RECONNECT, &pctx);
                return 1;
        }
        adjust_inode_count(ctx, inode, +1);

        return 0;
}

/*
 * Utility routine to adjust the inode counts on an inode.
 */
static errcode_t adjust_inode_count(e2fsck_t ctx, ino_t ino, int adj)
{
        ext2_filsys fs = ctx->fs;
        errcode_t               retval;
        struct ext2_inode       inode;
        
        if (!ino)
                return 0;

        retval = ext2fs_read_inode(fs, ino, &inode);
        if (retval)
                return retval;

#if 0
        printf("Adjusting link count for inode %lu by %d (from %d)\n", ino, adj,
               inode.i_links_count);
#endif

        inode.i_links_count += adj;
        if (adj == 1) {
                ext2fs_icount_increment(ctx->inode_count, ino, 0);
                ext2fs_icount_increment(ctx->inode_link_info, ino, 0);
        } else {
                ext2fs_icount_decrement(ctx->inode_count, ino, 0);
                ext2fs_icount_decrement(ctx->inode_link_info, ino, 0);
        }
        

        retval = ext2fs_write_inode(fs, ino, &inode);
        if (retval)
                return retval;

        return 0;
}

/*
 * Fix parent --- this routine fixes up the parent of a directory.
 */
struct fix_dotdot_struct {
        ext2_filsys     fs;
        ino_t           parent;
        int             done;
        e2fsck_t        ctx;
};

static int fix_dotdot_proc(struct ext2_dir_entry *dirent,
                           int  offset,
                           int  blocksize,
                           char *buf,
                           void *private)
{
        struct fix_dotdot_struct *fp = (struct fix_dotdot_struct *) private;
        errcode_t       retval;
        struct problem_context pctx;

        if (dirent->name_len != 2)
                return 0;
        if (strncmp(dirent->name, "..", 2))
                return 0;

        clear_problem_context(&pctx);
        
        retval = adjust_inode_count(fp->ctx, dirent->inode, -1);
        if (retval) {
                pctx.errcode = retval;
                fix_problem(fp->ctx, PR_3_ADJUST_INODE, &pctx);
        }
        retval = adjust_inode_count(fp->ctx, fp->parent, 1);
        if (retval) {
                pctx.errcode = retval;
                fix_problem(fp->ctx, PR_3_ADJUST_INODE, &pctx);
        }
        dirent->inode = fp->parent;

        fp->done++;
        return DIRENT_ABORT | DIRENT_CHANGED;
}

static void fix_dotdot(e2fsck_t ctx, struct dir_info *dir, ino_t parent)
{
        ext2_filsys fs = ctx->fs;
        errcode_t       retval;
        struct fix_dotdot_struct fp;
        struct problem_context pctx;

        fp.fs = fs;
        fp.parent = parent;
        fp.done = 0;
        fp.ctx = ctx;

#if 0
        printf("Fixing '..' of inode %lu to be %lu...\n", dir->ino, parent);
#endif
        
        retval = ext2fs_dir_iterate(fs, dir->ino, DIRENT_FLAG_INCLUDE_EMPTY,
                                    0, fix_dotdot_proc, &fp);
        if (retval || !fp.done) {
                clear_problem_context(&pctx);
                pctx.ino = dir->ino;
                pctx.errcode = retval;
                fix_problem(ctx, retval ? PR_3_FIX_PARENT_ERR :
                            PR_3_FIX_PARENT_NOFIND, &pctx);
                ext2fs_unmark_valid(fs);
        }
        dir->dotdot = parent;
        
        return;
}

/*
 * These routines are responsible for expanding a /lost+found if it is
 * too small.
 */

struct expand_dir_struct {
        int     done;
        errcode_t       err;
        e2fsck_t        ctx;
};

static int expand_dir_proc(ext2_filsys fs,
                           blk_t        *blocknr,
                           int  blockcnt,
                           void *private)
{
        struct expand_dir_struct *es = (struct expand_dir_struct *) private;
        blk_t   new_blk;
        static blk_t    last_blk = 0;
        char            *block;
        errcode_t       retval;
        e2fsck_t        ctx;

        ctx = es->ctx;
        
        if (*blocknr) {
                last_blk = *blocknr;
                return 0;
        }
        retval = ext2fs_new_block(fs, last_blk, ctx->block_found_map,
                                  &new_blk);
        if (retval) {
                es->err = retval;
                return BLOCK_ABORT;
        }
        if (blockcnt > 0) {
                retval = ext2fs_new_dir_block(fs, 0, 0, &block);
                if (retval) {
                        es->err = retval;
                        return BLOCK_ABORT;
                }
                es->done = 1;
        } else {
                block = malloc(fs->blocksize);
                if (!block) {
                        es->err = ENOMEM;
                        return BLOCK_ABORT;
                }
                memset(block, 0, fs->blocksize);
        }       
        retval = ext2fs_write_dir_block(fs, new_blk, block);
        if (retval) {
                es->err = retval;
                return BLOCK_ABORT;
        }
        free(block);
        *blocknr = new_blk;
        ext2fs_mark_block_bitmap(ctx->block_found_map, new_blk);
        ext2fs_mark_block_bitmap(fs->block_map, new_blk);
        ext2fs_mark_bb_dirty(fs);
        if (es->done)
                return (BLOCK_CHANGED | BLOCK_ABORT);
        else
                return BLOCK_CHANGED;
}

static errcode_t expand_directory(e2fsck_t ctx, ino_t dir)
{
        ext2_filsys fs = ctx->fs;
        errcode_t       retval;
        struct expand_dir_struct es;
        struct ext2_inode       inode;
        
        if (!(fs->flags & EXT2_FLAG_RW))
                return EXT2_ET_RO_FILSYS;

        retval = ext2fs_check_directory(fs, dir);
        if (retval)
                return retval;
        
        es.done = 0;
        es.err = 0;
        es.ctx = ctx;
        
        retval = ext2fs_block_iterate(fs, dir, BLOCK_FLAG_APPEND,
                                      0, expand_dir_proc, &es);

        if (es.err)
                return es.err;
        if (!es.done)
                return EXT2_ET_EXPAND_DIR_ERR;

        /*
         * Update the size and block count fields in the inode.
         */
        retval = ext2fs_read_inode(fs, dir, &inode);
        if (retval)
                return retval;
        
        inode.i_size += fs->blocksize;
        inode.i_blocks += fs->blocksize / 512;

        e2fsck_write_inode(fs, dir, &inode, "expand_directory");

        return 0;
}