dir40.c

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/* Copyright (C) 2001-2005 by Hans Reiser, licensing governed by
   reiser4progs/COPYING.
   
   dir40.c -- reiser4 directory object plugin. */

#ifndef ENABLE_MINIMAL
#  include <unistd.h>
#endif

#include "dir40.h"
#include "dir40_repair.h"

/* Return current position in directory into passed @offset. */
static errno_t dir40_telldir(reiser4_object_t *dir,
			     reiser4_key_t *position)
{
	aal_assert("umka-1985", dir != NULL);
	aal_assert("umka-1986", position != NULL);

	/* Getting current dir key and adjust. */
	aal_memcpy(position, &dir->position, sizeof(*position));

#ifndef ENABLE_MINIMAL
	/* Adjust is offset inside collided keys arrays and needed for
	   positioning right in such a case. In normal case it is zero. */
	position->adjust = dir->position.adjust;
#endif
	
	return 0;
}

/* Positioning inside directory by passed @position key. Normally, user should use
   key got from telldir() function. But, this is possible to generate directory
   key by himself and pass here. */
static errno_t dir40_seekdir(reiser4_object_t *dir,
			     reiser4_key_t *position)
{
	aal_assert("umka-1983", dir != NULL);
	aal_assert("umka-1984", position != NULL);

	/* Set directory position to the given one. */
	aal_memcpy(&dir->position, position, sizeof(*position));
	return 0;
}

/* Resets current direntry position to zero. */
errno_t dir40_reset(reiser4_object_t *dir) {
	aal_assert("umka-864", dir != NULL);
	
	/* Preparing key of the first entry in directory and set directory
	   adjust to zero. */
#ifndef ENABLE_MINIMAL
	dir->position.adjust = 0;
#endif

	/* Building key itself. */
	plugcall(dir->info.object.plug, build_hashed, &dir->position,
		  reiser4_pshash(dir), reiser4_psfibre(dir), 
		  objcall(&dir->info.object, get_locality),
		  objcall(&dir->info.object, get_objectid), ".");

	return 0;
}

/* Fetches current unit to passed @entry */
errno_t dir40_fetch(reiser4_object_t *dir, entry_hint_t *entry) {
	trans_hint_t hint;

	aal_memset(&hint, 0, sizeof(hint));
	hint.count = 1;
	hint.specific = entry;
	hint.shift_flags = SF_DEFAULT;

	/* Reading entry to passed @entry */
	if (objcall(&dir->body, object->fetch_units, &hint) != 1)
		return -EIO;
	
	/* Copying entry place. */
	aal_memcpy(&entry->place, &dir->body,
		   sizeof(reiser4_place_t));

	return 0;
}

#ifndef ENABLE_MINIMAL
static void dir40_entry_type(entry_hint_t *entry) {
	entry->type = ET_NAME;

	if (aal_strlen(entry->name) == 1 &&
	    !aal_strncmp(entry->name, ".", 1))
	{
		entry->type = ET_SPCL;
	}

	if (aal_strlen(entry->name) == 2 &&
	    !aal_strncmp(entry->name, "..",2))
	{
		entry->type = ET_SPCL;
	}
}
#else
#define dir40_entry_type(entry) do{;} while(0)
#endif

errno_t dir40_entry_comp(reiser4_object_t *dir, void *data) {
	entry_hint_t entry;
	reiser4_key_t *key;

	aal_assert("vpf-1834", dir != NULL);

	if (!dir->body.plug)
		return -EINVAL;
#ifndef EINVAL	
	if (dir->body.plug->id.group != DIR_ITEM)
		return -ESTRUCT;
#endif
	if (dir40_fetch(dir, &entry))
		return -EIO;

	if (!data) {
		key = &dir->position;
	} else {
		key = (reiser4_key_t *)data;
	}
	
	/* If greater key is reached, return PRESENT. */
	return objcall(&entry.offset, compfull, key) ? 1 : 0;
}

/* Reads one current directory entry to passed @entry hint. Returns count of
   read entries, zero for the case directory is over and nagtive values fopr
   errors. */
static int32_t dir40_readdir(reiser4_object_t *dir, 
			     entry_hint_t *entry)
{
	uint32_t units;
	errno_t res;

	aal_assert("umka-845", entry != NULL);
	aal_assert("umka-844", dir != NULL);

	/* Getting place of current unit */
	if ((res = obj40_update_body(dir, dir40_entry_comp)) != PRESENT)
		return res == ABSENT ? 0 : res;

	/* Reading next entry */
	if ((res = dir40_fetch(dir, entry)))
		return res;

	/* Setting up the entry type. It is essential for fsck to know what is
	   the NAME -- that needs to be traversed semantically to be recovered
	   completely -- and what is not -- that needs some other special
	   actions, e.g. check_attach for ".." (and even "..." if it is needed
	   one day), etc. */
	dir40_entry_type(entry);

	units = objcall(&dir->body, balance->units);

	/* Getting next entry in odrer to set up @dir->position correctly. */
	if (++dir->body.pos.unit >= units) {
		/* Switching to the next directory item */
		if ((res = obj40_next_item(dir)) < 0)
			return res;

		if (res == ABSENT) {
			uint64_t offset;
			
			/* Set offset to non-existent value. */
			offset = objcall(&dir->position, get_offset);
			objcall(&dir->position, set_offset, offset + 1);
		}
	} else {
		/* There is no need to switch */
		res = 1;
	}

	if (res == 1) {
		entry_hint_t temp;
		
		if ((res = dir40_fetch(dir, &temp)))
			return res;

#ifndef ENABLE_MINIMAL
		/* Taking care about adjust */
		if (!objcall(&temp.offset, compfull, &dir->position))
			temp.offset.adjust = dir->position.adjust + 1;
		else
			temp.offset.adjust = 0;
#endif
		dir40_seekdir(dir, &temp.offset);
	}
	
	return 1;
}

/* Makes lookup inside directory. This is needed to be used in add_entry() for
   two reasons: for make sure, that passed entry does not exists and to use
   lookup result for consequent insert. */
static lookup_t dir40_search(reiser4_object_t *dir, char *name,
			     lookup_bias_t bias, entry_hint_t *entry)
{
	lookup_t res;
#ifndef ENABLE_MINIMAL
	coll_hint_t hint;
	coll_func_t func;
#endif

	aal_assert("umka-1118", name != NULL);
	aal_assert("umka-1117", dir != NULL);

	/* Preparing key to be used for lookup. It is generating from the
	   directory oid, locality and name by menas of using hash plugin. */
	plugcall(dir->info.object.plug, build_hashed, &dir->body.key,
		 reiser4_pshash(dir), reiser4_psfibre(dir),
		 objcall(&dir->info.object, get_locality),
		 objcall(&dir->info.object, get_objectid), name);

#ifndef ENABLE_MINIMAL
	hint.specific = name;
	hint.type = DIR_ITEM;
	func = obj40_core->tree_ops.collision;
#endif
	
	if ((res = obj40_find_item(dir, &dir->body.key, bias, 
#ifndef ENABLE_MINIMAL
				   func, &hint,
#else
				   NULL, NULL,
#endif
				   &dir->body)) < 0)
	{
		return res;
	}

	if (entry) {
		aal_memset(entry, 0, sizeof(*entry));
		
		aal_memcpy(&entry->place, &dir->body,
			   sizeof(reiser4_place_t));

		aal_memcpy(&entry->offset, &dir->body.key,
			   sizeof(reiser4_key_t));

		if (res == PRESENT) {
			if (dir40_fetch(dir, entry))
				return -EIO;

			dir40_entry_type(entry);
		}
	}

	return res;
}

/* Makes lookup inside @dir by passed @name. Saves found entry in passed
   @entry hint. */
lookup_t dir40_lookup(reiser4_object_t *dir,
		      char *name, entry_hint_t *entry) 
{
	return dir40_search(dir, name, FIND_EXACT, entry);
}

#ifndef ENABLE_MINIMAL
/* Creates dir40 instance. Creates its stat data item, and body item with one
   "." unit. Yet another unit ".." will be inserted latter, then directiry will
   be attached to a parent object. */
static errno_t dir40_create(reiser4_object_t *dir, object_hint_t *hint) {
	trans_hint_t body_hint;
	entry_hint_t entry;
	reiser4_key_t *key;
	uint32_t mode;
	errno_t res;
    
	aal_assert("vpf-1816",  dir != NULL);
	aal_assert("vpf-1095",  dir->info.tree != NULL);

	aal_memset(&body_hint, 0, sizeof(body_hint));
	
	/* Initializing direntry item hint. This should be done before the stat
	   data item hint, because we will need size of direntry item during
	   stat data initialization. */
   	body_hint.count = 1;
	body_hint.plug = reiser4_psdiren(dir);
	
	key = &dir->info.object;
	plugcall(key->plug, build_hashed, &body_hint.offset, 
		 reiser4_pshash(dir), reiser4_psfibre(dir),
		 objcall(&dir->info.object, get_locality),
		 objcall(&dir->info.object, get_objectid), ".");

	/* Preparing hint for the empty directory. It consists only "." for
	   unlinked directories. */
	aal_strncpy(entry.name, ".", 1);

	/* Initializing entry stat data key. */
	aal_memcpy(&entry.object, key, sizeof(*key));

	/* Initializing entry hash key. */
	aal_memcpy(&entry.offset, &body_hint.offset, sizeof(entry.offset));

	body_hint.specific = &entry;
	body_hint.shift_flags = SF_DEFAULT;
	
	dir40_reset(dir);
	
        /* Looking for place to insert directory body */
	switch (obj40_find_item(dir, &body_hint.offset,
				FIND_CONV, NULL, NULL, &dir->body))
	{
	case ABSENT:
		/* Inserting the direntry body item into the tree. */
		if ((res = obj40_insert(dir, &dir->body,
					&body_hint, LEAF_LEVEL)) < 0)
		{
			return res;
		}
		
		break;
	default:
		return -EIO;
	}
	
	mode = (hint ? hint->mode : 0) | S_IFDIR | 0755;
	
	/* Create stat data item. */
	if ((res = obj40_create_stat(dir, 1, body_hint.len, 
				     0, 1, mode, NULL)))