inode.c

linux 内核源代码

									    allocated_block_nr,
									    1);
					}
					goto failure;
				}
				goto research;
			}
			retval =
			    direct2indirect(th, inode, &path, unbh,
					    tail_offset);
			if (retval) {
				reiserfs_unmap_buffer(unbh);
				reiserfs_free_block(th, inode,
						    allocated_block_nr, 1);
				goto failure;
			}
			/* it is important the set_buffer_uptodate is done after
			 ** the direct2indirect.  The buffer might contain valid
			 ** data newer than the data on disk (read by readpage, changed,
			 ** and then sent here by writepage).  direct2indirect needs
			 ** to know if unbh was already up to date, so it can decide
			 ** if the data in unbh needs to be replaced with data from
			 ** the disk
			 */
			set_buffer_uptodate(unbh);

			/* unbh->b_page == NULL in case of DIRECT_IO request, this means
			   buffer will disappear shortly, so it should not be added to
			 */
			if (unbh->b_page) {
				/* we've converted the tail, so we must
				 ** flush unbh before the transaction commits
				 */
				reiserfs_add_tail_list(inode, unbh);

				/* mark it dirty now to prevent commit_write from adding
				 ** this buffer to the inode's dirty buffer list
				 */
				/*
				 * AKPM: changed __mark_buffer_dirty to mark_buffer_dirty().
				 * It's still atomic, but it sets the page dirty too,
				 * which makes it eligible for writeback at any time by the
				 * VM (which was also the case with __mark_buffer_dirty())
				 */
				mark_buffer_dirty(unbh);
			}
		} else {
			/* append indirect item with holes if needed, when appending
			   pointer to 'block'-th block use block, which is already
			   allocated */
			struct cpu_key tmp_key;
			unp_t unf_single = 0;	// We use this in case we need to allocate only
			// one block which is a fastpath
			unp_t *un;
			__u64 max_to_insert =
			    MAX_ITEM_LEN(inode->i_sb->s_blocksize) /
			    UNFM_P_SIZE;
			__u64 blocks_needed;

			RFALSE(pos_in_item != ih_item_len(ih) / UNFM_P_SIZE,
			       "vs-804: invalid position for append");
			/* indirect item has to be appended, set up key of that position */
			make_cpu_key(&tmp_key, inode,
				     le_key_k_offset(version,
						     &(ih->ih_key)) +
				     op_bytes_number(ih,
						     inode->i_sb->s_blocksize),
				     //pos_in_item * inode->i_sb->s_blocksize,
				     TYPE_INDIRECT, 3);	// key type is unimportant

			RFALSE(cpu_key_k_offset(&tmp_key) > cpu_key_k_offset(&key),
			       "green-805: invalid offset");
			blocks_needed =
			    1 +
			    ((cpu_key_k_offset(&key) -
			      cpu_key_k_offset(&tmp_key)) >> inode->i_sb->
			     s_blocksize_bits);

			if (blocks_needed == 1) {
				un = &unf_single;
			} else {
				un = kzalloc(min(blocks_needed, max_to_insert) * UNFM_P_SIZE, GFP_ATOMIC);	// We need to avoid scheduling.
				if (!un) {
					un = &unf_single;
					blocks_needed = 1;
					max_to_insert = 0;
				}
			}
			if (blocks_needed <= max_to_insert) {
				/* we are going to add target block to the file. Use allocated
				   block for that */
				un[blocks_needed - 1] =
				    cpu_to_le32(allocated_block_nr);
				set_block_dev_mapped(bh_result,
						     allocated_block_nr, inode);
				set_buffer_new(bh_result);
				done = 1;
			} else {
				/* paste hole to the indirect item */
				/* If kmalloc failed, max_to_insert becomes zero and it means we
				   only have space for one block */
				blocks_needed =
				    max_to_insert ? max_to_insert : 1;
			}
			retval =
			    reiserfs_paste_into_item(th, &path, &tmp_key, inode,
						     (char *)un,
						     UNFM_P_SIZE *
						     blocks_needed);

			if (blocks_needed != 1)
				kfree(un);

			if (retval) {
				reiserfs_free_block(th, inode,
						    allocated_block_nr, 1);
				goto failure;
			}
			if (!done) {
				/* We need to mark new file size in case this function will be
				   interrupted/aborted later on. And we may do this only for
				   holes. */
				inode->i_size +=
				    inode->i_sb->s_blocksize * blocks_needed;
			}
		}

		if (done == 1)
			break;

		/* this loop could log more blocks than we had originally asked
		 ** for.  So, we have to allow the transaction to end if it is
		 ** too big or too full.  Update the inode so things are 
		 ** consistent if we crash before the function returns
		 **
		 ** release the path so that anybody waiting on the path before
		 ** ending their transaction will be able to continue.
		 */
		if (journal_transaction_should_end(th, th->t_blocks_allocated)) {
			retval = restart_transaction(th, inode, &path);
			if (retval)
				goto failure;
		}
		/* inserting indirect pointers for a hole can take a 
		 ** long time.  reschedule if needed
		 */
		cond_resched();

		retval = search_for_position_by_key(inode->i_sb, &key, &path);
		if (retval == IO_ERROR) {
			retval = -EIO;
			goto failure;
		}
		if (retval == POSITION_FOUND) {
			reiserfs_warning(inode->i_sb,
					 "vs-825: reiserfs_get_block: "
					 "%K should not be found", &key);
			retval = -EEXIST;
			if (allocated_block_nr)
				reiserfs_free_block(th, inode,
						    allocated_block_nr, 1);
			pathrelse(&path);
			goto failure;
		}
		bh = get_last_bh(&path);
		ih = get_ih(&path);
		item = get_item(&path);
		pos_in_item = path.pos_in_item;
	} while (1);

	retval = 0;

      failure:
	if (th && (!dangle || (retval && !th->t_trans_id))) {
		int err;
		if (th->t_trans_id)
			reiserfs_update_sd(th, inode);
		err = reiserfs_end_persistent_transaction(th);
		if (err)
			retval = err;
	}

	reiserfs_write_unlock(inode->i_sb);
	reiserfs_check_path(&path);
	return retval;
}

static int
reiserfs_readpages(struct file *file, struct address_space *mapping,
		   struct list_head *pages, unsigned nr_pages)
{
	return mpage_readpages(mapping, pages, nr_pages, reiserfs_get_block);
}

/* Compute real number of used bytes by file
 * Following three functions can go away when we'll have enough space in stat item
 */
static int real_space_diff(struct inode *inode, int sd_size)
{
	int bytes;
	loff_t blocksize = inode->i_sb->s_blocksize;

	if (S_ISLNK(inode->i_mode) || S_ISDIR(inode->i_mode))
		return sd_size;

	/* End of file is also in full block with indirect reference, so round
	 ** up to the next block.
	 **
	 ** there is just no way to know if the tail is actually packed
	 ** on the file, so we have to assume it isn't.  When we pack the
	 ** tail, we add 4 bytes to pretend there really is an unformatted
	 ** node pointer
	 */
	bytes =
	    ((inode->i_size +
	      (blocksize - 1)) >> inode->i_sb->s_blocksize_bits) * UNFM_P_SIZE +
	    sd_size;
	return bytes;
}

static inline loff_t to_real_used_space(struct inode *inode, ulong blocks,
					int sd_size)
{
	if (S_ISLNK(inode->i_mode) || S_ISDIR(inode->i_mode)) {
		return inode->i_size +
		    (loff_t) (real_space_diff(inode, sd_size));
	}
	return ((loff_t) real_space_diff(inode, sd_size)) +
	    (((loff_t) blocks) << 9);
}

/* Compute number of blocks used by file in ReiserFS counting */
static inline ulong to_fake_used_blocks(struct inode *inode, int sd_size)
{
	loff_t bytes = inode_get_bytes(inode);
	loff_t real_space = real_space_diff(inode, sd_size);

	/* keeps fsck and non-quota versions of reiserfs happy */
	if (S_ISLNK(inode->i_mode) || S_ISDIR(inode->i_mode)) {
		bytes += (loff_t) 511;
	}

	/* files from before the quota patch might i_blocks such that
	 ** bytes < real_space.  Deal with that here to prevent it from
	 ** going negative.
	 */
	if (bytes < real_space)
		return 0;
	return (bytes - real_space) >> 9;
}

//
// BAD: new directories have stat data of new type and all other items
// of old type. Version stored in the inode says about body items, so
// in update_stat_data we can not rely on inode, but have to check
// item version directly
//

// called by read_locked_inode
static void init_inode(struct inode *inode, struct treepath *path)
{
	struct buffer_head *bh;
	struct item_head *ih;
	__u32 rdev;
	//int version = ITEM_VERSION_1;

	bh = PATH_PLAST_BUFFER(path);
	ih = PATH_PITEM_HEAD(path);

	copy_key(INODE_PKEY(inode), &(ih->ih_key));

	INIT_LIST_HEAD(&(REISERFS_I(inode)->i_prealloc_list));
	REISERFS_I(inode)->i_flags = 0;
	REISERFS_I(inode)->i_prealloc_block = 0;
	REISERFS_I(inode)->i_prealloc_count = 0;
	REISERFS_I(inode)->i_trans_id = 0;
	REISERFS_I(inode)->i_jl = NULL;
	mutex_init(&(REISERFS_I(inode)->i_mmap));
	reiserfs_init_acl_access(inode);
	reiserfs_init_acl_default(inode);
	reiserfs_init_xattr_rwsem(inode);

	if (stat_data_v1(ih)) {
		struct stat_data_v1 *sd =
		    (struct stat_data_v1 *)B_I_PITEM(bh, ih);
		unsigned long blocks;

		set_inode_item_key_version(inode, KEY_FORMAT_3_5);
		set_inode_sd_version(inode, STAT_DATA_V1);
		inode->i_mode = sd_v1_mode(sd);
		inode->i_nlink = sd_v1_nlink(sd);
		inode->i_uid = sd_v1_uid(sd);
		inode->i_gid = sd_v1_gid(sd);
		inode->i_size = sd_v1_size(sd);
		inode->i_atime.tv_sec = sd_v1_atime(sd);
		inode->i_mtime.tv_sec = sd_v1_mtime(sd);
		inode->i_ctime.tv_sec = sd_v1_ctime(sd);
		inode->i_atime.tv_nsec = 0;
		inode->i_ctime.tv_nsec = 0;
		inode->i_mtime.tv_nsec = 0;

		inode->i_blocks = sd_v1_blocks(sd);
		inode->i_generation = le32_to_cpu(INODE_PKEY(inode)->k_dir_id);
		blocks = (inode->i_size + 511) >> 9;
		blocks = _ROUND_UP(blocks, inode->i_sb->s_blocksize >> 9);
		if (inode->i_blocks > blocks) {
			// there was a bug in <=3.5.23 when i_blocks could take negative
			// values. Starting from 3.5.17 this value could even be stored in
			// stat data. For such files we set i_blocks based on file
			// size. Just 2 notes: this can be wrong for sparce files. On-disk value will be
			// only updated if file's inode will ever change
			inode->i_blocks = blocks;
		}

		rdev = sd_v1_rdev(sd);
		REISERFS_I(inode)->i_first_direct_byte =
		    sd_v1_first_direct_byte(sd);
		/* an early bug in the quota code can give us an odd number for the
		 ** block count.  This is incorrect, fix it here.
		 */
		if (inode->i_blocks & 1) {
			inode->i_blocks++;
		}
		inode_set_bytes(inode,
				to_real_used_space(inode, inode->i_blocks,
						   SD_V1_SIZE));
		/* nopack is initially zero for v1 objects. For v2 objects,
		   nopack is initialised from sd_attrs */
		REISERFS_I(inode)->i_flags &= ~i_nopack_mask;
	} else {
		// new stat data found, but object may have old items
		// (directories and symlinks)
		struct stat_data *sd = (struct stat_data *)B_I_PITEM(bh, ih);

		inode->i_mode = sd_v2_mode(sd);
		inode->i_nlink = sd_v2_nlink(sd);
		inode->i_uid = sd_v2_uid(sd);
		inode->i_size = sd_v2_size(sd);
		inode->i_gid = sd_v2_gid(sd);
		inode->i_mtime.tv_sec = sd_v2_mtime(sd);
		inode->i_atime.tv_sec = sd_v2_atime(sd);
		inode->i_ctime.tv_sec = sd_v2_ctime(sd);
		inode->i_ctime.tv_nsec = 0;
		inode->i_mtime.tv_nsec = 0;
		inode->i_atime.tv_nsec = 0;
		inode->i_blocks = sd_v2_blocks(sd);
		rdev = sd_v2_rdev(sd);
		if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
			inode->i_generation =
			    le32_to_cpu(INODE_PKEY(inode)->k_dir_id);
		else
			inode->i_generation = sd_v2_generation(sd);

		if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
			set_inode_item_key_version(inode, KEY_FORMAT_3_5);
		else
			set_inode_item_key_version(inode, KEY_FORMAT_3_6);
		REISERFS_I(inode)->i_first_direct_byte = 0;
		set_inode_sd_version(inode, STAT_DATA_V2);
		inode_set_bytes(inode,
				to_real_used_space(inode, inode->i_blocks,
						   SD_V2_SIZE));
		/* read persistent inode attributes from sd and initalise
		   generic inode flags from them */
		REISERFS_I(inode)->i_attrs = sd_v2_attrs(sd);
		sd_attrs_to_i_attrs(sd_v2_attrs(sd), inode);
	}

	pathrelse(path);
	if (S_ISREG(inode->i_mode)) {
		inode->i_op = &reiserfs_file_inode_operations;
		inode->i_fop = &reiserfs_file_operations;
		inode->i_mapping->a_ops = &reiserfs_address_space_operations;
	} else if (S_ISDIR(inode->i_mode)) {
		inode->i_op = &reiserfs_dir_inode_operations;
		inode->i_fop = &reiserfs_dir_operations;
	} else if (S_ISLNK(inode->i_mode)) {
		inode->i_op = &reiserfs_symlink_inode_operations;
		inode->i_mapping->a_ops = &reiserfs_address_space_operations;
	} else {
		inode->i_blocks = 0;
		inode->i_op = &reiserfs_special_inode_operations;
		init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
	}
}

// update new stat data with inode fields
static void inode2sd(void *sd, struct inode *inode, loff_t size)
{
	struct stat_data *sd_v2 = (struct stat_data *)sd;
	__u16 flags;

	set_sd_v2_mode(sd_v2, inode->i_mode);
	set_sd_v2_nlink(sd_v2, inode->i_nlink);
	set_sd_v2_uid(sd_v2, inode->i_uid);
	set_sd_v2_size(sd_v2, size);
	set_sd_v2_gid(sd_v2, inode->i_gid);
	set_sd_v2_mtime(sd_v2, inode->i_mtime.tv_sec);
	set_sd_v2_atime(sd_v2, inode->i_atime.tv_sec);
	set_sd_v2_ctime(sd_v2, inode->i_ctime.tv_sec);
	set_sd_v2_blocks(sd_v2, to_fake_used_blocks(inode, SD_V2_SIZE));
	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
		set_sd_v2_rdev(sd_v2, new_encode_dev(inode->i_rdev));
	else
		set_sd_v2_generation(sd_v2, inode->i_generation);
	flags = REISERFS_I(inode)->i_attrs;
	i_attrs_to_sd_attrs(inode, &flags);
	set_sd_v2_attrs(sd_v2, flags);
}

// used to copy inode's fields to old stat data
static void inode2sd_v1(void *sd, struct inode *inode, loff_t size)
{
	struct stat_data_v1 *sd_v1 = (struct stat_data_v1 *)sd;

	set_sd_v1_mode(sd_v1, inode->i_mode);
	set_sd_v1_uid(sd_v1, inode->i_uid);
	set_sd_v1_gid(sd_v1, inode->i_gid);
	set_sd_v1_nlink(sd_v1, inode->i_nlink);
	set_sd_v1_size(sd_v1, size);
	set_sd_v1_atime(sd_v1, inode->i_atime.tv_sec);
	set_sd_v1_ctime(sd_v1, inode->i_ctime.tv_sec);
	set_sd_v1_mtime(sd_v1, inode->i_mtime.tv_sec);

	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
		set_sd_v1_rdev(sd_v1, new_encode_dev(inode->i_rdev));