#include "ext4_config.h"#include "ext4_types.h"#include "ext4_misc.h"#include "ext4_debug.h"#include "ext4_trans.h"#include "ext4_ialloc.h"#include "ext4_super.h"#include "ext4_crc32.h"#include "ext4_fs.h"#include "ext4_blockdev.h"#include "ext4_block_group.h"#include "ext4_bitmap.h" /**@brief  Convert i-node number to relative index in block group. * @param sb    Superblock * @param inode I-node number to be converted * @return Index of the i-node in the block group */static u32int ext4_ialloc_inode_to_bgidx(struct ext4_sblock *sb,					   u32int inode){	u32int inodes_per_group = ext4_get32(sb, inodes_per_group);	return (inode - 1) % inodes_per_group;} /**@brief Convert relative index of i-node to absolute i-node number. * @param sb    Superblock * @param index Index to be converted * @return Absolute number of the i-node * */static u32int ext4_ialloc_bgidx_to_inode(struct ext4_sblock *sb,					   u32int index, u32int bgid){	u32int inodes_per_group = ext4_get32(sb, inodes_per_group);	return bgid * inodes_per_group + (index + 1);} /**@brief Compute block group number from the i-node number. * @param sb    Superblock * @param inode I-node number to be found the block group for * @return Block group number computed from i-node number */static u32int ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,					      u32int inode){	u32int inodes_per_group = ext4_get32(sb, inodes_per_group);	return (inode - 1) / inodes_per_group;} static u32int ext4_ialloc_bitmap_csum(struct ext4_fs *fs, void *bitmap){	u32int csum = 0;	if (ext4_sb_feature_ro_com(&fs->sb, EXT4_FRO_COM_METADATA_CSUM)) {		u32int inodes_per_group =			ext4_get32(&fs->sb, inodes_per_group); 		/* First calculate crc32 checksum against fs uuid */		csum = fs->uuid_crc32c;		/* Then calculate crc32 checksum against inode bitmap */		csum = ext4_crc32c(csum, bitmap, (inodes_per_group + 7) / 8);	}	return csum;} void ext4_ialloc_set_bitmap_csum(struct ext4_fs *fs, struct ext4_bgroup *bg, void *bitmap){	int desc_size = ext4_sb_get_desc_size(&fs->sb);	u32int csum = ext4_ialloc_bitmap_csum(fs, bitmap);	u16int lo_csum = to_le16(csum & 0xFFFF),		 hi_csum = to_le16(csum >> 16); 	if (!ext4_sb_feature_ro_com(&fs->sb, EXT4_FRO_COM_METADATA_CSUM))		return; 	/* See if we need to assign a 32bit checksum */	bg->inode_bitmap_csum_lo = lo_csum;	if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)		bg->inode_bitmap_csum_hi = hi_csum; } static boolext4_ialloc_verify_bitmap_csum(struct ext4_fs *fs, struct ext4_bgroup *bg, void *bitmap){	int desc_size = ext4_sb_get_desc_size(&fs->sb);	u32int csum = ext4_ialloc_bitmap_csum(fs, bitmap);	u16int lo_csum = to_le16(csum & 0xFFFF),		 hi_csum = to_le16(csum >> 16); 	if (!ext4_sb_feature_ro_com(&fs->sb, EXT4_FRO_COM_METADATA_CSUM))		return true; 	if (bg->inode_bitmap_csum_lo != lo_csum)		return false; 	if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)		if (bg->inode_bitmap_csum_hi != hi_csum)			return false; 	return true;} int ext4_ialloc_free_inode(struct ext4_fs *fs, u32int index, bool is_dir){	struct ext4_sblock *sb = &fs->sb; 	/* Compute index of block group and load it */	u32int block_group = ext4_ialloc_get_bgid_of_inode(sb, index); 	struct ext4_block_group_ref bg_ref;	int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);	if (rc != 0)		return rc; 	struct ext4_bgroup *bg = bg_ref.block_group; 	/* Load i-node bitmap */	ext4_fsblk_t bitmap_block_addr =	    ext4_bg_get_inode_bitmap(bg, sb); 	struct ext4_block b;	rc = ext4_trans_block_get(fs->bdev, &b, bitmap_block_addr);	if (rc != 0)		return rc; 	if (!ext4_ialloc_verify_bitmap_csum(fs, bg, b.data)) {		ext4_dbg(DEBUG_IALLOC,			DBG_WARN "Bitmap checksum failed."			"Group: %ud\n",			bg_ref.index);	} 	/* Free i-node in the bitmap */	u32int index_in_group = ext4_ialloc_inode_to_bgidx(sb, index);	ext4_bmap_bit_clr(b.data, index_in_group);	ext4_ialloc_set_bitmap_csum(fs, bg, b.data);	ext4_trans_set_block_dirty(b.buf); 	/* Put back the block with bitmap */	rc = ext4_block_set(fs->bdev, &b);	if (rc != 0) {		/* Error in saving bitmap */		ext4_fs_put_block_group_ref(&bg_ref);		return rc;	} 	/* If released i-node is a directory, decrement used directories count	 */	if (is_dir) {		u32int bg_used_dirs = ext4_bg_get_used_dirs_count(bg, sb);		bg_used_dirs--;		ext4_bg_set_used_dirs_count(bg, sb, bg_used_dirs);	} 	/* Update block group free inodes count */	u32int free_inodes = ext4_bg_get_free_inodes_count(bg, sb);	free_inodes++;	ext4_bg_set_free_inodes_count(bg, sb, free_inodes); 	bg_ref.dirty = true; 	/* Put back the modified block group */	rc = ext4_fs_put_block_group_ref(&bg_ref);	if (rc != 0)		return rc; 	/* Update superblock free inodes count */	ext4_set32(sb, free_inodes_count,		   ext4_get32(sb, free_inodes_count) + 1); 	return 0;} int ext4_ialloc_alloc_inode(struct ext4_fs *fs, u32int *idx, bool is_dir){	struct ext4_sblock *sb = &fs->sb; 	u32int bgid = fs->last_inode_bg_id;	u32int bg_count = ext4_block_group_cnt(sb);	u32int sb_free_inodes = ext4_get32(sb, free_inodes_count);	bool rewind = false; 	/* Try to find free i-node in all block groups */	while (bgid <= bg_count) { 		if (bgid == bg_count) {			if (rewind)				break;			bg_count = fs->last_inode_bg_id;			bgid = 0;			rewind = true;			continue;		} 		/* Load block group to check */		struct ext4_block_group_ref bg_ref;		int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);		if (rc != 0)			return rc; 		struct ext4_bgroup *bg = bg_ref.block_group; 		/* Read necessary values for algorithm */		u32int free_inodes = ext4_bg_get_free_inodes_count(bg, sb);		u32int used_dirs = ext4_bg_get_used_dirs_count(bg, sb); 		/* Check if this block group is good candidate for allocation */		if (free_inodes > 0) {			/* Load block with bitmap */			ext4_fsblk_t bmp_blk_add = ext4_bg_get_inode_bitmap(bg, sb); 			struct ext4_block b;			rc = ext4_trans_block_get(fs->bdev, &b, bmp_blk_add);			if (rc != 0) {				ext4_fs_put_block_group_ref(&bg_ref);				return rc;			} 			if (!ext4_ialloc_verify_bitmap_csum(fs, bg, b.data)) {				ext4_dbg(DEBUG_IALLOC,					DBG_WARN "Bitmap checksum failed."					"Group: %ud\n",					bg_ref.index);			} 			/* Try to allocate i-node in the bitmap */			u32int inodes_in_bg;			u32int idx_in_bg; 			inodes_in_bg = ext4_inodes_in_group_cnt(sb, bgid);			bool no_space;			rc = ext4_bmap_bit_find_clr(b.data, 0, inodes_in_bg, &idx_in_bg, &no_space);			/* Block group does not have any free i-node */			if (no_space) {				rc = ext4_block_set(fs->bdev, &b);				if (rc != 0) {					ext4_fs_put_block_group_ref(&bg_ref);					return rc;				} 				rc = ext4_fs_put_block_group_ref(&bg_ref);				if (rc != 0)					return rc; 				continue;			} 			ext4_bmap_bit_set(b.data, idx_in_bg); 			/* Free i-node found, save the bitmap */			ext4_ialloc_set_bitmap_csum(fs, bg, b.data);			ext4_trans_set_block_dirty(b.buf); 			ext4_block_set(fs->bdev, &b);			if (rc != 0) {				ext4_fs_put_block_group_ref(&bg_ref);				return rc;			} 			/* Modify filesystem counters */			free_inodes--;			ext4_bg_set_free_inodes_count(bg, sb, free_inodes); 			/* Increment used directories counter */			if (is_dir) {				used_dirs++;				ext4_bg_set_used_dirs_count(bg, sb, used_dirs);			} 			/* Decrease unused inodes count */			u32int unused =			    ext4_bg_get_itable_unused(bg, sb); 			u32int free = inodes_in_bg - unused; 			if (idx_in_bg >= free) {				unused = inodes_in_bg - (idx_in_bg + 1);				ext4_bg_set_itable_unused(bg, sb, unused);			} 			/* Save modified block group */			bg_ref.dirty = true; 			rc = ext4_fs_put_block_group_ref(&bg_ref);			if (rc != 0)				return rc; 			/* Update superblock */			sb_free_inodes--;			ext4_set32(sb, free_inodes_count, sb_free_inodes); 			/* Compute the absolute i-nodex number */			*idx = ext4_ialloc_bgidx_to_inode(sb, idx_in_bg, bgid); 			fs->last_inode_bg_id = bgid; 			return 0;		} 		/* Block group not modified, put it and jump to the next block		 * group */		ext4_fs_put_block_group_ref(&bg_ref);		if (rc != 0)			return rc; 		++bgid;	} 	werrstr(Enospc);	return -1;}