/*
   *  fs/partitions/aix.c
   *
   *  Copyright (C) 2012-2013 Philippe De Muyter <phdm@macqel.be>
   */
  
  #include "check.h"
  #include "aix.h"
  
  struct lvm_rec {
  	char lvm_id[4]; /* "_LVM" */
  	char reserved4[16];
  	__be32 lvmarea_len;
  	__be32 vgda_len;
  	__be32 vgda_psn[2];
  	char reserved36[10];
  	__be16 pp_size; /* log2(pp_size) */
  	char reserved46[12];
  	__be16 version;
  	};
  
  struct vgda {
  	__be32 secs;
  	__be32 usec;
  	char reserved8[16];
  	__be16 numlvs;
  	__be16 maxlvs;
  	__be16 pp_size;
  	__be16 numpvs;
  	__be16 total_vgdas;
  	__be16 vgda_size;
  	};
  
  struct lvd {
  	__be16 lv_ix;
  	__be16 res2;
  	__be16 res4;
  	__be16 maxsize;
  	__be16 lv_state;
  	__be16 mirror;
  	__be16 mirror_policy;
  	__be16 num_lps;
  	__be16 res10[8];
  	};
  
  struct lvname {
  	char name[64];
  	};
  
  struct ppe {
  	__be16 lv_ix;
  	unsigned short res2;
  	unsigned short res4;
  	__be16 lp_ix;
  	unsigned short res8[12];
  	};
  
  struct pvd {
  	char reserved0[16];
  	__be16 pp_count;
  	char reserved18[2];
  	__be32 psn_part1;
  	char reserved24[8];
  	struct ppe ppe[1016];
  	};
  
  #define LVM_MAXLVS 256
  
  /**
   * last_lba(): return number of last logical block of device
   * @bdev: block device
   *
   * Description: Returns last LBA value on success, 0 on error.
   * This is stored (by sd and ide-geometry) in
   *  the part[0] entry for this disk, and is the number of
   *  physical sectors available on the disk.
   */
  static u64 last_lba(struct block_device *bdev)
  {
  	if (!bdev || !bdev->bd_inode)
  		return 0;
  	return (bdev->bd_inode->i_size >> 9) - 1ULL;
  }
  
  /**
   * read_lba(): Read bytes from disk, starting at given LBA
   * @state
   * @lba
   * @buffer
   * @count
   *
   * Description:  Reads @count bytes from @state->bdev into @buffer.
   * Returns number of bytes read on success, 0 on error.
   */
  static size_t read_lba(struct parsed_partitions *state, u64 lba, u8 *buffer,
  			size_t count)
  {
  	size_t totalreadcount = 0;
  
  	if (!buffer || lba + count / 512 > last_lba(state->bdev))
  		return 0;
  
  	while (count) {
  		int copied = 512;
  		Sector sect;
  		unsigned char *data = read_part_sector(state, lba++, &sect);
  		if (!data)
  			break;
  		if (copied > count)
  			copied = count;
  		memcpy(buffer, data, copied);
  		put_dev_sector(sect);
  		buffer += copied;
  		totalreadcount += copied;
  		count -= copied;
  	}
  	return totalreadcount;
  }
  
  /**
   * alloc_pvd(): reads physical volume descriptor
   * @state
   * @lba
   *
   * Description: Returns pvd on success,  NULL on error.
   * Allocates space for pvd and fill it with disk blocks at @lba
   * Notes: remember to free pvd when you're done!
   */
  static struct pvd *alloc_pvd(struct parsed_partitions *state, u32 lba)
  {
  	size_t count = sizeof(struct pvd);
  	struct pvd *p;
  
  	p = kmalloc(count, GFP_KERNEL);
  	if (!p)
  		return NULL;
  
  	if (read_lba(state, lba, (u8 *) p, count) < count) {
  		kfree(p);
  		return NULL;
  	}
  	return p;
  }
  
  /**
   * alloc_lvn(): reads logical volume names
   * @state
   * @lba
   *
   * Description: Returns lvn on success,  NULL on error.
   * Allocates space for lvn and fill it with disk blocks at @lba
   * Notes: remember to free lvn when you're done!
   */
  static struct lvname *alloc_lvn(struct parsed_partitions *state, u32 lba)
  {
  	size_t count = sizeof(struct lvname) * LVM_MAXLVS;
  	struct lvname *p;
  
  	p = kmalloc(count, GFP_KERNEL);
  	if (!p)
  		return NULL;
  
  	if (read_lba(state, lba, (u8 *) p, count) < count) {
  		kfree(p);
  		return NULL;
  	}
  	return p;
  }
  
  int aix_partition(struct parsed_partitions *state)
  {
  	int ret = 0;
  	Sector sect;
  	unsigned char *d;
  	u32 pp_bytes_size;
  	u32 pp_blocks_size = 0;
  	u32 vgda_sector = 0;
  	u32 vgda_len = 0;
  	int numlvs = 0;
  	struct pvd *pvd;
  	struct lv_info {
  		unsigned short pps_per_lv;
  		unsigned short pps_found;
  		unsigned char lv_is_contiguous;
  	} *lvip;
  	struct lvname *n = NULL;
  
  	d = read_part_sector(state, 7, &sect);
  	if (d) {
  		struct lvm_rec *p = (struct lvm_rec *)d;
  		u16 lvm_version = be16_to_cpu(p->version);
  		char tmp[64];
  
  		if (lvm_version == 1) {
  			int pp_size_log2 = be16_to_cpu(p->pp_size);
  
  			pp_bytes_size = 1 << pp_size_log2;
  			pp_blocks_size = pp_bytes_size / 512;
  			snprintf(tmp, sizeof(tmp),
  				" AIX LVM header version %u found
  ",
  				lvm_version);
  			vgda_len = be32_to_cpu(p->vgda_len);
  			vgda_sector = be32_to_cpu(p->vgda_psn[0]);
  		} else {
  			snprintf(tmp, sizeof(tmp),
  				" unsupported AIX LVM version %d found
  ",
  				lvm_version);
  		}
  		strlcat(state->pp_buf, tmp, PAGE_SIZE);
  		put_dev_sector(sect);
  	}
  	if (vgda_sector && (d = read_part_sector(state, vgda_sector, &sect))) {
  		struct vgda *p = (struct vgda *)d;
  
  		numlvs = be16_to_cpu(p->numlvs);
  		put_dev_sector(sect);
  	}
  	lvip = kcalloc(state->limit, sizeof(struct lv_info), GFP_KERNEL);
  	if (!lvip)
  		return 0;
  	if (numlvs && (d = read_part_sector(state, vgda_sector + 1, &sect))) {
  		struct lvd *p = (struct lvd *)d;
  		int i;
  
  		n = alloc_lvn(state, vgda_sector + vgda_len - 33);
  		if (n) {
  			int foundlvs = 0;
  
  			for (i = 0; foundlvs < numlvs && i < state->limit; i += 1) {
  				lvip[i].pps_per_lv = be16_to_cpu(p[i].num_lps);
  				if (lvip[i].pps_per_lv)
  					foundlvs += 1;
  			}
  		}
  		put_dev_sector(sect);
  	}
  	pvd = alloc_pvd(state, vgda_sector + 17);
  	if (pvd) {
  		int numpps = be16_to_cpu(pvd->pp_count);
  		int psn_part1 = be32_to_cpu(pvd->psn_part1);
  		int i;
  		int cur_lv_ix = -1;
  		int next_lp_ix = 1;
  		int lp_ix;
  
  		for (i = 0; i < numpps; i += 1) {
  			struct ppe *p = pvd->ppe + i;
  			unsigned int lv_ix;
  
  			lp_ix = be16_to_cpu(p->lp_ix);
  			if (!lp_ix) {
  				next_lp_ix = 1;
  				continue;
  			}
  			lv_ix = be16_to_cpu(p->lv_ix) - 1;
  			if (lv_ix >= state->limit) {
  				cur_lv_ix = -1;
  				continue;
  			}
  			lvip[lv_ix].pps_found += 1;
  			if (lp_ix == 1) {
  				cur_lv_ix = lv_ix;
  				next_lp_ix = 1;
  			} else if (lv_ix != cur_lv_ix || lp_ix != next_lp_ix) {
  				next_lp_ix = 1;
  				continue;
  			}
  			if (lp_ix == lvip[lv_ix].pps_per_lv) {
  				char tmp[70];
  
  				put_partition(state, lv_ix + 1,
  				  (i + 1 - lp_ix) * pp_blocks_size + psn_part1,
  				  lvip[lv_ix].pps_per_lv * pp_blocks_size);
  				snprintf(tmp, sizeof(tmp), " <%s>
  ",
  					 n[lv_ix].name);
  				strlcat(state->pp_buf, tmp, PAGE_SIZE);
  				lvip[lv_ix].lv_is_contiguous = 1;
  				ret = 1;
  				next_lp_ix = 1;
  			} else
  				next_lp_ix += 1;
  		}
  		for (i = 0; i < state->limit; i += 1)
  			if (lvip[i].pps_found && !lvip[i].lv_is_contiguous)
  				pr_warn("partition %s (%u pp's found) is "
  					"not contiguous
  ",
  					n[i].name, lvip[i].pps_found);
  		kfree(pvd);
  	}
  	kfree(n);
  	kfree(lvip);
  	return ret;
  }