/*
   *   Copyright (C) International Business Machines Corp., 2000-2004
   *
   *   This program is free software;  you can redistribute it and/or modify
   *   it under the terms of the GNU General Public License as published by
   *   the Free Software Foundation; either version 2 of the License, or
   *   (at your option) any later version.
   *
   *   This program is distributed in the hope that it will be useful,
   *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
   *   the GNU General Public License for more details.
   *
   *   You should have received a copy of the GNU General Public License
   *   along with this program;  if not, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  /*
   * Module: jfs_mount.c
   *
   * note: file system in transition to aggregate/fileset:
   *
   * file system mount is interpreted as the mount of aggregate,
   * if not already mounted, and mount of the single/only fileset in
   * the aggregate;
   *
   * a file system/aggregate is represented by an internal inode
   * (aka mount inode) initialized with aggregate superblock;
   * each vfs represents a fileset, and points to its "fileset inode
   * allocation map inode" (aka fileset inode):
   * (an aggregate itself is structured recursively as a filset:
   * an internal vfs is constructed and points to its "fileset inode
   * allocation map inode" (aka aggregate inode) where each inode
   * represents a fileset inode) so that inode number is mapped to
   * on-disk inode in uniform way at both aggregate and fileset level;
   *
   * each vnode/inode of a fileset is linked to its vfs (to facilitate
   * per fileset inode operations, e.g., unmount of a fileset, etc.);
   * each inode points to the mount inode (to facilitate access to
   * per aggregate information, e.g., block size, etc.) as well as
   * its file set inode.
   *
   *   aggregate
   *   ipmnt
   *   mntvfs -> fileset ipimap+ -> aggregate ipbmap -> aggregate ipaimap;
   *             fileset vfs     -> vp(1) <-> ... <-> vp(n) <->vproot;
   */
  
  #include <linux/fs.h>
  #include <linux/buffer_head.h>
  
  #include "jfs_incore.h"
  #include "jfs_filsys.h"
  #include "jfs_superblock.h"
  #include "jfs_dmap.h"
  #include "jfs_imap.h"
  #include "jfs_metapage.h"
  #include "jfs_debug.h"
  
  
  /*
   * forward references
   */
  static int chkSuper(struct super_block *);
  static int logMOUNT(struct super_block *sb);
  
  /*
   * NAME:	jfs_mount(sb)
   *
   * FUNCTION:	vfs_mount()
   *
   * PARAMETER:	sb	- super block
   *
   * RETURN:	-EBUSY	- device already mounted or open for write
   *		-EBUSY	- cvrdvp already mounted;
   *		-EBUSY	- mount table full
   *		-ENOTDIR- cvrdvp not directory on a device mount
   *		-ENXIO	- device open failure
   */
  int jfs_mount(struct super_block *sb)
  {
  	int rc = 0;		/* Return code */
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	struct inode *ipaimap = NULL;
  	struct inode *ipaimap2 = NULL;
  	struct inode *ipimap = NULL;
  	struct inode *ipbmap = NULL;
  
  	/*
  	 * read/validate superblock
  	 * (initialize mount inode from the superblock)
  	 */
  	if ((rc = chkSuper(sb))) {
  		goto errout20;
  	}
  
  	ipaimap = diReadSpecial(sb, AGGREGATE_I, 0);
  	if (ipaimap == NULL) {
  		jfs_err("jfs_mount: Failed to read AGGREGATE_I");
  		rc = -EIO;
  		goto errout20;
  	}
  	sbi->ipaimap = ipaimap;
  
  	jfs_info("jfs_mount: ipaimap:0x%p", ipaimap);
  
  	/*
  	 * initialize aggregate inode allocation map
  	 */
  	if ((rc = diMount(ipaimap))) {
  		jfs_err("jfs_mount: diMount(ipaimap) failed w/rc = %d", rc);
  		goto errout21;
  	}
  
  	/*
  	 * open aggregate block allocation map
  	 */
  	ipbmap = diReadSpecial(sb, BMAP_I, 0);
  	if (ipbmap == NULL) {
  		rc = -EIO;
  		goto errout22;
  	}
  
  	jfs_info("jfs_mount: ipbmap:0x%p", ipbmap);
  
  	sbi->ipbmap = ipbmap;
  
  	/*
  	 * initialize aggregate block allocation map
  	 */
  	if ((rc = dbMount(ipbmap))) {
  		jfs_err("jfs_mount: dbMount failed w/rc = %d", rc);
  		goto errout22;
  	}
  
  	/*
  	 * open the secondary aggregate inode allocation map
  	 *
  	 * This is a duplicate of the aggregate inode allocation map.
  	 *
  	 * hand craft a vfs in the same fashion as we did to read ipaimap.
  	 * By adding INOSPEREXT (32) to the inode number, we are telling
  	 * diReadSpecial that we are reading from the secondary aggregate
  	 * inode table.  This also creates a unique entry in the inode hash
  	 * table.
  	 */
  	if ((sbi->mntflag & JFS_BAD_SAIT) == 0) {
  		ipaimap2 = diReadSpecial(sb, AGGREGATE_I, 1);
  		if (!ipaimap2) {
  			jfs_err("jfs_mount: Failed to read AGGREGATE_I");
  			rc = -EIO;
  			goto errout35;
  		}
  		sbi->ipaimap2 = ipaimap2;
  
  		jfs_info("jfs_mount: ipaimap2:0x%p", ipaimap2);
  
  		/*
  		 * initialize secondary aggregate inode allocation map
  		 */
  		if ((rc = diMount(ipaimap2))) {
  			jfs_err("jfs_mount: diMount(ipaimap2) failed, rc = %d",
  				rc);
  			goto errout35;
  		}
  	} else
  		/* Secondary aggregate inode table is not valid */
  		sbi->ipaimap2 = NULL;
  
  	/*
  	 *	mount (the only/single) fileset
  	 */
  	/*
  	 * open fileset inode allocation map (aka fileset inode)
  	 */
  	ipimap = diReadSpecial(sb, FILESYSTEM_I, 0);
  	if (ipimap == NULL) {
  		jfs_err("jfs_mount: Failed to read FILESYSTEM_I");
  		/* open fileset secondary inode allocation map */
  		rc = -EIO;
  		goto errout40;
  	}
  	jfs_info("jfs_mount: ipimap:0x%p", ipimap);
  
  	/* map further access of per fileset inodes by the fileset inode */
  	sbi->ipimap = ipimap;
  
  	/* initialize fileset inode allocation map */
  	if ((rc = diMount(ipimap))) {
  		jfs_err("jfs_mount: diMount failed w/rc = %d", rc);
  		goto errout41;
  	}
  
  	goto out;
  
  	/*
  	 *	unwind on error
  	 */
        errout41:		/* close fileset inode allocation map inode */
  	diFreeSpecial(ipimap);
  
        errout40:		/* fileset closed */
  
  	/* close secondary aggregate inode allocation map */
  	if (ipaimap2) {
  		diUnmount(ipaimap2, 1);
  		diFreeSpecial(ipaimap2);
  	}
  
        errout35:
  
  	/* close aggregate block allocation map */
  	dbUnmount(ipbmap, 1);
  	diFreeSpecial(ipbmap);
  
        errout22:		/* close aggregate inode allocation map */
  
  	diUnmount(ipaimap, 1);
  
        errout21:		/* close aggregate inodes */
  	diFreeSpecial(ipaimap);
        errout20:		/* aggregate closed */
  
        out:
  
  	if (rc)
  		jfs_err("Mount JFS Failure: %d", rc);
  
  	return rc;
  }
  
  /*
   * NAME:	jfs_mount_rw(sb, remount)
   *
   * FUNCTION:	Completes read-write mount, or remounts read-only volume
   *		as read-write
   */
  int jfs_mount_rw(struct super_block *sb, int remount)
  {
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	int rc;
  
  	/*
  	 * If we are re-mounting a previously read-only volume, we want to
  	 * re-read the inode and block maps, since fsck.jfs may have updated
  	 * them.
  	 */
  	if (remount) {
  		if (chkSuper(sb) || (sbi->state != FM_CLEAN))
  			return -EINVAL;
  
  		truncate_inode_pages(sbi->ipimap->i_mapping, 0);
  		truncate_inode_pages(sbi->ipbmap->i_mapping, 0);
  		diUnmount(sbi->ipimap, 1);
  		if ((rc = diMount(sbi->ipimap))) {
  			jfs_err("jfs_mount_rw: diMount failed!");
  			return rc;
  		}
  
  		dbUnmount(sbi->ipbmap, 1);
  		if ((rc = dbMount(sbi->ipbmap))) {
  			jfs_err("jfs_mount_rw: dbMount failed!");
  			return rc;
  		}
  	}
  
  	/*
  	 * open/initialize log
  	 */
  	if ((rc = lmLogOpen(sb)))
  		return rc;
  
  	/*
  	 * update file system superblock;
  	 */
  	if ((rc = updateSuper(sb, FM_MOUNT))) {
  		jfs_err("jfs_mount: updateSuper failed w/rc = %d", rc);
  		lmLogClose(sb);
  		return rc;
  	}
  
  	/*
  	 * write MOUNT log record of the file system
  	 */
  	logMOUNT(sb);
  
  	return rc;
  }
  
  /*
   *	chkSuper()
   *
   * validate the superblock of the file system to be mounted and
   * get the file system parameters.
   *
   * returns
   *	0 with fragsize set if check successful
   *	error code if not successful
   */
  static int chkSuper(struct super_block *sb)
  {
  	int rc = 0;
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	struct jfs_superblock *j_sb;
  	struct buffer_head *bh;
  	int AIM_bytesize, AIT_bytesize;
  	int expected_AIM_bytesize, expected_AIT_bytesize;
  	s64 AIM_byte_addr, AIT_byte_addr, fsckwsp_addr;
  	s64 byte_addr_diff0, byte_addr_diff1;
  	s32 bsize;
  
  	if ((rc = readSuper(sb, &bh)))
  		return rc;
  	j_sb = (struct jfs_superblock *)bh->b_data;
  
  	/*
  	 * validate superblock
  	 */
  	/* validate fs signature */
  	if (strncmp(j_sb->s_magic, JFS_MAGIC, 4) ||
  	    le32_to_cpu(j_sb->s_version) > JFS_VERSION) {
  		rc = -EINVAL;
  		goto out;
  	}
  
  	bsize = le32_to_cpu(j_sb->s_bsize);
  #ifdef _JFS_4K
  	if (bsize != PSIZE) {
  		jfs_err("Currently only 4K block size supported!");
  		rc = -EINVAL;
  		goto out;
  	}
  #endif				/* _JFS_4K */
  
  	jfs_info("superblock: flag:0x%08x state:0x%08x size:0x%Lx",
  		 le32_to_cpu(j_sb->s_flag), le32_to_cpu(j_sb->s_state),
  		 (unsigned long long) le64_to_cpu(j_sb->s_size));
  
  	/* validate the descriptors for Secondary AIM and AIT */
  	if ((j_sb->s_flag & cpu_to_le32(JFS_BAD_SAIT)) !=
  	    cpu_to_le32(JFS_BAD_SAIT)) {
  		expected_AIM_bytesize = 2 * PSIZE;
  		AIM_bytesize = lengthPXD(&(j_sb->s_aim2)) * bsize;
  		expected_AIT_bytesize = 4 * PSIZE;
  		AIT_bytesize = lengthPXD(&(j_sb->s_ait2)) * bsize;
  		AIM_byte_addr = addressPXD(&(j_sb->s_aim2)) * bsize;
  		AIT_byte_addr = addressPXD(&(j_sb->s_ait2)) * bsize;
  		byte_addr_diff0 = AIT_byte_addr - AIM_byte_addr;
  		fsckwsp_addr = addressPXD(&(j_sb->s_fsckpxd)) * bsize;
  		byte_addr_diff1 = fsckwsp_addr - AIT_byte_addr;
  		if ((AIM_bytesize != expected_AIM_bytesize) ||
  		    (AIT_bytesize != expected_AIT_bytesize) ||
  		    (byte_addr_diff0 != AIM_bytesize) ||
  		    (byte_addr_diff1 <= AIT_bytesize))
  			j_sb->s_flag |= cpu_to_le32(JFS_BAD_SAIT);
  	}
  
  	if ((j_sb->s_flag & cpu_to_le32(JFS_GROUPCOMMIT)) !=
  	    cpu_to_le32(JFS_GROUPCOMMIT))
  		j_sb->s_flag |= cpu_to_le32(JFS_GROUPCOMMIT);
  
  	/* validate fs state */
  	if (j_sb->s_state != cpu_to_le32(FM_CLEAN) &&
  	    !(sb->s_flags & MS_RDONLY)) {
  		jfs_err("jfs_mount: Mount Failure: File System Dirty.");
  		rc = -EINVAL;
  		goto out;
  	}
  
  	sbi->state = le32_to_cpu(j_sb->s_state);
  	sbi->mntflag = le32_to_cpu(j_sb->s_flag);
  
  	/*
  	 * JFS always does I/O by 4K pages.  Don't tell the buffer cache
  	 * that we use anything else (leave s_blocksize alone).
  	 */
  	sbi->bsize = bsize;
  	sbi->l2bsize = le16_to_cpu(j_sb->s_l2bsize);
  
  	/*
  	 * For now, ignore s_pbsize, l2bfactor.  All I/O going through buffer
  	 * cache.
  	 */
  	sbi->nbperpage = PSIZE >> sbi->l2bsize;
  	sbi->l2nbperpage = L2PSIZE - sbi->l2bsize;
  	sbi->l2niperblk = sbi->l2bsize - L2DISIZE;
  	if (sbi->mntflag & JFS_INLINELOG)
  		sbi->logpxd = j_sb->s_logpxd;
  	else {
  		sbi->logdev = new_decode_dev(le32_to_cpu(j_sb->s_logdev));
  		memcpy(sbi->uuid, j_sb->s_uuid, sizeof(sbi->uuid));
  		memcpy(sbi->loguuid, j_sb->s_loguuid, sizeof(sbi->uuid));
  	}
  	sbi->fsckpxd = j_sb->s_fsckpxd;
  	sbi->ait2 = j_sb->s_ait2;
  
        out:
  	brelse(bh);
  	return rc;
  }
  
  
  /*
   *	updateSuper()
   *
   * update synchronously superblock if it is mounted read-write.
   */
  int updateSuper(struct super_block *sb, uint state)
  {
  	struct jfs_superblock *j_sb;
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	struct buffer_head *bh;
  	int rc;
  
  	if (sbi->flag & JFS_NOINTEGRITY) {
  		if (state == FM_DIRTY) {
  			sbi->p_state = state;
  			return 0;
  		} else if (state == FM_MOUNT) {
  			sbi->p_state = sbi->state;
  			state = FM_DIRTY;
  		} else if (state == FM_CLEAN) {
  			state = sbi->p_state;
  		} else
  			jfs_err("updateSuper: bad state");
  	} else if (sbi->state == FM_DIRTY)
  		return 0;
  
  	if ((rc = readSuper(sb, &bh)))
  		return rc;
  
  	j_sb = (struct jfs_superblock *)bh->b_data;
  
  	j_sb->s_state = cpu_to_le32(state);
  	sbi->state = state;
  
  	if (state == FM_MOUNT) {
  		/* record log's dev_t and mount serial number */
  		j_sb->s_logdev = cpu_to_le32(new_encode_dev(sbi->log->bdev->bd_dev));
  		j_sb->s_logserial = cpu_to_le32(sbi->log->serial);
  	} else if (state == FM_CLEAN) {
  		/*
  		 * If this volume is shared with OS/2, OS/2 will need to
  		 * recalculate DASD usage, since we don't deal with it.
  		 */
  		if (j_sb->s_flag & cpu_to_le32(JFS_DASD_ENABLED))
  			j_sb->s_flag |= cpu_to_le32(JFS_DASD_PRIME);
  	}
  
  	mark_buffer_dirty(bh);
  	sync_dirty_buffer(bh);
  	brelse(bh);
  
  	return 0;
  }
  
  
  /*
   *	readSuper()
   *
   * read superblock by raw sector address
   */
  int readSuper(struct super_block *sb, struct buffer_head **bpp)
  {
  	/* read in primary superblock */
  	*bpp = sb_bread(sb, SUPER1_OFF >> sb->s_blocksize_bits);
  	if (*bpp)
  		return 0;
  
  	/* read in secondary/replicated superblock */
  	*bpp = sb_bread(sb, SUPER2_OFF >> sb->s_blocksize_bits);
  	if (*bpp)
  		return 0;
  
  	return -EIO;
  }
  
  
  /*
   *	logMOUNT()
   *
   * function: write a MOUNT log record for file system.
   *
   * MOUNT record keeps logredo() from processing log records
   * for this file system past this point in log.
   * it is harmless if mount fails.
   *
   * note: MOUNT record is at aggregate level, not at fileset level,
   * since log records of previous mounts of a fileset
   * (e.g., AFTER record of extent allocation) have to be processed
   * to update block allocation map at aggregate level.
   */
  static int logMOUNT(struct super_block *sb)
  {
  	struct jfs_log *log = JFS_SBI(sb)->log;
  	struct lrd lrd;
  
  	lrd.logtid = 0;
  	lrd.backchain = 0;
  	lrd.type = cpu_to_le16(LOG_MOUNT);
  	lrd.length = 0;
  	lrd.aggregate = cpu_to_le32(new_encode_dev(sb->s_bdev->bd_dev));
  	lmLog(log, NULL, &lrd, NULL);
  
  	return 0;
  }