/*
   *   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
   */
  
  #include <linux/fs.h>
  #include <linux/quotaops.h>
  #include "jfs_incore.h"

  #include "jfs_inode.h"

  #include "jfs_superblock.h"
  #include "jfs_dmap.h"
  #include "jfs_extent.h"
  #include "jfs_debug.h"
  
  /*
   * forward references
   */
  static int extBalloc(struct inode *, s64, s64 *, s64 *);
  #ifdef _NOTYET
  static int extBrealloc(struct inode *, s64, s64, s64 *, s64 *);
  #endif
  static s64 extRoundDown(s64 nb);

  #define DPD(a)		(printk("(a): %d
  ",(a)))
  #define DPC(a)		(printk("(a): %c
  ",(a)))

  #define DPL1(a)					\
  {						\
  	if ((a) >> 32)				\
  		printk("(a): %x%08x  ",(a));	\
  	else					\
  		printk("(a): %x  ",(a) << 32);	\
  }
  #define DPL(a)					\
  {						\
  	if ((a) >> 32)				\
  		printk("(a): %x%08x
  ",(a));	\
  	else					\
  		printk("(a): %x
  ",(a) << 32);	\
  }

  #define DPD1(a)		(printk("(a): %d  ",(a)))
  #define DPX(a)		(printk("(a): %08x
  ",(a)))
  #define DPX1(a)		(printk("(a): %08x  ",(a)))
  #define DPS(a)		(printk("%s
  ",(a)))
  #define DPE(a)		(printk("
  ENTERING: %s
  ",(a)))
  #define DPE1(a)		(printk("
  ENTERING: %s",(a)))
  #define DPS1(a)		(printk("  %s  ",(a)))

  
  
  /*
   * NAME:	extAlloc()
   *

   * FUNCTION:	allocate an extent for a specified page range within a

   *		file.
   *
   * PARAMETERS:
   *	ip	- the inode of the file.
   *	xlen	- requested extent length.
   *	pno	- the starting page number with the file.
   *	xp	- pointer to an xad.  on entry, xad describes an
   *		  extent that is used as an allocation hint if the
   *		  xaddr of the xad is non-zero.  on successful exit,
   *		  the xad describes the newly allocated extent.

   *	abnr	- bool indicating whether the newly allocated extent

   *		  should be marked as allocated but not recorded.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.
   *	-ENOSPC	- insufficient disk resources.

   */
  int

  extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)

  {
  	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
  	s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
  	int rc;
  	int xflag;
  
  	/* This blocks if we are low on resources */
  	txBeginAnon(ip->i_sb);
  
  	/* Avoid race with jfs_commit_inode() */

  	mutex_lock(&JFS_IP(ip)->commit_mutex);

  
  	/* validate extent length */
  	if (xlen > MAXXLEN)
  		xlen = MAXXLEN;
  
  	/* get the page's starting extent offset */
  	xoff = pno << sbi->l2nbperpage;
  
  	/* check if an allocation hint was provided */
  	if ((hint = addressXAD(xp))) {
  		/* get the size of the extent described by the hint */
  		nxlen = lengthXAD(xp);
  
  		/* check if the hint is for the portion of the file
  		 * immediately previous to the current allocation
  		 * request and if hint extent has the same abnr
  		 * value as the current request.  if so, we can
  		 * extend the hint extent to include the current
  		 * extent if we can allocate the blocks immediately
  		 * following the hint extent.
  		 */
  		if (offsetXAD(xp) + nxlen == xoff &&

  		    abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))

  			xaddr = hint + nxlen;
  
  		/* adjust the hint to the last block of the extent */
  		hint += (nxlen - 1);
  	}
  
  	/* allocate the disk blocks for the extent.  initially, extBalloc()

  	 * will try to allocate disk blocks for the requested size (xlen).

  	 * if this fails (xlen contiguous free blocks not available), it'll

  	 * try to allocate a smaller number of blocks (producing a smaller
  	 * extent), with this smaller number of blocks consisting of the
  	 * requested number of blocks rounded down to the next smaller
  	 * power of 2 number (i.e. 16 -> 8).  it'll continue to round down
  	 * and retry the allocation until the number of blocks to allocate
  	 * is smaller than the number of blocks per page.
  	 */
  	nxlen = xlen;
  	if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {

  		mutex_unlock(&JFS_IP(ip)->commit_mutex);

  		return (rc);
  	}
  
  	/* Allocate blocks to quota. */

  	rc = dquot_alloc_block(ip, nxlen);
  	if (rc) {

  		dbFree(ip, nxaddr, (s64) nxlen);

  		mutex_unlock(&JFS_IP(ip)->commit_mutex);

  		return rc;

  	}
  
  	/* determine the value of the extent flag */

  	xflag = abnr ? XAD_NOTRECORDED : 0;

  	/* if we can extend the hint extent to cover the current request,

  	 * extend it.  otherwise, insert a new extent to
  	 * cover the current request.
  	 */
  	if (xaddr && xaddr == nxaddr)
  		rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
  	else
  		rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);

  	/* if the extend or insert failed,

  	 * free the newly allocated blocks and return the error.
  	 */
  	if (rc) {
  		dbFree(ip, nxaddr, nxlen);

  		dquot_free_block(ip, nxlen);

  		mutex_unlock(&JFS_IP(ip)->commit_mutex);

  		return (rc);
  	}
  
  	/* set the results of the extent allocation */
  	XADaddress(xp, nxaddr);
  	XADlength(xp, nxlen);
  	XADoffset(xp, xoff);
  	xp->flag = xflag;
  
  	mark_inode_dirty(ip);

  	mutex_unlock(&JFS_IP(ip)->commit_mutex);

  	/*
  	 * COMMIT_SyncList flags an anonymous tlock on page that is on
  	 * sync list.
  	 * We need to commit the inode to get the page written disk.
  	 */
  	if (test_and_clear_cflag(COMMIT_Synclist,ip))
  		jfs_commit_inode(ip, 0);
  
  	return (0);
  }
  
  
  #ifdef _NOTYET
  /*

   * NAME:	extRealloc()

   *

   * FUNCTION:	extend the allocation of a file extent containing a

   *		partial back last page.
   *
   * PARAMETERS:
   *	ip	- the inode of the file.
   *	cp	- cbuf for the partial backed last page.
   *	xlen	- request size of the resulting extent.
   *	xp	- pointer to an xad. on successful exit, the xad
   *		  describes the newly allocated extent.

   *	abnr	- bool indicating whether the newly allocated extent

   *		  should be marked as allocated but not recorded.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.
   *	-ENOSPC	- insufficient disk resources.

   */

  int extRealloc(struct inode *ip, s64 nxlen, xad_t * xp, bool abnr)

  {
  	struct super_block *sb = ip->i_sb;
  	s64 xaddr, xlen, nxaddr, delta, xoff;
  	s64 ntail, nextend, ninsert;
  	int rc, nbperpage = JFS_SBI(sb)->nbperpage;
  	int xflag;
  
  	/* This blocks if we are low on resources */
  	txBeginAnon(ip->i_sb);

  	mutex_lock(&JFS_IP(ip)->commit_mutex);

  	/* validate extent length */
  	if (nxlen > MAXXLEN)
  		nxlen = MAXXLEN;
  
  	/* get the extend (partial) page's disk block address and
  	 * number of blocks.
  	 */
  	xaddr = addressXAD(xp);
  	xlen = lengthXAD(xp);
  	xoff = offsetXAD(xp);
  
  	/* if the extend page is abnr and if the request is for

  	 * the extent to be allocated and recorded,

  	 * make the page allocated and recorded.
  	 */
  	if ((xp->flag & XAD_NOTRECORDED) && !abnr) {
  		xp->flag = 0;
  		if ((rc = xtUpdate(0, ip, xp)))
  			goto exit;
  	}
  
  	/* try to allocated the request number of blocks for the
  	 * extent.  dbRealloc() first tries to satisfy the request
  	 * by extending the allocation in place. otherwise, it will
  	 * try to allocate a new set of blocks large enough for the
  	 * request.  in satisfying a request, dbReAlloc() may allocate
  	 * less than what was request but will always allocate enough
  	 * space as to satisfy the extend page.
  	 */
  	if ((rc = extBrealloc(ip, xaddr, xlen, &nxlen, &nxaddr)))
  		goto exit;
  
  	/* Allocat blocks to quota. */

  	rc = dquot_alloc_block(ip, nxlen);
  	if (rc) {

  		dbFree(ip, nxaddr, (s64) nxlen);

  		mutex_unlock(&JFS_IP(ip)->commit_mutex);

  		return rc;

  	}
  
  	delta = nxlen - xlen;
  
  	/* check if the extend page is not abnr but the request is abnr
  	 * and the allocated disk space is for more than one page.  if this
  	 * is the case, there is a miss match of abnr between the extend page
  	 * and the one or more pages following the extend page.  as a result,
  	 * two extents will have to be manipulated. the first will be that
  	 * of the extent of the extend page and will be manipulated thru
  	 * an xtExtend() or an xtTailgate(), depending upon whether the
  	 * disk allocation occurred as an inplace extension.  the second
  	 * extent will be manipulated (created) through an xtInsert() and
  	 * will be for the pages following the extend page.
  	 */
  	if (abnr && (!(xp->flag & XAD_NOTRECORDED)) && (nxlen > nbperpage)) {
  		ntail = nbperpage;
  		nextend = ntail - xlen;
  		ninsert = nxlen - nbperpage;
  
  		xflag = XAD_NOTRECORDED;
  	} else {
  		ntail = nxlen;
  		nextend = delta;
  		ninsert = 0;
  
  		xflag = xp->flag;
  	}
  
  	/* if we were able to extend the disk allocation in place,
  	 * extend the extent.  otherwise, move the extent to a
  	 * new disk location.
  	 */
  	if (xaddr == nxaddr) {
  		/* extend the extent */
  		if ((rc = xtExtend(0, ip, xoff + xlen, (int) nextend, 0))) {
  			dbFree(ip, xaddr + xlen, delta);

  			dquot_free_block(ip, nxlen);

  			goto exit;
  		}
  	} else {
  		/*
  		 * move the extent to a new location:
  		 *
  		 * xtTailgate() accounts for relocated tail extent;
  		 */
  		if ((rc = xtTailgate(0, ip, xoff, (int) ntail, nxaddr, 0))) {
  			dbFree(ip, nxaddr, nxlen);

  			dquot_free_block(ip, nxlen);

  			goto exit;
  		}
  	}
  
  
  	/* check if we need to also insert a new extent */
  	if (ninsert) {
  		/* perform the insert.  if it fails, free the blocks
  		 * to be inserted and make it appear that we only did
  		 * the xtExtend() or xtTailgate() above.
  		 */
  		xaddr = nxaddr + ntail;
  		if (xtInsert (0, ip, xflag, xoff + ntail, (int) ninsert,
  			      &xaddr, 0)) {
  			dbFree(ip, xaddr, (s64) ninsert);
  			delta = nextend;
  			nxlen = ntail;
  			xflag = 0;
  		}
  	}
  
  	/* set the return results */
  	XADaddress(xp, nxaddr);
  	XADlength(xp, nxlen);
  	XADoffset(xp, xoff);
  	xp->flag = xflag;
  
  	mark_inode_dirty(ip);
  exit:

  	mutex_unlock(&JFS_IP(ip)->commit_mutex);

  	return (rc);
  }
  #endif			/* _NOTYET */
  
  
  /*

   * NAME:	extHint()

   *

   * FUNCTION:	produce an extent allocation hint for a file offset.

   *
   * PARAMETERS:
   *	ip	- the inode of the file.
   *	offset  - file offset for which the hint is needed.
   *	xp	- pointer to the xad that is to be filled in with
   *		  the hint.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.

   */
  int extHint(struct inode *ip, s64 offset, xad_t * xp)
  {
  	struct super_block *sb = ip->i_sb;

  	int nbperpage = JFS_SBI(sb)->nbperpage;

  	s64 prev;

  	int rc = 0;
  	s64 xaddr;
  	int xlen;
  	int xflag;

  
  	/* init the hint as "no hint provided" */
  	XADaddress(xp, 0);
  
  	/* determine the starting extent offset of the page previous
  	 * to the page containing the offset.
  	 */
  	prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;

  	/* if the offset is in the first page of the file, no hint provided.

  	 */
  	if (prev < 0)

  		goto out;

  	rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);

  	if ((rc == 0) && xlen) {
  		if (xlen != nbperpage) {
  			jfs_error(ip->i_sb, "extHint: corrupt xtree");
  			rc = -EIO;
  		}
  		XADaddress(xp, xaddr);
  		XADlength(xp, xlen);

  		XADoffset(xp, prev);

  		/*
  		 * only preserve the abnr flag within the xad flags
  		 * of the returned hint.
  		 */
  		xp->flag  = xflag & XAD_NOTRECORDED;
  	} else
  		rc = 0;

  out:
  	return (rc);

  }
  
  
  /*

   * NAME:	extRecord()

   *

   * FUNCTION:	change a page with a file from not recorded to recorded.

   *
   * PARAMETERS:
   *	ip	- inode of the file.
   *	cp	- cbuf of the file page.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.
   *	-ENOSPC	- insufficient disk resources.

   */
  int extRecord(struct inode *ip, xad_t * xp)
  {
  	int rc;
  
  	txBeginAnon(ip->i_sb);

  	mutex_lock(&JFS_IP(ip)->commit_mutex);

  
  	/* update the extent */
  	rc = xtUpdate(0, ip, xp);

  	mutex_unlock(&JFS_IP(ip)->commit_mutex);

  	return rc;
  }
  
  
  #ifdef _NOTYET
  /*

   * NAME:	extFill()

   *

   * FUNCTION:	allocate disk space for a file page that represents

   *		a file hole.
   *
   * PARAMETERS:
   *	ip	- the inode of the file.
   *	cp	- cbuf of the file page represent the hole.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.
   *	-ENOSPC	- insufficient disk resources.

   */
  int extFill(struct inode *ip, xad_t * xp)
  {
  	int rc, nbperpage = JFS_SBI(ip->i_sb)->nbperpage;

  	s64 blkno = offsetXAD(xp) >> ip->i_blkbits;

  //	assert(ISSPARSE(ip));

  
  	/* initialize the extent allocation hint */
  	XADaddress(xp, 0);
  
  	/* allocate an extent to fill the hole */

  	if ((rc = extAlloc(ip, nbperpage, blkno, xp, false)))

  		return (rc);
  
  	assert(lengthPXD(xp) == nbperpage);
  
  	return (0);
  }
  #endif			/* _NOTYET */
  
  
  /*
   * NAME:	extBalloc()
   *

   * FUNCTION:	allocate disk blocks to form an extent.

   *
   *		initially, we will try to allocate disk blocks for the

   *		requested size (nblocks).  if this fails (nblocks

   *		contiguous free blocks not available), we'll try to allocate

   *		a smaller number of blocks (producing a smaller extent), with
   *		this smaller number of blocks consisting of the requested
   *		number of blocks rounded down to the next smaller power of 2
   *		number (i.e. 16 -> 8).  we'll continue to round down and
   *		retry the allocation until the number of blocks to allocate
   *		is smaller than the number of blocks per page.

   *

   * PARAMETERS:
   *	ip	 - the inode of the file.
   *	hint	 - disk block number to be used as an allocation hint.
   *	*nblocks - pointer to an s64 value.  on entry, this value specifies
   *		   the desired number of block to be allocated. on successful
   *		   exit, this value is set to the number of blocks actually
   *		   allocated.
   *	blkno	 - pointer to a block address that is filled in on successful

   *		   return with the starting block number of the newly

   *		   allocated block range.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.
   *	-ENOSPC	- insufficient disk resources.

   */
  static int
  extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
  {
  	struct jfs_inode_info *ji = JFS_IP(ip);
  	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
  	s64 nb, nblks, daddr, max;
  	int rc, nbperpage = sbi->nbperpage;
  	struct bmap *bmp = sbi->bmap;
  	int ag;
  
  	/* get the number of blocks to initially attempt to allocate.
  	 * we'll first try the number of blocks requested unless this

  	 * number is greater than the maximum number of contiguous free

  	 * blocks in the map. in that case, we'll start off with the

  	 * maximum free.
  	 */
  	max = (s64) 1 << bmp->db_maxfreebud;
  	if (*nblocks >= max && *nblocks > nbperpage)
  		nb = nblks = (max > nbperpage) ? max : nbperpage;
  	else
  		nb = nblks = *nblocks;
  
  	/* try to allocate blocks */
  	while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
  		/* if something other than an out of space error,
  		 * stop and return this error.
  		 */
  		if (rc != -ENOSPC)
  			return (rc);
  
  		/* decrease the allocation request size */
  		nb = min(nblks, extRoundDown(nb));
  
  		/* give up if we cannot cover a page */
  		if (nb < nbperpage)
  			return (rc);
  	}
  
  	*nblocks = nb;
  	*blkno = daddr;
  
  	if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
  		ag = BLKTOAG(daddr, sbi);
  		spin_lock_irq(&ji->ag_lock);
  		if (ji->active_ag == -1) {
  			atomic_inc(&bmp->db_active[ag]);
  			ji->active_ag = ag;
  		} else if (ji->active_ag != ag) {
  			atomic_dec(&bmp->db_active[ji->active_ag]);
  			atomic_inc(&bmp->db_active[ag]);
  			ji->active_ag = ag;
  		}
  		spin_unlock_irq(&ji->ag_lock);
  	}
  
  	return (0);
  }
  
  
  #ifdef _NOTYET
  /*
   * NAME:	extBrealloc()
   *

   * FUNCTION:	attempt to extend an extent's allocation.

   *

   *		Initially, we will try to extend the extent's allocation
   *		in place.  If this fails, we'll try to move the extent
   *		to a new set of blocks.  If moving the extent, we initially

   *		will try to allocate disk blocks for the requested size

   *		(newnblks).  if this fails (new contiguous free blocks not

   *		available), we'll try to allocate a smaller number of

   *		blocks (producing a smaller extent), with this smaller
   *		number of blocks consisting of the requested number of
   *		blocks rounded down to the next smaller power of 2

   *		number (i.e. 16 -> 8).  We'll continue to round down and

   *		retry the allocation until the number of blocks to allocate
   *		is smaller than the number of blocks per page.

   *

   * PARAMETERS:
   *	ip	 - the inode of the file.

   *	blkno	 - starting block number of the extents current allocation.
   *	nblks	 - number of blocks within the extents current allocation.

   *	newnblks - pointer to a s64 value.  on entry, this value is the
   *		   the new desired extent size (number of blocks).  on
   *		   successful exit, this value is set to the extent's actual
   *		   new size (new number of blocks).
   *	newblkno - the starting block number of the extents new allocation.
   *
   * RETURN VALUES:

   *	0	- success
   *	-EIO	- i/o error.
   *	-ENOSPC	- insufficient disk resources.

   */
  static int
  extBrealloc(struct inode *ip,
  	    s64 blkno, s64 nblks, s64 * newnblks, s64 * newblkno)
  {
  	int rc;
  
  	/* try to extend in place */
  	if ((rc = dbExtend(ip, blkno, nblks, *newnblks - nblks)) == 0) {
  		*newblkno = blkno;
  		return (0);
  	} else {
  		if (rc != -ENOSPC)
  			return (rc);
  	}

  	/* in place extension not possible.

  	 * try to move the extent to a new set of blocks.
  	 */
  	return (extBalloc(ip, blkno, newnblks, newblkno));
  }
  #endif			/* _NOTYET */
  
  
  /*

   * NAME:	extRoundDown()

   *

   * FUNCTION:	round down a specified number of blocks to the next

   *		smallest power of 2 number.
   *
   * PARAMETERS:
   *	nb	- the inode of the file.
   *
   * RETURN VALUES:

   *	next smallest power of 2 number.

   */
  static s64 extRoundDown(s64 nb)
  {
  	int i;
  	u64 m, k;
  
  	for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
  		if (m & nb)
  			break;
  	}
  
  	i = 63 - i;
  	k = (u64) 1 << i;
  	k = ((k - 1) & nb) ? k : k >> 1;
  
  	return (k);
  }