patch-2.4.20 linux-2.4.20/fs/jfs/jfs_extent.c

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diff -urN linux-2.4.19/fs/jfs/jfs_extent.c linux-2.4.20/fs/jfs/jfs_extent.c
@@ -0,0 +1,655 @@
+/*
+ *   Copyright (c) International Business Machines Corp., 2000-2002
+ *
+ *   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 "jfs_incore.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);
+
+/*
+ * external references
+ */
+extern int dbExtend(struct inode *, s64, s64, s64);
+extern int jfs_commit_inode(struct inode *, int);
+
+
+#define DPD(a)          (printk("(a): %d\n",(a)))
+#define DPC(a)          (printk("(a): %c\n",(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\n",(a));	\
+	else					\
+		printk("(a): %x\n",(a) << 32);	\
+}
+
+#define DPD1(a)         (printk("(a): %d  ",(a)))
+#define DPX(a)          (printk("(a): %08x\n",(a)))
+#define DPX1(a)         (printk("(a): %08x  ",(a)))
+#define DPS(a)          (printk("%s\n",(a)))
+#define DPE(a)          (printk("\nENTERING: %s\n",(a)))
+#define DPE1(a)          (printk("\nENTERING: %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	- boolean_t 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, boolean_t abnr)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
+	int rc, nbperpage;
+	int xflag;
+
+	/* This blocks if we are low on resources */
+	txBeginAnon(ip->i_sb);
+
+	/* Avoid race with jfs_commit_inode() */
+	down(&JFS_IP(ip)->commit_sem);
+
+	/* validate extent length */
+	if (xlen > MAXXLEN)
+		xlen = MAXXLEN;
+
+	/* get the number of blocks per page */
+	nbperpage = sbi->nbperpage;
+
+	/* 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 contigious free blocks not avaliable), 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))) {
+		up(&JFS_IP(ip)->commit_sem);
+		return (rc);
+	}
+
+	/* determine the value of the extent flag */
+	xflag = (abnr == TRUE) ? 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);
+		up(&JFS_IP(ip)->commit_sem);
+		return (rc);
+	}
+
+	/* update the number of blocks allocated to the file */
+	ip->i_blocks += LBLK2PBLK(ip->i_sb, nxlen);
+
+	/* set the results of the extent allocation */
+	XADaddress(xp, nxaddr);
+	XADlength(xp, nxlen);
+	XADoffset(xp, xoff);
+	xp->flag = xflag;
+
+	mark_inode_dirty(ip);
+
+	up(&JFS_IP(ip)->commit_sem);
+	/*
+	 * 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	- boolean_t 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, boolean_t 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);
+
+	down(&JFS_IP(ip)->commit_sem);
+	/* 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;
+
+	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);
+			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);
+			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;
+		}
+	}
+
+	/* update the inode with the number of blocks allocated */
+	ip->i_blocks += LBLK2PBLK(sb, delta);
+
+	/* set the return results */
+	XADaddress(xp, nxaddr);
+	XADlength(xp, nxlen);
+	XADoffset(xp, xoff);
+	xp->flag = xflag;
+
+	mark_inode_dirty(ip);
+exit:
+	up(&JFS_IP(ip)->commit_sem);
+	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;
+	struct xadlist xadl;
+	struct lxdlist lxdl;
+	lxd_t lxd;
+	s64 prev;
+	int rc, nbperpage = JFS_SBI(sb)->nbperpage;
+
+	/* 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 offsets in the first page of the file,
+	 * no hint provided.
+	 */
+	if (prev < 0)
+		return (0);
+
+	/* prepare to lookup the previous page's extent info */
+	lxdl.maxnlxd = 1;
+	lxdl.nlxd = 1;
+	lxdl.lxd = &lxd;
+	LXDoffset(&lxd, prev)
+	    LXDlength(&lxd, nbperpage);
+
+	xadl.maxnxad = 1;
+	xadl.nxad = 0;
+	xadl.xad = xp;
+
+	/* perform the lookup */
+	if ((rc = xtLookupList(ip, &lxdl, &xadl, 0)))
+		return (rc);
+
+	/* check if not extent exists for the previous page.  
+	 * this is possible for sparse files.
+	 */
+	if (xadl.nxad == 0) {
+//              assert(ISSPARSE(ip));
+		return (0);
+	}
+
+	/* only preserve the abnr flag within the xad flags
+	 * of the returned hint.
+	 */
+	xp->flag &= XAD_NOTRECORDED;
+
+	assert(xadl.nxad == 1);
+	assert(lengthXAD(xp) == nbperpage);
+
+	return (0);
+}
+
+
+/*
+ * 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);
+
+	down(&JFS_IP(ip)->commit_sem);
+
+	/* update the extent */
+	rc = xtUpdate(0, ip, xp);
+
+	up(&JFS_IP(ip)->commit_sem);
+	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_blksize;
+
+//      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 
+ *		contigious free blocks not avaliable), 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 contigious 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))) {
+		/* 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);
+		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;
+		}
+	}
+
+	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
+ *		(nnew).  if this fails 	(nnew contigious free blocks not
+ *		avaliable), 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);
+}
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