jfs_imap.c

linux 内核源代码

		iagp = (struct iag *) mp->data;

		/* set the ag number if this a brand new iag
		 */
		iagp->agstart =
		    cpu_to_le64(AGTOBLK(agno, imap->im_ipimap));
	} else {
		/* read the iag.
		 */
		IREAD_LOCK(imap->im_ipimap, RDWRLOCK_IMAP);
		if ((rc = diIAGRead(imap, iagno, &mp))) {
			IREAD_UNLOCK(imap->im_ipimap);
			jfs_error(ip->i_sb, "diAllocExt: error reading iag");
			return rc;
		}
		iagp = (struct iag *) mp->data;
	}

	/* using the free extent summary map, find a free extent.
	 */
	for (sword = 0;; sword++) {
		if (sword >= SMAPSZ) {
			release_metapage(mp);
			IREAD_UNLOCK(imap->im_ipimap);
			jfs_error(ip->i_sb,
				  "diAllocExt: free ext summary map not found");
			return -EIO;
		}
		if (~iagp->extsmap[sword])
			break;
	}

	/* determine the extent number of the free extent.
	 */
	rem = diFindFree(le32_to_cpu(iagp->extsmap[sword]), 0);
	if (rem >= EXTSPERSUM) {
		release_metapage(mp);
		IREAD_UNLOCK(imap->im_ipimap);
		jfs_error(ip->i_sb, "diAllocExt: free extent not found");
		return -EIO;
	}
	extno = (sword << L2EXTSPERSUM) + rem;

	/* initialize the new extent.
	 */
	rc = diNewExt(imap, iagp, extno);
	IREAD_UNLOCK(imap->im_ipimap);
	if (rc) {
		/* something bad happened.  if a new iag was allocated,
		 * place it back on the inode map's iag free list, and
		 * clear the ag number information.
		 */
		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
			IAGFREE_LOCK(imap);
			iagp->iagfree = cpu_to_le32(imap->im_freeiag);
			imap->im_freeiag = iagno;
			IAGFREE_UNLOCK(imap);
		}
		write_metapage(mp);
		return (rc);
	}

	/* set the results of the allocation and write the iag.
	 */
	diInitInode(ip, iagno, extno << L2INOSPEREXT, extno, iagp);

	write_metapage(mp);

	return (0);
}


/*
 * NAME:	diAllocBit(imap,iagp,ino)
 *
 * FUNCTION:	allocate a backed inode from an iag.
 *
 *		this routine performs the mechanics of allocating a
 *		specified inode from a backed extent.
 *
 *		if the inode to be allocated represents the last free
 *		inode within the iag, the iag will be removed from the
 *		ag free inode list.
 *
 *		a careful update approach is used to provide consistency
 *		in the face of updates to multiple buffers.  under this
 *		approach, all required buffers are obtained before making
 *		any updates and are held all are updates are complete.
 *
 * PRE CONDITION: Already have buffer lock on iagp.  Already have AG lock on
 *	this AG.  Must have read lock on imap inode.
 *
 * PARAMETERS:
 *	imap	- pointer to inode map control structure.
 *	iagp	- pointer to iag.
 *	ino	- inode number to be allocated within the iag.
 *
 * RETURN VALUES:
 *	0	- success.
 *	-ENOSPC	- insufficient disk resources.
 *	-EIO	- i/o error.
 */
static int diAllocBit(struct inomap * imap, struct iag * iagp, int ino)
{
	int extno, bitno, agno, sword, rc;
	struct metapage *amp = NULL, *bmp = NULL;
	struct iag *aiagp = NULL, *biagp = NULL;
	u32 mask;

	/* check if this is the last free inode within the iag.
	 * if so, it will have to be removed from the ag free
	 * inode list, so get the iags preceeding and following
	 * it on the list.
	 */
	if (iagp->nfreeinos == cpu_to_le32(1)) {
		if ((int) le32_to_cpu(iagp->inofreefwd) >= 0) {
			if ((rc =
			     diIAGRead(imap, le32_to_cpu(iagp->inofreefwd),
				       &amp)))
				return (rc);
			aiagp = (struct iag *) amp->data;
		}

		if ((int) le32_to_cpu(iagp->inofreeback) >= 0) {
			if ((rc =
			     diIAGRead(imap,
				       le32_to_cpu(iagp->inofreeback),
				       &bmp))) {
				if (amp)
					release_metapage(amp);
				return (rc);
			}
			biagp = (struct iag *) bmp->data;
		}
	}

	/* get the ag number, extent number, inode number within
	 * the extent.
	 */
	agno = BLKTOAG(le64_to_cpu(iagp->agstart), JFS_SBI(imap->im_ipimap->i_sb));
	extno = ino >> L2INOSPEREXT;
	bitno = ino & (INOSPEREXT - 1);

	/* compute the mask for setting the map.
	 */
	mask = HIGHORDER >> bitno;

	/* the inode should be free and backed.
	 */
	if (((le32_to_cpu(iagp->pmap[extno]) & mask) != 0) ||
	    ((le32_to_cpu(iagp->wmap[extno]) & mask) != 0) ||
	    (addressPXD(&iagp->inoext[extno]) == 0)) {
		if (amp)
			release_metapage(amp);
		if (bmp)
			release_metapage(bmp);

		jfs_error(imap->im_ipimap->i_sb,
			  "diAllocBit: iag inconsistent");
		return -EIO;
	}

	/* mark the inode as allocated in the working map.
	 */
	iagp->wmap[extno] |= cpu_to_le32(mask);

	/* check if all inodes within the extent are now
	 * allocated.  if so, update the free inode summary
	 * map to reflect this.
	 */
	if (iagp->wmap[extno] == cpu_to_le32(ONES)) {
		sword = extno >> L2EXTSPERSUM;
		bitno = extno & (EXTSPERSUM - 1);
		iagp->inosmap[sword] |= cpu_to_le32(HIGHORDER >> bitno);
	}

	/* if this was the last free inode in the iag, remove the
	 * iag from the ag free inode list.
	 */
	if (iagp->nfreeinos == cpu_to_le32(1)) {
		if (amp) {
			aiagp->inofreeback = iagp->inofreeback;
			write_metapage(amp);
		}

		if (bmp) {
			biagp->inofreefwd = iagp->inofreefwd;
			write_metapage(bmp);
		} else {
			imap->im_agctl[agno].inofree =
			    le32_to_cpu(iagp->inofreefwd);
		}
		iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
	}

	/* update the free inode count at the iag, ag, inode
	 * map levels.
	 */
	iagp->nfreeinos = cpu_to_le32(le32_to_cpu(iagp->nfreeinos) - 1);
	imap->im_agctl[agno].numfree -= 1;
	atomic_dec(&imap->im_numfree);

	return (0);
}


/*
 * NAME:	diNewExt(imap,iagp,extno)
 *
 * FUNCTION:	initialize a new extent of inodes for an iag, allocating
 *		the first inode of the extent for use for the current
 *		allocation request.
 *
 *		disk resources are allocated for the new extent of inodes
 *		and the inodes themselves are initialized to reflect their
 *		existence within the extent (i.e. their inode numbers and
 *		inode extent addresses are set) and their initial state
 *		(mode and link count are set to zero).
 *
 *		if the iag is new, it is not yet on an ag extent free list
 *		but will now be placed on this list.
 *
 *		if the allocation of the new extent causes the iag to
 *		have no free extent, the iag will be removed from the
 *		ag extent free list.
 *
 *		if the iag has no free backed inodes, it will be placed
 *		on the ag free inode list, since the addition of the new
 *		extent will now cause it to have free inodes.
 *
 *		a careful update approach is used to provide consistency
 *		(i.e. list consistency) in the face of updates to multiple
 *		buffers.  under this approach, all required buffers are
 *		obtained before making any updates and are held until all
 *		updates are complete.
 *
 * PRE CONDITION: Already have buffer lock on iagp.  Already have AG lock on
 *	this AG.  Must have read lock on imap inode.
 *
 * PARAMETERS:
 *	imap	- pointer to inode map control structure.
 *	iagp	- pointer to iag.
 *	extno	- extent number.
 *
 * RETURN VALUES:
 *	0	- success.
 *	-ENOSPC	- insufficient disk resources.
 *	-EIO	- i/o error.
 */
static int diNewExt(struct inomap * imap, struct iag * iagp, int extno)
{
	int agno, iagno, fwd, back, freei = 0, sword, rc;
	struct iag *aiagp = NULL, *biagp = NULL, *ciagp = NULL;
	struct metapage *amp, *bmp, *cmp, *dmp;
	struct inode *ipimap;
	s64 blkno, hint;
	int i, j;
	u32 mask;
	ino_t ino;
	struct dinode *dp;
	struct jfs_sb_info *sbi;

	/* better have free extents.
	 */
	if (!iagp->nfreeexts) {
		jfs_error(imap->im_ipimap->i_sb, "diNewExt: no free extents");
		return -EIO;
	}

	/* get the inode map inode.
	 */
	ipimap = imap->im_ipimap;
	sbi = JFS_SBI(ipimap->i_sb);

	amp = bmp = cmp = NULL;

	/* get the ag and iag numbers for this iag.
	 */
	agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
	iagno = le32_to_cpu(iagp->iagnum);

	/* check if this is the last free extent within the
	 * iag.  if so, the iag must be removed from the ag
	 * free extent list, so get the iags preceeding and
	 * following the iag on this list.
	 */
	if (iagp->nfreeexts == cpu_to_le32(1)) {
		if ((fwd = le32_to_cpu(iagp->extfreefwd)) >= 0) {
			if ((rc = diIAGRead(imap, fwd, &amp)))
				return (rc);
			aiagp = (struct iag *) amp->data;
		}

		if ((back = le32_to_cpu(iagp->extfreeback)) >= 0) {
			if ((rc = diIAGRead(imap, back, &bmp)))
				goto error_out;
			biagp = (struct iag *) bmp->data;
		}
	} else {
		/* the iag has free extents.  if all extents are free
		 * (as is the case for a newly allocated iag), the iag
		 * must be added to the ag free extent list, so get
		 * the iag at the head of the list in preparation for
		 * adding this iag to this list.
		 */
		fwd = back = -1;
		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
			if ((fwd = imap->im_agctl[agno].extfree) >= 0) {
				if ((rc = diIAGRead(imap, fwd, &amp)))
					goto error_out;
				aiagp = (struct iag *) amp->data;
			}
		}
	}

	/* check if the iag has no free inodes.  if so, the iag
	 * will have to be added to the ag free inode list, so get
	 * the iag at the head of the list in preparation for
	 * adding this iag to this list.  in doing this, we must
	 * check if we already have the iag at the head of
	 * the list in hand.
	 */
	if (iagp->nfreeinos == 0) {
		freei = imap->im_agctl[agno].inofree;

		if (freei >= 0) {
			if (freei == fwd) {
				ciagp = aiagp;
			} else if (freei == back) {
				ciagp = biagp;
			} else {
				if ((rc = diIAGRead(imap, freei, &cmp)))
					goto error_out;
				ciagp = (struct iag *) cmp->data;
			}
			if (ciagp == NULL) {
				jfs_error(imap->im_ipimap->i_sb,
					  "diNewExt: ciagp == NULL");
				rc = -EIO;
				goto error_out;
			}
		}
	}

	/* allocate disk space for the inode extent.
	 */
	if ((extno == 0) || (addressPXD(&iagp->inoext[extno - 1]) == 0))
		hint = ((s64) agno << sbi->bmap->db_agl2size) - 1;
	else
		hint = addressPXD(&iagp->inoext[extno - 1]) +
		    lengthPXD(&iagp->inoext[extno - 1]) - 1;

	if ((rc = dbAlloc(ipimap, hint, (s64) imap->im_nbperiext, &blkno)))
		goto error_out;

	/* compute the inode number of the first inode within the
	 * extent.
	 */
	ino = (iagno << L2INOSPERIAG) + (extno << L2INOSPEREXT);

	/* initialize the inodes within the newly allocated extent a
	 * page at a time.
	 */
	for (i = 0; i < imap->im_nbperiext; i += sbi->nbperpage) {
		/* get a buffer for this page of disk inodes.
		 */
		dmp = get_metapage(ipimap, blkno + i, PSIZE, 1);
		if (dmp == NULL) {
			rc = -EIO;
			goto error_out;
		}
		dp = (struct dinode *) dmp->data;

		/* initialize the inode number, mode, link count and
		 * inode extent address.
		 */
		for (j = 0; j < INOSPERPAGE; j++, dp++, ino++) {
			dp->di_inostamp = cpu_to_le32(sbi->inostamp);
			dp->di_number = cpu_to_le32(ino);
			dp->di_fileset = cpu_to_le32(FILESYSTEM_I);
			dp->di_mode = 0;
			dp->di_nlink = 0;
			PXDaddress(&(dp->di_ixpxd), blkno);
			PXDlength(&(dp->di_ixpxd), imap->im_nbperiext);
		}
		write_metapage(dmp);
	}

	/* if this is the last free extent within the iag, remove the
	 * iag from the ag free extent list.
	 */
	if (iagp->nfreeexts == cpu_to_le32(1)) {
		if (fwd >= 0)
			aiagp->extfreeback = iagp->extfreeback;

		if (back >= 0)
			biagp->extfreefwd = iagp->extfreefwd;
		else
			imap->im_agctl[agno].extfree =
			    le32_to_cpu(iagp->extfreefwd);

		iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);
	} else {
		/* if the iag has all free extents (newly allocated iag),
		 * add the iag to the ag free extent list.
		 */
		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
			if (fwd >= 0)
				aiagp->extfreeback = cpu_to_le32(iagno);

			iagp->extfreefwd = cpu_to_le32(fwd);
			iagp->extfreeback = cpu_to_le32(-1);
			imap->im_agctl[agno].extfree = iagno;
		}
	}

	/* if the iag has no free inodes, add the iag to the
	 * ag free inode list.
	 */
	if (iagp->nfreeinos == 0) {
		if (freei >= 0)
			ciagp->inofreeback = cpu_to_le32(iagno);

		iagp->inofreefwd =
		    cpu_to_le32(imap->im_agctl[agno].inofree);
		iagp->inofreeback = cpu_to_le32(-1);
		imap->im_agctl[agno].inofree = iagno;
	}

	/* initialize the extent descriptor of the extent. */
	PXDlength(&iagp->inoext[extno], imap->im_nbperiext);
	PXDaddress(&iagp->inoext[extno], blkno);

	/* initialize the working and persistent map of the extent.
	 * the working map will be initialized such that
	 * it indicates the first inode of the extent is allocated.
	 */
	iagp->wmap[extno] = cpu_to_le32(HIGHORDER);
	iagp->pmap[extno] = 0;

	/* update the free inode and free extent summary maps
	 * for the extent to indicate the extent has free inodes
	 * and no longer represents a free extent.
	 */
	sword = extno >> L2EXTSPERSUM;
	mask = HIGHORDER >> (extno & (EXTSPERSUM - 1));
	iagp->extsmap[sword] |= cpu_to_le32(mask);
	iagp->inosmap[sword] &= cpu_to_le32(~mask);

	/* update the free inode and free extent counts for the
	 * iag.
	 */
	iagp->nfreeinos = cpu_to_le32(le32_to_cpu(iagp->nfreeinos) +
				      (INOSPEREXT - 1));
	iagp->nfreeexts = cpu_to_le32(le32_to_cpu(iagp->nfreeexts) - 1);

	/* update the free and backed inode counts for the ag.
	 */
	imap->im_agctl[agno].numfree += (INOSPEREXT - 1);
	imap->im_agctl[agno].numinos += INOSPEREXT;

	/* update the free and backed inode counts for the inode map.
	 */
	atomic_add(INOSPEREXT - 1, &imap->im_numfree);
	atomic_add(INOSPEREXT, &imap->im_numinos);

	/* write the iags.
	 */
	if (amp)
		write_metapage(amp);
	if (bmp)
		write_metapage(bmp);
	if (cmp)
		write_metapage(cmp);

	return (0);