[PATCH] (13/1) Do not allocate extents in file holes that overlap existing extents

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2005/04/25 08:47:19-05:00 [email protected] 
#   JFS: Don't allocate extents in file holes that overlap existing extents
#   
#   Modify xtSearch so that it returns the next allocated block when the
#   requested block is unmapped.  This can be used to make sure we don't
#   create a new extent that overlaps the next one.
#   
#   Signed-off-by: Dave Kleikamp <[email protected]>
# 
diff -Nru a/fs/jfs/inode.c b/fs/jfs/inode.c
--- a/fs/jfs/inode.c	2005-04-25 08:49:26 -05:00
+++ b/fs/jfs/inode.c	2005-04-25 08:49:26 -05:00
@@ -178,7 +178,7 @@
 	xad_t xad;
 	s64 xaddr;
 	int xflag;
-	s32 xlen;
+	s32 xlen = max_blocks;
 
 	/*
 	 * Take appropriate lock on inode
@@ -190,7 +190,7 @@
 
 	if (((lblock64 << ip->i_sb->s_blocksize_bits) < ip->i_size) &&
 	    (!xtLookup(ip, lblock64, max_blocks, &xflag, &xaddr, &xlen, 0)) &&
-	    xlen) {
+	    xaddr) {
 		if (xflag & XAD_NOTRECORDED) {
 			if (!create)
 				/*
@@ -229,7 +229,7 @@
 #ifdef _JFS_4K
 	if ((rc = extHint(ip, lblock64 << ip->i_sb->s_blocksize_bits, &xad)))
 		goto unlock;
-	rc = extAlloc(ip, max_blocks, lblock64, &xad, FALSE);
+	rc = extAlloc(ip, xlen, lblock64, &xad, FALSE);
 	if (rc)
 		goto unlock;
 
diff -Nru a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
--- a/fs/jfs/jfs_dtree.c	2005-04-25 08:49:26 -05:00
+++ b/fs/jfs/jfs_dtree.c	2005-04-25 08:49:26 -05:00
@@ -212,7 +212,7 @@
 	s32 xlen;
 
 	rc = xtLookup(inode, blkno, 1, &xflag, &xaddr, &xlen, 1);
-	if (rc || (xlen == 0))
+	if (rc || (xaddr == 0))
 		return NULL;
 
 	return read_metapage(inode, xaddr, PSIZE, 1);
@@ -231,7 +231,7 @@
 	s32 xlen;
 
 	rc = xtLookup(inode, blkno, 1, &xflag, &xaddr, &xlen, 1);
-	if (rc || (xlen == 0))
+	if (rc || (xaddr == 0))
 		return NULL;
 
 	return get_metapage(inode, xaddr, PSIZE, 1);
diff -Nru a/fs/jfs/jfs_xtree.c b/fs/jfs/jfs_xtree.c
--- a/fs/jfs/jfs_xtree.c	2005-04-25 08:49:26 -05:00
+++ b/fs/jfs/jfs_xtree.c	2005-04-25 08:49:26 -05:00
@@ -111,8 +111,8 @@
 /*
  * forward references
  */
-static int xtSearch(struct inode *ip,
-		    s64 xoff, int *cmpp, struct btstack * btstack, int flag);
+static int xtSearch(struct inode *ip, s64 xoff, s64 *next, int *cmpp,
+		    struct btstack * btstack, int flag);
 
 static int xtSplitUp(tid_t tid,
 		     struct inode *ip,
@@ -159,11 +159,12 @@
 	xtpage_t *p;
 	int index;
 	xad_t *xad;
-	s64 size, xoff, xend;
+	s64 next, size, xoff, xend;
 	int xlen;
 	s64 xaddr;
 
-	*plen = 0;
+	*paddr = 0;
+	*plen = llen;
 
 	if (!no_check) {
 		/* is lookup offset beyond eof ? */
@@ -180,7 +181,7 @@
 	 * search for the xad entry covering the logical extent
 	 */
 //search:
-	if ((rc = xtSearch(ip, lstart, &cmp, &btstack, 0))) {
+	if ((rc = xtSearch(ip, lstart, &next, &cmp, &btstack, 0))) {
 		jfs_err("xtLookup: xtSearch returned %d", rc);
 		return rc;
 	}
@@ -198,8 +199,11 @@
 	 * lstart is a page start address,
 	 * i.e., lstart cannot start in a hole;
 	 */
-	if (cmp)
+	if (cmp) {
+		if (next)
+			*plen = min(next - lstart, llen);
 		goto out;
+	}
 
 	/*
 	 * lxd covered by xad
@@ -284,7 +288,7 @@
 	if (lstart >= size)
 		return 0;
 
-	if ((rc = xtSearch(ip, lstart, &cmp, &btstack, 0)))
+	if ((rc = xtSearch(ip, lstart, NULL, &cmp, &btstack, 0)))
 		return rc;
 
 	/*
@@ -488,6 +492,7 @@
  * parameters:
  *      ip      - file object;
  *      xoff    - extent offset;
+ *      nextp	- address of next extent (if any) for search miss
  *      cmpp    - comparison result:
  *      btstack - traverse stack;
  *      flag    - search process flag (XT_INSERT);
@@ -497,7 +502,7 @@
  *      *cmpp is set to result of comparison with the entry returned.
  *      the page containing the entry is pinned at exit.
  */
-static int xtSearch(struct inode *ip, s64 xoff,	/* offset of extent */
+static int xtSearch(struct inode *ip, s64 xoff,	s64 *nextp,
 		    int *cmpp, struct btstack * btstack, int flag)
 {
 	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
@@ -511,6 +516,7 @@
 	struct btframe *btsp;
 	int nsplit = 0;		/* number of pages to split */
 	s64 t64;
+	s64 next = 0;
 
 	INCREMENT(xtStat.search);
 
@@ -579,6 +585,7 @@
 						 * previous and this entry
 						 */
 						*cmpp = 1;
+						next = t64;
 						goto out;
 					}
 
@@ -623,6 +630,9 @@
 			/* update sequential access heuristics */
 			jfs_ip->btindex = index;
 
+			if (nextp)
+				*nextp = next;
+
 			INCREMENT(xtStat.fastSearch);
 			return 0;
 		}
@@ -675,10 +685,11 @@
 
 					return 0;
 				}
-
 				/* search hit - internal page:
 				 * descend/search its child page
 				 */
+				if (index < p->header.nextindex - 1)
+					next = offsetXAD(&p->xad[index + 1]);
 				goto next;
 			}
 
@@ -694,6 +705,8 @@
 		 * base is the smallest index with key (Kj) greater than
 		 * search key (K) and may be zero or maxentry index.
 		 */
+		if (base < p->header.nextindex)
+			next = offsetXAD(&p->xad[base]);
 		/*
 		 * search miss - leaf page:
 		 *
@@ -727,6 +740,9 @@
 				jfs_ip->btorder = BT_RANDOM;
 			jfs_ip->btindex = base;
 
+			if (nextp)
+				*nextp = next;
+
 			return 0;
 		}
 
@@ -793,6 +809,7 @@
 	struct xtsplit split;	/* split information */
 	xad_t *xad;
 	int cmp;
+	s64 next;
 	struct tlock *tlck;
 	struct xtlock *xtlck;
 
@@ -806,7 +823,7 @@
 	 * n.b. xtSearch() may return index of maxentry of
 	 * the full page.
 	 */
-	if ((rc = xtSearch(ip, xoff, &cmp, &btstack, XT_INSERT)))
+	if ((rc = xtSearch(ip, xoff, &next, &cmp, &btstack, XT_INSERT)))
 		return rc;
 
 	/* retrieve search result */
@@ -814,7 +831,7 @@
 
 	/* This test must follow XT_GETSEARCH since mp must be valid if
 	 * we branch to out: */
-	if (cmp == 0) {
+	if ((cmp == 0) || (next && (xlen > next - xoff))) {
 		rc = -EEXIST;
 		goto out;
 	}
@@ -1626,7 +1643,7 @@
 	jfs_info("xtExtend: nxoff:0x%lx nxlen:0x%x", (ulong) xoff, xlen);
 
 	/* there must exist extent to be extended */
-	if ((rc = xtSearch(ip, xoff - 1, &cmp, &btstack, XT_INSERT)))
+	if ((rc = xtSearch(ip, xoff - 1, NULL, &cmp, &btstack, XT_INSERT)))
 		return rc;
 
 	/* retrieve search result */
@@ -1794,7 +1811,7 @@
 */
 
 	/* there must exist extent to be tailgated */
-	if ((rc = xtSearch(ip, xoff, &cmp, &btstack, XT_INSERT)))
+	if ((rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, XT_INSERT)))
 		return rc;
 
 	/* retrieve search result */
@@ -1977,7 +1994,7 @@
 	nxlen = lengthXAD(nxad);
 	nxaddr = addressXAD(nxad);
 
-	if ((rc = xtSearch(ip, nxoff, &cmp, &btstack, XT_INSERT)))
+	if ((rc = xtSearch(ip, nxoff, NULL, &cmp, &btstack, XT_INSERT)))
 		return rc;
 
 	/* retrieve search result */
@@ -2291,7 +2308,7 @@
 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
 		XT_PUTPAGE(mp);
 
-		if ((rc = xtSearch(ip, nxoff, &cmp, &btstack, XT_INSERT)))
+		if ((rc = xtSearch(ip, nxoff, NULL, &cmp, &btstack, XT_INSERT)))
 			return rc;
 
 		/* retrieve search result */
@@ -2438,6 +2455,7 @@
 	int nsplit, nblocks, xlen;
 	struct pxdlist pxdlist;
 	pxd_t *pxd;
+	s64 next;
 
 	xaddr = *xaddrp;
 	xlen = *xlenp;
@@ -2452,7 +2470,7 @@
 	 * n.b. xtSearch() may return index of maxentry of
 	 * the full page.
 	 */
-	if ((rc = xtSearch(ip, xoff, &cmp, &btstack, XT_INSERT)))
+	if ((rc = xtSearch(ip, xoff, &next, &cmp, &btstack, XT_INSERT)))
 		return rc;
 
 	/* retrieve search result */
@@ -2462,6 +2480,9 @@
 		rc = -EEXIST;
 		goto out;
 	}
+
+	if (next)
+		xlen = min(xlen, (int)(next - xoff));
 //insert:
 	/*
 	 *      insert entry for new extent
@@ -2600,7 +2621,7 @@
 	/*
 	 * find the matching entry; xtSearch() pins the page
 	 */
-	if ((rc = xtSearch(ip, xoff, &cmp, &btstack, 0)))
+	if ((rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0)))
 		return rc;
 
 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
@@ -2852,7 +2873,7 @@
 	 */
 	if (xtype == DATAEXT) {
 		/* search in leaf entry */
-		rc = xtSearch(ip, xoff, &cmp, &btstack, 0);
+		rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0);
 		if (rc)
 			return rc;
 
@@ -2958,7 +2979,7 @@
 		}
 
 		/* get back parent page */
-		if ((rc = xtSearch(ip, xoff, &cmp, &btstack, 0)))
+		if ((rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0)))
 			return rc;
 
 		XT_GETSEARCH(ip, btstack.top, bn, pmp, pp, index);
@@ -3991,7 +4012,7 @@
 
 	if (committed_size) {
 		xoff = (committed_size >> JFS_SBI(ip->i_sb)->l2bsize) - 1;
-		rc = xtSearch(ip, xoff, &cmp, &btstack, 0);
+		rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0);
 		if (rc)
 			return rc;
 


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