[PATCH] ufs: ufs_trunc_indirect: infinite cycle

Currently, ufs write support have two sets of problems: work with files and
work with directories.

This series of patches should solve the first problem.

This patch is similar to http://lkml.org/lkml/2006/1/17/61 this patch
complements it.

The situation the same: in ufs_trunc_(not direct), we read block, check if
count of links to it is equal to one, if so we finish cycle, if not
continue.  Because of "count of links" always >=2 this operation cause
infinite cycle and hang up the kernel.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ufs/truncate.c

@@ -238,18 +238,13 @@ static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
 		if (*ubh_get_addr32(ind_ubh,i))
 			break;
 	if (i >= uspi->s_apb) {
-		if (ubh_max_bcount(ind_ubh) != 1) {
-			retry = 1;
-		}
-		else {
-			tmp = fs32_to_cpu(sb, *p);
-			*p = 0;
-			inode->i_blocks -= uspi->s_nspb;
-			mark_inode_dirty(inode);
-			ufs_free_blocks (inode, tmp, uspi->s_fpb);
-			ubh_bforget(ind_ubh);
-			ind_ubh = NULL;
-		}
+		tmp = fs32_to_cpu(sb, *p);
+		*p = 0;
+		inode->i_blocks -= uspi->s_nspb;
+		mark_inode_dirty(inode);
+		ufs_free_blocks (inode, tmp, uspi->s_fpb);
+		ubh_bforget(ind_ubh);
+		ind_ubh = NULL;
 	}
 	if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
 		ubh_ll_rw_block (SWRITE, 1, &ind_ubh);
@@ -306,17 +301,13 @@ static int ufs_trunc_dindirect (struct inode *inode, unsigned offset, __fs32 *p)
 		if (*ubh_get_addr32 (dind_bh, i))
 			break;
 	if (i >= uspi->s_apb) {
-		if (ubh_max_bcount(dind_bh) != 1)
-			retry = 1;
-		else {
-			tmp = fs32_to_cpu(sb, *p);
-			*p = 0;
-			inode->i_blocks -= uspi->s_nspb;
-			mark_inode_dirty(inode);
-			ufs_free_blocks (inode, tmp, uspi->s_fpb);
-			ubh_bforget(dind_bh);
-			dind_bh = NULL;
-		}
+		tmp = fs32_to_cpu(sb, *p);
+		*p = 0;
+		inode->i_blocks -= uspi->s_nspb;
+		mark_inode_dirty(inode);
+		ufs_free_blocks (inode, tmp, uspi->s_fpb);
+		ubh_bforget(dind_bh);
+		dind_bh = NULL;
 	}
 	if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
 		ubh_ll_rw_block (SWRITE, 1, &dind_bh);
@@ -370,17 +361,13 @@ static int ufs_trunc_tindirect (struct inode * inode)
 		if (*ubh_get_addr32 (tind_bh, i))
 			break;
 	if (i >= uspi->s_apb) {
-		if (ubh_max_bcount(tind_bh) != 1)
-			retry = 1;
-		else {
-			tmp = fs32_to_cpu(sb, *p);
-			*p = 0;
-			inode->i_blocks -= uspi->s_nspb;
-			mark_inode_dirty(inode);
-			ufs_free_blocks (inode, tmp, uspi->s_fpb);
-			ubh_bforget(tind_bh);
-			tind_bh = NULL;
-		}
+		tmp = fs32_to_cpu(sb, *p);
+		*p = 0;
+		inode->i_blocks -= uspi->s_nspb;
+		mark_inode_dirty(inode);
+		ufs_free_blocks (inode, tmp, uspi->s_fpb);
+		ubh_bforget(tind_bh);
+		tind_bh = NULL;
 	}
 	if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
 		ubh_ll_rw_block (SWRITE, 1, &tind_bh);

fs/ufs/util.c

@@ -139,18 +139,6 @@ void ubh_wait_on_buffer (struct ufs_buffer_head * ubh)
 		wait_on_buffer (ubh->bh[i]);
 }
 
-unsigned ubh_max_bcount (struct ufs_buffer_head * ubh)
-{
-	unsigned i;
-	unsigned max = 0;
-	if (!ubh)
-		return 0;
-	for ( i = 0; i < ubh->count; i++ ) 
-		if ( atomic_read(&ubh->bh[i]->b_count) > max )
-			max = atomic_read(&ubh->bh[i]->b_count);
-	return max;
-}
-
 void ubh_bforget (struct ufs_buffer_head * ubh)
 {
 	unsigned i;

fs/ufs/util.h

@@ -238,7 +238,6 @@ extern void ubh_mark_buffer_dirty (struct ufs_buffer_head *);
 extern void ubh_mark_buffer_uptodate (struct ufs_buffer_head *, int);
 extern void ubh_ll_rw_block (int, unsigned, struct ufs_buffer_head **);
 extern void ubh_wait_on_buffer (struct ufs_buffer_head *);
-extern unsigned ubh_max_bcount (struct ufs_buffer_head *);
 extern void ubh_bforget (struct ufs_buffer_head *);
 extern int  ubh_buffer_dirty (struct ufs_buffer_head *);
 #define ubh_ubhcpymem(mem,ubh,size) _ubh_ubhcpymem_(uspi,mem,ubh,size)