[PATCH] types fixup for mballoc

[PATCH] types fixup for mballoc

[Eric Sandeen]

I ran into a potential overflow in ext4_mb_scan_aligned, 
and went looking for others in mballoc.  This patch hits a 
few spots, compile-tested only at this point, comments welcome.

This patch:

changes fe_len to an int, I don't think we need it to be a long,
looking at how it's used (should it be a grpblk_t?)  Also change
anything assigned to return value of mb_find_extent, since it returns
fe_len.

changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
or pa->pa_pstart + <whatever> to an ext4_fsblk_t

fixes up any related formats

The change to ext4_mb_scan_aligned to add a modulo to avoid an overflow
may be too clever... it could use an extra look I think.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

---

Index: linux-2.6.24-rc1/fs/ext4/mballoc.c
===================================================================
--- linux-2.6.23.orig/fs/ext4/mballoc.c
+++ linux-2.6.23/fs/ext4/mballoc.c
@@ -363,7 +363,7 @@ struct ext4_free_extent {
 	ext4_lblk_t fe_logical;
 	ext4_grpblk_t fe_start;
 	ext4_grpnum_t fe_group;
-	unsigned long fe_len;
+	int fe_len;
 };
 
 /*
@@ -586,14 +586,14 @@ static void mb_free_blocks_double(struct
 	BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group));
 	for (i = 0; i < count; i++) {
 		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += first + i;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr,
 				   first + i, e4b->bd_group);
 		}
@@ -1226,14 +1226,14 @@ static int mb_free_blocks(struct inode *
 		order = 0;
 
 		if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += block;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr, block,
 				   e4b->bd_group);
 		}
@@ -1416,7 +1416,7 @@ static void ext4_mb_use_best_found(struc
 					struct ext4_buddy *e4b)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
-	unsigned long ret;
+	int ret;
 
 	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
 	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
@@ -1609,7 +1609,7 @@ static int ext4_mb_find_by_goal(struct e
 			     ac->ac_g_ex.fe_len, &ex);
 
 	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
-		unsigned long start;
+		ext4_fsblk_t start;
 		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
 			ex.fe_start + le32_to_cpu(es->s_first_data_block));
 		if (start % sbi->s_stripe == 0) {
@@ -1732,13 +1732,14 @@ static void ext4_mb_scan_aligned(struct 
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	void *bitmap = EXT4_MB_BITMAP(e4b);
 	struct ext4_free_extent ex;
-	unsigned long i;
-	unsigned long max;
+	ext4_grpblk_t i;
+	int max;
 
 	BUG_ON(sbi->s_stripe == 0);
 
-	/* find first stripe-aligned block */
-	i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
+	/* find first stripe-aligned block in group */
+	/* early modulo here to avoid 32-bit overflow */
+	i = (e4b->bd_group % sbi->s_stripe)  * EXT4_BLOCKS_PER_GROUP(sb)
 		+ le32_to_cpu(sbi->s_es->s_first_data_block);
 	i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe;
 	i = (i - le32_to_cpu(sbi->s_es->s_first_data_block))
@@ -2026,35 +2027,35 @@ static int ext4_mb_seq_history_show(stru
 	if (hs->op == EXT4_MB_HISTORY_ALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
 			"%-5u %-5s %-5u %-6u\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
-		sprintf(buf3, "%lu/%d/%lu@%lu", hs->goal.fe_group,
+			hs->orig.fe_logical);
+		sprintf(buf3, "%lu/%d/%u@%u", hs->goal.fe_group,
 			hs->goal.fe_start, hs->goal.fe_len,
-			(unsigned long)hs->goal.fe_logical);
+			hs->goal.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
 				hs->found, hs->groups, hs->cr, hs->flags,
 				hs->merged ? "M" : "", hs->tail,
 				hs->buddy ? 1 << hs->buddy : 0);
 	} else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
+			hs->orig.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s discard\n",
 				hs->pid, hs->ino, buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_FREE) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s free\n",
 				hs->pid, hs->ino, buf2);
@@ -2942,7 +2943,7 @@ static int ext4_mb_mark_diskspace_used(s
 	struct buffer_head *gdp_bh;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
-	sector_t block;
+	ext4_fsblk_t block;
 	int err;
 
 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
@@ -2983,8 +2984,8 @@ static int ext4_mb_mark_diskspace_used(s
 				EXT4_SB(sb)->s_itb_per_group)) {
 
 		ext4_error(sb, __FUNCTION__,
-			   "Allocating block in system zone - block = %lu",
-			   (unsigned long) block);
+			   "Allocating block in system zone - block = %llu",
+			   block);
 	}
 #ifdef AGGRESSIVE_CHECK
 	{
@@ -3249,12 +3250,13 @@ static void ext4_mb_use_inode_pa(struct 
 				struct ext4_prealloc_space *pa)
 {
 	ext4_fsblk_t start;
-	unsigned long len;
+	ext4_fsblk_t end;
+	int len;
 
 	/* found preallocated blocks, use them */
 	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
-	len = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
-	len = len - start;
+	end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
+	len = end - start;
 	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
 					&ac->ac_b_ex.fe_start);
 	ac->ac_b_ex.fe_len = len;
@@ -3953,8 +3955,8 @@ static void ext4_mb_show_ac(struct ext4_
 
 	printk(KERN_ERR "EXT4-fs: can't allocate: status %d flags %d\n",
 			ac->ac_status, ac->ac_flags);
-	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
-			"best %lu/%lu/%lu@%lu cr %d\n",
+	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%u@%u, goal %lu/%lu/%u@%u, "
+			"best %lu/%lu/%u@%u cr %d\n",
 			ac->ac_o_ex.fe_group, ac->ac_o_ex.fe_start,
 			ac->ac_o_ex.fe_len, ac->ac_o_ex.fe_logical,
 			ac->ac_g_ex.fe_group, ac->ac_g_ex.fe_start,

Re: [PATCH] types fixup for mballoc

[Eric Sandeen]

Eric Sandeen wrote:
> I ran into a potential overflow in ext4_mb_scan_aligned, 
> and went looking for others in mballoc.  This patch hits a 
> few spots, compile-tested only at this point, comments welcome.
> 
> This patch:
> 

... introduces a 64-bit divide.  Oops... will fix that up & resend.

-Eric

[PATCH] UPDATED: types fixup for mballoc

[Eric Sandeen]

Eric Sandeen wrote:
> Eric Sandeen wrote:
>   
>> I ran into a potential overflow in ext4_mb_scan_aligned, 
>> and went looking for others in mballoc.  This patch hits a 
>> few spots, compile-tested only at this point, comments welcome.
>>
>> This patch:
>>
>>     
>
> ... introduces a 64-bit divide.  Oops... will fix that up & resend.
>
>   
Took a while to get back to this :)  But just used do_div return value
for remainder instead of modulo (which would have been a 64-bit modulo)

There's another do_div trick, and a bitwise round-up in there too,
now that there are more 64-bit containers...  Anyway, patch follows.

-------------

I ran into a potential overflow in ext4_mb_scan_aligned, 
and went looking for others in mballoc.  This patch hits a 
few spots, compile-tested only at this point, comments welcome.

This patch:

changes fe_len to an int, I don't think we need it to be a long,
looking at how it's used (should it be a grpblk_t?)  Also change
anything assigned to return value of mb_find_extent, since it returns
fe_len.

changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
or pa->pa_pstart + <whatever> to an ext4_fsblk_t

fixes up any related formats

The change to ext4_mb_scan_aligned to avoid a 64-bit modulo
could use an extra look I think.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

---


Index: linux-2.6.24-rc3/fs/ext4/mballoc.c
===================================================================
--- linux-2.6.24-rc3.orig/fs/ext4/mballoc.c
+++ linux-2.6.24-rc3/fs/ext4/mballoc.c
@@ -363,7 +363,7 @@ struct ext4_free_extent {
 	ext4_lblk_t fe_logical;
 	ext4_grpblk_t fe_start;
 	ext4_group_t fe_group;
-	unsigned long fe_len;
+	int fe_len;
 };
 
 /*
@@ -586,14 +586,14 @@ static void mb_free_blocks_double(struct
 	BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group));
 	for (i = 0; i < count; i++) {
 		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += first + i;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr,
 				   first + i, e4b->bd_group);
 		}
@@ -1226,14 +1226,14 @@ static int mb_free_blocks(struct inode *
 		order = 0;
 
 		if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += block;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr, block,
 				   e4b->bd_group);
 		}
@@ -1416,7 +1416,7 @@ static void ext4_mb_use_best_found(struc
 					struct ext4_buddy *e4b)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
-	unsigned long ret;
+	int ret;
 
 	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
 	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
@@ -1609,10 +1609,12 @@ static int ext4_mb_find_by_goal(struct e
 			     ac->ac_g_ex.fe_len, &ex);
 
 	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
-		unsigned long start;
-		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
-			ex.fe_start + le32_to_cpu(es->s_first_data_block));
-		if (start % sbi->s_stripe == 0) {
+		ext4_fsblk_t start;
+
+		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) +
+			ex.fe_start + le32_to_cpu(es->s_first_data_block);
+		/* use do_div to get remainder (would be 64-bit modulo) */
+		if (do_div(start, sbi->s_stripe) == 0) {
 			ac->ac_found++;
 			ac->ac_b_ex = ex;
 			ext4_mb_use_best_found(ac, e4b);
@@ -1724,6 +1726,7 @@ static void ext4_mb_complex_scan_group(s
 /*
  * This is a special case for storages like raid5
  * we try to find stripe-aligned chunks for stripe-size requests
+ * XXX should do so at least for multiples of stripe size as well
  */
 static void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
 				 struct ext4_buddy *e4b)
@@ -1732,17 +1735,18 @@ static void ext4_mb_scan_aligned(struct 
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	void *bitmap = EXT4_MB_BITMAP(e4b);
 	struct ext4_free_extent ex;
-	unsigned long i;
-	unsigned long max;
+	ext4_fsblk_t a;
+	ext4_grpblk_t i;
+	int max;
 
 	BUG_ON(sbi->s_stripe == 0);
 
-	/* find first stripe-aligned block */
-	i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
+	/* find first stripe-aligned block in group */
+	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
 		+ le32_to_cpu(sbi->s_es->s_first_data_block);
-	i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe;
-	i = (i - le32_to_cpu(sbi->s_es->s_first_data_block))
-			% EXT4_BLOCKS_PER_GROUP(sb);
+	a = (a + sbi->s_stripe - 1) & ~((ext4_fsblk_t)sbi->s_stripe - 1);
+	a = a - le32_to_cpu(sbi->s_es->s_first_data_block);
+	i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb));
 
 	while (i < sb->s_blocksize * 8) {
 		if (!mb_test_bit(i, bitmap)) {
@@ -2026,35 +2030,35 @@ static int ext4_mb_seq_history_show(stru
 	if (hs->op == EXT4_MB_HISTORY_ALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
 			"%-5u %-5s %-5u %-6u\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
-		sprintf(buf3, "%lu/%d/%lu@%lu", hs->goal.fe_group,
+			hs->orig.fe_logical);
+		sprintf(buf3, "%lu/%d/%u@%u", hs->goal.fe_group,
 			hs->goal.fe_start, hs->goal.fe_len,
-			(unsigned long)hs->goal.fe_logical);
+			hs->goal.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
 				hs->found, hs->groups, hs->cr, hs->flags,
 				hs->merged ? "M" : "", hs->tail,
 				hs->buddy ? 1 << hs->buddy : 0);
 	} else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
+			hs->orig.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s discard\n",
 				hs->pid, hs->ino, buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_FREE) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s free\n",
 				hs->pid, hs->ino, buf2);
@@ -2943,7 +2947,7 @@ static int ext4_mb_mark_diskspace_used(s
 	struct buffer_head *gdp_bh;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
-	sector_t block;
+	ext4_fsblk_t block;
 	int err;
 
 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
@@ -2984,8 +2988,8 @@ static int ext4_mb_mark_diskspace_used(s
 				EXT4_SB(sb)->s_itb_per_group)) {
 
 		ext4_error(sb, __FUNCTION__,
-			   "Allocating block in system zone - block = %lu",
-			   (unsigned long) block);
+			   "Allocating block in system zone - block = %llu",
+			   block);
 	}
 #ifdef AGGRESSIVE_CHECK
 	{
@@ -3250,12 +3254,13 @@ static void ext4_mb_use_inode_pa(struct 
 				struct ext4_prealloc_space *pa)
 {
 	ext4_fsblk_t start;
-	unsigned long len;
+	ext4_fsblk_t end;
+	int len;
 
 	/* found preallocated blocks, use them */
 	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
-	len = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
-	len = len - start;
+	end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
+	len = end - start;
 	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
 					&ac->ac_b_ex.fe_start);
 	ac->ac_b_ex.fe_len = len;
@@ -3954,8 +3959,8 @@ static void ext4_mb_show_ac(struct ext4_
 
 	printk(KERN_ERR "EXT4-fs: can't allocate: status %d flags %d\n",
 			ac->ac_status, ac->ac_flags);
-	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
-			"best %lu/%lu/%lu@%lu cr %d\n",
+	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%u@%u, goal %lu/%lu/%u@%u, "
+			"best %lu/%lu/%u@%u cr %d\n",
 			ac->ac_o_ex.fe_group, ac->ac_o_ex.fe_start,
 			ac->ac_o_ex.fe_len, ac->ac_o_ex.fe_logical,
 			ac->ac_g_ex.fe_group, ac->ac_g_ex.fe_start,
Index: linux-2.6.24-rc3/fs/ext4/inode.c
===================================================================
--- linux-2.6.24-rc3.orig/fs/ext4/inode.c
+++ linux-2.6.24-rc3/fs/ext4/inode.c
@@ -309,7 +309,7 @@ static int ext4_block_to_path(struct ino
 		offsets[n++] = i_block & (ptrs - 1);
 		final = ptrs;
 	} else {
-		ext4_warning(inode->i_sb, "ext4_block_to_path", "block %u > max",
+		ext4_warning(inode->i_sb, "ext4_block_to_path", "block %lu > max",
 				i_block + direct_blocks +
 				indirect_blocks + double_blocks);
 	}

Re: [PATCH] UPDATED: types fixup for mballoc

[Andreas Dilger]

On Jan 02, 2008  14:01 -0600, Eric Sandeen wrote:
> This patch:
> 
> changes fe_len to an int, I don't think we need it to be a long,
> looking at how it's used (should it be a grpblk_t?)  Also change
> anything assigned to return value of mb_find_extent, since it returns
> fe_len.
> 
> changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
> or pa->pa_pstart + <whatever> to an ext4_fsblk_t
> 
> fixes up any related formats
> 
> The change to ext4_mb_scan_aligned to avoid a 64-bit modulo
> could use an extra look I think.
>
> @@ -1732,17 +1735,18 @@ static void ext4_mb_scan_aligned(struct 
>  	BUG_ON(sbi->s_stripe == 0);
>  
> -	/* find first stripe-aligned block */
> -	i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
> -		+ le32_to_cpu(sbi->s_es->s_first_data_block);
> -	i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe;
> -	i = (i - le32_to_cpu(sbi->s_es->s_first_data_block))
> -			% EXT4_BLOCKS_PER_GROUP(sb);

> +	/* find first stripe-aligned block in group */
> +	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
> +		+ le32_to_cpu(sbi->s_es->s_first_data_block);
> +	a = (a + sbi->s_stripe - 1) & ~((ext4_fsblk_t)sbi->s_stripe - 1);
> +	a = a - le32_to_cpu(sbi->s_es->s_first_data_block);
> +	i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb));

I don't think this is correct...  This code should only be used if s_stripe
is NOT a power-of-two value, otherwise we can just use the buddy maps to
find aligned chunks.  As a result I don't think that "& (s_stripe - 1)"
change is equivalent to "/ s_stripe * s_stripe".

>  	while (i < sb->s_blocksize * 8) {
>  		if (!mb_test_bit(i, bitmap)) {

Hrmmm, I thought this should be "while (i < EXT4_BLOCKS_PER_GROUP(sb))"
and not "sb->s_blocksize * 8"?  Did that fix get lost somewhere?

There are a few other changes in the patch related to this fix:
https://bugzilla.lustre.org/attachment.cgi?id=13275

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

Re: [PATCH] UPDATED: types fixup for mballoc

[Eric Sandeen]

Andreas Dilger wrote:
> On Jan 02, 2008  14:01 -0600, Eric Sandeen wrote:
>> This patch:
>>
>> changes fe_len to an int, I don't think we need it to be a long,
>> looking at how it's used (should it be a grpblk_t?)  Also change
>> anything assigned to return value of mb_find_extent, since it returns
>> fe_len.
>>
>> changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
>> or pa->pa_pstart + <whatever> to an ext4_fsblk_t
>>
>> fixes up any related formats
>>
>> The change to ext4_mb_scan_aligned to avoid a 64-bit modulo
>> could use an extra look I think.
>>
>> @@ -1732,17 +1735,18 @@ static void ext4_mb_scan_aligned(struct 
>>  	BUG_ON(sbi->s_stripe == 0);
>>  
>> -	/* find first stripe-aligned block */
>> -	i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
>> -		+ le32_to_cpu(sbi->s_es->s_first_data_block);
>> -	i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe;
>> -	i = (i - le32_to_cpu(sbi->s_es->s_first_data_block))
>> -			% EXT4_BLOCKS_PER_GROUP(sb);
> 
>> +	/* find first stripe-aligned block in group */
>> +	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
>> +		+ le32_to_cpu(sbi->s_es->s_first_data_block);
>> +	a = (a + sbi->s_stripe - 1) & ~((ext4_fsblk_t)sbi->s_stripe - 1);
>> +	a = a - le32_to_cpu(sbi->s_es->s_first_data_block);
>> +	i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb));
> 
> I don't think this is correct...  This code should only be used if s_stripe
> is NOT a power-of-two value, otherwise we can just use the buddy maps to
> find aligned chunks.  As a result I don't think that "& (s_stripe - 1)"
> change is equivalent to "/ s_stripe * s_stripe".

Hmmm ok let me re-check that then.

(...curses 64-bit math trickiness...)

>>  	while (i < sb->s_blocksize * 8) {
>>  		if (!mb_test_bit(i, bitmap)) {
> 
> Hrmmm, I thought this should be "while (i < EXT4_BLOCKS_PER_GROUP(sb))"
> and not "sb->s_blocksize * 8"?  Did that fix get lost somewhere?

I did wonder about that.... wondered about the magic 8 number but forgot
to comment.

Thanks,
-Eric

[PATCH] UPDATED2: types fixup for mballoc

[Eric Sandeen]

3rd time's the charm I hope!

-------------

I ran into a potential overflow in ext4_mb_scan_aligned, 
and went looking for others in mballoc.  This patch hits a 
few spots, compile-tested only at this point, comments welcome.

This patch:

changes fe_len to an int, I don't think we need it to be a long,
looking at how it's used (should it be a grpblk_t?)  Also change
anything assigned to return value of mb_find_extent, since it returns
fe_len.

changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
or pa->pa_pstart + <whatever> to an ext4_fsblk_t

avoids 64-bit divides & modulos, and...

fixes up any related formats

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

---

Index: linux-2.6.24-rc3/fs/ext4/mballoc.c
===================================================================
--- linux-2.6.24-rc3.orig/fs/ext4/mballoc.c
+++ linux-2.6.24-rc3/fs/ext4/mballoc.c
@@ -363,7 +363,7 @@ struct ext4_free_extent {
 	ext4_lblk_t fe_logical;
 	ext4_grpblk_t fe_start;
 	ext4_group_t fe_group;
-	unsigned long fe_len;
+	int fe_len;
 };
 
 /*
@@ -586,14 +586,14 @@ static void mb_free_blocks_double(struct
 	BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group));
 	for (i = 0; i < count; i++) {
 		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += first + i;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr,
 				   first + i, e4b->bd_group);
 		}
@@ -1226,14 +1226,14 @@ static int mb_free_blocks(struct inode *
 		order = 0;
 
 		if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += block;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr, block,
 				   e4b->bd_group);
 		}
@@ -1416,7 +1416,7 @@ static void ext4_mb_use_best_found(struc
 					struct ext4_buddy *e4b)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
-	unsigned long ret;
+	int ret;
 
 	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
 	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
@@ -1609,10 +1609,12 @@ static int ext4_mb_find_by_goal(struct e
 			     ac->ac_g_ex.fe_len, &ex);
 
 	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
-		unsigned long start;
-		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
-			ex.fe_start + le32_to_cpu(es->s_first_data_block));
-		if (start % sbi->s_stripe == 0) {
+		ext4_fsblk_t start;
+
+		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) +
+			ex.fe_start + le32_to_cpu(es->s_first_data_block);
+		/* use do_div to get remainder (would be 64-bit modulo) */
+		if (do_div(start, sbi->s_stripe) == 0) {
 			ac->ac_found++;
 			ac->ac_b_ex = ex;
 			ext4_mb_use_best_found(ac, e4b);
@@ -1724,6 +1726,7 @@ static void ext4_mb_complex_scan_group(s
 /*
  * This is a special case for storages like raid5
  * we try to find stripe-aligned chunks for stripe-size requests
+ * XXX should do so at least for multiples of stripe size as well
  */
 static void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
 				 struct ext4_buddy *e4b)
@@ -1732,17 +1735,19 @@ static void ext4_mb_scan_aligned(struct 
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	void *bitmap = EXT4_MB_BITMAP(e4b);
 	struct ext4_free_extent ex;
-	unsigned long i;
-	unsigned long max;
+	ext4_fsblk_t a;
+	ext4_grpblk_t i;
+	int max;
 
 	BUG_ON(sbi->s_stripe == 0);
 
-	/* find first stripe-aligned block */
-	i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
+	/* find first stripe-aligned block in group */
+	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
 		+ le32_to_cpu(sbi->s_es->s_first_data_block);
-	i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe;
-	i = (i - le32_to_cpu(sbi->s_es->s_first_data_block))
-			% EXT4_BLOCKS_PER_GROUP(sb);
+	a += sbi->s_stripe - 1;
+	do_div(a, sbi->s_stripe);
+	a = (a * sbi->s_stripe) - le32_to_cpu(sbi->s_es->s_first_data_block);
+	i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb));
 
 	while (i < sb->s_blocksize * 8) {
 		if (!mb_test_bit(i, bitmap)) {
@@ -2026,35 +2031,35 @@ static int ext4_mb_seq_history_show(stru
 	if (hs->op == EXT4_MB_HISTORY_ALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
 			"%-5u %-5s %-5u %-6u\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
-		sprintf(buf3, "%lu/%d/%lu@%lu", hs->goal.fe_group,
+			hs->orig.fe_logical);
+		sprintf(buf3, "%lu/%d/%u@%u", hs->goal.fe_group,
 			hs->goal.fe_start, hs->goal.fe_len,
-			(unsigned long)hs->goal.fe_logical);
+			hs->goal.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
 				hs->found, hs->groups, hs->cr, hs->flags,
 				hs->merged ? "M" : "", hs->tail,
 				hs->buddy ? 1 << hs->buddy : 0);
 	} else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
+			hs->orig.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s discard\n",
 				hs->pid, hs->ino, buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_FREE) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s free\n",
 				hs->pid, hs->ino, buf2);
@@ -2943,7 +2948,7 @@ static int ext4_mb_mark_diskspace_used(s
 	struct buffer_head *gdp_bh;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
-	sector_t block;
+	ext4_fsblk_t block;
 	int err;
 
 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
@@ -2984,8 +2989,8 @@ static int ext4_mb_mark_diskspace_used(s
 				EXT4_SB(sb)->s_itb_per_group)) {
 
 		ext4_error(sb, __FUNCTION__,
-			   "Allocating block in system zone - block = %lu",
-			   (unsigned long) block);
+			   "Allocating block in system zone - block = %llu",
+			   block);
 	}
 #ifdef AGGRESSIVE_CHECK
 	{
@@ -3250,12 +3255,13 @@ static void ext4_mb_use_inode_pa(struct 
 				struct ext4_prealloc_space *pa)
 {
 	ext4_fsblk_t start;
-	unsigned long len;
+	ext4_fsblk_t end;
+	int len;
 
 	/* found preallocated blocks, use them */
 	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
-	len = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
-	len = len - start;
+	end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
+	len = end - start;
 	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
 					&ac->ac_b_ex.fe_start);
 	ac->ac_b_ex.fe_len = len;
@@ -3954,8 +3960,8 @@ static void ext4_mb_show_ac(struct ext4_
 
 	printk(KERN_ERR "EXT4-fs: can't allocate: status %d flags %d\n",
 			ac->ac_status, ac->ac_flags);
-	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
-			"best %lu/%lu/%lu@%lu cr %d\n",
+	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%u@%u, goal %lu/%lu/%u@%u, "
+			"best %lu/%lu/%u@%u cr %d\n",
 			ac->ac_o_ex.fe_group, ac->ac_o_ex.fe_start,
 			ac->ac_o_ex.fe_len, ac->ac_o_ex.fe_logical,
 			ac->ac_g_ex.fe_group, ac->ac_g_ex.fe_start,
Index: linux-2.6.24-rc3/fs/ext4/inode.c
===================================================================
--- linux-2.6.24-rc3.orig/fs/ext4/inode.c
+++ linux-2.6.24-rc3/fs/ext4/inode.c
@@ -309,7 +309,7 @@ static int ext4_block_to_path(struct ino
 		offsets[n++] = i_block & (ptrs - 1);
 		final = ptrs;
 	} else {
-		ext4_warning(inode->i_sb, "ext4_block_to_path", "block %u > max",
+		ext4_warning(inode->i_sb, "ext4_block_to_path", "block %lu > max",
 				i_block + direct_blocks +
 				indirect_blocks + double_blocks);
 	}

Re: [PATCH] UPDATED2: types fixup for mballoc

[Andreas Dilger]

On Jan 03, 2008  14:10 -0600, Eric Sandeen wrote:
> @@ -1732,17 +1735,19 @@ static void ext4_mb_scan_aligned(struct 
> +	/* find first stripe-aligned block in group */
> +	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
>  		+ le32_to_cpu(sbi->s_es->s_first_data_block);
> +	a += sbi->s_stripe - 1;

Why not just have "+ sbi->s_stipe - 1" on the previous line, instead of "+="?
Also minor coding style nit: the "+" is normally at the end of the previous
line instead of at the start of the next line, so:

	/* find first stripe-aligned block in group */
	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) +
		le32_to_cpu(sbi->s_es->s_first_data_block) + sbi->s_stripe - 1;

> +	a = (a * sbi->s_stripe) - le32_to_cpu(sbi->s_es->s_first_data_block);
> +	i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb));

I guess this doesn't stricly need to be a modulus either, because we know
which group this will be in and can just subtract the start.  You can just do:
 
	/* find first stripe-aligned block in this group */
	group_start = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) +;
		le32_to_cpu(sbi->s_es->s_first_data_block);

	a = group_start + sbi->s_stripe - 1;
	do_div(a, sbi->s_stripe);
	a = (a * sbi->s_stripe) - group_start;

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

Re: [PATCH] UPDATED2: types fixup for mballoc

[Eric Sandeen]

Andreas Dilger wrote:
> On Jan 03, 2008  14:10 -0600, Eric Sandeen wrote:
>> @@ -1732,17 +1735,19 @@ static void ext4_mb_scan_aligned(struct 
>> +	/* find first stripe-aligned block in group */
>> +	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
>>  		+ le32_to_cpu(sbi->s_es->s_first_data_block);
>> +	a += sbi->s_stripe - 1;
> 
> Why not just have "+ sbi->s_stipe - 1" on the previous line, instead of "+="?

hmm good point.

> Also minor coding style nit: the "+" is normally at the end of the previous
> line instead of at the start of the next line, so:
> 
> 	/* find first stripe-aligned block in group */
> 	a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) +
> 		le32_to_cpu(sbi->s_es->s_first_data_block) + sbi->s_stripe - 1;

Ok, that was inherited :)

>> +	a = (a * sbi->s_stripe) - le32_to_cpu(sbi->s_es->s_first_data_block);
>> +	i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb));
> 
> I guess this doesn't stricly need to be a modulus either, because we know
> which group this will be in and can just subtract the start.  You can just do:
>  
> 	/* find first stripe-aligned block in this group */
> 	group_start = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) +;
> 		le32_to_cpu(sbi->s_es->s_first_data_block);
> 
> 	a = group_start + sbi->s_stripe - 1;
> 	do_div(a, sbi->s_stripe);
> 	a = (a * sbi->s_stripe) - group_start;

Ok, I knew I had stared at this for too long :)

4th try coming soon.

-Eric

[PATCH] UPDATED3: types fixup for mballoc

[Eric Sandeen]

4th time's the charm?

Note, the calculations Andreas & I were discussing only work properly
for stripe <= blocks per group... I don't know if we'd need to enforce
that at mount time?

-------------

I ran into a potential overflow in ext4_mb_scan_aligned, 
and went looking for others in mballoc.  This patch hits a 
few spots, compile-tested only at this point, comments welcome.

This patch:

changes fe_len to an int, I don't think we need it to be a long,
looking at how it's used (should it be a grpblk_t?)  Also change
anything assigned to return value of mb_find_extent, since it returns
fe_len.

changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
or pa->pa_pstart + <whatever> to an ext4_fsblk_t

avoids 64-bit divides & modulos, and...

fixes up any related formats

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

---

Index: linux-2.6.24-rc3/fs/ext4/mballoc.c
===================================================================
--- linux-2.6.24-rc3.orig/fs/ext4/mballoc.c
+++ linux-2.6.24-rc3/fs/ext4/mballoc.c
@@ -363,7 +363,7 @@ struct ext4_free_extent {
 	ext4_lblk_t fe_logical;
 	ext4_grpblk_t fe_start;
 	ext4_group_t fe_group;
-	unsigned long fe_len;
+	int fe_len;
 };
 
 /*
@@ -586,14 +586,14 @@ static void mb_free_blocks_double(struct
 	BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group));
 	for (i = 0; i < count; i++) {
 		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += first + i;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr,
 				   first + i, e4b->bd_group);
 		}
@@ -1226,14 +1226,14 @@ static int mb_free_blocks(struct inode *
 		order = 0;
 
 		if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
-			unsigned long blocknr;
+			ext4_fsblk_t blocknr;
 			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
 			blocknr += block;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 
 			ext4_error(sb, __FUNCTION__, "double-free of inode"
-				   " %lu's block %lu(bit %u in group %lu)\n",
+				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr, block,
 				   e4b->bd_group);
 		}
@@ -1416,7 +1416,7 @@ static void ext4_mb_use_best_found(struc
 					struct ext4_buddy *e4b)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
-	unsigned long ret;
+	int ret;
 
 	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
 	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
@@ -1609,10 +1609,12 @@ static int ext4_mb_find_by_goal(struct e
 			     ac->ac_g_ex.fe_len, &ex);
 
 	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
-		unsigned long start;
-		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
-			ex.fe_start + le32_to_cpu(es->s_first_data_block));
-		if (start % sbi->s_stripe == 0) {
+		ext4_fsblk_t start;
+
+		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) +
+			ex.fe_start + le32_to_cpu(es->s_first_data_block);
+		/* use do_div to get remainder (would be 64-bit modulo) */
+		if (do_div(start, sbi->s_stripe) == 0) {
 			ac->ac_found++;
 			ac->ac_b_ex = ex;
 			ext4_mb_use_best_found(ac, e4b);
@@ -1724,6 +1726,7 @@ static void ext4_mb_complex_scan_group(s
 /*
  * This is a special case for storages like raid5
  * we try to find stripe-aligned chunks for stripe-size requests
+ * XXX should do so at least for multiples of stripe size as well
  */
 static void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
 				 struct ext4_buddy *e4b)
@@ -1732,17 +1735,19 @@ static void ext4_mb_scan_aligned(struct 
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	void *bitmap = EXT4_MB_BITMAP(e4b);
 	struct ext4_free_extent ex;
-	unsigned long i;
-	unsigned long max;
+	ext4_fsblk_t first_group_block;
+	ext4_fsblk_t a;
+	ext4_grpblk_t i;
+	int max;
 
 	BUG_ON(sbi->s_stripe == 0);
 
-	/* find first stripe-aligned block */
-	i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
+	/* find first stripe-aligned block in group */
+	first_group_block = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
 		+ le32_to_cpu(sbi->s_es->s_first_data_block);
-	i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe;
-	i = (i - le32_to_cpu(sbi->s_es->s_first_data_block))
-			% EXT4_BLOCKS_PER_GROUP(sb);
+	a = first_group_block + sbi->s_stripe - 1;
+	do_div(a, sbi->s_stripe);
+	i = (a * sbi->s_stripe) - first_group_block;
 
 	while (i < sb->s_blocksize * 8) {
 		if (!mb_test_bit(i, bitmap)) {
@@ -2026,35 +2031,35 @@ static int ext4_mb_seq_history_show(stru
 	if (hs->op == EXT4_MB_HISTORY_ALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
 			"%-5u %-5s %-5u %-6u\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
-		sprintf(buf3, "%lu/%d/%lu@%lu", hs->goal.fe_group,
+			hs->orig.fe_logical);
+		sprintf(buf3, "%lu/%d/%u@%u", hs->goal.fe_group,
 			hs->goal.fe_start, hs->goal.fe_len,
-			(unsigned long)hs->goal.fe_logical);
+			hs->goal.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
 				hs->found, hs->groups, hs->cr, hs->flags,
 				hs->merged ? "M" : "", hs->tail,
 				hs->buddy ? 1 << hs->buddy : 0);
 	} else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
 		fmt = "%-5u %-8u %-23s %-23s %-23s\n";
-		sprintf(buf2, "%lu/%d/%lu@%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len,
-			(unsigned long)hs->result.fe_logical);
-		sprintf(buf, "%lu/%d/%lu@%lu", hs->orig.fe_group,
+			hs->result.fe_logical);
+		sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group,
 			hs->orig.fe_start, hs->orig.fe_len,
-			(unsigned long)hs->orig.fe_logical);
+			hs->orig.fe_logical);
 		seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s discard\n",
 				hs->pid, hs->ino, buf2);
 	} else if (hs->op == EXT4_MB_HISTORY_FREE) {
-		sprintf(buf2, "%lu/%d/%lu", hs->result.fe_group,
+		sprintf(buf2, "%lu/%d/%u", hs->result.fe_group,
 			hs->result.fe_start, hs->result.fe_len);
 		seq_printf(seq, "%-5u %-8u %-23s free\n",
 				hs->pid, hs->ino, buf2);
@@ -2943,7 +2948,7 @@ static int ext4_mb_mark_diskspace_used(s
 	struct buffer_head *gdp_bh;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
-	sector_t block;
+	ext4_fsblk_t block;
 	int err;
 
 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
@@ -2984,8 +2989,8 @@ static int ext4_mb_mark_diskspace_used(s
 				EXT4_SB(sb)->s_itb_per_group)) {
 
 		ext4_error(sb, __FUNCTION__,
-			   "Allocating block in system zone - block = %lu",
-			   (unsigned long) block);
+			   "Allocating block in system zone - block = %llu",
+			   block);
 	}
 #ifdef AGGRESSIVE_CHECK
 	{
@@ -3250,12 +3255,13 @@ static void ext4_mb_use_inode_pa(struct 
 				struct ext4_prealloc_space *pa)
 {
 	ext4_fsblk_t start;
-	unsigned long len;
+	ext4_fsblk_t end;
+	int len;
 
 	/* found preallocated blocks, use them */
 	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
-	len = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
-	len = len - start;
+	end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
+	len = end - start;
 	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
 					&ac->ac_b_ex.fe_start);
 	ac->ac_b_ex.fe_len = len;
@@ -3952,8 +3958,8 @@ static void ext4_mb_show_ac(struct ext4_
 
 	printk(KERN_ERR "EXT4-fs: can't allocate: status %d flags %d\n",
 			ac->ac_status, ac->ac_flags);
-	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
-			"best %lu/%lu/%lu@%lu cr %d\n",
+	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%u@%u, goal %lu/%lu/%u@%u, "
+			"best %lu/%lu/%u@%u cr %d\n",
 			ac->ac_o_ex.fe_group, ac->ac_o_ex.fe_start,
 			ac->ac_o_ex.fe_len, ac->ac_o_ex.fe_logical,
 			ac->ac_g_ex.fe_group, ac->ac_g_ex.fe_start,

Re: [PATCH] UPDATED3: types fixup for mballoc

[Andreas Dilger]

On Jan 08, 2008  13:54 -0600, Eric Sandeen wrote:
> Note, the calculations Andreas & I were discussing only work properly
> for stripe <= blocks per group... I don't know if we'd need to enforce
> that at mount time?

I think that would be prudent, but can be done in a separate patch.
If the RAID stripe width is so large that one has to do read-modify-write
for a whole group write (8MB @ 1kB blocksize, 128MB @ 4kB blocksize)
then I don't think we can use that to align allocations.

I think Aneesh might be working on getting s_raid_stripe_width from the
superblock, and we may as well do the sanity checking in the same patch.
If sb->s_raid_stripe_width > EXT4_BLOCKS_PER_GROUP, then as a fallback
I'd suggest using sb->s_raid_stride if < EXT4_BLOCKS_PER_GROUP, or just
ignoring both if unsuitable.

> I ran into a potential overflow in ext4_mb_scan_aligned, 
> and went looking for others in mballoc.  This patch hits a 
> few spots, compile-tested only at this point, comments welcome.
> 
> This patch:
> 
> changes fe_len to an int, I don't think we need it to be a long,
> looking at how it's used (should it be a grpblk_t?)  Also change
> anything assigned to return value of mb_find_extent, since it returns
> fe_len.
> 
> changes anything that does groupno * EXT4_BLOCKS_PER_GROUP
> or pa->pa_pstart + <whatever> to an ext4_fsblk_t
> 
> avoids 64-bit divides & modulos, and...
> 
> fixes up any related formats
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

You can add a "Signed-off-by: Andreas Dilger <adilger@sun.com>" too.
The revised calcs look good to me.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.