[PATCH] block: allow deleting zero length partition

[PATCH] block: allow deleting zero length partition

[Tejun Heo]

delete_partition() was noop for zero length partition.  As the
addition code allows creating zero lenght partition and deletion is
assumed to always succeed, this causes memory leak for zero length
partitions.  Allow zero length partitions to end their meaningless
lives.

While at it, allow deleting zero lenght partition via
BLKPG_DEL_PARTITION ioctl too.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 block/ioctl.c         |    2 --
 fs/partitions/check.c |    2 --
 2 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 52d6385..f0178c4 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -67,8 +67,6 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 		case BLKPG_DEL_PARTITION:
 			if (!disk->part[part-1])
 				return -ENXIO;
-			if (disk->part[part - 1]->nr_sects == 0)
-				return -ENXIO;
 			bdevp = bdget_disk(disk, part);
 			if (!bdevp)
 				return -ENOMEM;
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 6149e4b..3e0bf3f 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -325,8 +325,6 @@ void delete_partition(struct gendisk *disk, int part)
 
 	if (!p)
 		return;
-	if (!p->nr_sects)
-		return;
 	disk->part[part-1] = NULL;
 	p->start_sect = 0;
 	p->nr_sects = 0;
-- 
1.5.4.5

[PATCHSET 1/3 blk-for-2.6.28] block: misc fixes and improvements

[Tejun Heo]

Hello,

This patchset contains the following five patches containing misc
fixes and improvements.

  0001-block-fix-partition-info-printouts.patch
  0002-block-don-t-grab-block_class_lock-unnecessarily.patch
  0003-block-use-class_dev_iterator-instead-of-class_for_e.patch
  0004-block-allow-deleting-zero-length-partition.patch
  0005-block-update-add_partition-error-handling.patch

Recent block_class iteration updates 5c6f35c5..27f3025 introduced a
few bugs and trivial user visible behavior change.  0001-0003 update
those issues and simplify related code using new class iterator.

0004 fixes deletion of zero sized partitions.

d805dda4 tried to fix error handling path in add_partition() but had a
few problems.  0005 fixes those and moves busy partition check into
add_partition().

This patchset is against

  blk-for-2.6.28 (9abd7c437c02e7448fb1d2d3cfc0b9c1ab77cf2d)
+ [1] klist-dont-iterate-over-deleted-entries
+ [2] use-klist-for-class-device-list-and-implement-iterator

and available in the following git tree.

  http://git.kernel.org/?p=linux/kernel/git/tj/misc.git;a=shortlog;h=block-misc-fixes
  git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git block-misc-fixes

with the following combined diffstat

 block/genhd.c         |  246 +++++++++++++++++++-------------------------------
 block/ioctl.c         |    9 -
 fs/partitions/check.c |   42 ++++----
 3 files changed, 121 insertions(+), 176 deletions(-)

Thanks.

--
tejun

[1] http://article.gmane.org/gmane.linux.kernel/725706
[2] http://article.gmane.org/gmane.linux.kernel/725708

[PATCH] block: allow deleting zero length partition

[Tejun Heo]

delete_partition() was noop for zero length partition.  As the
addition code allows creating zero lenght partition and deletion is
assumed to always succeed, this causes memory leak for zero length
partitions.  Allow zero length partitions to end their meaningless
lives.

While at it, allow deleting zero lenght partition via
BLKPG_DEL_PARTITION ioctl too.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 block/ioctl.c         |    2 --
 fs/partitions/check.c |    2 --
 2 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 375c579..c722de0 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -68,8 +68,6 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 		case BLKPG_DEL_PARTITION:
 			if (!disk->part[part-1])
 				return -ENXIO;
-			if (disk->part[part - 1]->nr_sects == 0)
-				return -ENXIO;
 			bdevp = bdget_disk(disk, part);
 			if (!bdevp)
 				return -ENOMEM;
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 7d6b34e..1b1808e 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -325,8 +325,6 @@ void delete_partition(struct gendisk *disk, int part)
 
 	if (!p)
 		return;
-	if (!p->nr_sects)
-		return;
 	disk->part[part-1] = NULL;
 	p->start_sect = 0;
 	p->nr_sects = 0;
-- 
1.5.4.5