block: return EBUSY from drop_partitions on mounted whole disk device
Subsystems (2)
PATCH 1/1 block: return EBUSY from drop_partitions on mounted whole disk device
The BLKRRPART ioctl already fails today if any partition under the device is mounted. However, if we mkfs a whole disk and mount it, BLKRRPART happily proceeds down the invalidation path, which seems like a bad idea.
Check whether the whole device is mounted by checking bd_super, and return -EBUSY if so.
---
I don't know for sure if this is the right approach, but figure I'll ask in the form of a patch. ;)
block/partition-generic.c +1 -1
@@ -397,7 +397,7 @@ static int drop_partitions(struct gendisk *disk, struct block_device *bdev)struct hd_struct *part;int res; -if (bdev->bd_part_count) +if (bdev->bd_super || bdev->bd_part_count)return -EBUSY ; res =invalidate_partition (disk,0 );if (res)
Quoted 5 lines · Eric Sandeen
The BLKRRPART ioctl already fails today if any partition under the device is mounted. However, if we mkfs a whole disk and mount it, BLKRRPART happily proceeds down the invalidation path, which seems like a bad idea.
Quoted 8 lines
Check whether the whole device is mounted by checking
bd_super, and return-EBUSYif so.Signed-off-by Eric Sandeen <[email protected]>---
I don't know for sure if this is the right approach, but figure I'll ask in the form of a patch. ;)
I'm now thinking that this is not the right approach. :( I got a bug report stating that during some md raid1 testing with replacing failed disks, filesystems were losing data. I haven't reproduced that part yet, but...
It's hitting the "bd_super" case added in the patch below, and returning -EBUSY to md when mdadm tries to to remove a disk:
# mdadm /dev/md0 -r /dev/loop0 mdadm: hot remove failed for /dev/loop0: Device or resource busy
[ 1309.894718] md: cannot remove active disk loop0 from md0 ... [ 1309.906270] drop_partitions: bd_part_count 0 bd_super ffff880111364000 [ 1309.919295] drop_partitions: s_id md0 uuid 6bb155fe-3ea1-4a84-b66a-d44d44829c36 [ 1309.933878] CPU: 2 PID: 531 Comm: systemd-udevd Not tainted 3.10.0+ #4
I had not thought about "bd_super" existing in this case; I just had my filesystem hat on. I'm still digging through the somewhat messy bug report, I don't know how he's getting to data loss, but that patch might be half-baked if nothing else because of this behavior...
Note that there are no partitions on md0...
This patch should probably be reverted for now, unless there is some obvious better fix.
-Eric
Quoted 14 lines
block/partition-generic.c +1
-1@@ -397,7 +397,7 @@ static int drop_partitions(struct gendisk *disk, struct block_device *bdev)struct hd_struct *part;int res; -if (bdev->bd_part_count) +if (bdev->bd_super || bdev->bd_part_count)return -EBUSY ; res =invalidate_partition (disk,0 );if (res)
Quoted 23 lines · Eric Sandeen
Quoted 5 lines · Eric Sandeen
The BLKRRPART ioctl already fails today if any partition under the device is mounted. However, if we mkfs a whole disk and mount it, BLKRRPART happily proceeds down the invalidation path, which seems like a bad idea.
Quoted 8 lines
Check whether the whole device is mounted by checking
bd_super, and return-EBUSYif so.Signed-off-by Eric Sandeen <[email protected]>---
I don't know for sure if this is the right approach, but figure I'll ask in the form of a patch. ;)
I'm now thinking that this is not the right approach. :( I got a bug report stating that during some md raid1 testing with replacing failed disks, filesystems were losing data. I haven't reproduced that part yet, but...
It's hitting the "
bd_super" case added in the patch below, and returning-EBUSYto md when mdadm tries to to remove a disk:
Quoted 7 lines
# mdadm /dev/md0 -r /dev/loop0 mdadm: hot remove failed for /dev/loop0: Device or resource busy[ 1309.894718] md: cannot remove active disk loop0 from md0 ... [ 1309.906270] drop_partitions: bd_part_count 0 bd_super ffff880111364000 [ 1309.919295] drop_partitions: s_id md0 uuid 6bb155fe-3ea1-4a84-b66a-d44d44829c36 [ 1309.933878] CPU: 2 PID: 531 Comm: systemd-udevd Not tainted 3.10.0+ #4
Urk, forgot I was testing an old kernel, sorry. I think upstream is ok. I'll shut up and investigate more.
-Eric
Quoted 20 lines · Eric Sandeen
Quoted 5 lines · Eric Sandeen
The BLKRRPART ioctl already fails today if any partition under the device is mounted. However, if we mkfs a whole disk and mount it, BLKRRPART happily proceeds down the invalidation path, which seems like a bad idea.
Quoted 8 lines
Check whether the whole device is mounted by checking
bd_super, and return-EBUSYif so.Signed-off-by Eric Sandeen <[email protected]>---
I don't know for sure if this is the right approach, but figure I'll ask in the form of a patch. ;)
I'm now thinking that this is not the right approach. :( I got a bug report stating that during some md raid1 testing with replacing failed disks, filesystems were losing data. I haven't reproduced that part yet, but...
Quoted 5 lines
It's hitting the "
bd_super" case added in the patch below, and returning-EBUSYto md when mdadm tries to to remove a disk:# mdadm /dev/md0 -r /dev/loop0 mdadm: hot remove failed for /dev/loop0: Device or resource busy
FWIW, just ignore me, I was being an idiot. a) the patch *prevents* the corruption; does not cause it; without the EBUSY, drop_partitions will get to invalidate_inodes() etc, and no wonder data is lost. And b) the above EBUSY is because I forgot to fail the disk first. :/
Nothing to see here, move along, sorry!
-Eric
Jens Axboe
maintainerQuoted 29 lines · Eric Sandeen
Quoted 20 lines · Eric Sandeen
Quoted 5 lines · Eric Sandeen
The BLKRRPART ioctl already fails today if any partition under the device is mounted. However, if we mkfs a whole disk and mount it, BLKRRPART happily proceeds down the invalidation path, which seems like a bad idea.
Quoted 8 lines
Check whether the whole device is mounted by checking
bd_super, and return-EBUSYif so.Signed-off-by Eric Sandeen <[email protected]>---
I don't know for sure if this is the right approach, but figure I'll ask in the form of a patch. ;)
I'm now thinking that this is not the right approach. :( I got a bug report stating that during some md raid1 testing with replacing failed disks, filesystems were losing data. I haven't reproduced that part yet, but...
Quoted 5 lines
It's hitting the "
bd_super" case added in the patch below, and returning-EBUSYto md when mdadm tries to to remove a disk:# mdadm /dev/md0 -r /dev/loop0 mdadm: hot remove failed for /dev/loop0: Device or resource busy
Quoted 6 lines
FWIW, just ignore me, I was being an idiot. a) the patch *prevents* the corruption; does not cause it; without the EBUSY,
drop_partitionswill get toinvalidate_inodes()etc, and no wonder data is lost. And b) the above EBUSY is because I forgot to fail the disk first. :/Nothing to see here, move along, sorry!
Still beats a regression :-)
Signature · 1 line
Jens Axboe