kernel.git/block/genhd.c, branch linux-2.6.37.y

Fix over-zealous flush_disk when changing device size.

2011-03-07T23:05:12Z

commit 93b270f76e7ef3b81001576860c2701931cdc78b upstream. There are two cases when we call flush_disk. In one, the device has disappeared (check_disk_change) so any data will hold becomes irrelevant. In the oter, the device has changed size (check_disk_size_change) so data we hold may be irrelevant. In both cases it makes sense to discard any 'clean' buffers, so they will be read back from the device if needed. In the former case it makes sense to discard 'dirty' buffers as there will never be anywhere safe to write the data. In the second case it *does*not* make sense to discard dirty buffers as that will lead to file system corruption when you simply enlarge the containing devices. flush_disk calls __invalidate_devices. __invalidate_device calls both invalidate_inodes and invalidate_bdev. invalidate_inodes *does* discard I_DIRTY inodes and this does lead to fs corruption. invalidate_bev *does*not* discard dirty pages, but I don't really care about that at present. So this patch adds a flag to __invalidate_device (calling it __invalidate_device2) to indicate whether dirty buffers should be killed, and this is passed to invalidate_inodes which can choose to skip dirty inodes. flusk_disk then passes true from check_disk_change and false from check_disk_size_change. dm avoids tripping over this problem by calling i_size_write directly rathher than using check_disk_size_change. md does use check_disk_size_change and so is affected. This regression was introduced by commit 608aeef17a which causes check_disk_size_change to call flush_disk, so it is suitable for any kernel since 2.6.27. Acked-by: Jeff Moyer Cc: Andrew Patterson Cc: Jens Axboe Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman

block: fix accounting bug on cross partition merges

2011-02-17T23:14:17Z

commit 09e099d4bafea3b15be003d548bdf94b4b6e0e17 upstream. /proc/diskstats would display a strange output as follows. $ cat /proc/diskstats |grep sda 8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089 8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691 ~~~~~~~~~~ 8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390 8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92 8 4 sda4 4 0 8 0 0 0 0 0 0 0 0 8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137 Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE. The detailed root cause is as follows. Assuming that there are two partition, sda1 and sda2. 1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight is 0 and sda2's one is 1. | hd_struct->in_flight --------------------------- sda1 | 0 sda2 | 1 --------------------------- 2. A bio belongs to sda1 is issued and is merged into the request mentioned on step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed from sda2 region to sda1 region. However the two partition's hd_struct->in_flight are not changed. | hd_struct->in_flight --------------------------- sda1 | 0 sda2 | 1 --------------------------- 3. The request is finished and blk_account_io_done() is called. In this case, sda2's hd_struct->in_flight, not a sda1's one, is decremented. | hd_struct->in_flight --------------------------- sda1 | -1 sda2 | 1 --------------------------- The patch fixes the problem by caching the partition lookup inside the request structure, hence making sure that the increment and decrement will always happen on the same partition struct. This also speeds up IO with accounting enabled, since it cuts down on the number of lookups we have to do. Also add a refcount to struct hd_struct to keep the partition in memory as long as users exist. We use kref_test_and_get() to ensure we don't add a reference to a partition which is going away. Signed-off-by: Jerome Marchand Signed-off-by: Yasuaki Ishimatsu Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

Revert "block: fix accounting bug on cross partition merges"

2010-10-24T20:06:02Z

This reverts commit 7681bfeeccff5efa9eb29bf09249a3c400b15327. Conflicts: include/linux/genhd.h It has numerous issues with the cleanup path and non-elevator devices. Revert it for now so we can come up with a clean version without rushing things. Signed-off-by: Jens Axboe

Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6

2010-10-23T02:36:42Z

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (31 commits) driver core: Display error codes when class suspend fails Driver core: Add section count to memory_block struct Driver core: Add mutex for adding/removing memory blocks Driver core: Move find_memory_block routine hpilo: Despecificate driver from iLO generation driver core: Convert link_mem_sections to use find_memory_block_hinted. driver core: Introduce find_memory_block_hinted which utilizes kset_find_obj_hinted. kobject: Introduce kset_find_obj_hinted. driver core: fix build for CONFIG_BLOCK not enabled driver-core: base: change to new flag variable sysfs: only access bin file vm_ops with the active lock sysfs: Fail bin file mmap if vma close is implemented. FW_LOADER: fix kconfig dependency warning on HOTPLUG uio: Statically allocate uio_class and use class .dev_attrs. uio: Support 2^MINOR_BITS minors uio: Cleanup irq handling. uio: Don't clear driver data uio: Fix lack of locking in init_uio_class SYSFS: Allow boot time switching between deprecated and modern sysfs layout driver core: remove CONFIG_SYSFS_DEPRECATED_V2 but keep it for block devices ...

SYSFS: Allow boot time switching between deprecated and modern sysfs layout

2010-10-22T17:16:43Z

I have some systems which need legacy sysfs due to old tools that are making assumptions that a directory can never be a symlink to another directory, and it's a big hazzle to compile separate kernels for them. This patch turns CONFIG_SYSFS_DEPRECATED into a run time option that can be switched on/off the kernel command line. This way the same binary can be used in both cases with just a option on the command line. The old CONFIG_SYSFS_DEPRECATED_V2 option is still there to set the default. I kept the weird name to not break existing config files. Also the compat code can be still completely disabled by undefining CONFIG_SYSFS_DEPRECATED_SWITCH -- just the optimizer takes care of this now instead of lots of ifdefs. This makes the code look nicer. v2: This is an updated version on top of Kay's patch to only handle the block devices. I tested it on my old systems and that seems to work. Cc: axboe@kernel.dk Signed-off-by: Andi Kleen Cc: Kay Sievers Signed-off-by: Greg Kroah-Hartman

block: fix accounting bug on cross partition merges

2010-10-19T07:07:02Z

/proc/diskstats would display a strange output as follows. $ cat /proc/diskstats |grep sda 8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089 8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691 ~~~~~~~~~~ 8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390 8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92 8 4 sda4 4 0 8 0 0 0 0 0 0 0 0 8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137 Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE. The detailed root cause is as follows. Assuming that there are two partition, sda1 and sda2. 1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight is 0 and sda2's one is 1. | hd_struct->in_flight --------------------------- sda1 | 0 sda2 | 1 --------------------------- 2. A bio belongs to sda1 is issued and is merged into the request mentioned on step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed from sda2 region to sda1 region. However the two partition's hd_struct->in_flight are not changed. | hd_struct->in_flight --------------------------- sda1 | 0 sda2 | 1 --------------------------- 3. The request is finished and blk_account_io_done() is called. In this case, sda2's hd_struct->in_flight, not a sda1's one, is decremented. | hd_struct->in_flight --------------------------- sda1 | -1 sda2 | 1 --------------------------- The patch fixes the problem by caching the partition lookup inside the request structure, hence making sure that the increment and decrement will always happen on the same partition struct. This also speeds up IO with accounting enabled, since it cuts down on the number of lookups we have to do. When reloading partition tables, quiesce IO to ensure that no request references to the partition struct exists. When it is safe to free the partition table, the IO for that device is restarted again. Signed-off-by: Yasuaki Ishimatsu Cc: stable@kernel.org Signed-off-by: Jens Axboe

block: Fix race during disk initialization

2010-09-16T18:36:36Z

When a new disk is being discovered, add_disk() first ties the bdev to gendisk (via register_disk()->blkdev_get()) and only after that calls bdi_register_bdev(). Because register_disk() also creates disk's kobject, it can happen that userspace manages to open and modify the device's data (or inode) before its BDI is properly initialized leading to a warning in __mark_inode_dirty(). Fix the problem by registering BDI early enough. This patch addresses https://bugzilla.kernel.org/show_bug.cgi?id=16312 Cc: stable@kernel.org Reported-by: Larry Finger Signed-off-by: Jan Kara Signed-off-by: Jens Axboe

init: add support for root devices specified by partition UUID

2010-09-15T14:14:03Z

This is the third patch in a series which adds support for storing partition metadata, optionally, off of the hd_struct. One major use for that data is being able to resolve partition by other identities than just the index on a block device. Device enumeration varies by platform and there's a benefit to being able to use something like EFI GPT's GUIDs to determine the correct block device and partition to mount as the root. This change adds that support to root= by adding support for the following syntax: root=PARTUUID=hex-uuid Signed-off-by: Will Drewry Signed-off-by: Jens Axboe

block, partition: add partition_meta_info to hd_struct

2010-09-15T14:13:18Z

I'm reposting this patch series as v4 since there have been no additional comments, and I cleaned up one extra bit of unneeded code (in 3/3). The patches are against Linus's tree: 2bfc96a127bc1cc94d26bfaa40159966064f9c8c (2.6.36-rc3). Would this patchset be suitable for inclusion in an mm branch? This changes adds a partition_meta_info struct which itself contains a union of structures that provide partition table specific metadata. This change leaves the union empty. The subsequent patch includes an implementation for CONFIG_EFI_PARTITION-based metadata. Signed-off-by: Will Drewry Signed-off-by: Jens Axboe

block: remove all rcu head initializations

2010-05-21T18:01:02Z

Remove all rcu head inits. We don't care about the RCU head state before passing it to call_rcu() anyway. Only leave the "on_stack" variants so debugobjects can keep track of objects on stack. Signed-off-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney Signed-off-by: Jens Axboe