From 393737a28b63836b3f12613b1c031e6f32cc3476 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 2 Feb 2017 15:56:49 +0100 Subject: block: Unhash block device inodes on gendisk destruction Currently, block device inodes stay around after corresponding gendisk hash died until memory reclaim finds them and frees them. Since we will make block device inode pin the bdi, we want to free the block device inode as soon as the device goes away so that bdi does not stay around unnecessarily. Furthermore we need to avoid issues when new device with the same major,minor pair gets created since reusing the bdi structure would be rather difficult in this case. Unhashing block device inode on gendisk destruction nicely deals with these problems. Once last block device inode reference is dropped (which may be directly in del_gendisk()), the inode gets evicted. Furthermore if the major,minor pair gets reallocated, we are guaranteed to get new block device inode even if old block device inode is not yet evicted and thus we avoid issues with possible reuse of bdi. Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Change-Id: I41087d3bc818c4e58e0b4e20876e136ec1cbb07b Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git Git-commit: f44f1ab5a2dcd4e16eab850fd08e40ff2d0c28d4 [riteshh@codeaurora.org: resolved merge conflicts] Signed-off-by: Ritesh Harjani --- include/linux/fs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index c6de40668e08..82c5da84efe4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2331,6 +2331,7 @@ extern struct kmem_cache *names_cachep; #ifdef CONFIG_BLOCK extern int register_blkdev(unsigned int, const char *); extern void unregister_blkdev(unsigned int, const char *); +extern void bdev_unhash_inode(dev_t dev); extern struct block_device *bdget(dev_t); extern struct block_device *bdgrab(struct block_device *bdev); extern void bd_set_size(struct block_device *, loff_t size); -- cgit v1.2.3 From 1c6dd645345c75a6cafc6fc0ab41c60c7f381e99 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 2 Feb 2017 15:56:50 +0100 Subject: block: Use pointer to backing_dev_info from request_queue We will want to have struct backing_dev_info allocated separately from struct request_queue. As the first step add pointer to backing_dev_info to request_queue and convert all users touching it. No functional changes in this patch. Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Change-Id: I77fbb181de7e39c83fbfba8cfb128d6ace161f31 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git Git-commit: 97419acd22a0bacc52dbc34d5bbc96d315e48acb [riteshh@codeaurora.org: resolved merge conflicts] Signed-off-by: Ritesh Harjani --- include/linux/blkdev.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ae64a897622c..74f53ea5c267 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -332,7 +332,8 @@ struct request_queue { */ struct delayed_work delay_work; - struct backing_dev_info backing_dev_info; + struct backing_dev_info *backing_dev_info; + struct backing_dev_info _backing_dev_info; /* * The queue owner gets to use this for whatever they like. -- cgit v1.2.3 From b56ec58cde8aa78d30f0af2f71c5ffcbe5def4ce Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 2 Feb 2017 15:56:51 +0100 Subject: block: Dynamically allocate and refcount backing_dev_info Instead of storing backing_dev_info inside struct request_queue, allocate it dynamically, reference count it, and free it when the last reference is dropped. Currently only request_queue holds the reference but in the following patch we add other users referencing backing_dev_info. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Change-Id: Ibcee7b4c014018f9243cd3edbfd9c4a8877c3862 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git Git-commit: d03f6cdc1fc422accb734c7c07a661a0018d8631 [riteshh@codeaurora.org: resolved merge conflicts] Signed-off-by: Ritesh Harjani --- include/linux/backing-dev-defs.h | 2 ++ include/linux/backing-dev.h | 10 +++++++++- include/linux/blkdev.h | 1 - 3 files changed, 11 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 140c29635069..c104d4aed62a 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -10,6 +10,7 @@ #include #include #include +#include struct page; struct device; @@ -141,6 +142,7 @@ struct backing_dev_info { void *congested_data; /* Pointer to aux data for congested func */ char *name; + struct kref refcnt; /* Reference counter for the structure */ unsigned int min_ratio; unsigned int max_ratio, max_prop_frac; diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 89d3de3e096b..125bc67319b4 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -18,7 +18,14 @@ #include int __must_check bdi_init(struct backing_dev_info *bdi); -void bdi_exit(struct backing_dev_info *bdi); + +static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi) +{ + kref_get(&bdi->refcnt); + return bdi; +} + +void bdi_put(struct backing_dev_info *bdi); __printf(3, 4) int bdi_register(struct backing_dev_info *bdi, struct device *parent, @@ -29,6 +36,7 @@ void bdi_unregister(struct backing_dev_info *bdi); int __must_check bdi_setup_and_register(struct backing_dev_info *, char *); void bdi_destroy(struct backing_dev_info *bdi); +struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id); void wb_start_writeback(struct bdi_writeback *wb, long nr_pages, bool range_cyclic, enum wb_reason reason); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 74f53ea5c267..8150e164385c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -333,7 +333,6 @@ struct request_queue { struct delayed_work delay_work; struct backing_dev_info *backing_dev_info; - struct backing_dev_info _backing_dev_info; /* * The queue owner gets to use this for whatever they like. -- cgit v1.2.3 From 9c197e78d2888e51936f5794ae9356ef42aca160 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 2 Feb 2017 15:56:52 +0100 Subject: block: Make blk_get_backing_dev_info() safe without open bdev Currenly blk_get_backing_dev_info() is not safe to be called when the block device is not open as bdev->bd_disk is NULL in that case. However inode_to_bdi() uses this function and may be call called from flusher worker or other writeback related functions without bdev being open which leads to crashes such as: [113031.075540] Unable to handle kernel paging request for data at address 0x00000000 [113031.075614] Faulting instruction address: 0xc0000000003692e0 0:mon> t [c0000000fb65f900] c00000000036cb6c writeback_sb_inodes+0x30c/0x590 [c0000000fb65fa10] c00000000036ced4 __writeback_inodes_wb+0xe4/0x150 [c0000000fb65fa70] c00000000036d33c wb_writeback+0x30c/0x450 [c0000000fb65fb40] c00000000036e198 wb_workfn+0x268/0x580 [c0000000fb65fc50] c0000000000f3470 process_one_work+0x1e0/0x590 [c0000000fb65fce0] c0000000000f38c8 worker_thread+0xa8/0x660 [c0000000fb65fd80] c0000000000fc4b0 kthread+0x110/0x130 [c0000000fb65fe30] c0000000000098f0 ret_from_kernel_thread+0x5c/0x6c Signed-off-by: Jens Axboe Change-Id: I26955b919bd05fe34dc60aab1797ea2739ad5fd7 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git Git-commit: b1d2dc5659b41741f5a29b2ade76ffb4e5bb13d8 [riteshh@codeaurora.org: resolved merge conflicts] Signed-off-by: Ritesh Harjani --- include/linux/fs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index 82c5da84efe4..d5264dcaaa26 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -481,6 +481,7 @@ struct block_device { int bd_invalidated; struct gendisk * bd_disk; struct request_queue * bd_queue; + struct backing_dev_info *bd_bdi; struct list_head bd_list; /* * Private data. You must have bd_claim'ed the block_device -- cgit v1.2.3