From 53362a05ae683e12a20d9ffdf58a88094a0bed9d Mon Sep 17 00:00:00 2001 From: Jianpeng Ma Date: Thu, 2 Aug 2012 09:50:39 +0200 Subject: fs/block-dev.c:fix performance regression in O_DIRECT writes to md block devices For regular file, write operaion used blk_plug function.But for block file,write operation did not use blk_plug. This patch is also for write-cache mode for block-device. Signed-off-by: Jianpeng Ma Reviewed-by: NeilBrown Signed-off-by: Jens Axboe --- fs/block_dev.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs') diff --git a/fs/block_dev.c b/fs/block_dev.c index 1e519195d45b..38e721b35d45 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1578,10 +1578,12 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct file *file = iocb->ki_filp; + struct blk_plug plug; ssize_t ret; BUG_ON(iocb->ki_pos != pos); + blk_start_plug(&plug); ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); if (ret > 0 || ret == -EIOCBQUEUED) { ssize_t err; @@ -1590,6 +1592,7 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov, if (err < 0 && ret > 0) ret = err; } + blk_finish_plug(&plug); return ret; } EXPORT_SYMBOL_GPL(blkdev_aio_write); -- cgit v1.2.3 From 389d7b26d9e4f78b17366c23a3aa16b3c5cb3bde Mon Sep 17 00:00:00 2001 From: Alexey Khoroshilov Date: Thu, 9 Aug 2012 15:19:25 +0200 Subject: bio: Fix potential memory leak in bio_find_or_create_slab() Do not leak memory by updating pointer with potentially NULL realloc return value. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov Acked-by: Jeff Moyer Signed-off-by: Jens Axboe --- fs/bio.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'fs') diff --git a/fs/bio.c b/fs/bio.c index 73922abba832..fed1f799cb56 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -73,7 +73,7 @@ static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) { unsigned int sz = sizeof(struct bio) + extra_size; struct kmem_cache *slab = NULL; - struct bio_slab *bslab; + struct bio_slab *bslab, *new_bio_slabs; unsigned int i, entry = -1; mutex_lock(&bio_slab_lock); @@ -97,11 +97,12 @@ static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) if (bio_slab_nr == bio_slab_max && entry == -1) { bio_slab_max <<= 1; - bio_slabs = krealloc(bio_slabs, - bio_slab_max * sizeof(struct bio_slab), - GFP_KERNEL); - if (!bio_slabs) + new_bio_slabs = krealloc(bio_slabs, + bio_slab_max * sizeof(struct bio_slab), + GFP_KERNEL); + if (!new_bio_slabs) goto out_unlock; + bio_slabs = new_bio_slabs; } if (entry == -1) entry = bio_slab_nr++; -- cgit v1.2.3 From 647d1e4c5235763b83fbfe74a09d148edc6ca152 Mon Sep 17 00:00:00 2001 From: Fengguang Wu Date: Thu, 9 Aug 2012 15:23:09 +0200 Subject: block: move down direct IO plugging Move unplugging for direct I/O from around ->direct_IO() down to do_blockdev_direct_IO(). This implicitly adds plugging for direct writes. CC: Li Shaohua Acked-by: Jeff Moyer Signed-off-by: Wu Fengguang Signed-off-by: Jens Axboe --- fs/direct-io.c | 5 +++++ mm/filemap.c | 4 ---- 2 files changed, 5 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/direct-io.c b/fs/direct-io.c index 1faf4cb56f39..f86c720dba0e 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1062,6 +1062,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, unsigned long user_addr; size_t bytes; struct buffer_head map_bh = { 0, }; + struct blk_plug plug; if (rw & WRITE) rw = WRITE_ODIRECT; @@ -1177,6 +1178,8 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, PAGE_SIZE - user_addr / PAGE_SIZE); } + blk_start_plug(&plug); + for (seg = 0; seg < nr_segs; seg++) { user_addr = (unsigned long)iov[seg].iov_base; sdio.size += bytes = iov[seg].iov_len; @@ -1235,6 +1238,8 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, if (sdio.bio) dio_bio_submit(dio, &sdio); + blk_finish_plug(&plug); + /* * It is possible that, we return short IO due to end of file. * In that case, we need to release all the pages we got hold on. diff --git a/mm/filemap.c b/mm/filemap.c index 2b0952974cb9..384344575c37 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1412,12 +1412,8 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, retval = filemap_write_and_wait_range(mapping, pos, pos + iov_length(iov, nr_segs) - 1); if (!retval) { - struct blk_plug plug; - - blk_start_plug(&plug); retval = mapping->a_ops->direct_IO(READ, iocb, iov, pos, nr_segs); - blk_finish_plug(&plug); } if (retval > 0) { *ppos = pos + retval; -- cgit v1.2.3 From 676ce6d5ca3098339c028d44fe0427d1566a4d2d Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 23 Aug 2012 12:17:36 +0200 Subject: block: replace __getblk_slow misfix by grow_dev_page fix Commit 91f68c89d8f3 ("block: fix infinite loop in __getblk_slow") is not good: a successful call to grow_buffers() cannot guarantee that the page won't be reclaimed before the immediate next call to __find_get_block(), which is why there was always a loop there. Yesterday I got "EXT4-fs error (device loop0): __ext4_get_inode_loc:3595: inode #19278: block 664: comm cc1: unable to read itable block" on console, which pointed to this commit. I've been trying to bisect for weeks, why kbuild-on-ext4-on-loop-on-tmpfs sometimes fails from a missing header file, under memory pressure on ppc G5. I've never seen this on x86, and I've never seen it on 3.5-rc7 itself, despite that commit being in there: bisection pointed to an irrelevant pinctrl merge, but hard to tell when failure takes between 18 minutes and 38 hours (but so far it's happened quicker on 3.6-rc2). (I've since found such __ext4_get_inode_loc errors in /var/log/messages from previous weeks: why the message never appeared on console until yesterday morning is a mystery for another day.) Revert 91f68c89d8f3, restoring __getblk_slow() to how it was (plus a checkpatch nitfix). Simplify the interface between grow_buffers() and grow_dev_page(), and avoid the infinite loop beyond end of device by instead checking init_page_buffers()'s end_block there (I presume that's more efficient than a repeated call to blkdev_max_block()), returning -ENXIO to __getblk_slow() in that case. And remove akpm's ten-year-old "__getblk() cannot fail ... weird" comment, but that is worrying: are all users of __getblk() really now prepared for a NULL bh beyond end of device, or will some oops?? Signed-off-by: Hugh Dickins Cc: stable@vger.kernel.org # 3.0 3.2 3.4 3.5 Signed-off-by: Jens Axboe --- fs/buffer.c | 66 ++++++++++++++++++++++++++++--------------------------------- 1 file changed, 30 insertions(+), 36 deletions(-) (limited to 'fs') diff --git a/fs/buffer.c b/fs/buffer.c index 9f6d2e41281d..58e2e7b77372 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -914,7 +914,7 @@ link_dev_buffers(struct page *page, struct buffer_head *head) /* * Initialise the state of a blockdev page's buffers. */ -static void +static sector_t init_page_buffers(struct page *page, struct block_device *bdev, sector_t block, int size) { @@ -936,33 +936,41 @@ init_page_buffers(struct page *page, struct block_device *bdev, block++; bh = bh->b_this_page; } while (bh != head); + + /* + * Caller needs to validate requested block against end of device. + */ + return end_block; } /* * Create the page-cache page that contains the requested block. * - * This is user purely for blockdev mappings. + * This is used purely for blockdev mappings. */ -static struct page * +static int grow_dev_page(struct block_device *bdev, sector_t block, - pgoff_t index, int size) + pgoff_t index, int size, int sizebits) { struct inode *inode = bdev->bd_inode; struct page *page; struct buffer_head *bh; + sector_t end_block; + int ret = 0; /* Will call free_more_memory() */ page = find_or_create_page(inode->i_mapping, index, (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); if (!page) - return NULL; + return ret; BUG_ON(!PageLocked(page)); if (page_has_buffers(page)) { bh = page_buffers(page); if (bh->b_size == size) { - init_page_buffers(page, bdev, block, size); - return page; + end_block = init_page_buffers(page, bdev, + index << sizebits, size); + goto done; } if (!try_to_free_buffers(page)) goto failed; @@ -982,14 +990,14 @@ grow_dev_page(struct block_device *bdev, sector_t block, */ spin_lock(&inode->i_mapping->private_lock); link_dev_buffers(page, bh); - init_page_buffers(page, bdev, block, size); + end_block = init_page_buffers(page, bdev, index << sizebits, size); spin_unlock(&inode->i_mapping->private_lock); - return page; - +done: + ret = (block < end_block) ? 1 : -ENXIO; failed: unlock_page(page); page_cache_release(page); - return NULL; + return ret; } /* @@ -999,7 +1007,6 @@ failed: static int grow_buffers(struct block_device *bdev, sector_t block, int size) { - struct page *page; pgoff_t index; int sizebits; @@ -1023,22 +1030,14 @@ grow_buffers(struct block_device *bdev, sector_t block, int size) bdevname(bdev, b)); return -EIO; } - block = index << sizebits; + /* Create a page with the proper size buffers.. */ - page = grow_dev_page(bdev, block, index, size); - if (!page) - return 0; - unlock_page(page); - page_cache_release(page); - return 1; + return grow_dev_page(bdev, block, index, size, sizebits); } static struct buffer_head * __getblk_slow(struct block_device *bdev, sector_t block, int size) { - int ret; - struct buffer_head *bh; - /* Size must be multiple of hard sectorsize */ if (unlikely(size & (bdev_logical_block_size(bdev)-1) || (size < 512 || size > PAGE_SIZE))) { @@ -1051,21 +1050,20 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size) return NULL; } -retry: - bh = __find_get_block(bdev, block, size); - if (bh) - return bh; + for (;;) { + struct buffer_head *bh; + int ret; - ret = grow_buffers(bdev, block, size); - if (ret == 0) { - free_more_memory(); - goto retry; - } else if (ret > 0) { bh = __find_get_block(bdev, block, size); if (bh) return bh; + + ret = grow_buffers(bdev, block, size); + if (ret < 0) + return NULL; + if (ret == 0) + free_more_memory(); } - return NULL; } /* @@ -1321,10 +1319,6 @@ EXPORT_SYMBOL(__find_get_block); * which corresponds to the passed block_device, block and size. The * returned buffer has its reference count incremented. * - * __getblk() cannot fail - it just keeps trying. If you pass it an - * illegal block number, __getblk() will happily return a buffer_head - * which represents the non-existent block. Very weird. - * * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() * attempt is failing. FIXME, perhaps? */ -- cgit v1.2.3