From: Michael Halcrow Subject: [PATCH 1/5] ext4: Adds callback support for bio read completion Date: Wed, 23 Jul 2014 14:23:24 -0700 Message-ID: <1406150608-19351-2-git-send-email-mhalcrow@google.com> References: <1406150608-19351-1-git-send-email-mhalcrow@google.com> Cc: zohar@linux.vnet.ibm.com, mhalcrow@google.com, herbert@gondor.apana.org.au, pavel@ucw.cz, hch@infradead.org, lczerner@redhat.com, tytso@mit.edu, tyhicks@canonical.com, serge.hallyn@canonical.com To: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: Received: from mail-oa0-f74.google.com ([209.85.219.74]:64549 "EHLO mail-oa0-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933282AbaGWV27 (ORCPT ); Wed, 23 Jul 2014 17:28:59 -0400 Received: by mail-oa0-f74.google.com with SMTP id eb12so530144oac.1 for ; Wed, 23 Jul 2014 14:28:59 -0700 (PDT) In-Reply-To: <1406150608-19351-1-git-send-email-mhalcrow@google.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Adds callback support for bio read completion. This supports data transformation such as encryption. Signed-off-by: Michael Halcrow --- fs/buffer.c | 46 +++++++++++++++++++++++++++++++++++++++------ include/linux/blk_types.h | 4 ++++ include/linux/buffer_head.h | 8 ++++++++ 3 files changed, 52 insertions(+), 6 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index eba6e4f..a5527c5 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -296,7 +296,7 @@ static void free_more_memory(void) * I/O completion handler for block_read_full_page() - pages * which come unlocked at the end of I/O. */ -static void end_buffer_async_read(struct buffer_head *bh, int uptodate) +void end_buffer_async_read(struct buffer_head *bh, int uptodate) { unsigned long flags; struct buffer_head *first; @@ -339,6 +339,13 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); local_irq_restore(flags); + if (bh->b_private) { + struct bio *bio = (struct bio *)bh->b_private; + BUG_ON(!bio->bi_cb); + if (!bio->bi_cb(bio, !(page_uptodate && !PageError(page)))) + goto out; + } + /* * If none of the buffers had errors and they are all * uptodate then we can set the page uptodate. @@ -346,6 +353,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) if (page_uptodate && !PageError(page)) SetPageUptodate(page); unlock_page(page); +out: return; still_busy: @@ -353,6 +361,7 @@ still_busy: local_irq_restore(flags); return; } +EXPORT_SYMBOL_GPL(end_buffer_async_read); /* * Completion handler for block_write_full_page() - pages which are unlocked @@ -431,11 +440,12 @@ EXPORT_SYMBOL(end_buffer_async_write); * PageLocked prevents anyone from starting writeback of a page which is * under read I/O (PageWriteback is only ever set against a locked page). */ -static void mark_buffer_async_read(struct buffer_head *bh) +void mark_buffer_async_read(struct buffer_head *bh) { bh->b_end_io = end_buffer_async_read; set_buffer_async_read(bh); } +EXPORT_SYMBOL_GPL(mark_buffer_async_read); static void mark_buffer_async_write_endio(struct buffer_head *bh, bh_end_io_t *handler) @@ -1654,14 +1664,17 @@ static inline int block_size_bits(unsigned int blocksize) return ilog2(blocksize); } -static struct buffer_head *create_page_buffers(struct page *page, struct inode *inode, unsigned int b_state) +struct buffer_head *create_page_buffers(struct page *page, struct inode *inode, + unsigned int b_state) { BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) - create_empty_buffers(page, 1 << ACCESS_ONCE(inode->i_blkbits), b_state); + create_empty_buffers(page, 1 << ACCESS_ONCE(inode->i_blkbits), + b_state); return page_buffers(page); } +EXPORT_SYMBOL_GPL(create_page_buffers); /* * NOTE! All mapped/uptodate combinations are valid: @@ -3009,7 +3022,8 @@ static void guard_bh_eod(int rw, struct bio *bio, struct buffer_head *bh) } } -int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) +int _submit_bh_cb(int rw, struct buffer_head *bh, unsigned long bio_flags, + bio_completion_cb_t *cb, void *cb_ctx) { struct bio *bio; int ret = 0; @@ -3043,6 +3057,8 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) bio->bi_end_io = end_bio_bh_io_sync; bio->bi_private = bh; + bio->bi_cb = cb; + bio->bi_cb_ctx = cb_ctx; bio->bi_flags |= bio_flags; /* Take care of bh's that straddle the end of the device */ @@ -3054,6 +3070,12 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) rw |= REQ_PRIO; bio_get(bio); + + if (bio->bi_cb) { + BUG_ON(bh->b_private); + bh->b_private = bio; + } + submit_bio(rw, bio); if (bio_flagged(bio, BIO_EOPNOTSUPP)) @@ -3062,14 +3084,26 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) bio_put(bio); return ret; } + +int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) +{ + return _submit_bh_cb(rw, bh, bio_flags, NULL, NULL); +} EXPORT_SYMBOL_GPL(_submit_bh); int submit_bh(int rw, struct buffer_head *bh) { - return _submit_bh(rw, bh, 0); + return submit_bh_cb(rw, bh, NULL, NULL); } EXPORT_SYMBOL(submit_bh); +int submit_bh_cb(int rw, struct buffer_head *bh, bio_completion_cb_t *cb, + void *cb_ctx) +{ + return _submit_bh_cb(rw, bh, 0, cb, cb_ctx); +} +EXPORT_SYMBOL_GPL(submit_bh_cb); + /** * ll_rw_block: low-level access to block devices (DEPRECATED) * @rw: whether to %READ or %WRITE or maybe %READA (readahead) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 66c2167..06102df 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -16,6 +16,7 @@ struct io_context; struct cgroup_subsys_state; typedef void (bio_end_io_t) (struct bio *, int); typedef void (bio_destructor_t) (struct bio *); +typedef int (bio_completion_cb_t) (struct bio *, int); /* * was unsigned short, but we might as well be ready for > 64kB I/O pages @@ -96,6 +97,9 @@ struct bio { struct bio_set *bi_pool; + bio_completion_cb_t *bi_cb; /* completion callback */ + void *bi_cb_ctx; /* callback context */ + /* * We can inline a number of vecs at the end of the bio, to avoid * double allocations for a small number of bio_vecs. This member diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 324329c..24ea03a 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -160,7 +160,9 @@ void create_empty_buffers(struct page *, unsigned long, unsigned long b_state); void end_buffer_read_sync(struct buffer_head *bh, int uptodate); void end_buffer_write_sync(struct buffer_head *bh, int uptodate); +void end_buffer_async_read(struct buffer_head *bh, int uptodate); void end_buffer_async_write(struct buffer_head *bh, int uptodate); +void mark_buffer_async_read(struct buffer_head *bh); /* Things to do with buffers at mapping->private_list */ void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); @@ -169,6 +171,8 @@ void invalidate_inode_buffers(struct inode *); int remove_inode_buffers(struct inode *inode); int sync_mapping_buffers(struct address_space *mapping); void unmap_underlying_metadata(struct block_device *bdev, sector_t block); +struct buffer_head *create_page_buffers(struct page *page, struct inode *inode, + unsigned int b_state); void mark_buffer_async_write(struct buffer_head *bh); void __wait_on_buffer(struct buffer_head *); @@ -191,7 +195,11 @@ int sync_dirty_buffer(struct buffer_head *bh); int __sync_dirty_buffer(struct buffer_head *bh, int rw); void write_dirty_buffer(struct buffer_head *bh, int rw); int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags); +int _submit_bh_cb(int rw, struct buffer_head *bh, unsigned long bio_flags, + bio_completion_cb_t *cb, void *cb_ctx); int submit_bh(int, struct buffer_head *); +int submit_bh_cb(int rw, struct buffer_head *bh, bio_completion_cb_t *cb, + void *cb_ctx); void write_boundary_block(struct block_device *bdev, sector_t bblock, unsigned blocksize); int bh_uptodate_or_lock(struct buffer_head *bh); -- 2.0.0.526.g5318336