On Monday 20 Jul 2015 16:34:35 Liu Bo wrote: > On Mon, Jun 01, 2015 at 08:52:49PM +0530, Chandan Rajendra wrote: > > In subpagesize-blocksize scenario a page can have more than one block. So > > in addition to PagePrivate2 flag, we would have to track the I/O status of > > each block of a page to reliably mark the ordered extent as complete. > > > > Signed-off-by: Chandan Rajendra <chan...@linux.vnet.ibm.com> > > --- > > > > fs/btrfs/extent_io.c | 19 +-- > > fs/btrfs/extent_io.h | 5 +- > > fs/btrfs/inode.c | 346 > > +++++++++++++++++++++++++++++++++++------------- fs/btrfs/ordered-data.c > > | 17 +++ > > fs/btrfs/ordered-data.h | 4 + > > 5 files changed, 287 insertions(+), 104 deletions(-) > > > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > > index 0110abc..55f900a 100644 > > --- a/fs/btrfs/extent_io.c > > +++ b/fs/btrfs/extent_io.c > > @@ -4545,11 +4545,10 @@ int extent_invalidatepage(struct extent_io_tree > > *tree,> > > * to drop the page. > > */ > > > > static int try_release_extent_state(struct extent_map_tree *map, > > > > - struct extent_io_tree *tree, > > - struct page *page, gfp_t mask) > > + struct extent_io_tree *tree, > > + struct page *page, u64 start, u64 end, > > + gfp_t mask) > > > > { > > > > - u64 start = page_offset(page); > > - u64 end = start + PAGE_CACHE_SIZE - 1; > > > > int ret = 1; > > > > if (test_range_bit(tree, start, end, > > > > @@ -4583,12 +4582,12 @@ static int try_release_extent_state(struct > > extent_map_tree *map,> > > * map records are removed > > */ > > > > int try_release_extent_mapping(struct extent_map_tree *map, > > > > - struct extent_io_tree *tree, struct page *page, > > - gfp_t mask) > > + struct extent_io_tree *tree, struct page *page, > > + u64 start, u64 end, gfp_t mask) > > > > { > > > > struct extent_map *em; > > > > - u64 start = page_offset(page); > > - u64 end = start + PAGE_CACHE_SIZE - 1; > > + u64 orig_start = start; > > + u64 orig_end = end; > > > > if ((mask & __GFP_WAIT) && > > > > page->mapping->host->i_size > 16 * 1024 * 1024) { > > > > @@ -4622,7 +4621,9 @@ int try_release_extent_mapping(struct > > extent_map_tree *map,> > > free_extent_map(em); > > > > } > > > > } > > > > - return try_release_extent_state(map, tree, page, mask); > > + return try_release_extent_state(map, tree, page, > > + orig_start, orig_end, > > + mask); > > > > } > > > > /* > > > > diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h > > index 8fe5ac3..c629e53 100644 > > --- a/fs/btrfs/extent_io.h > > +++ b/fs/btrfs/extent_io.h > > @@ -217,8 +217,9 @@ typedef struct extent_map *(get_extent_t)(struct inode > > *inode,> > > void extent_io_tree_init(struct extent_io_tree *tree, > > > > struct address_space *mapping); > > > > int try_release_extent_mapping(struct extent_map_tree *map, > > > > - struct extent_io_tree *tree, struct page *page, > > - gfp_t mask); > > + struct extent_io_tree *tree, struct page *page, > > + u64 start, u64 end, > > + gfp_t mask); > > > > int try_release_extent_buffer(struct page *page); > > int lock_extent(struct extent_io_tree *tree, u64 start, u64 end); > > int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, > > > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > > index bff60c6..bfffc62 100644 > > --- a/fs/btrfs/inode.c > > +++ b/fs/btrfs/inode.c > > @@ -2990,56 +2990,115 @@ static void finish_ordered_fn(struct btrfs_work > > *work)> > > btrfs_finish_ordered_io(ordered_extent); > > > > } > > > > -static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 > > end, - struct extent_state *state, int uptodate) > > +static void mark_blks_io_complete(struct btrfs_ordered_extent *ordered, > > + u64 blk, u64 nr_blks, int uptodate) > > > > { > > > > - struct inode *inode = page->mapping->host; > > + struct inode *inode = ordered->inode; > > > > struct btrfs_root *root = BTRFS_I(inode)->root; > > > > - struct btrfs_ordered_extent *ordered_extent = NULL; > > > > struct btrfs_workqueue *wq; > > btrfs_work_func_t func; > > > > - u64 ordered_start, ordered_end; > > > > int done; > > > > - trace_btrfs_writepage_end_io_hook(page, start, end, uptodate); > > + while (nr_blks--) { > > + if (test_and_set_bit(blk, ordered->blocks_done)) { > > + blk++; > > + continue; > > + } > > > > - ClearPagePrivate2(page); > > -loop: > > - ordered_extent = btrfs_lookup_ordered_range(inode, start, > > - end - start + 1); > > - if (!ordered_extent) > > - goto out; > > + done = btrfs_dec_test_ordered_pending(inode, &ordered, > > + ordered->file_offset > > + + (blk << inode->i_sb- >s_blocksize_bits), > > + root->sectorsize, > > + uptodate); > > + if (done) { > > + if (btrfs_is_free_space_inode(inode)) { > > + wq = root->fs_info->endio_freespace_worker; > > + func = btrfs_freespace_write_helper; > > + } else { > > + wq = root->fs_info->endio_write_workers; > > + func = btrfs_endio_write_helper; > > + } > > > > - ordered_start = max_t(u64, start, ordered_extent->file_offset); > > - ordered_end = min_t(u64, end, > > - ordered_extent->file_offset + ordered_extent->len - 1); > > - > > - done = btrfs_dec_test_ordered_pending(inode, &ordered_extent, > > - ordered_start, > > - ordered_end - ordered_start + 1, > > - uptodate); > > - if (done) { > > - if (btrfs_is_free_space_inode(inode)) { > > - wq = root->fs_info->endio_freespace_worker; > > - func = btrfs_freespace_write_helper; > > - } else { > > - wq = root->fs_info->endio_write_workers; > > - func = btrfs_endio_write_helper; > > + btrfs_init_work(&ordered->work, func, > > + finish_ordered_fn, NULL, NULL); > > + btrfs_queue_work(wq, &ordered->work); > > > > } > > > > - btrfs_init_work(&ordered_extent->work, func, > > - finish_ordered_fn, NULL, NULL); > > - btrfs_queue_work(wq, &ordered_extent->work); > > + blk++; > > > > } > > > > +} > > > > - btrfs_put_ordered_extent(ordered_extent); > > +int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end, > > + struct extent_state *state, int uptodate) > > +{ > > + struct inode *inode = page->mapping->host; > > + struct btrfs_root *root = BTRFS_I(inode)->root; > > + struct btrfs_ordered_extent *ordered_extent = NULL; > > + u64 blk, nr_blks; > > + int clear; > > > > - start = ordered_end + 1; > > + trace_btrfs_writepage_end_io_hook(page, start, end, uptodate); > > > > - if (start < end) > > - goto loop; > > + while (start < end) { > > + ordered_extent = btrfs_lookup_ordered_extent(inode, start); > > + if (!ordered_extent) { > > + start += root->sectorsize; > > + continue; > > + } > > + > > + blk = (start - ordered_extent->file_offset) > > + >> inode->i_sb->s_blocksize_bits; > > + > > + nr_blks = (min(end, ordered_extent->file_offset + ordered_extent->len - > > 1) + + 1 - start) >> inode->i_sb->s_blocksize_bits; > > + > > + BUG_ON(!nr_blks); > > + > > + mark_blks_io_complete(ordered_extent, blk, nr_blks, uptodate); > > Range [start, end] is surely contiguous, so why are we processing blocks > one by one in mark_blks_io_complete()? > Liu, Thanks for pointing it out. We can actually get rid of the loop in mark_blks_io_complete() and set the bits (corresponding to the blocks in the range [start, end]) at btrfs_ordered_extent->blocks_done using bitmap_set().
> Same question for invalidatepage(). Unfortunately for btrfs_invalidatepage(), we need to loop across the blocks sequentially. Consider the following file operations, 1. Write blocks [0, 7] to a file. Assume all the 8 blocks are part of the same ordered extent. 2. Punch a hole starting at block 4 and spanning two blocks in length. Here btrfs_invalidatepage() gets invoked and hence btrfs_ordered_extent->bytes_left gets decremented by (2 * sectorsize). 3. Punch a hole starting at block 3 and spanning two blocks in length. Again, btrfs_invalidatepage() gets invoked and hence btrfs_ordered_extent->bytes_left gets decremented by (2 * sectorsize). This isn't corrent since block 4 was already accounted for in step 2. Hence we will have to check each block's completion status before invoking btrfs_dec_test_ordered_pending(). > > Thanks, > > -liubo > > > + > > + start = ordered_extent->file_offset + ordered_extent->len; > > + > > + btrfs_put_ordered_extent(ordered_extent); > > + } > > + > > + start = page_offset(page); > > + end = start + PAGE_CACHE_SIZE - 1; > > + clear = 1; > > + > > + while (start < end) { > > + ordered_extent = btrfs_lookup_ordered_extent(inode, start); > > + if (!ordered_extent) { > > + start += root->sectorsize; > > + continue; > > + } > > + > > + blk = (start - ordered_extent->file_offset) > > + >> inode->i_sb->s_blocksize_bits; > > + nr_blks = (min(end, ordered_extent->file_offset + ordered_extent->len - > > 1) + + 1 - start) >> inode->i_sb- >s_blocksize_bits; > > + > > + BUG_ON(!nr_blks); > > + > > + while (nr_blks--) { > > + if (!test_bit(blk++, ordered_extent->blocks_done)) { > > + clear = 0; > > + break; > > + } > > + } > > + > > + if (!clear) { > > + btrfs_put_ordered_extent(ordered_extent); > > + break; > > + } > > + > > + start += ordered_extent->len; > > + > > + btrfs_put_ordered_extent(ordered_extent); > > + } > > + > > + if (clear) > > + ClearPagePrivate2(page); > > > > -out: > > return 0; > > > > } > > > > @@ -8472,7 +8531,9 @@ btrfs_readpages(struct file *file, struct > > address_space *mapping,> > > return extent_readpages(tree, mapping, pages, nr_pages, > > > > btrfs_get_extent); > > > > } > > > > -static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags) > > + > > +static int __btrfs_releasepage(struct page *page, u64 start, u64 end, > > + gfp_t gfp_flags) > > > > { > > > > struct extent_io_tree *tree; > > struct extent_map_tree *map; > > > > @@ -8480,31 +8541,149 @@ static int __btrfs_releasepage(struct page *page, > > gfp_t gfp_flags)> > > tree = &BTRFS_I(page->mapping->host)->io_tree; > > map = &BTRFS_I(page->mapping->host)->extent_tree; > > > > - ret = try_release_extent_mapping(map, tree, page, gfp_flags); > > - if (ret == 1) > > + > > + ret = try_release_extent_mapping(map, tree, page, start, end, > > + gfp_flags); > > + if ((ret == 1) && ((end - start + 1) == PAGE_CACHE_SIZE)) { > > > > clear_page_extent_mapped(page); > > > > + } else { > > + ret = 0; > > + } > > > > return ret; > > > > } > > > > static int btrfs_releasepage(struct page *page, gfp_t gfp_flags) > > { > > > > + u64 start = page_offset(page); > > + u64 end = start + PAGE_CACHE_SIZE - 1; > > + > > > > if (PageWriteback(page) || PageDirty(page)) > > > > return 0; > > > > - return __btrfs_releasepage(page, gfp_flags & GFP_NOFS); > > + > > + return __btrfs_releasepage(page, start, end, gfp_flags & GFP_NOFS); > > +} > > + > > +static void invalidate_ordered_extent_blocks(struct inode *inode, > > + struct btrfs_ordered_extent *ordered, > > + u64 locked_start, u64 locked_end, > > + u64 cur, > > + int inode_evicting) > > +{ > > + struct btrfs_root *root = BTRFS_I(inode)->root; > > + struct btrfs_ordered_inode_tree *ordered_tree; > > + struct extent_io_tree *tree; > > + u64 blk, blk_done, nr_blks; > > + u64 end; > > + u64 new_len; > > + > > + tree = &BTRFS_I(inode)->io_tree; > > + > > + end = min(locked_end, ordered->file_offset + ordered->len - 1); > > + > > + if (!inode_evicting) { > > + clear_extent_bit(tree, cur, end, > > + EXTENT_DIRTY | EXTENT_DELALLOC | > > + EXTENT_DO_ACCOUNTING | > > + EXTENT_DEFRAG, 1, 0, NULL, > > + GFP_NOFS); > > + unlock_extent(tree, locked_start, locked_end); > > + } > > + > > + > > + ordered_tree = &BTRFS_I(inode)->ordered_tree; > > + spin_lock_irq(&ordered_tree->lock); > > + set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags); > > + new_len = cur - ordered->file_offset; > > + if (new_len < ordered->truncated_len) > > + ordered->truncated_len = new_len; > > + > > + blk = (cur - ordered->file_offset) >> inode->i_sb->s_blocksize_bits; > > + nr_blks = (end + 1 - cur) >> inode->i_sb->s_blocksize_bits; > > + > > + while (nr_blks--) { > > + blk_done = !test_and_set_bit(blk, ordered->blocks_done); > > + if (blk_done) { > > + spin_unlock_irq(&ordered_tree->lock); > > + if (btrfs_dec_test_ordered_pending(inode, &ordered, > > + ordered- >file_offset + (blk << inode->i_sb->s_blocksize_bits), > > + root- >sectorsize, > > + 1)) > > + btrfs_finish_ordered_io(ordered); > > + > > + spin_lock_irq(&ordered_tree->lock); > > + } > > + blk++; > > + } > > + > > + spin_unlock_irq(&ordered_tree->lock); > > + > > + if (!inode_evicting) > > + lock_extent_bits(tree, locked_start, locked_end, 0, NULL); > > +} > > + > > +static int page_blocks_written(struct page *page) > > +{ > > + struct btrfs_ordered_extent *ordered; > > + struct btrfs_root *root; > > + struct inode *inode; > > + unsigned long outstanding_blk; > > + u64 page_start, page_end; > > + u64 blk, last_blk, nr_blks; > > + u64 cur; > > + u64 len; > > + > > + inode = page->mapping->host; > > + root = BTRFS_I(inode)->root; > > + > > + page_start = page_offset(page); > > + page_end = page_start + PAGE_CACHE_SIZE - 1; > > + > > + cur = page_start; > > + while (cur < page_end) { > > + ordered = btrfs_lookup_ordered_extent(inode, cur); > > + if (!ordered) { > > + cur += root->sectorsize; > > + continue; > > + } > > + > > + blk = (cur - ordered->file_offset) > > + >> inode->i_sb->s_blocksize_bits; > > + len = min(page_end, ordered->file_offset + ordered->len - 1) > > + - cur + 1; > > + nr_blks = len >> inode->i_sb->s_blocksize_bits; > > + > > + last_blk = blk + nr_blks - 1; > > + > > + outstanding_blk = find_next_zero_bit(ordered->blocks_done, > > + ordered->len >> inode->i_sb- >s_blocksize_bits, > > + blk); > > + if (outstanding_blk <= last_blk) { > > + btrfs_put_ordered_extent(ordered); > > + return 0; > > + } > > + > > + btrfs_put_ordered_extent(ordered); > > + cur += len; > > + } > > + > > + return 1; > > > > } > > > > static void btrfs_invalidatepage(struct page *page, unsigned int offset, > > > > - unsigned int length) > > + unsigned int length) > > > > { > > > > struct inode *inode = page->mapping->host; > > > > + struct btrfs_root *root = BTRFS_I(inode)->root; > > > > struct extent_io_tree *tree; > > struct btrfs_ordered_extent *ordered; > > > > - struct extent_state *cached_state = NULL; > > - u64 page_start = page_offset(page); > > - u64 page_end = page_start + PAGE_CACHE_SIZE - 1; > > + u64 start, end, cur; > > + u64 page_start, page_end; > > > > int inode_evicting = inode->i_state & I_FREEING; > > > > + page_start = page_offset(page); > > + page_end = page_start + PAGE_CACHE_SIZE - 1; > > + > > > > /* > > > > * we have the page locked, so new writeback can't start, > > * and the dirty bit won't be cleared while we are here. > > > > @@ -8515,73 +8694,54 @@ static void btrfs_invalidatepage(struct page > > *page, unsigned int offset,> > > wait_on_page_writeback(page); > > > > tree = &BTRFS_I(inode)->io_tree; > > > > - if (offset) { > > + > > + start = round_up(offset, root->sectorsize); > > + end = round_down(offset + length, root->sectorsize) - 1; > > + if (end - start + 1 < root->sectorsize) { > > > > btrfs_releasepage(page, GFP_NOFS); > > return; > > > > } > > > > + start = round_up(page_start + offset, root->sectorsize); > > + end = round_down(page_start + offset + length, > > + root->sectorsize) - 1; > > + > > > > if (!inode_evicting) > > > > - lock_extent_bits(tree, page_start, page_end, 0, &cached_state); > > - ordered = btrfs_lookup_ordered_range(inode, page_start, > > PAGE_CACHE_SIZE); > > - if (ordered) { > > - /* > > - * IO on this page will never be started, so we need > > - * to account for any ordered extents now > > - */ > > - if (!inode_evicting) > > - clear_extent_bit(tree, page_start, page_end, > > - EXTENT_DIRTY | EXTENT_DELALLOC | > > - EXTENT_LOCKED | EXTENT_DO_ACCOUNTING | > > - EXTENT_DEFRAG, 1, 0, &cached_state, > > - GFP_NOFS); > > - /* > > - * whoever cleared the private bit is responsible > > - * for the finish_ordered_io > > - */ > > - if (TestClearPagePrivate2(page)) { > > - struct btrfs_ordered_inode_tree *tree; > > - u64 new_len; > > + lock_extent_bits(tree, start, end, 0, NULL); > > > > - tree = &BTRFS_I(inode)->ordered_tree; > > + cur = start; > > + while (cur < end) { > > + ordered = btrfs_lookup_ordered_extent(inode, cur); > > + if (!ordered) { > > + cur += root->sectorsize; > > + continue; > > + } > > > > - spin_lock_irq(&tree->lock); > > - set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags); > > - new_len = page_start - ordered->file_offset; > > - if (new_len < ordered->truncated_len) > > - ordered->truncated_len = new_len; > > - spin_unlock_irq(&tree->lock); > > + invalidate_ordered_extent_blocks(inode, ordered, > > + start, end, cur, > > + inode_evicting); > > > > - if (btrfs_dec_test_ordered_pending(inode, &ordered, > > - page_start, > > - PAGE_CACHE_SIZE, 1)) > > - btrfs_finish_ordered_io(ordered); > > - } > > + cur = min(end + 1, ordered->file_offset + ordered->len); > > > > btrfs_put_ordered_extent(ordered); > > > > - if (!inode_evicting) { > > - cached_state = NULL; > > - lock_extent_bits(tree, page_start, page_end, 0, > > - &cached_state); > > - } > > > > } > > > > - if (!inode_evicting) { > > - clear_extent_bit(tree, page_start, page_end, > > - EXTENT_LOCKED | EXTENT_DIRTY | > > - EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | > > - EXTENT_DEFRAG, 1, 1, > > - &cached_state, GFP_NOFS); > > + if (page_blocks_written(page)) > > + ClearPagePrivate2(page); > > > > - __btrfs_releasepage(page, GFP_NOFS); > > + if (!inode_evicting) { > > + clear_extent_bit(tree, start, end, > > + EXTENT_LOCKED | EXTENT_DIRTY | > > + EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | > > + EXTENT_DEFRAG, 1, 1, NULL, GFP_NOFS); > > > > } > > > > - ClearPageChecked(page); > > - if (PagePrivate(page)) { > > - ClearPagePrivate(page); > > - set_page_private(page, 0); > > - page_cache_release(page); > > + if (!offset && length == PAGE_CACHE_SIZE) { > > + WARN_ON(!__btrfs_releasepage(page, start, end, GFP_NOFS)); > > + ClearPageChecked(page); > > > > } > > > > } > > > > + > > > > /* > > > > * btrfs_page_mkwrite() is not allowed to change the file size as it gets > > * called from a page fault handler when a page is first dirtied. Hence > > we must> > > diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c > > index 157cc54..8e614ca 100644 > > --- a/fs/btrfs/ordered-data.c > > +++ b/fs/btrfs/ordered-data.c > > @@ -189,12 +189,25 @@ static int __btrfs_add_ordered_extent(struct inode > > *inode, u64 file_offset,> > > struct btrfs_ordered_inode_tree *tree; > > struct rb_node *node; > > struct btrfs_ordered_extent *entry; > > > > + u64 nr_longs; > > > > tree = &BTRFS_I(inode)->ordered_tree; > > entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS); > > if (!entry) > > > > return -ENOMEM; > > > > + nr_longs = BITS_TO_LONGS(len >> inode->i_sb->s_blocksize_bits); > > + if (nr_longs == 1) { > > + entry->blocks_done = &entry->blocks_bitmap; > > + } else { > > + entry->blocks_done = kzalloc(nr_longs * sizeof(unsigned long), > > + GFP_NOFS); > > + if (!entry->blocks_done) { > > + kmem_cache_free(btrfs_ordered_extent_cache, entry); > > + return -ENOMEM; > > + } > > + } > > + > > > > entry->file_offset = file_offset; > > entry->start = start; > > entry->len = len; > > > > @@ -553,6 +566,10 @@ void btrfs_put_ordered_extent(struct > > btrfs_ordered_extent *entry)> > > list_del(&sum->list); > > kfree(sum); > > > > } > > > > + > > + if (entry->blocks_done != &entry->blocks_bitmap) > > + kfree(entry->blocks_done); > > + > > > > kmem_cache_free(btrfs_ordered_extent_cache, entry); > > > > } > > > > } > > > > diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h > > index e96cd4c..4b3356a 100644 > > --- a/fs/btrfs/ordered-data.h > > +++ b/fs/btrfs/ordered-data.h > > @@ -140,6 +140,10 @@ struct btrfs_ordered_extent { > > > > struct completion completion; > > struct btrfs_work flush_work; > > struct list_head work_list; > > > > + > > + /* bitmap to track the blocks that have been written to disk */ > > + unsigned long *blocks_done; > > + unsigned long blocks_bitmap; > > > > }; > > > > /* -- chandan -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html