From 96150606e2fb82d242c9e4a414e4e922849f7bf7 Mon Sep 17 00:00:00 2001 From: Prasad Joshi Date: Sat, 26 Nov 2011 11:00:47 +0530 Subject: [PATCH] logfs: update page reference count for pined pages LogFS sets PG_private flag to indicate a pined page. We assumed that marking a page as private is enough to ensure its existence. But instead it is necessary to hold a reference count to the page. The change resolves the following BUG BUG: Bad page state in process flush-253:16 pfn:6a6d0 page flags: 0x100000000000808(uptodate|private) Suggested-and-Acked-by: Joern Engel Signed-off-by: Prasad Joshi --- fs/logfs/readwrite.c | 29 ++++++++++++++++++++++------- fs/logfs/segment.c | 37 +++++++++++++++++++++++++++++-------- 2 files changed, 51 insertions(+), 15 deletions(-) diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c index 2ac4217b7901..6d663e8ea6da 100644 --- a/fs/logfs/readwrite.c +++ b/fs/logfs/readwrite.c @@ -560,8 +560,13 @@ static void inode_free_block(struct super_block *sb, struct logfs_block *block) static void indirect_free_block(struct super_block *sb, struct logfs_block *block) { - ClearPagePrivate(block->page); - block->page->private = 0; + struct page *page = block->page; + + if (PagePrivate(page)) { + ClearPagePrivate(page); + page_cache_release(page); + set_page_private(page, 0); + } __free_block(sb, block); } @@ -650,8 +655,11 @@ static void alloc_data_block(struct inode *inode, struct page *page) logfs_unpack_index(page->index, &bix, &level); block = __alloc_block(inode->i_sb, inode->i_ino, bix, level); block->page = page; + SetPagePrivate(page); - page->private = (unsigned long)block; + page_cache_get(page); + set_page_private(page, (unsigned long) block); + block->ops = &indirect_block_ops; } @@ -1901,8 +1909,11 @@ static void move_page_to_inode(struct inode *inode, struct page *page) li->li_block = block; block->page = NULL; - page->private = 0; - ClearPagePrivate(page); + if (PagePrivate(page)) { + ClearPagePrivate(page); + page_cache_release(page); + set_page_private(page, 0); + } } static void move_inode_to_page(struct page *page, struct inode *inode) @@ -1918,8 +1929,12 @@ static void move_inode_to_page(struct page *page, struct inode *inode) BUG_ON(PagePrivate(page)); block->ops = &indirect_block_ops; block->page = page; - page->private = (unsigned long)block; - SetPagePrivate(page); + + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + set_page_private(page, (unsigned long) block); + } block->inode = NULL; li->li_block = NULL; diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c index 9d5187353255..6aee6092860d 100644 --- a/fs/logfs/segment.c +++ b/fs/logfs/segment.c @@ -86,7 +86,11 @@ int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len, BUG_ON(!page); /* FIXME: reserve a pool */ SetPageUptodate(page); memcpy(page_address(page) + offset, buf, copylen); - SetPagePrivate(page); + + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + } page_cache_release(page); buf += copylen; @@ -110,7 +114,10 @@ static void pad_partial_page(struct logfs_area *area) page = get_mapping_page(sb, index, 0); BUG_ON(!page); /* FIXME: reserve a pool */ memset(page_address(page) + offset, 0xff, len); - SetPagePrivate(page); + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + } page_cache_release(page); } } @@ -130,7 +137,10 @@ static void pad_full_pages(struct logfs_area *area) BUG_ON(!page); /* FIXME: reserve a pool */ SetPageUptodate(page); memset(page_address(page), 0xff, PAGE_CACHE_SIZE); - SetPagePrivate(page); + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + } page_cache_release(page); index++; no_indizes--; @@ -485,8 +495,12 @@ static void move_btree_to_page(struct inode *inode, struct page *page, mempool_free(item, super->s_alias_pool); } block->page = page; - SetPagePrivate(page); - page->private = (unsigned long)block; + + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + set_page_private(page, (unsigned long) block); + } block->ops = &indirect_block_ops; initialize_block_counters(page, block, data, 0); } @@ -536,8 +550,12 @@ void move_page_to_btree(struct page *page) list_add(&item->list, &block->item_list); } block->page = NULL; - ClearPagePrivate(page); - page->private = 0; + + if (PagePrivate(page)) { + ClearPagePrivate(page); + page_cache_release(page); + set_page_private(page, 0); + } block->ops = &btree_block_ops; err = alias_tree_insert(block->sb, block->ino, block->bix, block->level, block); @@ -702,7 +720,10 @@ void freeseg(struct super_block *sb, u32 segno) page = find_get_page(mapping, ofs >> PAGE_SHIFT); if (!page) continue; - ClearPagePrivate(page); + if (PagePrivate(page)) { + ClearPagePrivate(page); + page_cache_release(page); + } page_cache_release(page); } }