From 08b39fbd59781729da9fb6367decaf4804a22721 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Thu, 8 Oct 2015 13:27:34 +0800 Subject: f2fs crypto: fix racing of accessing encrypted page among different competitors Since we use different page cache (normally inode's page cache for R/W and meta inode's page cache for GC) to cache the same physical block which is belong to an encrypted inode. Writeback of these two page cache should be exclusive, but now we didn't handle writeback state well, so there may be potential racing problem: a) kworker: f2fs_gc: - f2fs_write_data_pages - f2fs_write_data_page - do_write_data_page - write_data_page - f2fs_submit_page_mbio (page#1 in inode's page cache was queued in f2fs bio cache, and be ready to write to new blkaddr) - gc_data_segment - move_encrypted_block - pagecache_get_page (page#2 in meta inode's page cache was cached with the invalid datas of physical block located in new blkaddr) - f2fs_submit_page_mbio (page#1 was submitted, later, page#2 with invalid data will be submitted) b) f2fs_gc: - gc_data_segment - move_encrypted_block - f2fs_submit_page_mbio (page#1 in meta inode's page cache was queued in f2fs bio cache, and be ready to write to new blkaddr) user thread: - f2fs_write_begin - f2fs_submit_page_bio (we submit the request to block layer to update page#2 in inode's page cache with physical block located in new blkaddr, so here we may read gabbage data from new blkaddr since GC hasn't writebacked the page#1 yet) This patch fixes above potential racing problem for encrypted inode. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 20 +++++++++++--------- fs/f2fs/f2fs.h | 1 + fs/f2fs/file.c | 5 +++++ fs/f2fs/gc.c | 12 ++++++++++-- fs/f2fs/segment.c | 17 +++++++++++++++++ 5 files changed, 44 insertions(+), 11 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 228537657723..77dfc9eee380 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -956,21 +956,14 @@ submit_and_realloc: if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) { - struct page *cpage; ctx = f2fs_get_crypto_ctx(inode); if (IS_ERR(ctx)) goto set_error_page; /* wait the page to be moved by cleaning */ - cpage = find_lock_page( - META_MAPPING(F2FS_I_SB(inode)), - block_nr); - if (cpage) { - f2fs_wait_on_page_writeback(cpage, - DATA); - f2fs_put_page(cpage, 1); - } + f2fs_wait_on_encrypted_page_writeback( + F2FS_I_SB(inode), block_nr); } bio = bio_alloc(GFP_KERNEL, @@ -1064,6 +1057,11 @@ int do_write_data_page(struct f2fs_io_info *fio) } if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) { + + /* wait for GCed encrypted page writeback */ + f2fs_wait_on_encrypted_page_writeback(F2FS_I_SB(inode), + fio->blk_addr); + fio->encrypted_page = f2fs_encrypt(inode, fio->page); if (IS_ERR(fio->encrypted_page)) { err = PTR_ERR(fio->encrypted_page); @@ -1452,6 +1450,10 @@ put_next: f2fs_wait_on_page_writeback(page, DATA); + /* wait for GCed encrypted page writeback */ + if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) + f2fs_wait_on_encrypted_page_writeback(sbi, dn.data_blkaddr); + if (len == PAGE_CACHE_SIZE) goto out_update; if (PageUptodate(page)) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 94cf6bc1303f..c3443da2f991 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1792,6 +1792,7 @@ void f2fs_replace_block(struct f2fs_sb_info *, struct dnode_of_data *, void allocate_data_block(struct f2fs_sb_info *, struct page *, block_t, block_t *, struct f2fs_summary *, int); void f2fs_wait_on_page_writeback(struct page *, enum page_type); +void f2fs_wait_on_encrypted_page_writeback(struct f2fs_sb_info *, block_t); void write_data_summaries(struct f2fs_sb_info *, block_t); void write_node_summaries(struct f2fs_sb_info *, block_t); int lookup_journal_in_cursum(struct f2fs_summary_block *, diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 5d2a2ee35742..91c51a6d42dd 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -87,6 +87,11 @@ static int f2fs_vm_page_mkwrite(struct vm_area_struct *vma, mapped: /* fill the page */ f2fs_wait_on_page_writeback(page, DATA); + + /* wait for GCed encrypted page writeback */ + if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) + f2fs_wait_on_encrypted_page_writeback(sbi, dn.data_blkaddr); + /* if gced page is attached, don't write to cold segment */ clear_cold_data(page); out: diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 3f19634e2aa5..af7c24caeef9 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -559,8 +559,16 @@ static void move_encrypted_block(struct inode *inode, block_t bidx) if (err) goto out; - if (unlikely(dn.data_blkaddr == NULL_ADDR)) + if (unlikely(dn.data_blkaddr == NULL_ADDR)) { + ClearPageUptodate(page); goto put_out; + } + + /* + * don't cache encrypted data into meta inode until previous dirty + * data were writebacked to avoid racing between GC and flush. + */ + f2fs_wait_on_page_writeback(page, DATA); get_node_info(fio.sbi, dn.nid, &ni); set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version); @@ -589,7 +597,7 @@ static void move_encrypted_block(struct inode *inode, block_t bidx) goto put_page_out; set_page_dirty(fio.encrypted_page); - f2fs_wait_on_page_writeback(fio.encrypted_page, META); + f2fs_wait_on_page_writeback(fio.encrypted_page, DATA); if (clear_page_dirty_for_io(fio.encrypted_page)) dec_page_count(fio.sbi, F2FS_DIRTY_META); diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 5337fd6fdc32..f37c21233b5c 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1484,6 +1484,23 @@ void f2fs_wait_on_page_writeback(struct page *page, } } +void f2fs_wait_on_encrypted_page_writeback(struct f2fs_sb_info *sbi, + block_t blkaddr) +{ + struct page *cpage; + + if (blkaddr == NEW_ADDR) + return; + + f2fs_bug_on(sbi, blkaddr == NULL_ADDR); + + cpage = find_lock_page(META_MAPPING(sbi), blkaddr); + if (cpage) { + f2fs_wait_on_page_writeback(cpage, DATA); + f2fs_put_page(cpage, 1); + } +} + static int read_compacted_summaries(struct f2fs_sb_info *sbi) { struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi); -- cgit v1.2.3-58-ga151