As Gao Xiang reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202749
f2fs may skip pageout() due to incorrect page reference count. The problem here is that MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. But currently, f2fs won't add/del refcount when changing PG_private flag. Anyway, f2fs should follow MM's rule to make MM's related flows running as expected. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7...@aol.com/ Reported-by: Gao Xiang <gaoxian...@huawei.com> Signed-off-by: Chao Yu <yuch...@huawei.com> --- v2: - introduce generic function f2fs_{set,clear}_page_private() to wrap related operations as Jaegeuk suggested. fs/f2fs/checkpoint.c | 4 ++-- fs/f2fs/data.c | 23 ++++++++++------------- fs/f2fs/dir.c | 2 +- fs/f2fs/f2fs.h | 19 +++++++++++++++++++ fs/f2fs/node.c | 2 +- fs/f2fs/segment.c | 8 +++----- 6 files changed, 36 insertions(+), 22 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index c65a1e8e1e95..9ce38a0ad2fe 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -406,7 +406,7 @@ static int f2fs_set_meta_page_dirty(struct page *page) if (!PageDirty(page)) { __set_page_dirty_nobuffers(page); inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_META); - SetPagePrivate(page); + f2fs_set_page_private(page); f2fs_trace_pid(page); return 1; } @@ -957,7 +957,7 @@ void f2fs_update_dirty_page(struct inode *inode, struct page *page) inode_inc_dirty_pages(inode); spin_unlock(&sbi->inode_lock[type]); - SetPagePrivate(page); + f2fs_set_page_private(page); f2fs_trace_pid(page); } diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 3f3becd46362..14ee7dd0c6bc 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2715,8 +2715,7 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset, if (IS_ATOMIC_WRITTEN_PAGE(page)) return f2fs_drop_inmem_page(inode, page); - set_page_private(page, 0); - ClearPagePrivate(page); + f2fs_clear_page_private(page); } int f2fs_release_page(struct page *page, gfp_t wait) @@ -2730,8 +2729,7 @@ int f2fs_release_page(struct page *page, gfp_t wait) return 0; clear_cold_data(page); - set_page_private(page, 0); - ClearPagePrivate(page); + f2fs_clear_page_private(page); return 1; } @@ -2799,12 +2797,8 @@ int f2fs_migrate_page(struct address_space *mapping, return -EAGAIN; } - /* - * A reference is expected if PagePrivate set when move mapping, - * however F2FS breaks this for maintaining dirty page counts when - * truncating pages. So here adjusting the 'extra_count' make it work. - */ - extra_count = (atomic_written ? 1 : 0) - page_has_private(page); + /* one extra reference was held for atomic_write page */ + extra_count = atomic_written ? 1 : 0; rc = migrate_page_move_mapping(mapping, newpage, page, mode, extra_count); if (rc != MIGRATEPAGE_SUCCESS) { @@ -2825,9 +2819,12 @@ int f2fs_migrate_page(struct address_space *mapping, get_page(newpage); } - if (PagePrivate(page)) - SetPagePrivate(newpage); - set_page_private(newpage, page_private(page)); + if (PagePrivate(page)) { + f2fs_set_page_private(newpage); + set_page_private(newpage, page_private(page)); + + f2fs_clear_page_private(page); + } if (mode != MIGRATE_SYNC_NO_COPY) migrate_page_copy(newpage, page); diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 103f3686a045..fb647e58edb5 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -728,7 +728,7 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page, !f2fs_truncate_hole(dir, page->index, page->index + 1)) { f2fs_clear_page_cache_dirty_tag(page); clear_page_dirty_for_io(page); - ClearPagePrivate(page); + f2fs_clear_page_private(page); ClearPageUptodate(page); clear_cold_data(page); inode_dec_dirty_pages(dir); diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 3007759dd2dd..883354777d25 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2835,6 +2835,25 @@ static inline bool is_valid_data_blkaddr(struct f2fs_sb_info *sbi, return true; } +static inline void f2fs_set_page_private(struct page *page) +{ + if (PagePrivate(page)) + return; + + get_page(page); + SetPagePrivate(page); +} + +static inline void f2fs_clear_page_private(struct page *page) +{ + if (!PagePrivate(page)) + return; + + set_page_private(page, 0); + ClearPagePrivate(page); + f2fs_put_page(page, 0); +} + /* * file.c */ diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index f6ff84e29749..cf1f3dc79671 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1961,7 +1961,7 @@ static int f2fs_set_node_page_dirty(struct page *page) if (!PageDirty(page)) { __set_page_dirty_nobuffers(page); inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_NODES); - SetPagePrivate(page); + f2fs_set_page_private(page); f2fs_trace_pid(page); return 1; } diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index e730c334abba..42cc6fecdc36 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -191,8 +191,8 @@ void f2fs_register_inmem_page(struct inode *inode, struct page *page) f2fs_trace_pid(page); + f2fs_set_page_private(page); set_page_private(page, (unsigned long)ATOMIC_WRITTEN_PAGE); - SetPagePrivate(page); new = f2fs_kmem_cache_alloc(inmem_entry_slab, GFP_NOFS); @@ -280,8 +280,7 @@ static int __revoke_inmem_pages(struct inode *inode, ClearPageUptodate(page); clear_cold_data(page); } - set_page_private(page, 0); - ClearPagePrivate(page); + f2fs_clear_page_private(page); f2fs_put_page(page, 1); list_del(&cur->list); @@ -370,8 +369,7 @@ void f2fs_drop_inmem_page(struct inode *inode, struct page *page) kmem_cache_free(inmem_entry_slab, cur); ClearPageUptodate(page); - set_page_private(page, 0); - ClearPagePrivate(page); + f2fs_clear_page_private(page); f2fs_put_page(page, 0); trace_f2fs_commit_inmem_page(page, INMEM_INVALIDATE); -- 2.18.0.rc1
