On 04/10, Chao Yu wrote: > There may be subtle race condition, make PagePrivate and page_private > being inconsistent, result in decreasing page count incorrectly, > introduce a per-inode spinlock to avoid such condition.
No...what have you found? The set/clear.. were supposed to be done in page_lock, and checking the flag should not corrupt any memory. > > Signed-off-by: Chao Yu <[email protected]> > --- > fs/f2fs/f2fs.h | 19 ++++++++++++++++++- > fs/f2fs/super.c | 2 ++ > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index c378aedcadea..6b31bef5853e 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -856,6 +856,8 @@ struct f2fs_inode_info { > > unsigned int atomic_write_cnt; > loff_t original_i_size; /* original i_size before atomic write > */ > + > + spinlock_t private_lock; /* protect page->private */ > }; > > static inline void get_read_extent_info(struct extent_info *ext, > @@ -1413,21 +1415,28 @@ static inline bool page_private_##name(struct page > *page) \ > test_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ > } > > +static inline struct f2fs_inode_info *F2FS_I(struct inode *inode); > #define PAGE_PRIVATE_SET_FUNC(name, flagname) \ > static inline void set_page_private_##name(struct page *page) \ > { \ > + unsigned long flags; \ > + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); \ > if (!PagePrivate(page)) \ > attach_page_private(page, (void *)page->private); \ > set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); \ > set_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ > + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, > flags); \ > } > > #define PAGE_PRIVATE_CLEAR_FUNC(name, flagname) \ > static inline void clear_page_private_##name(struct page *page) \ > { \ > + unsigned long flags; \ > + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); \ > clear_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ > - if (page_private(page) == BIT(PAGE_PRIVATE_NOT_POINTER)) \ > + if (page_private(page) == (BIT(PAGE_PRIVATE_NOT_POINTER))) \ > detach_page_private(page); \ > + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, > flags); \ > } > > PAGE_PRIVATE_GET_FUNC(nonpointer, NOT_POINTER); > @@ -1456,17 +1465,25 @@ static inline unsigned long > get_page_private_data(struct page *page) > > static inline void set_page_private_data(struct page *page, unsigned long > data) > { > + unsigned long flags; > + > + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); > if (!PagePrivate(page)) > attach_page_private(page, 0); > set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); > page_private(page) |= data << PAGE_PRIVATE_MAX; > + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, > flags); > } > > static inline void clear_page_private_data(struct page *page) > { > + unsigned long flags; > + > + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); > page_private(page) &= GENMASK(PAGE_PRIVATE_MAX - 1, 0); > if (page_private(page) == BIT(PAGE_PRIVATE_NOT_POINTER)) > detach_page_private(page); > + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, > flags); > } > > /* For compression */ > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index a1b570a5e50f..555424dd85fd 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -1419,6 +1419,8 @@ static struct inode *f2fs_alloc_inode(struct > super_block *sb) > init_f2fs_rwsem(&fi->i_gc_rwsem[WRITE]); > init_f2fs_rwsem(&fi->i_xattr_sem); > > + spin_lock_init(&fi->private_lock); > + > /* Will be used by directory only */ > fi->i_dir_level = F2FS_SB(sb)->dir_level; > > -- > 2.25.1 _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
