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.
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
