From 965aab1cfc13dacc3d5ad0d8d8eb4e0a7ea8c1d1 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 6 Mar 2018 11:23:16 -0800 Subject: [PATCH] btrfs: Use filemap_range_has_page() The current implementation of btrfs_page_exists_in_range() gives the wrong answer if the workingset code has stored a shadow entry in the page cache. The filemap_range_has_page() function does not have this problem, and it's shared code, so use it instead. eigned-off-by: Matthew Wilcox Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/btrfs_inode.h | 6 ++++- fs/btrfs/inode.c | 70 -------------------------------------------------- 2 files changed, 5 insertions(+), 71 deletions(-) diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index f527e99..078a53e 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -364,6 +364,10 @@ static inline void btrfs_print_data_csum_error(struct btrfs_inode *inode, logical_start, csum, csum_expected, mirror_num); } -bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end); +static inline bool btrfs_page_exists_in_range(struct inode *inode, + loff_t start, loff_t end) +{ + return filemap_range_has_page(inode->i_mapping, start, end); +} #endif diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 4a07cce..c924554 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7464,76 +7464,6 @@ out: return ret; } -bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end) -{ - struct radix_tree_root *root = &inode->i_mapping->page_tree; - bool found = false; - void **pagep = NULL; - struct page *page = NULL; - unsigned long start_idx; - unsigned long end_idx; - - start_idx = start >> PAGE_SHIFT; - - /* - * end is the last byte in the last page. end == start is legal - */ - end_idx = end >> PAGE_SHIFT; - - rcu_read_lock(); - - /* Most of the code in this while loop is lifted from - * find_get_page. It's been modified to begin searching from a - * page and return just the first page found in that range. If the - * found idx is less than or equal to the end idx then we know that - * a page exists. If no pages are found or if those pages are - * outside of the range then we're fine (yay!) */ - while (page == NULL && - radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) { - page = radix_tree_deref_slot(pagep); - if (unlikely(!page)) - break; - - if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) { - page = NULL; - continue; - } - /* - * Otherwise, shmem/tmpfs must be storing a swap entry - * here as an exceptional entry: so return it without - * attempting to raise page count. - */ - page = NULL; - break; /* TODO: Is this relevant for this use case? */ - } - - if (!page_cache_get_speculative(page)) { - page = NULL; - continue; - } - - /* - * Has the page moved? - * This is part of the lockless pagecache protocol. See - * include/linux/pagemap.h for details. - */ - if (unlikely(page != *pagep)) { - put_page(page); - page = NULL; - } - } - - if (page) { - if (page->index <= end_idx) - found = true; - put_page(page); - } - - rcu_read_unlock(); - return found; -} - static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend, struct extent_state **cached_state, int writing) { -- 2.7.4