diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 33 | ||||
| -rw-r--r-- | mm/truncate.c | 54 | ||||
| -rw-r--r-- | mm/vmscan.c | 2 |
3 files changed, 80 insertions, 9 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index efc63876477f..05c44aa44188 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -107,12 +107,33 @@ * ->tasklist_lock (memory_failure, collect_procs_ao) */ +static void page_cache_tree_delete(struct address_space *mapping, + struct page *page, void *shadow) +{ + if (shadow) { + void **slot; + + slot = radix_tree_lookup_slot(&mapping->page_tree, page->index); + radix_tree_replace_slot(slot, shadow); + mapping->nrshadows++; + /* + * Make sure the nrshadows update is committed before + * the nrpages update so that final truncate racing + * with reclaim does not see both counters 0 at the + * same time and miss a shadow entry. + */ + smp_wmb(); + } else + radix_tree_delete(&mapping->page_tree, page->index); + mapping->nrpages--; +} + /* * Delete a page from the page cache and free it. Caller has to make * sure the page is locked and that nobody else uses it - or that usage * is safe. The caller must hold the mapping's tree_lock. */ -void __delete_from_page_cache(struct page *page) +void __delete_from_page_cache(struct page *page, void *shadow) { struct address_space *mapping = page->mapping; @@ -127,10 +148,11 @@ void __delete_from_page_cache(struct page *page) else cleancache_invalidate_page(mapping, page); - radix_tree_delete(&mapping->page_tree, page->index); + page_cache_tree_delete(mapping, page, shadow); + page->mapping = NULL; /* Leave page->index set: truncation lookup relies upon it */ - mapping->nrpages--; + __dec_zone_page_state(page, NR_FILE_PAGES); if (PageSwapBacked(page)) __dec_zone_page_state(page, NR_SHMEM); @@ -166,7 +188,7 @@ void delete_from_page_cache(struct page *page) freepage = mapping->a_ops->freepage; spin_lock_irq(&mapping->tree_lock); - __delete_from_page_cache(page); + __delete_from_page_cache(page, NULL); spin_unlock_irq(&mapping->tree_lock); mem_cgroup_uncharge_cache_page(page); @@ -426,7 +448,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) new->index = offset; spin_lock_irq(&mapping->tree_lock); - __delete_from_page_cache(old); + __delete_from_page_cache(old, NULL); error = radix_tree_insert(&mapping->page_tree, offset, new); BUG_ON(error); mapping->nrpages++; @@ -460,6 +482,7 @@ static int page_cache_tree_insert(struct address_space *mapping, if (!radix_tree_exceptional_entry(p)) return -EEXIST; radix_tree_replace_slot(slot, page); + mapping->nrshadows--; mapping->nrpages++; return 0; } diff --git a/mm/truncate.c b/mm/truncate.c index 2e84fe59190b..0db9258319f0 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -35,7 +35,8 @@ static void clear_exceptional_entry(struct address_space *mapping, * without the tree itself locked. These unlocked entries * need verification under the tree lock. */ - radix_tree_delete_item(&mapping->page_tree, index, entry); + if (radix_tree_delete_item(&mapping->page_tree, index, entry) == entry) + mapping->nrshadows--; spin_unlock_irq(&mapping->tree_lock); } @@ -229,7 +230,7 @@ void truncate_inode_pages_range(struct address_space *mapping, int i; cleancache_invalidate_inode(mapping); - if (mapping->nrpages == 0) + if (mapping->nrpages == 0 && mapping->nrshadows == 0) return; /* Offsets within partial pages */ @@ -392,6 +393,53 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart) EXPORT_SYMBOL(truncate_inode_pages); /** + * truncate_inode_pages_final - truncate *all* pages before inode dies + * @mapping: mapping to truncate + * + * Called under (and serialized by) inode->i_mutex. + * + * Filesystems have to use this in the .evict_inode path to inform the + * VM that this is the final truncate and the inode is going away. + */ +void truncate_inode_pages_final(struct address_space *mapping) +{ + unsigned long nrshadows; + unsigned long nrpages; + + /* + * Page reclaim can not participate in regular inode lifetime + * management (can't call iput()) and thus can race with the + * inode teardown. Tell it when the address space is exiting, + * so that it does not install eviction information after the + * final truncate has begun. + */ + mapping_set_exiting(mapping); + + /* + * When reclaim installs eviction entries, it increases + * nrshadows first, then decreases nrpages. Make sure we see + * this in the right order or we might miss an entry. + */ + nrpages = mapping->nrpages; + smp_rmb(); + nrshadows = mapping->nrshadows; + + if (nrpages || nrshadows) { + /* + * As truncation uses a lockless tree lookup, cycle + * the tree lock to make sure any ongoing tree + * modification that does not see AS_EXITING is + * completed before starting the final truncate. + */ + spin_lock_irq(&mapping->tree_lock); + spin_unlock_irq(&mapping->tree_lock); + + truncate_inode_pages(mapping, 0); + } +} +EXPORT_SYMBOL(truncate_inode_pages_final); + +/** * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode * @mapping: the address_space which holds the pages to invalidate * @start: the offset 'from' which to invalidate @@ -484,7 +532,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) goto failed; BUG_ON(page_has_private(page)); - __delete_from_page_cache(page); + __delete_from_page_cache(page, NULL); spin_unlock_irq(&mapping->tree_lock); mem_cgroup_uncharge_cache_page(page); diff --git a/mm/vmscan.c b/mm/vmscan.c index c53d1a54964c..2a0bb8fdb259 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -572,7 +572,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page) freepage = mapping->a_ops->freepage; - __delete_from_page_cache(page); + __delete_from_page_cache(page, NULL); spin_unlock_irq(&mapping->tree_lock); mem_cgroup_uncharge_cache_page(page); |