diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 1881 |
1 files changed, 1016 insertions, 865 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index ea89840fc65..900edfaf6df 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -9,7 +9,7 @@ * most "normal" filesystems (but you don't /have/ to use this: * the NFS filesystem used to do this differently, for example) */ -#include <linux/module.h> +#include <linux/export.h> #include <linux/compiler.h> #include <linux/fs.h> #include <linux/uaccess.h> @@ -29,13 +29,16 @@ #include <linux/pagevec.h> #include <linux/blkdev.h> #include <linux/security.h> -#include <linux/syscalls.h> #include <linux/cpuset.h> #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */ #include <linux/memcontrol.h> -#include <linux/mm_inline.h> /* for page_is_file_cache() */ +#include <linux/cleancache.h> +#include <linux/rmap.h> #include "internal.h" +#define CREATE_TRACE_POINTS +#include <trace/events/filemap.h> + /* * FIXME: remove all knowledge of the buffer layer from the core VM */ @@ -58,33 +61,30 @@ /* * Lock ordering: * - * ->i_mmap_lock (truncate_pagecache) + * ->i_mmap_mutex (truncate_pagecache) * ->private_lock (__free_pte->__set_page_dirty_buffers) * ->swap_lock (exclusive_swap_page, others) * ->mapping->tree_lock * * ->i_mutex - * ->i_mmap_lock (truncate->unmap_mapping_range) + * ->i_mmap_mutex (truncate->unmap_mapping_range) * * ->mmap_sem - * ->i_mmap_lock + * ->i_mmap_mutex * ->page_table_lock or pte_lock (various, mainly in memory.c) * ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock) * * ->mmap_sem * ->lock_page (access_process_vm) * - * ->i_mutex (generic_file_buffered_write) + * ->i_mutex (generic_perform_write) * ->mmap_sem (fault_in_pages_readable->do_page_fault) * - * ->i_mutex - * ->i_alloc_sem (various) - * - * ->inode_lock - * ->sb_lock (fs/fs-writeback.c) + * bdi->wb.list_lock + * sb_lock (fs/fs-writeback.c) * ->mapping->tree_lock (__sync_single_inode) * - * ->i_mmap_lock + * ->i_mmap_mutex * ->anon_vma.lock (vma_adjust) * * ->anon_vma.lock @@ -98,30 +98,104 @@ * ->zone.lru_lock (check_pte_range->isolate_lru_page) * ->private_lock (page_remove_rmap->set_page_dirty) * ->tree_lock (page_remove_rmap->set_page_dirty) - * ->inode_lock (page_remove_rmap->set_page_dirty) - * ->inode_lock (zap_pte_range->set_page_dirty) + * bdi.wb->list_lock (page_remove_rmap->set_page_dirty) + * ->inode->i_lock (page_remove_rmap->set_page_dirty) + * bdi.wb->list_lock (zap_pte_range->set_page_dirty) + * ->inode->i_lock (zap_pte_range->set_page_dirty) * ->private_lock (zap_pte_range->__set_page_dirty_buffers) * - * ->task->proc_lock - * ->dcache_lock (proc_pid_lookup) - * - * (code doesn't rely on that order, so you could switch it around) - * ->tasklist_lock (memory_failure, collect_procs_ao) - * ->i_mmap_lock + * ->i_mmap_mutex + * ->tasklist_lock (memory_failure, collect_procs_ao) */ +static void page_cache_tree_delete(struct address_space *mapping, + struct page *page, void *shadow) +{ + struct radix_tree_node *node; + unsigned long index; + unsigned int offset; + unsigned int tag; + void **slot; + + VM_BUG_ON(!PageLocked(page)); + + __radix_tree_lookup(&mapping->page_tree, page->index, &node, &slot); + + if (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(); + } + mapping->nrpages--; + + if (!node) { + /* Clear direct pointer tags in root node */ + mapping->page_tree.gfp_mask &= __GFP_BITS_MASK; + radix_tree_replace_slot(slot, shadow); + return; + } + + /* Clear tree tags for the removed page */ + index = page->index; + offset = index & RADIX_TREE_MAP_MASK; + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { + if (test_bit(offset, node->tags[tag])) + radix_tree_tag_clear(&mapping->page_tree, index, tag); + } + + /* Delete page, swap shadow entry */ + radix_tree_replace_slot(slot, shadow); + workingset_node_pages_dec(node); + if (shadow) + workingset_node_shadows_inc(node); + else + if (__radix_tree_delete_node(&mapping->page_tree, node)) + return; + + /* + * Track node that only contains shadow entries. + * + * Avoid acquiring the list_lru lock if already tracked. The + * list_empty() test is safe as node->private_list is + * protected by mapping->tree_lock. + */ + if (!workingset_node_pages(node) && + list_empty(&node->private_list)) { + node->private_data = mapping; + list_lru_add(&workingset_shadow_nodes, &node->private_list); + } +} + /* - * Remove a page from the page cache and free it. Caller has to make + * 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 __remove_from_page_cache(struct page *page) +void __delete_from_page_cache(struct page *page, void *shadow) { struct address_space *mapping = page->mapping; - radix_tree_delete(&mapping->page_tree, page->index); + trace_mm_filemap_delete_from_page_cache(page); + /* + * if we're uptodate, flush out into the cleancache, otherwise + * invalidate any existing cleancache entries. We can't leave + * stale data around in the cleancache once our page is gone + */ + if (PageUptodate(page) && PageMappedToDisk(page)) + cleancache_put_page(page); + else + cleancache_invalidate_page(mapping, page); + + page_cache_tree_delete(mapping, page, shadow); + page->mapping = NULL; - mapping->nrpages--; + /* Leave page->index set: truncation lookup relies upon it */ + __dec_zone_page_state(page, NR_FILE_PAGES); if (PageSwapBacked(page)) __dec_zone_page_state(page, NR_SHMEM); @@ -140,61 +214,58 @@ void __remove_from_page_cache(struct page *page) } } -void remove_from_page_cache(struct page *page) +/** + * delete_from_page_cache - delete page from page cache + * @page: the page which the kernel is trying to remove from page cache + * + * This must be called only on pages that have been verified to be in the page + * cache and locked. It will never put the page into the free list, the caller + * has a reference on the page. + */ +void delete_from_page_cache(struct page *page) { struct address_space *mapping = page->mapping; + void (*freepage)(struct page *); BUG_ON(!PageLocked(page)); + freepage = mapping->a_ops->freepage; spin_lock_irq(&mapping->tree_lock); - __remove_from_page_cache(page); + __delete_from_page_cache(page, NULL); spin_unlock_irq(&mapping->tree_lock); mem_cgroup_uncharge_cache_page(page); + + if (freepage) + freepage(page); + page_cache_release(page); } -EXPORT_SYMBOL(remove_from_page_cache); +EXPORT_SYMBOL(delete_from_page_cache); -static int sync_page(void *word) +static int sleep_on_page(void *word) { - struct address_space *mapping; - struct page *page; - - page = container_of((unsigned long *)word, struct page, flags); - - /* - * page_mapping() is being called without PG_locked held. - * Some knowledge of the state and use of the page is used to - * reduce the requirements down to a memory barrier. - * The danger here is of a stale page_mapping() return value - * indicating a struct address_space different from the one it's - * associated with when it is associated with one. - * After smp_mb(), it's either the correct page_mapping() for - * the page, or an old page_mapping() and the page's own - * page_mapping() has gone NULL. - * The ->sync_page() address_space operation must tolerate - * page_mapping() going NULL. By an amazing coincidence, - * this comes about because none of the users of the page - * in the ->sync_page() methods make essential use of the - * page_mapping(), merely passing the page down to the backing - * device's unplug functions when it's non-NULL, which in turn - * ignore it for all cases but swap, where only page_private(page) is - * of interest. When page_mapping() does go NULL, the entire - * call stack gracefully ignores the page and returns. - * -- wli - */ - smp_mb(); - mapping = page_mapping(page); - if (mapping && mapping->a_ops && mapping->a_ops->sync_page) - mapping->a_ops->sync_page(page); io_schedule(); return 0; } -static int sync_page_killable(void *word) +static int sleep_on_page_killable(void *word) { - sync_page(word); + sleep_on_page(word); return fatal_signal_pending(current) ? -EINTR : 0; } +static int filemap_check_errors(struct address_space *mapping) +{ + int ret = 0; + /* Check for outstanding write errors */ + if (test_bit(AS_ENOSPC, &mapping->flags) && + test_and_clear_bit(AS_ENOSPC, &mapping->flags)) + ret = -ENOSPC; + if (test_bit(AS_EIO, &mapping->flags) && + test_and_clear_bit(AS_EIO, &mapping->flags)) + ret = -EIO; + return ret; +} + /** * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range * @mapping: address space structure to write @@ -276,10 +347,10 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, pgoff_t end = end_byte >> PAGE_CACHE_SHIFT; struct pagevec pvec; int nr_pages; - int ret = 0; + int ret2, ret = 0; if (end_byte < start_byte) - return 0; + goto out; pagevec_init(&pvec, 0); while ((index <= end) && @@ -296,18 +367,16 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, continue; wait_on_page_writeback(page); - if (PageError(page)) + if (TestClearPageError(page)) ret = -EIO; } pagevec_release(&pvec); cond_resched(); } - - /* Check for outstanding write errors */ - if (test_and_clear_bit(AS_ENOSPC, &mapping->flags)) - ret = -ENOSPC; - if (test_and_clear_bit(AS_EIO, &mapping->flags)) - ret = -EIO; +out: + ret2 = filemap_check_errors(mapping); + if (!ret) + ret = ret2; return ret; } @@ -348,6 +417,8 @@ int filemap_write_and_wait(struct address_space *mapping) if (!err) err = err2; } + } else { + err = filemap_check_errors(mapping); } return err; } @@ -379,12 +450,155 @@ int filemap_write_and_wait_range(struct address_space *mapping, if (!err) err = err2; } + } else { + err = filemap_check_errors(mapping); } return err; } EXPORT_SYMBOL(filemap_write_and_wait_range); /** + * replace_page_cache_page - replace a pagecache page with a new one + * @old: page to be replaced + * @new: page to replace with + * @gfp_mask: allocation mode + * + * This function replaces a page in the pagecache with a new one. On + * success it acquires the pagecache reference for the new page and + * drops it for the old page. Both the old and new pages must be + * locked. This function does not add the new page to the LRU, the + * caller must do that. + * + * The remove + add is atomic. The only way this function can fail is + * memory allocation failure. + */ +int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) +{ + int error; + + VM_BUG_ON_PAGE(!PageLocked(old), old); + VM_BUG_ON_PAGE(!PageLocked(new), new); + VM_BUG_ON_PAGE(new->mapping, new); + + error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); + if (!error) { + struct address_space *mapping = old->mapping; + void (*freepage)(struct page *); + + pgoff_t offset = old->index; + freepage = mapping->a_ops->freepage; + + page_cache_get(new); + new->mapping = mapping; + new->index = offset; + + spin_lock_irq(&mapping->tree_lock); + __delete_from_page_cache(old, NULL); + error = radix_tree_insert(&mapping->page_tree, offset, new); + BUG_ON(error); + mapping->nrpages++; + __inc_zone_page_state(new, NR_FILE_PAGES); + if (PageSwapBacked(new)) + __inc_zone_page_state(new, NR_SHMEM); + spin_unlock_irq(&mapping->tree_lock); + /* mem_cgroup codes must not be called under tree_lock */ + mem_cgroup_replace_page_cache(old, new); + radix_tree_preload_end(); + if (freepage) + freepage(old); + page_cache_release(old); + } + + return error; +} +EXPORT_SYMBOL_GPL(replace_page_cache_page); + +static int page_cache_tree_insert(struct address_space *mapping, + struct page *page, void **shadowp) +{ + struct radix_tree_node *node; + void **slot; + int error; + + error = __radix_tree_create(&mapping->page_tree, page->index, + &node, &slot); + if (error) + return error; + if (*slot) { + void *p; + + p = radix_tree_deref_slot_protected(slot, &mapping->tree_lock); + if (!radix_tree_exceptional_entry(p)) + return -EEXIST; + if (shadowp) + *shadowp = p; + mapping->nrshadows--; + if (node) + workingset_node_shadows_dec(node); + } + radix_tree_replace_slot(slot, page); + mapping->nrpages++; + if (node) { + workingset_node_pages_inc(node); + /* + * Don't track node that contains actual pages. + * + * Avoid acquiring the list_lru lock if already + * untracked. The list_empty() test is safe as + * node->private_list is protected by + * mapping->tree_lock. + */ + if (!list_empty(&node->private_list)) + list_lru_del(&workingset_shadow_nodes, + &node->private_list); + } + return 0; +} + +static int __add_to_page_cache_locked(struct page *page, + struct address_space *mapping, + pgoff_t offset, gfp_t gfp_mask, + void **shadowp) +{ + int error; + + VM_BUG_ON_PAGE(!PageLocked(page), page); + VM_BUG_ON_PAGE(PageSwapBacked(page), page); + + error = mem_cgroup_charge_file(page, current->mm, + gfp_mask & GFP_RECLAIM_MASK); + if (error) + return error; + + error = radix_tree_maybe_preload(gfp_mask & ~__GFP_HIGHMEM); + if (error) { + mem_cgroup_uncharge_cache_page(page); + return error; + } + + page_cache_get(page); + page->mapping = mapping; + page->index = offset; + + spin_lock_irq(&mapping->tree_lock); + error = page_cache_tree_insert(mapping, page, shadowp); + radix_tree_preload_end(); + if (unlikely(error)) + goto err_insert; + __inc_zone_page_state(page, NR_FILE_PAGES); + spin_unlock_irq(&mapping->tree_lock); + trace_mm_filemap_add_to_page_cache(page); + return 0; +err_insert: + page->mapping = NULL; + /* Leave page->index set: truncation relies upon it */ + spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_cache_page(page); + page_cache_release(page); + return error; +} + +/** * add_to_page_cache_locked - add a locked page to the pagecache * @page: page to add * @mapping: the page's address_space @@ -397,63 +611,34 @@ EXPORT_SYMBOL(filemap_write_and_wait_range); int add_to_page_cache_locked(struct page *page, struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) { - int error; - - VM_BUG_ON(!PageLocked(page)); - - error = mem_cgroup_cache_charge(page, current->mm, - gfp_mask & GFP_RECLAIM_MASK); - if (error) - goto out; - - error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); - if (error == 0) { - page_cache_get(page); - page->mapping = mapping; - page->index = offset; - - spin_lock_irq(&mapping->tree_lock); - error = radix_tree_insert(&mapping->page_tree, offset, page); - if (likely(!error)) { - mapping->nrpages++; - __inc_zone_page_state(page, NR_FILE_PAGES); - if (PageSwapBacked(page)) - __inc_zone_page_state(page, NR_SHMEM); - spin_unlock_irq(&mapping->tree_lock); - } else { - page->mapping = NULL; - spin_unlock_irq(&mapping->tree_lock); - mem_cgroup_uncharge_cache_page(page); - page_cache_release(page); - } - radix_tree_preload_end(); - } else - mem_cgroup_uncharge_cache_page(page); -out: - return error; + return __add_to_page_cache_locked(page, mapping, offset, + gfp_mask, NULL); } EXPORT_SYMBOL(add_to_page_cache_locked); int add_to_page_cache_lru(struct page *page, struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) { + void *shadow = NULL; int ret; - /* - * Splice_read and readahead add shmem/tmpfs pages into the page cache - * before shmem_readpage has a chance to mark them as SwapBacked: they - * need to go on the anon lru below, and mem_cgroup_cache_charge - * (called in add_to_page_cache) needs to know where they're going too. - */ - if (mapping_cap_swap_backed(mapping)) - SetPageSwapBacked(page); - - ret = add_to_page_cache(page, mapping, offset, gfp_mask); - if (ret == 0) { - if (page_is_file_cache(page)) - lru_cache_add_file(page); - else - lru_cache_add_anon(page); + __set_page_locked(page); + ret = __add_to_page_cache_locked(page, mapping, offset, + gfp_mask, &shadow); + if (unlikely(ret)) + __clear_page_locked(page); + else { + /* + * The page might have been evicted from cache only + * recently, in which case it should be activated like + * any other repeatedly accessed page. + */ + if (shadow && workingset_refault(shadow)) { + SetPageActive(page); + workingset_activation(page); + } else + ClearPageActive(page); + lru_cache_add(page); } return ret; } @@ -466,10 +651,13 @@ struct page *__page_cache_alloc(gfp_t gfp) struct page *page; if (cpuset_do_page_mem_spread()) { - get_mems_allowed(); - n = cpuset_mem_spread_node(); - page = alloc_pages_exact_node(n, gfp, 0); - put_mems_allowed(); + unsigned int cpuset_mems_cookie; + do { + cpuset_mems_cookie = read_mems_allowed_begin(); + n = cpuset_mem_spread_node(); + page = alloc_pages_exact_node(n, gfp, 0); + } while (!page && read_mems_allowed_retry(cpuset_mems_cookie)); + return page; } return alloc_pages(gfp, 0); @@ -477,12 +665,6 @@ struct page *__page_cache_alloc(gfp_t gfp) EXPORT_SYMBOL(__page_cache_alloc); #endif -static int __sleep_on_page_lock(void *word) -{ - io_schedule(); - return 0; -} - /* * In order to wait for pages to become available there must be * waitqueues associated with pages. By using a hash table of @@ -510,11 +692,22 @@ void wait_on_page_bit(struct page *page, int bit_nr) DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); if (test_bit(bit_nr, &page->flags)) - __wait_on_bit(page_waitqueue(page), &wait, sync_page, + __wait_on_bit(page_waitqueue(page), &wait, sleep_on_page, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(wait_on_page_bit); +int wait_on_page_bit_killable(struct page *page, int bit_nr) +{ + DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); + + if (!test_bit(bit_nr, &page->flags)) + return 0; + + return __wait_on_bit(page_waitqueue(page), &wait, + sleep_on_page_killable, TASK_KILLABLE); +} + /** * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue * @page: Page defining the wait queue of interest @@ -547,9 +740,9 @@ EXPORT_SYMBOL_GPL(add_page_wait_queue); */ void unlock_page(struct page *page) { - VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON_PAGE(!PageLocked(page), page); clear_bit_unlock(PG_locked, &page->flags); - smp_mb__after_clear_bit(); + smp_mb__after_atomic(); wake_up_page(page, PG_locked); } EXPORT_SYMBOL(unlock_page); @@ -560,31 +753,60 @@ EXPORT_SYMBOL(unlock_page); */ void end_page_writeback(struct page *page) { - if (TestClearPageReclaim(page)) + /* + * TestClearPageReclaim could be used here but it is an atomic + * operation and overkill in this particular case. Failing to + * shuffle a page marked for immediate reclaim is too mild to + * justify taking an atomic operation penalty at the end of + * ever page writeback. + */ + if (PageReclaim(page)) { + ClearPageReclaim(page); rotate_reclaimable_page(page); + } if (!test_clear_page_writeback(page)) BUG(); - smp_mb__after_clear_bit(); + smp_mb__after_atomic(); wake_up_page(page, PG_writeback); } EXPORT_SYMBOL(end_page_writeback); +/* + * After completing I/O on a page, call this routine to update the page + * flags appropriately + */ +void page_endio(struct page *page, int rw, int err) +{ + if (rw == READ) { + if (!err) { + SetPageUptodate(page); + } else { + ClearPageUptodate(page); + SetPageError(page); + } + unlock_page(page); + } else { /* rw == WRITE */ + if (err) { + SetPageError(page); + if (page->mapping) + mapping_set_error(page->mapping, err); + } + end_page_writeback(page); + } +} +EXPORT_SYMBOL_GPL(page_endio); + /** * __lock_page - get a lock on the page, assuming we need to sleep to get it * @page: the page to lock - * - * Ugly. Running sync_page() in state TASK_UNINTERRUPTIBLE is scary. If some - * random driver's requestfn sets TASK_RUNNING, we could busywait. However - * chances are that on the second loop, the block layer's plug list is empty, - * so sync_page() will then return in state TASK_UNINTERRUPTIBLE. */ void __lock_page(struct page *page) { DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); - __wait_on_bit_lock(page_waitqueue(page), &wait, sync_page, + __wait_on_bit_lock(page_waitqueue(page), &wait, sleep_on_page, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(__lock_page); @@ -594,46 +816,138 @@ int __lock_page_killable(struct page *page) DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); return __wait_on_bit_lock(page_waitqueue(page), &wait, - sync_page_killable, TASK_KILLABLE); + sleep_on_page_killable, TASK_KILLABLE); } EXPORT_SYMBOL_GPL(__lock_page_killable); +int __lock_page_or_retry(struct page *page, struct mm_struct *mm, + unsigned int flags) +{ + if (flags & FAULT_FLAG_ALLOW_RETRY) { + /* + * CAUTION! In this case, mmap_sem is not released + * even though return 0. + */ + if (flags & FAULT_FLAG_RETRY_NOWAIT) + return 0; + + up_read(&mm->mmap_sem); + if (flags & FAULT_FLAG_KILLABLE) + wait_on_page_locked_killable(page); + else + wait_on_page_locked(page); + return 0; + } else { + if (flags & FAULT_FLAG_KILLABLE) { + int ret; + + ret = __lock_page_killable(page); + if (ret) { + up_read(&mm->mmap_sem); + return 0; + } + } else + __lock_page(page); + return 1; + } +} + /** - * __lock_page_nosync - get a lock on the page, without calling sync_page() - * @page: the page to lock - * - * Variant of lock_page that does not require the caller to hold a reference - * on the page's mapping. + * page_cache_next_hole - find the next hole (not-present entry) + * @mapping: mapping + * @index: index + * @max_scan: maximum range to search + * + * Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the + * lowest indexed hole. + * + * Returns: the index of the hole if found, otherwise returns an index + * outside of the set specified (in which case 'return - index >= + * max_scan' will be true). In rare cases of index wrap-around, 0 will + * be returned. + * + * page_cache_next_hole may be called under rcu_read_lock. However, + * like radix_tree_gang_lookup, this will not atomically search a + * snapshot of the tree at a single point in time. For example, if a + * hole is created at index 5, then subsequently a hole is created at + * index 10, page_cache_next_hole covering both indexes may return 10 + * if called under rcu_read_lock. */ -void __lock_page_nosync(struct page *page) +pgoff_t page_cache_next_hole(struct address_space *mapping, + pgoff_t index, unsigned long max_scan) { - DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); - __wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock, - TASK_UNINTERRUPTIBLE); + unsigned long i; + + for (i = 0; i < max_scan; i++) { + struct page *page; + + page = radix_tree_lookup(&mapping->page_tree, index); + if (!page || radix_tree_exceptional_entry(page)) + break; + index++; + if (index == 0) + break; + } + + return index; } +EXPORT_SYMBOL(page_cache_next_hole); -int __lock_page_or_retry(struct page *page, struct mm_struct *mm, - unsigned int flags) +/** + * page_cache_prev_hole - find the prev hole (not-present entry) + * @mapping: mapping + * @index: index + * @max_scan: maximum range to search + * + * Search backwards in the range [max(index-max_scan+1, 0), index] for + * the first hole. + * + * Returns: the index of the hole if found, otherwise returns an index + * outside of the set specified (in which case 'index - return >= + * max_scan' will be true). In rare cases of wrap-around, ULONG_MAX + * will be returned. + * + * page_cache_prev_hole may be called under rcu_read_lock. However, + * like radix_tree_gang_lookup, this will not atomically search a + * snapshot of the tree at a single point in time. For example, if a + * hole is created at index 10, then subsequently a hole is created at + * index 5, page_cache_prev_hole covering both indexes may return 5 if + * called under rcu_read_lock. + */ +pgoff_t page_cache_prev_hole(struct address_space *mapping, + pgoff_t index, unsigned long max_scan) { - if (!(flags & FAULT_FLAG_ALLOW_RETRY)) { - __lock_page(page); - return 1; - } else { - up_read(&mm->mmap_sem); - wait_on_page_locked(page); - return 0; + unsigned long i; + + for (i = 0; i < max_scan; i++) { + struct page *page; + + page = radix_tree_lookup(&mapping->page_tree, index); + if (!page || radix_tree_exceptional_entry(page)) + break; + index--; + if (index == ULONG_MAX) + break; } + + return index; } +EXPORT_SYMBOL(page_cache_prev_hole); /** - * find_get_page - find and get a page reference + * find_get_entry - find and get a page cache entry * @mapping: the address_space to search - * @offset: the page index + * @offset: the page cache index * - * Is there a pagecache struct page at the given (mapping, offset) tuple? - * If yes, increment its refcount and return it; if no, return NULL. + * Looks up the page cache slot at @mapping & @offset. If there is a + * page cache page, it is returned with an increased refcount. + * + * If the slot holds a shadow entry of a previously evicted page, or a + * swap entry from shmem/tmpfs, it is returned. + * + * Otherwise, %NULL is returned. */ -struct page *find_get_page(struct address_space *mapping, pgoff_t offset) +struct page *find_get_entry(struct address_space *mapping, pgoff_t offset) { void **pagep; struct page *page; @@ -646,9 +960,16 @@ repeat: page = radix_tree_deref_slot(pagep); if (unlikely(!page)) goto out; - if (radix_tree_deref_retry(page)) - goto repeat; - + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) + goto repeat; + /* + * A shadow entry of a recently evicted page, + * or a swap entry from shmem/tmpfs. Return + * it without attempting to raise page count. + */ + goto out; + } if (!page_cache_get_speculative(page)) goto repeat; @@ -667,25 +988,31 @@ out: return page; } -EXPORT_SYMBOL(find_get_page); +EXPORT_SYMBOL(find_get_entry); /** - * find_lock_page - locate, pin and lock a pagecache page + * find_lock_entry - locate, pin and lock a page cache entry * @mapping: the address_space to search - * @offset: the page index + * @offset: the page cache index * - * Locates the desired pagecache page, locks it, increments its reference - * count and returns its address. + * Looks up the page cache slot at @mapping & @offset. If there is a + * page cache page, it is returned locked and with an increased + * refcount. * - * Returns zero if the page was not present. find_lock_page() may sleep. + * If the slot holds a shadow entry of a previously evicted page, or a + * swap entry from shmem/tmpfs, it is returned. + * + * Otherwise, %NULL is returned. + * + * find_lock_entry() may sleep. */ -struct page *find_lock_page(struct address_space *mapping, pgoff_t offset) +struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset) { struct page *page; repeat: - page = find_get_page(mapping, offset); - if (page) { + page = find_get_entry(mapping, offset); + if (page && !radix_tree_exception(page)) { lock_page(page); /* Has the page been truncated? */ if (unlikely(page->mapping != mapping)) { @@ -693,48 +1020,94 @@ repeat: page_cache_release(page); goto repeat; } - VM_BUG_ON(page->index != offset); + VM_BUG_ON_PAGE(page->index != offset, page); } return page; } -EXPORT_SYMBOL(find_lock_page); +EXPORT_SYMBOL(find_lock_entry); /** - * find_or_create_page - locate or add a pagecache page - * @mapping: the page's address_space - * @index: the page's index into the mapping - * @gfp_mask: page allocation mode + * pagecache_get_page - find and get a page reference + * @mapping: the address_space to search + * @offset: the page index + * @fgp_flags: PCG flags + * @cache_gfp_mask: gfp mask to use for the page cache data page allocation + * @radix_gfp_mask: gfp mask to use for radix tree node allocation * - * Locates a page in the pagecache. If the page is not present, a new page - * is allocated using @gfp_mask and is added to the pagecache and to the VM's - * LRU list. The returned page is locked and has its reference count - * incremented. + * Looks up the page cache slot at @mapping & @offset. * - * find_or_create_page() may sleep, even if @gfp_flags specifies an atomic - * allocation! + * PCG flags modify how the page is returned. * - * find_or_create_page() returns the desired page's address, or zero on - * memory exhaustion. + * FGP_ACCESSED: the page will be marked accessed + * FGP_LOCK: Page is return locked + * FGP_CREAT: If page is not present then a new page is allocated using + * @cache_gfp_mask and added to the page cache and the VM's LRU + * list. If radix tree nodes are allocated during page cache + * insertion then @radix_gfp_mask is used. The page is returned + * locked and with an increased refcount. Otherwise, %NULL is + * returned. + * + * If FGP_LOCK or FGP_CREAT are specified then the function may sleep even + * if the GFP flags specified for FGP_CREAT are atomic. + * + * If there is a page cache page, it is returned with an increased refcount. */ -struct page *find_or_create_page(struct address_space *mapping, - pgoff_t index, gfp_t gfp_mask) +struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, + int fgp_flags, gfp_t cache_gfp_mask, gfp_t radix_gfp_mask) { struct page *page; - int err; + repeat: - page = find_lock_page(mapping, index); - if (!page) { - page = __page_cache_alloc(gfp_mask); + page = find_get_entry(mapping, offset); + if (radix_tree_exceptional_entry(page)) + page = NULL; + if (!page) + goto no_page; + + if (fgp_flags & FGP_LOCK) { + if (fgp_flags & FGP_NOWAIT) { + if (!trylock_page(page)) { + page_cache_release(page); + return NULL; + } + } else { + lock_page(page); + } + + /* Has the page been truncated? */ + if (unlikely(page->mapping != mapping)) { + unlock_page(page); + page_cache_release(page); + goto repeat; + } + VM_BUG_ON_PAGE(page->index != offset, page); + } + + if (page && (fgp_flags & FGP_ACCESSED)) + mark_page_accessed(page); + +no_page: + if (!page && (fgp_flags & FGP_CREAT)) { + int err; + if ((fgp_flags & FGP_WRITE) && mapping_cap_account_dirty(mapping)) + cache_gfp_mask |= __GFP_WRITE; + if (fgp_flags & FGP_NOFS) { + cache_gfp_mask &= ~__GFP_FS; + radix_gfp_mask &= ~__GFP_FS; + } + + page = __page_cache_alloc(cache_gfp_mask); if (!page) return NULL; - /* - * We want a regular kernel memory (not highmem or DMA etc) - * allocation for the radix tree nodes, but we need to honour - * the context-specific requirements the caller has asked for. - * GFP_RECLAIM_MASK collects those requirements. - */ - err = add_to_page_cache_lru(page, mapping, index, - (gfp_mask & GFP_RECLAIM_MASK)); + + if (WARN_ON_ONCE(!(fgp_flags & FGP_LOCK))) + fgp_flags |= FGP_LOCK; + + /* Init accessed so avoit atomic mark_page_accessed later */ + if (fgp_flags & FGP_ACCESSED) + init_page_accessed(page); + + err = add_to_page_cache_lru(page, mapping, offset, radix_gfp_mask); if (unlikely(err)) { page_cache_release(page); page = NULL; @@ -742,9 +1115,80 @@ repeat: goto repeat; } } + return page; } -EXPORT_SYMBOL(find_or_create_page); +EXPORT_SYMBOL(pagecache_get_page); + +/** + * find_get_entries - gang pagecache lookup + * @mapping: The address_space to search + * @start: The starting page cache index + * @nr_entries: The maximum number of entries + * @entries: Where the resulting entries are placed + * @indices: The cache indices corresponding to the entries in @entries + * + * find_get_entries() will search for and return a group of up to + * @nr_entries entries in the mapping. The entries are placed at + * @entries. find_get_entries() takes a reference against any actual + * pages it returns. + * + * The search returns a group of mapping-contiguous page cache entries + * with ascending indexes. There may be holes in the indices due to + * not-present pages. + * + * Any shadow entries of evicted pages, or swap entries from + * shmem/tmpfs, are included in the returned array. + * + * find_get_entries() returns the number of pages and shadow entries + * which were found. + */ +unsigned find_get_entries(struct address_space *mapping, + pgoff_t start, unsigned int nr_entries, + struct page **entries, pgoff_t *indices) +{ + void **slot; + unsigned int ret = 0; + struct radix_tree_iter iter; + + if (!nr_entries) + return 0; + + rcu_read_lock(); +restart: + radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { + struct page *page; +repeat: + page = radix_tree_deref_slot(slot); + if (unlikely(!page)) + continue; + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) + goto restart; + /* + * A shadow entry of a recently evicted page, + * or a swap entry from shmem/tmpfs. Return + * it without attempting to raise page count. + */ + goto export; + } + if (!page_cache_get_speculative(page)) + goto repeat; + + /* Has the page moved? */ + if (unlikely(page != *slot)) { + page_cache_release(page); + goto repeat; + } +export: + indices[ret] = iter.index; + entries[ret] = page; + if (++ret == nr_entries) + break; + } + rcu_read_unlock(); + return ret; +} /** * find_get_pages - gang pagecache lookup @@ -765,39 +1209,54 @@ EXPORT_SYMBOL(find_or_create_page); unsigned find_get_pages(struct address_space *mapping, pgoff_t start, unsigned int nr_pages, struct page **pages) { - unsigned int i; - unsigned int ret; - unsigned int nr_found; + struct radix_tree_iter iter; + void **slot; + unsigned ret = 0; + + if (unlikely(!nr_pages)) + return 0; rcu_read_lock(); restart: - nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, - (void ***)pages, start, nr_pages); - ret = 0; - for (i = 0; i < nr_found; i++) { + radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { struct page *page; repeat: - page = radix_tree_deref_slot((void **)pages[i]); + page = radix_tree_deref_slot(slot); if (unlikely(!page)) continue; - if (radix_tree_deref_retry(page)) { - if (ret) - start = pages[ret-1]->index; - goto restart; + + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) { + /* + * Transient condition which can only trigger + * when entry at index 0 moves out of or back + * to root: none yet gotten, safe to restart. + */ + WARN_ON(iter.index); + goto restart; + } + /* + * A shadow entry of a recently evicted page, + * or a swap entry from shmem/tmpfs. Skip + * over it. + */ + continue; } if (!page_cache_get_speculative(page)) goto repeat; /* Has the page moved? */ - if (unlikely(page != *((void **)pages[i]))) { + if (unlikely(page != *slot)) { page_cache_release(page); goto repeat; } pages[ret] = page; - ret++; + if (++ret == nr_pages) + break; } + rcu_read_unlock(); return ret; } @@ -817,39 +1276,62 @@ repeat: unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, unsigned int nr_pages, struct page **pages) { - unsigned int i; - unsigned int ret; - unsigned int nr_found; + struct radix_tree_iter iter; + void **slot; + unsigned int ret = 0; + + if (unlikely(!nr_pages)) + return 0; rcu_read_lock(); restart: - nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, - (void ***)pages, index, nr_pages); - ret = 0; - for (i = 0; i < nr_found; i++) { + radix_tree_for_each_contig(slot, &mapping->page_tree, &iter, index) { struct page *page; repeat: - page = radix_tree_deref_slot((void **)pages[i]); + page = radix_tree_deref_slot(slot); + /* The hole, there no reason to continue */ if (unlikely(!page)) - continue; - if (radix_tree_deref_retry(page)) - goto restart; + break; - if (page->mapping == NULL || page->index != index) + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) { + /* + * Transient condition which can only trigger + * when entry at index 0 moves out of or back + * to root: none yet gotten, safe to restart. + */ + goto restart; + } + /* + * A shadow entry of a recently evicted page, + * or a swap entry from shmem/tmpfs. Stop + * looking for contiguous pages. + */ break; + } if (!page_cache_get_speculative(page)) goto repeat; /* Has the page moved? */ - if (unlikely(page != *((void **)pages[i]))) { + if (unlikely(page != *slot)) { page_cache_release(page); goto repeat; } + /* + * must check mapping and index after taking the ref. + * otherwise we can get both false positives and false + * negatives, which is just confusing to the caller. + */ + if (page->mapping == NULL || page->index != iter.index) { + page_cache_release(page); + break; + } + pages[ret] = page; - ret++; - index++; + if (++ret == nr_pages) + break; } rcu_read_unlock(); return ret; @@ -870,36 +1352,60 @@ EXPORT_SYMBOL(find_get_pages_contig); unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, int tag, unsigned int nr_pages, struct page **pages) { - unsigned int i; - unsigned int ret; - unsigned int nr_found; + struct radix_tree_iter iter; + void **slot; + unsigned ret = 0; + + if (unlikely(!nr_pages)) + return 0; rcu_read_lock(); restart: - nr_found = radix_tree_gang_lookup_tag_slot(&mapping->page_tree, - (void ***)pages, *index, nr_pages, tag); - ret = 0; - for (i = 0; i < nr_found; i++) { + radix_tree_for_each_tagged(slot, &mapping->page_tree, + &iter, *index, tag) { struct page *page; repeat: - page = radix_tree_deref_slot((void **)pages[i]); + page = radix_tree_deref_slot(slot); if (unlikely(!page)) continue; - if (radix_tree_deref_retry(page)) - goto restart; + + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) { + /* + * Transient condition which can only trigger + * when entry at index 0 moves out of or back + * to root: none yet gotten, safe to restart. + */ + goto restart; + } + /* + * A shadow entry of a recently evicted page. + * + * Those entries should never be tagged, but + * this tree walk is lockless and the tags are + * looked up in bulk, one radix tree node at a + * time, so there is a sizable window for page + * reclaim to evict a page we saw tagged. + * + * Skip over it. + */ + continue; + } if (!page_cache_get_speculative(page)) goto repeat; /* Has the page moved? */ - if (unlikely(page != *((void **)pages[i]))) { + if (unlikely(page != *slot)) { page_cache_release(page); goto repeat; } pages[ret] = page; - ret++; + if (++ret == nr_pages) + break; } + rcu_read_unlock(); if (ret) @@ -909,39 +1415,6 @@ repeat: } EXPORT_SYMBOL(find_get_pages_tag); -/** - * grab_cache_page_nowait - returns locked page at given index in given cache - * @mapping: target address_space - * @index: the page index - * - * Same as grab_cache_page(), but do not wait if the page is unavailable. - * This is intended for speculative data generators, where the data can - * be regenerated if the page couldn't be grabbed. This routine should - * be safe to call while holding the lock for another page. - * - * Clear __GFP_FS when allocating the page to avoid recursion into the fs - * and deadlock against the caller's locked page. - */ -struct page * -grab_cache_page_nowait(struct address_space *mapping, pgoff_t index) -{ - struct page *page = find_get_page(mapping, index); - - if (page) { - if (trylock_page(page)) - return page; - page_cache_release(page); - return NULL; - } - page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); - if (page && add_to_page_cache_lru(page, mapping, index, GFP_NOFS)) { - page_cache_release(page); - page = NULL; - } - return page; -} -EXPORT_SYMBOL(grab_cache_page_nowait); - /* * CD/DVDs are error prone. When a medium error occurs, the driver may fail * a _large_ part of the i/o request. Imagine the worst scenario: @@ -967,8 +1440,8 @@ static void shrink_readahead_size_eio(struct file *filp, * do_generic_file_read - generic file read routine * @filp: the file to read * @ppos: current file position - * @desc: read_descriptor - * @actor: read method + * @iter: data destination + * @written: already copied * * This is a generic file read routine, and uses the * mapping->a_ops->readpage() function for the actual low-level stuff. @@ -976,8 +1449,8 @@ static void shrink_readahead_size_eio(struct file *filp, * This is really ugly. But the goto's actually try to clarify some * of the logic when it comes to error handling etc. */ -static void do_generic_file_read(struct file *filp, loff_t *ppos, - read_descriptor_t *desc, read_actor_t actor) +static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, + struct iov_iter *iter, ssize_t written) { struct address_space *mapping = filp->f_mapping; struct inode *inode = mapping->host; @@ -987,12 +1460,12 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, pgoff_t prev_index; unsigned long offset; /* offset into pagecache page */ unsigned int prev_offset; - int error; + int error = 0; index = *ppos >> PAGE_CACHE_SHIFT; prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT; prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1); - last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; + last_index = (*ppos + iter->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; offset = *ppos & ~PAGE_CACHE_MASK; for (;;) { @@ -1027,7 +1500,7 @@ find_page: if (!page->mapping) goto page_not_up_to_date_locked; if (!mapping->a_ops->is_partially_uptodate(page, - desc, offset)) + offset, iter->count)) goto page_not_up_to_date_locked; unlock_page(page); } @@ -1077,23 +1550,23 @@ page_ok: /* * Ok, we have the page, and it's up-to-date, so * now we can copy it to user space... - * - * The actor routine returns how many bytes were actually used.. - * NOTE! This may not be the same as how much of a user buffer - * we filled up (we may be padding etc), so we can only update - * "pos" here (the actor routine has to update the user buffer - * pointers and the remaining count). */ - ret = actor(desc, page, offset, nr); + + ret = copy_page_to_iter(page, offset, nr, iter); offset += ret; index += offset >> PAGE_CACHE_SHIFT; offset &= ~PAGE_CACHE_MASK; prev_offset = offset; page_cache_release(page); - if (ret == nr && desc->count) - continue; - goto out; + written += ret; + if (!iov_iter_count(iter)) + goto out; + if (ret < nr) { + error = -EFAULT; + goto out; + } + continue; page_not_up_to_date: /* Get exclusive access to the page ... */ @@ -1128,6 +1601,7 @@ readpage: if (unlikely(error)) { if (error == AOP_TRUNCATED_PAGE) { page_cache_release(page); + error = 0; goto find_page; } goto readpage_error; @@ -1158,7 +1632,6 @@ readpage: readpage_error: /* UHHUH! A synchronous read error occurred. Report it */ - desc->error = error; page_cache_release(page); goto out; @@ -1169,16 +1642,17 @@ no_cached_page: */ page = page_cache_alloc_cold(mapping); if (!page) { - desc->error = -ENOMEM; + error = -ENOMEM; goto out; } error = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL); if (error) { page_cache_release(page); - if (error == -EEXIST) + if (error == -EEXIST) { + error = 0; goto find_page; - desc->error = error; + } goto out; } goto readpage; @@ -1191,223 +1665,66 @@ out: *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset; file_accessed(filp); + return written ? written : error; } -int file_read_actor(read_descriptor_t *desc, struct page *page, - unsigned long offset, unsigned long size) -{ - char *kaddr; - unsigned long left, count = desc->count; - - if (size > count) - size = count; - - /* - * Faults on the destination of a read are common, so do it before - * taking the kmap. - */ - if (!fault_in_pages_writeable(desc->arg.buf, size)) { - kaddr = kmap_atomic(page, KM_USER0); - left = __copy_to_user_inatomic(desc->arg.buf, - kaddr + offset, size); - kunmap_atomic(kaddr, KM_USER0); - if (left == 0) - goto success; - } - - /* Do it the slow way */ - kaddr = kmap(page); - left = __copy_to_user(desc->arg.buf, kaddr + offset, size); - kunmap(page); - - if (left) { - size -= left; - desc->error = -EFAULT; - } -success: - desc->count = count - size; - desc->written += size; - desc->arg.buf += size; - return size; -} - -/* - * Performs necessary checks before doing a write - * @iov: io vector request - * @nr_segs: number of segments in the iovec - * @count: number of bytes to write - * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE - * - * Adjust number of segments and amount of bytes to write (nr_segs should be - * properly initialized first). Returns appropriate error code that caller - * should return or zero in case that write should be allowed. - */ -int generic_segment_checks(const struct iovec *iov, - unsigned long *nr_segs, size_t *count, int access_flags) -{ - unsigned long seg; - size_t cnt = 0; - for (seg = 0; seg < *nr_segs; seg++) { - const struct iovec *iv = &iov[seg]; - - /* - * If any segment has a negative length, or the cumulative - * length ever wraps negative then return -EINVAL. - */ - cnt += iv->iov_len; - if (unlikely((ssize_t)(cnt|iv->iov_len) < 0)) - return -EINVAL; - if (access_ok(access_flags, iv->iov_base, iv->iov_len)) - continue; - if (seg == 0) - return -EFAULT; - *nr_segs = seg; - cnt -= iv->iov_len; /* This segment is no good */ - break; - } - *count = cnt; - return 0; -} -EXPORT_SYMBOL(generic_segment_checks); - /** - * generic_file_aio_read - generic filesystem read routine + * generic_file_read_iter - generic filesystem read routine * @iocb: kernel I/O control block - * @iov: io vector request - * @nr_segs: number of segments in the iovec - * @pos: current file position + * @iter: destination for the data read * - * This is the "read()" routine for all filesystems + * This is the "read_iter()" routine for all filesystems * that can use the page cache directly. */ ssize_t -generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) +generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) { - struct file *filp = iocb->ki_filp; - ssize_t retval; - unsigned long seg = 0; - size_t count; + struct file *file = iocb->ki_filp; + ssize_t retval = 0; loff_t *ppos = &iocb->ki_pos; - - count = 0; - retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); - if (retval) - return retval; + loff_t pos = *ppos; /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ - if (filp->f_flags & O_DIRECT) { + if (file->f_flags & O_DIRECT) { + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + size_t count = iov_iter_count(iter); loff_t size; - struct address_space *mapping; - struct inode *inode; - mapping = filp->f_mapping; - inode = mapping->host; if (!count) goto out; /* skip atime */ size = i_size_read(inode); - if (pos < size) { - retval = filemap_write_and_wait_range(mapping, pos, - pos + iov_length(iov, nr_segs) - 1); - if (!retval) { - retval = mapping->a_ops->direct_IO(READ, iocb, - iov, pos, nr_segs); - } - if (retval > 0) { - *ppos = pos + retval; - count -= retval; - } - - /* - * Btrfs can have a short DIO read if we encounter - * compressed extents, so if there was an error, or if - * we've already read everything we wanted to, or if - * there was a short read because we hit EOF, go ahead - * and return. Otherwise fallthrough to buffered io for - * the rest of the read. - */ - if (retval < 0 || !count || *ppos >= size) { - file_accessed(filp); - goto out; - } + retval = filemap_write_and_wait_range(mapping, pos, + pos + count - 1); + if (!retval) { + struct iov_iter data = *iter; + retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos); } - } - count = retval; - for (seg = 0; seg < nr_segs; seg++) { - read_descriptor_t desc; - loff_t offset = 0; + if (retval > 0) { + *ppos = pos + retval; + iov_iter_advance(iter, retval); + } /* - * If we did a short DIO read we need to skip the section of the - * iov that we've already read data into. + * Btrfs can have a short DIO read if we encounter + * compressed extents, so if there was an error, or if + * we've already read everything we wanted to, or if + * there was a short read because we hit EOF, go ahead + * and return. Otherwise fallthrough to buffered io for + * the rest of the read. */ - if (count) { - if (count > iov[seg].iov_len) { - count -= iov[seg].iov_len; - continue; - } - offset = count; - count = 0; - } - - desc.written = 0; - desc.arg.buf = iov[seg].iov_base + offset; - desc.count = iov[seg].iov_len - offset; - if (desc.count == 0) - continue; - desc.error = 0; - do_generic_file_read(filp, ppos, &desc, file_read_actor); - retval += desc.written; - if (desc.error) { - retval = retval ?: desc.error; - break; + if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) { + file_accessed(file); + goto out; } - if (desc.count > 0) - break; } + + retval = do_generic_file_read(file, ppos, iter, retval); out: return retval; } -EXPORT_SYMBOL(generic_file_aio_read); - -static ssize_t -do_readahead(struct address_space *mapping, struct file *filp, - pgoff_t index, unsigned long nr) -{ - if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage) - return -EINVAL; - - force_page_cache_readahead(mapping, filp, index, nr); - return 0; -} - -SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count) -{ - ssize_t ret; - struct file *file; - - ret = -EBADF; - file = fget(fd); - if (file) { - if (file->f_mode & FMODE_READ) { - struct address_space *mapping = file->f_mapping; - pgoff_t start = offset >> PAGE_CACHE_SHIFT; - pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT; - unsigned long len = end - start + 1; - ret = do_readahead(mapping, file, start, len); - } - fput(file); - } - return ret; -} -#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS -asmlinkage long SyS_readahead(long fd, loff_t offset, long count) -{ - return SYSC_readahead((int) fd, offset, (size_t) count); -} -SYSCALL_ALIAS(sys_readahead, SyS_readahead); -#endif +EXPORT_SYMBOL(generic_file_read_iter); #ifdef CONFIG_MMU /** @@ -1457,17 +1774,19 @@ static void do_sync_mmap_readahead(struct vm_area_struct *vma, struct address_space *mapping = file->f_mapping; /* If we don't want any read-ahead, don't bother */ - if (VM_RandomReadHint(vma)) + if (vma->vm_flags & VM_RAND_READ) + return; + if (!ra->ra_pages) return; - if (VM_SequentialReadHint(vma) || - offset - 1 == (ra->prev_pos >> PAGE_CACHE_SHIFT)) { + if (vma->vm_flags & VM_SEQ_READ) { page_cache_sync_readahead(mapping, ra, file, offset, ra->ra_pages); return; } - if (ra->mmap_miss < INT_MAX) + /* Avoid banging the cache line if not needed */ + if (ra->mmap_miss < MMAP_LOTSAMISS * 10) ra->mmap_miss++; /* @@ -1481,12 +1800,10 @@ static void do_sync_mmap_readahead(struct vm_area_struct *vma, * mmap read-around */ ra_pages = max_sane_readahead(ra->ra_pages); - if (ra_pages) { - ra->start = max_t(long, 0, offset - ra_pages/2); - ra->size = ra_pages; - ra->async_size = 0; - ra_submit(ra, mapping, file); - } + ra->start = max_t(long, 0, offset - ra_pages / 2); + ra->size = ra_pages; + ra->async_size = ra_pages / 4; + ra_submit(ra, mapping, file); } /* @@ -1502,7 +1819,7 @@ static void do_async_mmap_readahead(struct vm_area_struct *vma, struct address_space *mapping = file->f_mapping; /* If we don't want any read-ahead, don't bother */ - if (VM_RandomReadHint(vma)) + if (vma->vm_flags & VM_RAND_READ) return; if (ra->mmap_miss > 0) ra->mmap_miss--; @@ -1532,27 +1849,28 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) struct inode *inode = mapping->host; pgoff_t offset = vmf->pgoff; struct page *page; - pgoff_t size; + loff_t size; int ret = 0; - size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - if (offset >= size) + size = round_up(i_size_read(inode), PAGE_CACHE_SIZE); + if (offset >= size >> PAGE_CACHE_SHIFT) return VM_FAULT_SIGBUS; /* * Do we have something in the page cache already? */ page = find_get_page(mapping, offset); - if (likely(page)) { + if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) { /* * We found the page, so try async readahead before * waiting for the lock. */ do_async_mmap_readahead(vma, ra, file, page, offset); - } else { + } else if (!page) { /* No page in the page cache at all */ do_sync_mmap_readahead(vma, ra, file, offset); count_vm_event(PGMAJFAULT); + mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); ret = VM_FAULT_MAJOR; retry_find: page = find_get_page(mapping, offset); @@ -1571,7 +1889,7 @@ retry_find: put_page(page); goto retry_find; } - VM_BUG_ON(page->index != offset); + VM_BUG_ON_PAGE(page->index != offset, page); /* * We have a locked page in the page cache, now we need to check @@ -1584,14 +1902,13 @@ retry_find: * Found the page and have a reference on it. * We must recheck i_size under page lock. */ - size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - if (unlikely(offset >= size)) { + size = round_up(i_size_read(inode), PAGE_CACHE_SIZE); + if (unlikely(offset >= size >> PAGE_CACHE_SHIFT)) { unlock_page(page); page_cache_release(page); return VM_FAULT_SIGBUS; } - ra->prev_pos = (loff_t)offset << PAGE_CACHE_SHIFT; vmf->page = page; return ret | VM_FAULT_LOCKED; @@ -1644,8 +1961,110 @@ page_not_uptodate: } EXPORT_SYMBOL(filemap_fault); +void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct radix_tree_iter iter; + void **slot; + struct file *file = vma->vm_file; + struct address_space *mapping = file->f_mapping; + loff_t size; + struct page *page; + unsigned long address = (unsigned long) vmf->virtual_address; + unsigned long addr; + pte_t *pte; + + rcu_read_lock(); + radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, vmf->pgoff) { + if (iter.index > vmf->max_pgoff) + break; +repeat: + page = radix_tree_deref_slot(slot); + if (unlikely(!page)) + goto next; + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) + break; + else + goto next; + } + + if (!page_cache_get_speculative(page)) + goto repeat; + + /* Has the page moved? */ + if (unlikely(page != *slot)) { + page_cache_release(page); + goto repeat; + } + + if (!PageUptodate(page) || + PageReadahead(page) || + PageHWPoison(page)) + goto skip; + if (!trylock_page(page)) + goto skip; + + if (page->mapping != mapping || !PageUptodate(page)) + goto unlock; + + size = round_up(i_size_read(mapping->host), PAGE_CACHE_SIZE); + if (page->index >= size >> PAGE_CACHE_SHIFT) + goto unlock; + + pte = vmf->pte + page->index - vmf->pgoff; + if (!pte_none(*pte)) + goto unlock; + + if (file->f_ra.mmap_miss > 0) + file->f_ra.mmap_miss--; + addr = address + (page->index - vmf->pgoff) * PAGE_SIZE; + do_set_pte(vma, addr, page, pte, false, false); + unlock_page(page); + goto next; +unlock: + unlock_page(page); +skip: + page_cache_release(page); +next: + if (iter.index == vmf->max_pgoff) + break; + } + rcu_read_unlock(); +} +EXPORT_SYMBOL(filemap_map_pages); + +int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page = vmf->page; + struct inode *inode = file_inode(vma->vm_file); + int ret = VM_FAULT_LOCKED; + + sb_start_pagefault(inode->i_sb); + file_update_time(vma->vm_file); + lock_page(page); + if (page->mapping != inode->i_mapping) { + unlock_page(page); + ret = VM_FAULT_NOPAGE; + goto out; + } + /* + * We mark the page dirty already here so that when freeze is in + * progress, we are guaranteed that writeback during freezing will + * see the dirty page and writeprotect it again. + */ + set_page_dirty(page); + wait_for_stable_page(page); +out: + sb_end_pagefault(inode->i_sb); + return ret; +} +EXPORT_SYMBOL(filemap_page_mkwrite); + const struct vm_operations_struct generic_file_vm_ops = { .fault = filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = filemap_page_mkwrite, + .remap_pages = generic_file_remap_pages, }; /* This is used for a general mmap of a disk file */ @@ -1658,7 +2077,6 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma) return -ENOEXEC; file_accessed(file); vma->vm_ops = &generic_file_vm_ops; - vma->vm_flags |= VM_CAN_NONLINEAR; return 0; } @@ -1685,9 +2103,21 @@ int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma) EXPORT_SYMBOL(generic_file_mmap); EXPORT_SYMBOL(generic_file_readonly_mmap); +static struct page *wait_on_page_read(struct page *page) +{ + if (!IS_ERR(page)) { + wait_on_page_locked(page); + if (!PageUptodate(page)) { + page_cache_release(page); + page = ERR_PTR(-EIO); + } + } + return page; +} + static struct page *__read_cache_page(struct address_space *mapping, pgoff_t index, - int (*filler)(void *,struct page*), + int (*filler)(void *, struct page *), void *data, gfp_t gfp) { @@ -1699,7 +2129,7 @@ repeat: page = __page_cache_alloc(gfp | __GFP_COLD); if (!page) return ERR_PTR(-ENOMEM); - err = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL); + err = add_to_page_cache_lru(page, mapping, index, gfp); if (unlikely(err)) { page_cache_release(page); if (err == -EEXIST) @@ -1711,6 +2141,8 @@ repeat: if (err < 0) { page_cache_release(page); page = ERR_PTR(err); + } else { + page = wait_on_page_read(page); } } return page; @@ -1718,7 +2150,7 @@ repeat: static struct page *do_read_cache_page(struct address_space *mapping, pgoff_t index, - int (*filler)(void *,struct page*), + int (*filler)(void *, struct page *), void *data, gfp_t gfp) @@ -1747,6 +2179,10 @@ retry: if (err < 0) { page_cache_release(page); return ERR_PTR(err); + } else { + page = wait_on_page_read(page); + if (IS_ERR(page)) + return page; } out: mark_page_accessed(page); @@ -1754,40 +2190,25 @@ out: } /** - * read_cache_page_async - read into page cache, fill it if needed + * read_cache_page - read into page cache, fill it if needed * @mapping: the page's address_space * @index: the page index * @filler: function to perform the read - * @data: destination for read data - * - * Same as read_cache_page, but don't wait for page to become unlocked - * after submitting it to the filler. + * @data: first arg to filler(data, page) function, often left as NULL * * Read into the page cache. If a page already exists, and PageUptodate() is - * not set, try to fill the page but don't wait for it to become unlocked. + * not set, try to fill the page and wait for it to become unlocked. * * If the page does not get brought uptodate, return -EIO. */ -struct page *read_cache_page_async(struct address_space *mapping, +struct page *read_cache_page(struct address_space *mapping, pgoff_t index, - int (*filler)(void *,struct page*), + int (*filler)(void *, struct page *), void *data) { return do_read_cache_page(mapping, index, filler, data, mapping_gfp_mask(mapping)); } -EXPORT_SYMBOL(read_cache_page_async); - -static struct page *wait_on_page_read(struct page *page) -{ - if (!IS_ERR(page)) { - wait_on_page_locked(page); - if (!PageUptodate(page)) { - page_cache_release(page); - page = ERR_PTR(-EIO); - } - } - return page; -} +EXPORT_SYMBOL(read_cache_page); /** * read_cache_page_gfp - read into page cache, using specified page allocation flags. @@ -1796,10 +2217,7 @@ static struct page *wait_on_page_read(struct page *page) * @gfp: the page allocator flags to use if allocating * * This is the same as "read_mapping_page(mapping, index, NULL)", but with - * any new page allocations done using the specified allocation flags. Note - * that the Radix tree operations will still use GFP_KERNEL, so you can't - * expect to do this atomically or anything like that - but you can pass in - * other page requirements. + * any new page allocations done using the specified allocation flags. * * If the page does not get brought uptodate, return -EIO. */ @@ -1809,227 +2227,10 @@ struct page *read_cache_page_gfp(struct address_space *mapping, { filler_t *filler = (filler_t *)mapping->a_ops->readpage; - return wait_on_page_read(do_read_cache_page(mapping, index, filler, NULL, gfp)); + return do_read_cache_page(mapping, index, filler, NULL, gfp); } EXPORT_SYMBOL(read_cache_page_gfp); -/** - * read_cache_page - read into page cache, fill it if needed - * @mapping: the page's address_space - * @index: the page index - * @filler: function to perform the read - * @data: destination for read data - * - * Read into the page cache. If a page already exists, and PageUptodate() is - * not set, try to fill the page then wait for it to become unlocked. - * - * If the page does not get brought uptodate, return -EIO. - */ -struct page *read_cache_page(struct address_space *mapping, - pgoff_t index, - int (*filler)(void *,struct page*), - void *data) -{ - return wait_on_page_read(read_cache_page_async(mapping, index, filler, data)); -} -EXPORT_SYMBOL(read_cache_page); - -/* - * The logic we want is - * - * if suid or (sgid and xgrp) - * remove privs - */ -int should_remove_suid(struct dentry *dentry) -{ - mode_t mode = dentry->d_inode->i_mode; - int kill = 0; - - /* suid always must be killed */ - if (unlikely(mode & S_ISUID)) - kill = ATTR_KILL_SUID; - - /* - * sgid without any exec bits is just a mandatory locking mark; leave - * it alone. If some exec bits are set, it's a real sgid; kill it. - */ - if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) - kill |= ATTR_KILL_SGID; - - if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) - return kill; - - return 0; -} -EXPORT_SYMBOL(should_remove_suid); - -static int __remove_suid(struct dentry *dentry, int kill) -{ - struct iattr newattrs; - - newattrs.ia_valid = ATTR_FORCE | kill; - return notify_change(dentry, &newattrs); -} - -int file_remove_suid(struct file *file) -{ - struct dentry *dentry = file->f_path.dentry; - int killsuid = should_remove_suid(dentry); - int killpriv = security_inode_need_killpriv(dentry); - int error = 0; - - if (killpriv < 0) - return killpriv; - if (killpriv) - error = security_inode_killpriv(dentry); - if (!error && killsuid) - error = __remove_suid(dentry, killsuid); - - return error; -} -EXPORT_SYMBOL(file_remove_suid); - -static size_t __iovec_copy_from_user_inatomic(char *vaddr, - const struct iovec *iov, size_t base, size_t bytes) -{ - size_t copied = 0, left = 0; - - while (bytes) { - char __user *buf = iov->iov_base + base; - int copy = min(bytes, iov->iov_len - base); - - base = 0; - left = __copy_from_user_inatomic(vaddr, buf, copy); - copied += copy; - bytes -= copy; - vaddr += copy; - iov++; - - if (unlikely(left)) - break; - } - return copied - left; -} - -/* - * Copy as much as we can into the page and return the number of bytes which - * were successfully copied. If a fault is encountered then return the number of - * bytes which were copied. - */ -size_t iov_iter_copy_from_user_atomic(struct page *page, - struct iov_iter *i, unsigned long offset, size_t bytes) -{ - char *kaddr; - size_t copied; - - BUG_ON(!in_atomic()); - kaddr = kmap_atomic(page, KM_USER0); - if (likely(i->nr_segs == 1)) { - int left; - char __user *buf = i->iov->iov_base + i->iov_offset; - left = __copy_from_user_inatomic(kaddr + offset, buf, bytes); - copied = bytes - left; - } else { - copied = __iovec_copy_from_user_inatomic(kaddr + offset, - i->iov, i->iov_offset, bytes); - } - kunmap_atomic(kaddr, KM_USER0); - - return copied; -} -EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); - -/* - * This has the same sideeffects and return value as - * iov_iter_copy_from_user_atomic(). - * The difference is that it attempts to resolve faults. - * Page must not be locked. - */ -size_t iov_iter_copy_from_user(struct page *page, - struct iov_iter *i, unsigned long offset, size_t bytes) -{ - char *kaddr; - size_t copied; - - kaddr = kmap(page); - if (likely(i->nr_segs == 1)) { - int left; - char __user *buf = i->iov->iov_base + i->iov_offset; - left = __copy_from_user(kaddr + offset, buf, bytes); - copied = bytes - left; - } else { - copied = __iovec_copy_from_user_inatomic(kaddr + offset, - i->iov, i->iov_offset, bytes); - } - kunmap(page); - return copied; -} -EXPORT_SYMBOL(iov_iter_copy_from_user); - -void iov_iter_advance(struct iov_iter *i, size_t bytes) -{ - BUG_ON(i->count < bytes); - - if (likely(i->nr_segs == 1)) { - i->iov_offset += bytes; - i->count -= bytes; - } else { - const struct iovec *iov = i->iov; - size_t base = i->iov_offset; - - /* - * The !iov->iov_len check ensures we skip over unlikely - * zero-length segments (without overruning the iovec). - */ - while (bytes || unlikely(i->count && !iov->iov_len)) { - int copy; - - copy = min(bytes, iov->iov_len - base); - BUG_ON(!i->count || i->count < copy); - i->count -= copy; - bytes -= copy; - base += copy; - if (iov->iov_len == base) { - iov++; - base = 0; - } - } - i->iov = iov; - i->iov_offset = base; - } -} -EXPORT_SYMBOL(iov_iter_advance); - -/* - * Fault in the first iovec of the given iov_iter, to a maximum length - * of bytes. Returns 0 on success, or non-zero if the memory could not be - * accessed (ie. because it is an invalid address). - * - * writev-intensive code may want this to prefault several iovecs -- that - * would be possible (callers must not rely on the fact that _only_ the - * first iovec will be faulted with the current implementation). - */ -int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) -{ - char __user *buf = i->iov->iov_base + i->iov_offset; - bytes = min(bytes, i->iov->iov_len - i->iov_offset); - return fault_in_pages_readable(buf, bytes); -} -EXPORT_SYMBOL(iov_iter_fault_in_readable); - -/* - * Return the count of just the current iov_iter segment. - */ -size_t iov_iter_single_seg_count(struct iov_iter *i) -{ - const struct iovec *iov = i->iov; - if (i->nr_segs == 1) - return i->count; - else - return min(i->count, iov->iov_len - i->iov_offset); -} -EXPORT_SYMBOL(iov_iter_single_seg_count); - /* * Performs necessary checks before doing a write * @@ -2129,15 +2330,12 @@ int pagecache_write_end(struct file *file, struct address_space *mapping, { const struct address_space_operations *aops = mapping->a_ops; - mark_page_accessed(page); return aops->write_end(file, mapping, pos, len, copied, page, fsdata); } EXPORT_SYMBOL(pagecache_write_end); ssize_t -generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long *nr_segs, loff_t pos, loff_t *ppos, - size_t count, size_t ocount) +generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; @@ -2145,11 +2343,9 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, ssize_t written; size_t write_len; pgoff_t end; + struct iov_iter data; - if (count != ocount) - *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count); - - write_len = iov_length(iov, *nr_segs); + write_len = iov_iter_count(from); end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT; written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1); @@ -2176,7 +2372,8 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, } } - written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs); + data = *from; + written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos); /* * Finally, try again to invalidate clean pages which might have been @@ -2193,11 +2390,12 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, if (written > 0) { pos += written; + iov_iter_advance(from, written); if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) { i_size_write(inode, pos); mark_inode_dirty(inode); } - *ppos = pos; + iocb->ki_pos = pos; } out: return written; @@ -2211,32 +2409,23 @@ EXPORT_SYMBOL(generic_file_direct_write); struct page *grab_cache_page_write_begin(struct address_space *mapping, pgoff_t index, unsigned flags) { - int status; struct page *page; - gfp_t gfp_notmask = 0; + int fgp_flags = FGP_LOCK|FGP_ACCESSED|FGP_WRITE|FGP_CREAT; + if (flags & AOP_FLAG_NOFS) - gfp_notmask = __GFP_FS; -repeat: - page = find_lock_page(mapping, index); - if (likely(page)) - return page; + fgp_flags |= FGP_NOFS; + + page = pagecache_get_page(mapping, index, fgp_flags, + mapping_gfp_mask(mapping), + GFP_KERNEL); + if (page) + wait_for_stable_page(page); - page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask); - if (!page) - return NULL; - status = add_to_page_cache_lru(page, mapping, index, - GFP_KERNEL & ~gfp_notmask); - if (unlikely(status)) { - page_cache_release(page); - if (status == -EEXIST) - goto repeat; - return NULL; - } return page; } EXPORT_SYMBOL(grab_cache_page_write_begin); -static ssize_t generic_perform_write(struct file *file, +ssize_t generic_perform_write(struct file *file, struct iov_iter *i, loff_t pos) { struct address_space *mapping = file->f_mapping; @@ -2263,7 +2452,6 @@ static ssize_t generic_perform_write(struct file *file, iov_iter_count(i)); again: - /* * Bring in the user page that we will copy from _first_. * Otherwise there's a nasty deadlock on copying from the @@ -2281,18 +2469,15 @@ again: status = a_ops->write_begin(file, mapping, pos, bytes, flags, &page, &fsdata); - if (unlikely(status)) + if (unlikely(status < 0)) break; if (mapping_writably_mapped(mapping)) flush_dcache_page(page); - pagefault_disable(); copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); - pagefault_enable(); flush_dcache_page(page); - mark_page_accessed(page); status = a_ops->write_end(file, mapping, pos, bytes, copied, page, fsdata); if (unlikely(status < 0)) @@ -2319,39 +2504,20 @@ again: written += copied; balance_dirty_pages_ratelimited(mapping); - + if (fatal_signal_pending(current)) { + status = -EINTR; + break; + } } while (iov_iter_count(i)); return written ? written : status; } - -ssize_t -generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos, loff_t *ppos, - size_t count, ssize_t written) -{ - struct file *file = iocb->ki_filp; - ssize_t status; - struct iov_iter i; - - iov_iter_init(&i, iov, nr_segs, count, written); - status = generic_perform_write(file, &i, pos); - - if (likely(status >= 0)) { - written += status; - *ppos = pos + status; - } - - return written ? written : status; -} -EXPORT_SYMBOL(generic_file_buffered_write); +EXPORT_SYMBOL(generic_perform_write); /** - * __generic_file_aio_write - write data to a file + * __generic_file_write_iter - write data to a file * @iocb: IO state structure (file, offset, etc.) - * @iov: vector with data to write - * @nr_segs: number of segments in the vector - * @ppos: position where to write + * @from: iov_iter with data to write * * This function does all the work needed for actually writing data to a * file. It does all basic checks, removes SUID from the file, updates @@ -2365,32 +2531,19 @@ EXPORT_SYMBOL(generic_file_buffered_write); * A caller has to handle it. This is mainly due to the fact that we want to * avoid syncing under i_mutex. */ -ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) +ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct address_space * mapping = file->f_mapping; - size_t ocount; /* original count */ - size_t count; /* after file limit checks */ struct inode *inode = mapping->host; - loff_t pos; - ssize_t written; + loff_t pos = iocb->ki_pos; + ssize_t written = 0; ssize_t err; - - ocount = 0; - err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); - if (err) - return err; - - count = ocount; - pos = *ppos; - - vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + ssize_t status; + size_t count = iov_iter_count(from); /* We can write back this queue in page reclaim */ current->backing_dev_info = mapping->backing_dev_info; - written = 0; - err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); if (err) goto out; @@ -2398,51 +2551,53 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, if (count == 0) goto out; + iov_iter_truncate(from, count); + err = file_remove_suid(file); if (err) goto out; - file_update_time(file); + err = file_update_time(file); + if (err) + goto out; /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (unlikely(file->f_flags & O_DIRECT)) { loff_t endbyte; - ssize_t written_buffered; - written = generic_file_direct_write(iocb, iov, &nr_segs, pos, - ppos, count, ocount); + written = generic_file_direct_write(iocb, from, pos); if (written < 0 || written == count) goto out; + /* * direct-io write to a hole: fall through to buffered I/O * for completing the rest of the request. */ pos += written; count -= written; - written_buffered = generic_file_buffered_write(iocb, iov, - nr_segs, pos, ppos, count, - written); + + status = generic_perform_write(file, from, pos); /* - * If generic_file_buffered_write() retuned a synchronous error + * If generic_perform_write() returned a synchronous error * then we want to return the number of bytes which were * direct-written, or the error code if that was zero. Note * that this differs from normal direct-io semantics, which * will return -EFOO even if some bytes were written. */ - if (written_buffered < 0) { - err = written_buffered; + if (unlikely(status < 0) && !written) { + err = status; goto out; } - + iocb->ki_pos = pos + status; /* * We need to ensure that the page cache pages are written to * disk and invalidated to preserve the expected O_DIRECT * semantics. */ - endbyte = pos + written_buffered - written - 1; + endbyte = pos + status - 1; err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte); if (err == 0) { - written = written_buffered; + written += status; invalidate_mapping_pages(mapping, pos >> PAGE_CACHE_SHIFT, endbyte >> PAGE_CACHE_SHIFT); @@ -2453,49 +2608,45 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, */ } } else { - written = generic_file_buffered_write(iocb, iov, nr_segs, - pos, ppos, count, written); + written = generic_perform_write(file, from, pos); + if (likely(written >= 0)) + iocb->ki_pos = pos + written; } out: current->backing_dev_info = NULL; return written ? written : err; } -EXPORT_SYMBOL(__generic_file_aio_write); +EXPORT_SYMBOL(__generic_file_write_iter); /** - * generic_file_aio_write - write data to a file + * generic_file_write_iter - write data to a file * @iocb: IO state structure - * @iov: vector with data to write - * @nr_segs: number of segments in the vector - * @pos: position in file where to write + * @from: iov_iter with data to write * - * This is a wrapper around __generic_file_aio_write() to be used by most + * This is a wrapper around __generic_file_write_iter() to be used by most * filesystems. It takes care of syncing the file in case of O_SYNC file * and acquires i_mutex as needed. */ -ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) +ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; ssize_t ret; - BUG_ON(iocb->ki_pos != pos); - mutex_lock(&inode->i_mutex); - ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); + ret = __generic_file_write_iter(iocb, from); mutex_unlock(&inode->i_mutex); - if (ret > 0 || ret == -EIOCBQUEUED) { + if (ret > 0) { ssize_t err; - err = generic_write_sync(file, pos, ret); - if (err < 0 && ret > 0) + err = generic_write_sync(file, iocb->ki_pos - ret, ret); + if (err < 0) ret = err; } return ret; } -EXPORT_SYMBOL(generic_file_aio_write); +EXPORT_SYMBOL(generic_file_write_iter); /** * try_to_release_page() - release old fs-specific metadata on a page |