nfsd: fix leak on error in nfsv3 readdir
[safe/jmp/linux-2.6] / mm / filemap.c
index ed53ce8..ccea3b6 100644 (file)
@@ -121,7 +121,6 @@ void __remove_from_page_cache(struct page *page)
        mapping->nrpages--;
        __dec_zone_page_state(page, NR_FILE_PAGES);
        BUG_ON(page_mapped(page));
-       mem_cgroup_uncharge_cache_page(page);
 
        /*
         * Some filesystems seem to re-dirty the page even after
@@ -145,6 +144,7 @@ void remove_from_page_cache(struct page *page)
        spin_lock_irq(&mapping->tree_lock);
        __remove_from_page_cache(page);
        spin_unlock_irq(&mapping->tree_lock);
+       mem_cgroup_uncharge_cache_page(page);
 }
 
 static int sync_page(void *word)
@@ -210,7 +210,7 @@ int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
        int ret;
        struct writeback_control wbc = {
                .sync_mode = sync_mode,
-               .nr_to_write = mapping->nrpages * 2,
+               .nr_to_write = LONG_MAX,
                .range_start = start,
                .range_end = end,
        };
@@ -441,6 +441,7 @@ int filemap_write_and_wait_range(struct address_space *mapping,
        }
        return err;
 }
+EXPORT_SYMBOL(filemap_write_and_wait_range);
 
 /**
  * add_to_page_cache_locked - add a locked page to the pagecache
@@ -460,7 +461,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
        VM_BUG_ON(!PageLocked(page));
 
        error = mem_cgroup_cache_charge(page, current->mm,
-                                       gfp_mask & ~__GFP_HIGHMEM);
+                                       gfp_mask & GFP_RECLAIM_MASK);
        if (error)
                goto out;
 
@@ -475,13 +476,13 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
                if (likely(!error)) {
                        mapping->nrpages++;
                        __inc_zone_page_state(page, NR_FILE_PAGES);
+                       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);
                }
-
-               spin_unlock_irq(&mapping->tree_lock);
                radix_tree_preload_end();
        } else
                mem_cgroup_uncharge_cache_page(page);
@@ -513,13 +514,14 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
        }
        return ret;
 }
+EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
 
 #ifdef CONFIG_NUMA
 struct page *__page_cache_alloc(gfp_t gfp)
 {
        if (cpuset_do_page_mem_spread()) {
                int n = cpuset_mem_spread_node();
-               return alloc_pages_node(n, gfp, 0);
+               return alloc_pages_exact_node(n, gfp, 0);
        }
        return alloc_pages(gfp, 0);
 }
@@ -565,6 +567,24 @@ void wait_on_page_bit(struct page *page, int bit_nr)
 EXPORT_SYMBOL(wait_on_page_bit);
 
 /**
+ * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue
+ * @page: Page defining the wait queue of interest
+ * @waiter: Waiter to add to the queue
+ *
+ * Add an arbitrary @waiter to the wait queue for the nominated @page.
+ */
+void add_page_wait_queue(struct page *page, wait_queue_t *waiter)
+{
+       wait_queue_head_t *q = page_waitqueue(page);
+       unsigned long flags;
+
+       spin_lock_irqsave(&q->lock, flags);
+       __add_wait_queue(q, waiter);
+       spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL_GPL(add_page_wait_queue);
+
+/**
  * unlock_page - unlock a locked page
  * @page: the page
  *
@@ -627,6 +647,7 @@ int __lock_page_killable(struct page *page)
        return __wait_on_bit_lock(page_waitqueue(page), &wait,
                                        sync_page_killable, TASK_KILLABLE);
 }
+EXPORT_SYMBOL_GPL(__lock_page_killable);
 
 /**
  * __lock_page_nosync - get a lock on the page, without calling sync_page()
@@ -741,7 +762,14 @@ repeat:
                page = __page_cache_alloc(gfp_mask);
                if (!page)
                        return NULL;
-               err = add_to_page_cache_lru(page, mapping, index, gfp_mask);
+               /*
+                * 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 (unlikely(err)) {
                        page_cache_release(page);
                        page = NULL;
@@ -950,7 +978,7 @@ grab_cache_page_nowait(struct address_space *mapping, pgoff_t index)
                return NULL;
        }
        page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS);
-       if (page && add_to_page_cache_lru(page, mapping, index, GFP_KERNEL)) {
+       if (page && add_to_page_cache_lru(page, mapping, index, GFP_NOFS)) {
                page_cache_release(page);
                page = NULL;
        }
@@ -976,9 +1004,6 @@ EXPORT_SYMBOL(grab_cache_page_nowait);
 static void shrink_readahead_size_eio(struct file *filp,
                                        struct file_ra_state *ra)
 {
-       if (!ra->ra_pages)
-               return;
-
        ra->ra_pages /= 4;
 }
 
@@ -1317,7 +1342,8 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
                        goto out; /* skip atime */
                size = i_size_read(inode);
                if (pos < size) {
-                       retval = filemap_write_and_wait(mapping);
+                       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);
@@ -1361,12 +1387,11 @@ do_readahead(struct address_space *mapping, struct file *filp,
        if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage)
                return -EINVAL;
 
-       force_page_cache_readahead(mapping, filp, index,
-                                       max_sane_readahead(nr));
+       force_page_cache_readahead(mapping, filp, index, nr);
        return 0;
 }
 
-asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count)
+SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count)
 {
        ssize_t ret;
        struct file *file;
@@ -1385,6 +1410,13 @@ asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count)
        }
        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
 
 #ifdef CONFIG_MMU
 /**
@@ -1421,6 +1453,73 @@ static int page_cache_read(struct file *file, pgoff_t offset)
 
 #define MMAP_LOTSAMISS  (100)
 
+/*
+ * Synchronous readahead happens when we don't even find
+ * a page in the page cache at all.
+ */
+static void do_sync_mmap_readahead(struct vm_area_struct *vma,
+                                  struct file_ra_state *ra,
+                                  struct file *file,
+                                  pgoff_t offset)
+{
+       unsigned long ra_pages;
+       struct address_space *mapping = file->f_mapping;
+
+       /* If we don't want any read-ahead, don't bother */
+       if (VM_RandomReadHint(vma))
+               return;
+
+       if (VM_SequentialReadHint(vma) ||
+                       offset - 1 == (ra->prev_pos >> PAGE_CACHE_SHIFT)) {
+               page_cache_sync_readahead(mapping, ra, file, offset,
+                                         ra->ra_pages);
+               return;
+       }
+
+       if (ra->mmap_miss < INT_MAX)
+               ra->mmap_miss++;
+
+       /*
+        * Do we miss much more than hit in this file? If so,
+        * stop bothering with read-ahead. It will only hurt.
+        */
+       if (ra->mmap_miss > MMAP_LOTSAMISS)
+               return;
+
+       /*
+        * 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);
+       }
+}
+
+/*
+ * Asynchronous readahead happens when we find the page and PG_readahead,
+ * so we want to possibly extend the readahead further..
+ */
+static void do_async_mmap_readahead(struct vm_area_struct *vma,
+                                   struct file_ra_state *ra,
+                                   struct file *file,
+                                   struct page *page,
+                                   pgoff_t offset)
+{
+       struct address_space *mapping = file->f_mapping;
+
+       /* If we don't want any read-ahead, don't bother */
+       if (VM_RandomReadHint(vma))
+               return;
+       if (ra->mmap_miss > 0)
+               ra->mmap_miss--;
+       if (PageReadahead(page))
+               page_cache_async_readahead(mapping, ra, file,
+                                          page, offset, ra->ra_pages);
+}
+
 /**
  * filemap_fault - read in file data for page fault handling
  * @vma:       vma in which the fault was taken
@@ -1440,78 +1539,44 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        struct address_space *mapping = file->f_mapping;
        struct file_ra_state *ra = &file->f_ra;
        struct inode *inode = mapping->host;
+       pgoff_t offset = vmf->pgoff;
        struct page *page;
        pgoff_t size;
-       int did_readaround = 0;
        int ret = 0;
 
        size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-       if (vmf->pgoff >= size)
+       if (offset >= size)
                return VM_FAULT_SIGBUS;
 
-       /* If we don't want any read-ahead, don't bother */
-       if (VM_RandomReadHint(vma))
-               goto no_cached_page;
-
        /*
         * Do we have something in the page cache already?
         */
-retry_find:
-       page = find_lock_page(mapping, vmf->pgoff);
-       /*
-        * For sequential accesses, we use the generic readahead logic.
-        */
-       if (VM_SequentialReadHint(vma)) {
-               if (!page) {
-                       page_cache_sync_readahead(mapping, ra, file,
-                                                          vmf->pgoff, 1);
-                       page = find_lock_page(mapping, vmf->pgoff);
-                       if (!page)
-                               goto no_cached_page;
-               }
-               if (PageReadahead(page)) {
-                       page_cache_async_readahead(mapping, ra, file, page,
-                                                          vmf->pgoff, 1);
-               }
-       }
-
-       if (!page) {
-               unsigned long ra_pages;
-
-               ra->mmap_miss++;
-
+       page = find_get_page(mapping, offset);
+       if (likely(page)) {
                /*
-                * Do we miss much more than hit in this file? If so,
-                * stop bothering with read-ahead. It will only hurt.
+                * We found the page, so try async readahead before
+                * waiting for the lock.
                 */
-               if (ra->mmap_miss > MMAP_LOTSAMISS)
-                       goto no_cached_page;
+               do_async_mmap_readahead(vma, ra, file, page, offset);
+               lock_page(page);
 
-               /*
-                * To keep the pgmajfault counter straight, we need to
-                * check did_readaround, as this is an inner loop.
-                */
-               if (!did_readaround) {
-                       ret = VM_FAULT_MAJOR;
-                       count_vm_event(PGMAJFAULT);
-               }
-               did_readaround = 1;
-               ra_pages = max_sane_readahead(file->f_ra.ra_pages);
-               if (ra_pages) {
-                       pgoff_t start = 0;
-
-                       if (vmf->pgoff > ra_pages / 2)
-                               start = vmf->pgoff - ra_pages / 2;
-                       do_page_cache_readahead(mapping, file, start, ra_pages);
+               /* Did it get truncated? */
+               if (unlikely(page->mapping != mapping)) {
+                       unlock_page(page);
+                       put_page(page);
+                       goto no_cached_page;
                }
-               page = find_lock_page(mapping, vmf->pgoff);
+       } else {
+               /* No page in the page cache at all */
+               do_sync_mmap_readahead(vma, ra, file, offset);
+               count_vm_event(PGMAJFAULT);
+               ret = VM_FAULT_MAJOR;
+retry_find:
+               page = find_lock_page(mapping, offset);
                if (!page)
                        goto no_cached_page;
        }
 
-       if (!did_readaround)
-               ra->mmap_miss--;
-
        /*
         * We have a locked page in the page cache, now we need to check
         * that it's up-to-date. If not, it is going to be due to an error.
@@ -1519,19 +1584,18 @@ retry_find:
        if (unlikely(!PageUptodate(page)))
                goto page_not_uptodate;
 
-       /* Must recheck i_size under page lock */
+       /*
+        * 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(vmf->pgoff >= size)) {
+       if (unlikely(offset >= size)) {
                unlock_page(page);
                page_cache_release(page);
                return VM_FAULT_SIGBUS;
        }
 
-       /*
-        * Found the page and have a reference on it.
-        */
-       mark_page_accessed(page);
-       ra->prev_pos = (loff_t)page->index << PAGE_CACHE_SHIFT;
+       ra->prev_pos = (loff_t)offset << PAGE_CACHE_SHIFT;
        vmf->page = page;
        return ret | VM_FAULT_LOCKED;
 
@@ -1540,7 +1604,7 @@ no_cached_page:
         * We're only likely to ever get here if MADV_RANDOM is in
         * effect.
         */
-       error = page_cache_read(file, vmf->pgoff);
+       error = page_cache_read(file, offset);
 
        /*
         * The page we want has now been added to the page cache.
@@ -1560,12 +1624,6 @@ no_cached_page:
        return VM_FAULT_SIGBUS;
 
 page_not_uptodate:
-       /* IO error path */
-       if (!did_readaround) {
-               ret = VM_FAULT_MAJOR;
-               count_vm_event(PGMAJFAULT);
-       }
-
        /*
         * Umm, take care of errors if the page isn't up-to-date.
         * Try to re-read it _once_. We do this synchronously,
@@ -1809,7 +1867,7 @@ static size_t __iovec_copy_from_user_inatomic(char *vaddr,
                int copy = min(bytes, iov->iov_len - base);
 
                base = 0;
-               left = __copy_from_user_inatomic_nocache(vaddr, buf, copy);
+               left = __copy_from_user_inatomic(vaddr, buf, copy);
                copied += copy;
                bytes -= copy;
                vaddr += copy;
@@ -1837,8 +1895,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
        if (likely(i->nr_segs == 1)) {
                int left;
                char __user *buf = i->iov->iov_base + i->iov_offset;
-               left = __copy_from_user_inatomic_nocache(kaddr + offset,
-                                                       buf, bytes);
+               left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
                copied = bytes - left;
        } else {
                copied = __iovec_copy_from_user_inatomic(kaddr + offset,
@@ -1866,7 +1923,7 @@ size_t iov_iter_copy_from_user(struct page *page,
        if (likely(i->nr_segs == 1)) {
                int left;
                char __user *buf = i->iov->iov_base + i->iov_offset;
-               left = __copy_from_user_nocache(kaddr + offset, buf, bytes);
+               left = __copy_from_user(kaddr + offset, buf, bytes);
                copied = bytes - left;
        } else {
                copied = __iovec_copy_from_user_inatomic(kaddr + offset,
@@ -2060,18 +2117,10 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
        if (count != ocount)
                *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count);
 
-       /*
-        * Unmap all mmappings of the file up-front.
-        *
-        * This will cause any pte dirty bits to be propagated into the
-        * pageframes for the subsequent filemap_write_and_wait().
-        */
        write_len = iov_length(iov, *nr_segs);
        end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT;
-       if (mapping_mapped(mapping))
-               unmap_mapping_range(mapping, pos, write_len, 0);
 
-       written = filemap_write_and_wait(mapping);
+       written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
        if (written)
                goto out;
 
@@ -2140,19 +2189,24 @@ EXPORT_SYMBOL(generic_file_direct_write);
  * Find or create a page at the given pagecache position. Return the locked
  * page. This function is specifically for buffered writes.
  */
-struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index)
+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;
+       if (flags & AOP_FLAG_NOFS)
+               gfp_notmask = __GFP_FS;
 repeat:
        page = find_lock_page(mapping, index);
        if (likely(page))
                return page;
 
-       page = page_cache_alloc(mapping);
+       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);
+       status = add_to_page_cache_lru(page, mapping, index,
+                                               GFP_KERNEL & ~gfp_notmask);
        if (unlikely(status)) {
                page_cache_release(page);
                if (status == -EEXIST)
@@ -2161,7 +2215,7 @@ repeat:
        }
        return page;
 }
-EXPORT_SYMBOL(__grab_cache_page);
+EXPORT_SYMBOL(grab_cache_page_write_begin);
 
 static ssize_t generic_perform_write(struct file *file,
                                struct iov_iter *i, loff_t pos)
@@ -2218,6 +2272,7 @@ again:
                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))
@@ -2286,7 +2341,8 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
         * the file data here, to try to honour O_DIRECT expectations.
         */
        if (unlikely(file->f_flags & O_DIRECT) && written)
-               status = filemap_write_and_wait(mapping);
+               status = filemap_write_and_wait_range(mapping,
+                                       pos, pos + written - 1);
 
        return written ? written : status;
 }
@@ -2452,6 +2508,9 @@ EXPORT_SYMBOL(generic_file_aio_write);
  * (presumably at page->private).  If the release was successful, return `1'.
  * Otherwise return zero.
  *
+ * This may also be called if PG_fscache is set on a page, indicating that the
+ * page is known to the local caching routines.
+ *
  * The @gfp_mask argument specifies whether I/O may be performed to release
  * this page (__GFP_IO), and whether the call may block (__GFP_WAIT & __GFP_FS).
  *