nfsd: nfsd should drop CAP_MKNOD for non-root

[safe/jmp/linux-2.6] / mm / truncate.c

diff --git a/mm/truncate.c b/mm/truncate.c
index 7c994f2..1229211 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -3,11 +3,12 @@
  *
  * Copyright (C) 2002, Linus Torvalds
  *
- * 10Sep2002   akpm@zip.com.au
+ * 10Sep2002   Andrew Morton
  *             Initial version.
  */
 
 #include <linux/kernel.h>
+#include <linux/backing-dev.h>
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/module.h>
@@ -17,10 +18,11 @@
 #include <linux/task_io_accounting_ops.h>
 #include <linux/buffer_head.h> /* grr. try_to_release_page,
                                   do_invalidatepage */
+#include "internal.h"
 
 
 /**
- * do_invalidatepage - invalidate part of all of a page
+ * do_invalidatepage - invalidate part or all of a page
  * @page: the page which is affected
  * @offset: the index of the truncation point
  *
@@ -47,7 +49,7 @@ void do_invalidatepage(struct page *page, unsigned long offset)
 
 static inline void truncate_partial_page(struct page *page, unsigned partial)
 {
-       zero_user_page(page, partial, PAGE_CACHE_SIZE - partial, KM_USER0);
+       zero_user_segment(page, partial, PAGE_CACHE_SIZE);
        if (PagePrivate(page))
                do_invalidatepage(page, partial);
 }
@@ -72,6 +74,8 @@ void cancel_dirty_page(struct page *page, unsigned int account_size)
                struct address_space *mapping = page->mapping;
                if (mapping && mapping_cap_account_dirty(mapping)) {
                        dec_zone_page_state(page, NR_FILE_DIRTY);
+                       dec_bdi_stat(mapping->backing_dev_info,
+                                       BDI_RECLAIMABLE);
                        if (account_size)
                                task_io_account_cancelled_write(account_size);
                }
@@ -81,8 +85,8 @@ EXPORT_SYMBOL(cancel_dirty_page);
 
 /*
  * If truncate cannot remove the fs-private metadata from the page, the page
- * becomes anonymous.  It will be left on the LRU and may even be mapped into
- * user pagetables if we're racing with filemap_nopage().
+ * becomes orphaned.  It will be left on the LRU and may even be mapped into
+ * user pagetables if we're racing with filemap_fault().
  *
  * We need to bale out if page->mapping is no longer equal to the original
  * mapping.  This happens a) when the VM reclaimed the page while we waited on
@@ -95,14 +99,14 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
        if (page->mapping != mapping)
                return;
 
-       cancel_dirty_page(page, PAGE_CACHE_SIZE);
-
        if (PagePrivate(page))
                do_invalidatepage(page, 0);
 
-       ClearPageUptodate(page);
-       ClearPageMappedToDisk(page);
+       cancel_dirty_page(page, PAGE_CACHE_SIZE);
+
+       clear_page_mlock(page);
        remove_from_page_cache(page);
+       ClearPageMappedToDisk(page);
        page_cache_release(page);       /* pagecache ref */
 }
 
@@ -125,14 +129,14 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
        if (PagePrivate(page) && !try_to_release_page(page, 0))
                return 0;
 
+       clear_page_mlock(page);
        ret = remove_mapping(mapping, page);
 
        return ret;
 }
 
 /**
- * truncate_inode_pages - truncate range of pages specified by start and
- * end byte offsets
+ * truncate_inode_pages - truncate range of pages specified by start & end byte offsets
  * @mapping: mapping to truncate
  * @lstart: offset from which to truncate
  * @lend: offset to which to truncate
@@ -186,12 +190,17 @@ void truncate_inode_pages_range(struct address_space *mapping,
                        if (page_index > next)
                                next = page_index;
                        next++;
-                       if (TestSetPageLocked(page))
+                       if (!trylock_page(page))
                                continue;
                        if (PageWriteback(page)) {
                                unlock_page(page);
                                continue;
                        }
+                       if (page_mapped(page)) {
+                               unmap_mapping_range(mapping,
+                                 (loff_t)page_index<<PAGE_CACHE_SHIFT,
+                                 PAGE_CACHE_SIZE, 0);
+                       }
                        truncate_complete_page(mapping, page);
                        unlock_page(page);
                }
@@ -229,6 +238,11 @@ void truncate_inode_pages_range(struct address_space *mapping,
                                break;
                        lock_page(page);
                        wait_on_page_writeback(page);
+                       if (page_mapped(page)) {
+                               unmap_mapping_range(mapping,
+                                 (loff_t)page->index<<PAGE_CACHE_SHIFT,
+                                 PAGE_CACHE_SIZE, 0);
+                       }
                        if (page->index > next)
                                next = page->index;
                        next++;
@@ -269,7 +283,7 @@ unsigned long __invalidate_mapping_pages(struct address_space *mapping,
                        pgoff_t index;
                        int lock_failed;
 
-                       lock_failed = TestSetPageLocked(page);
+                       lock_failed = !trylock_page(page);
 
                        /*
                         * We really shouldn't be looking at the ->index of an
@@ -337,18 +351,18 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
        if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
                return 0;
 
-       write_lock_irq(&mapping->tree_lock);
+       spin_lock_irq(&mapping->tree_lock);
        if (PageDirty(page))
                goto failed;
 
+       clear_page_mlock(page);
        BUG_ON(PagePrivate(page));
        __remove_from_page_cache(page);
-       write_unlock_irq(&mapping->tree_lock);
-       ClearPageUptodate(page);
+       spin_unlock_irq(&mapping->tree_lock);
        page_cache_release(page);       /* pagecache ref */
        return 1;
 failed:
-       write_unlock_irq(&mapping->tree_lock);
+       spin_unlock_irq(&mapping->tree_lock);
        return 0;
 }
 
@@ -370,7 +384,7 @@ static int do_launder_page(struct address_space *mapping, struct page *page)
  * Any pages which are found to be mapped into pagetables are unmapped prior to
  * invalidation.
  *
- * Returns -EIO if any pages could not be invalidated.
+ * Returns -EBUSY if any pages could not be invalidated.
  */
 int invalidate_inode_pages2_range(struct address_space *mapping,
                                  pgoff_t start, pgoff_t end)
@@ -379,6 +393,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
        pgoff_t next;
        int i;
        int ret = 0;
+       int ret2 = 0;
        int did_range_unmap = 0;
        int wrapped = 0;
 
@@ -405,7 +420,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
                                break;
                        }
                        wait_on_page_writeback(page);
-                       while (page_mapped(page)) {
+                       if (page_mapped(page)) {
                                if (!did_range_unmap) {
                                        /*
                                         * Zap the rest of the file in one hit.
@@ -425,9 +440,14 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
                                          PAGE_CACHE_SIZE, 0);
                                }
                        }
-                       ret = do_launder_page(mapping, page);
-                       if (ret == 0 && !invalidate_complete_page2(mapping, page))
-                               ret = -EIO;
+                       BUG_ON(page_mapped(page));
+                       ret2 = do_launder_page(mapping, page);
+                       if (ret2 == 0) {
+                               if (!invalidate_complete_page2(mapping, page))
+                                       ret2 = -EBUSY;
+                       }
+                       if (ret2 < 0)
+                               ret = ret2;
                        unlock_page(page);
                }
                pagevec_release(&pvec);