Merge branch 'btrfs-3.0' of git://github.com/chrismason/linux
authorLinus Torvalds <torvalds@linux-foundation.org>
Mon, 3 Oct 2011 19:17:44 +0000 (12:17 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 3 Oct 2011 19:17:44 +0000 (12:17 -0700)
* 'btrfs-3.0' of git://github.com/chrismason/linux:
  Btrfs: force a page fault if we have a shorty copy on a page boundary

fs/btrfs/file.c

index a381cd2..e4e57d5 100644 (file)
@@ -1036,11 +1036,13 @@ out:
  * on error we return an unlocked page and the error value
  * on success we return a locked page and 0
  */
-static int prepare_uptodate_page(struct page *page, u64 pos)
+static int prepare_uptodate_page(struct page *page, u64 pos,
+                                bool force_uptodate)
 {
        int ret = 0;
 
-       if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
+       if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
+           !PageUptodate(page)) {
                ret = btrfs_readpage(NULL, page);
                if (ret)
                        return ret;
@@ -1061,7 +1063,7 @@ static int prepare_uptodate_page(struct page *page, u64 pos)
 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
                         struct page **pages, size_t num_pages,
                         loff_t pos, unsigned long first_index,
-                        size_t write_bytes)
+                        size_t write_bytes, bool force_uptodate)
 {
        struct extent_state *cached_state = NULL;
        int i;
@@ -1086,10 +1088,11 @@ again:
                }
 
                if (i == 0)
-                       err = prepare_uptodate_page(pages[i], pos);
+                       err = prepare_uptodate_page(pages[i], pos,
+                                                   force_uptodate);
                if (i == num_pages - 1)
                        err = prepare_uptodate_page(pages[i],
-                                                   pos + write_bytes);
+                                                   pos + write_bytes, false);
                if (err) {
                        page_cache_release(pages[i]);
                        faili = i - 1;
@@ -1158,6 +1161,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
        size_t num_written = 0;
        int nrptrs;
        int ret = 0;
+       bool force_page_uptodate = false;
 
        nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
                     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
@@ -1200,7 +1204,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                 * contents of pages from loop to loop
                 */
                ret = prepare_pages(root, file, pages, num_pages,
-                                   pos, first_index, write_bytes);
+                                   pos, first_index, write_bytes,
+                                   force_page_uptodate);
                if (ret) {
                        btrfs_delalloc_release_space(inode,
                                        num_pages << PAGE_CACHE_SHIFT);
@@ -1217,12 +1222,15 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                if (copied < write_bytes)
                        nrptrs = 1;
 
-               if (copied == 0)
+               if (copied == 0) {
+                       force_page_uptodate = true;
                        dirty_pages = 0;
-               else
+               } else {
+                       force_page_uptodate = false;
                        dirty_pages = (copied + offset +
                                       PAGE_CACHE_SIZE - 1) >>
                                       PAGE_CACHE_SHIFT;
+               }
 
                /*
                 * If we had a short copy we need to release the excess delaloc