exofs: Support for RAID5 read-4-write interface.

[pandora-kernel.git] / fs / exofs / inode.c

diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 86c0ac8..3e5f3a6 100644 (file)
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -63,6 +63,7 @@ struct page_collect {
        bool read_4_write; /* This means two things: that the read is sync
                            * And the pages should not be unlocked.
                            */
+       struct page *that_locked_page;
 };
 
 static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
@@ -81,6 +82,7 @@ static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
        pcol->length = 0;
        pcol->pg_first = -1;
        pcol->read_4_write = false;
+       pcol->that_locked_page = NULL;
 }
 
 static void _pcol_reset(struct page_collect *pcol)
@@ -93,6 +95,7 @@ static void _pcol_reset(struct page_collect *pcol)
        pcol->length = 0;
        pcol->pg_first = -1;
        pcol->ios = NULL;
+       pcol->that_locked_page = NULL;
 
        /* this is probably the end of the loop but in writes
         * it might not end here. don't be left with nothing
@@ -391,6 +394,8 @@ static int readpage_strip(void *data, struct page *page)
                EXOFS_ERR("PageUptodate(0x%lx, 0x%lx)\n", pcol->inode->i_ino,
                          page->index);
 
+       pcol->that_locked_page = page;
+
        if (page->index < end_index)
                len = PAGE_CACHE_SIZE;
        else if (page->index == end_index)
@@ -560,6 +565,56 @@ static void writepages_done(struct ore_io_state *ios, void *p)
        EXOFS_DBGMSG2("writepages_done END\n");
 }
 
+static struct page *__r4w_get_page(void *priv, u64 offset, bool *uptodate)
+{
+       struct page_collect *pcol = priv;
+       pgoff_t index = offset / PAGE_SIZE;
+
+       if (!pcol->that_locked_page ||
+           (pcol->that_locked_page->index != index)) {
+               struct page *page = find_get_page(pcol->inode->i_mapping, index);
+
+               if (!page) {
+                       page = find_or_create_page(pcol->inode->i_mapping,
+                                                  index, GFP_NOFS);
+                       if (unlikely(!page)) {
+                               EXOFS_DBGMSG("grab_cache_page Failed "
+                                       "index=0x%llx\n", _LLU(index));
+                               return NULL;
+                       }
+                       unlock_page(page);
+               }
+               if (PageDirty(page) || PageWriteback(page))
+                       *uptodate = true;
+               else
+                       *uptodate = PageUptodate(page);
+               EXOFS_DBGMSG("index=0x%lx uptodate=%d\n", index, *uptodate);
+               return page;
+       } else {
+               EXOFS_DBGMSG("YES that_locked_page index=0x%lx\n",
+                            pcol->that_locked_page->index);
+               *uptodate = true;
+               return pcol->that_locked_page;
+       }
+}
+
+static void __r4w_put_page(void *priv, struct page *page)
+{
+       struct page_collect *pcol = priv;
+
+       if (pcol->that_locked_page != page) {
+               EXOFS_DBGMSG("index=0x%lx\n", page->index);
+               page_cache_release(page);
+               return;
+       }
+       EXOFS_DBGMSG("that_locked_page index=0x%lx\n", page->index);
+}
+
+static const struct _ore_r4w_op _r4w_op = {
+       .get_page = &__r4w_get_page,
+       .put_page = &__r4w_put_page,
+};
+
 static int write_exec(struct page_collect *pcol)
 {
        struct exofs_i_info *oi = exofs_i(pcol->inode);
@@ -589,6 +644,7 @@ static int write_exec(struct page_collect *pcol)
        ios = pcol->ios;
        ios->pages = pcol_copy->pages;
        ios->done = writepages_done;
+       ios->r4w = &_r4w_op;
        ios->private = pcol_copy;
 
        /* pages ownership was passed to pcol_copy */
@@ -773,6 +829,7 @@ static int exofs_writepages(struct address_space *mapping,
        return 0;
 }
 
+/*
 static int exofs_writepage(struct page *page, struct writeback_control *wbc)
 {
        struct page_collect pcol;
@@ -788,7 +845,7 @@ static int exofs_writepage(struct page *page, struct writeback_control *wbc)
 
        return write_exec(&pcol);
 }
-
+*/
 /* i_mutex held using inode->i_size directly */
 static void _write_failed(struct inode *inode, loff_t to)
 {
@@ -894,7 +951,7 @@ static void exofs_invalidatepage(struct page *page, unsigned long offset)
 const struct address_space_operations exofs_aops = {
        .readpage       = exofs_readpage,
        .readpages      = exofs_readpages,
-       .writepage      = exofs_writepage,
+       .writepage      = NULL,
        .writepages     = exofs_writepages,
        .write_begin    = exofs_write_begin_export,
        .write_end      = exofs_write_end,