1 files changed, 105 insertions, 14 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 8ea609718839..93853e337f07 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -973,13 +973,21 @@ repeat:
         page = NULL;
         pagep = radix_tree_lookup_slot(&mapping->page_tree, offset);
         if (pagep) {
-                void *pdesc;
-                pdesc = radix_tree_deref_slot(pagep);
-                if (pdesc)
-                        page = (struct page*)pdesc;
-                //page = radix_tree_deref_slot(pagep);
+                page = radix_tree_deref_slot(pagep);
                 if (unlikely(!page))
                         goto out;
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+printk(KERN_INFO "PCACHE_DESC\n");
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+                        
+                        unreplicate_pcache(mapping, page->index, 0);
+                        
+                        goto out;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page))
                                 goto repeat;
@@ -1178,6 +1186,20 @@ repeat:
                 page = radix_tree_deref_slot(slot);
                 if (unlikely(!page))
                         continue;
+                
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+                        printk(KERN_INFO "PCACHE_DESC\n");
+                        
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+                        
+                        unreplicate_pcache(mapping, page->index, 0);
+                        
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page))
                                 goto restart;
@@ -1241,6 +1263,20 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+                        printk(KERN_INFO "PCACHE_DESC\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+
+                        unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
                                 /*
@@ -1268,6 +1304,7 @@ repeat:
                         goto repeat;
                 }
 
+export:
                 pages[ret] = page;
                 if (++ret == nr_pages)
                         break;
@@ -1309,6 +1346,20 @@ repeat:
                 if (unlikely(!page))
                         break;
 
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+                        printk(KERN_INFO "PCACHE_DESC\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+
+                        unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
                                 /*
@@ -1334,7 +1385,7 @@ repeat:
                         page_cache_release(page);
                         goto repeat;
                 }
-
+export:
                 /*
                  * must check mapping and index after taking the ref.
                  * otherwise we can get both false positives and false
@@ -1385,6 +1436,20 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+                        printk(KERN_INFO "PCACHE_DESC BUG!!!!!!!!!!\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+
+                        unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
                                 /*
@@ -1416,7 +1481,7 @@ repeat:
                         page_cache_release(page);
                         goto repeat;
                 }
-
+export:
                 pages[ret] = page;
                 if (++ret == nr_pages)
                         break;
@@ -1492,7 +1557,11 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
 
                 cond_resched();
 find_page:
-                page = find_get_page(mapping, index);
+                if (is_realtime(current))
+                        page = find_get_page_readonly(mapping, index);
+                else
+                        page = find_get_page(mapping, index);
+                
                 if (!page) {
                         page_cache_sync_readahead(mapping,
                                         ra, filp,
@@ -1644,7 +1713,8 @@ readpage:
                         unlock_page(page);
                 }
 
-                goto page_ok;
+                page_cache_release(page);
+                goto find_page;
 
 readpage_error:
                 /* UHHUH! A synchronous read error occurred. Report it */
@@ -1888,9 +1958,11 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         /*
          * Do we have something in the page cache already?
          */
-if (is_realtime(current))
-        printk("FILEMAP_FAULT %ld\n", vma->vm_start);
-        page = find_get_page(mapping, offset);
+        if ((vmf->flags & FAULT_FLAG_WRITE) || !is_realtime(current))
+                page = find_get_page(mapping, offset);
+        else
+                page = find_get_page_readonly(mapping, offset);
+        
         if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) {
                 /*
                  * We found the page, so try async readahead before
@@ -1904,7 +1976,10 @@ if (is_realtime(current))
                 mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
                 ret = VM_FAULT_MAJOR;
 retry_find:
-                page = find_get_page(mapping, offset);
+                if ((vmf->flags & FAULT_FLAG_WRITE) || !is_realtime(current))
+                        page = find_get_page(mapping, offset);
+                else
+                        page = find_get_page_readonly(mapping, offset);
                 if (!page)
                         goto no_cached_page;
         }
@@ -2012,6 +2087,22 @@ repeat:
                 page = radix_tree_deref_slot(slot);
                 if (unlikely(!page))
                         goto next;
+                
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+printk(KERN_INFO "PCACHE_DESC FILE_MAP_PAGES\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        if (!page_cache_get_speculative(page))
+                                goto repeat;
+                        
+                        //unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page))
                                 break;
@@ -2027,7 +2118,7 @@ repeat:
                         page_cache_release(page);
                         goto repeat;
                 }
-
+export:
                 if (!PageUptodate(page) ||
                                 PageReadahead(page) ||
                                 PageHWPoison(page))