]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - mm/filemap.c
[PATCH] add AOP_TRUNCATED_PAGE, prepend AOP_ to WRITEPAGE_ACTIVATE
[linux-2.6.git] / mm / filemap.c
index 33a28bfde158a5c6e403fa11992cd2e897fe6868..6e1d08a2b8b9e1f8f690b91e2510f60070fecb55 100644 (file)
@@ -831,8 +831,13 @@ readpage:
                /* Start the actual read. The read will unlock the page. */
                error = mapping->a_ops->readpage(filp, page);
 
-               if (unlikely(error))
+               if (unlikely(error)) {
+                       if (error == AOP_TRUNCATED_PAGE) {
+                               page_cache_release(page);
+                               goto find_page;
+                       }
                        goto readpage_error;
+               }
 
                if (!PageUptodate(page)) {
                        lock_page(page);
@@ -1152,26 +1157,24 @@ static int fastcall page_cache_read(struct file * file, unsigned long offset)
 {
        struct address_space *mapping = file->f_mapping;
        struct page *page; 
-       int error;
+       int ret;
 
-       page = page_cache_alloc_cold(mapping);
-       if (!page)
-               return -ENOMEM;
+       do {
+               page = page_cache_alloc_cold(mapping);
+               if (!page)
+                       return -ENOMEM;
+
+               ret = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL);
+               if (ret == 0)
+                       ret = mapping->a_ops->readpage(file, page);
+               else if (ret == -EEXIST)
+                       ret = 0; /* losing race to add is OK */
 
-       error = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL);
-       if (!error) {
-               error = mapping->a_ops->readpage(file, page);
                page_cache_release(page);
-               return error;
-       }
 
-       /*
-        * We arrive here in the unlikely event that someone 
-        * raced with us and added our page to the cache first
-        * or we are out of memory for radix-tree nodes.
-        */
-       page_cache_release(page);
-       return error == -EEXIST ? 0 : error;
+       } while (ret == AOP_TRUNCATED_PAGE);
+               
+       return ret;
 }
 
 #define MMAP_LOTSAMISS  (100)
@@ -1331,10 +1334,14 @@ page_not_uptodate:
                goto success;
        }
 
-       if (!mapping->a_ops->readpage(file, page)) {
+       error = mapping->a_ops->readpage(file, page);
+       if (!error) {
                wait_on_page_locked(page);
                if (PageUptodate(page))
                        goto success;
+       } else if (error == AOP_TRUNCATED_PAGE) {
+               page_cache_release(page);
+               goto retry_find;
        }
 
        /*
@@ -1358,10 +1365,14 @@ page_not_uptodate:
                goto success;
        }
        ClearPageError(page);
-       if (!mapping->a_ops->readpage(file, page)) {
+       error = mapping->a_ops->readpage(file, page);
+       if (!error) {
                wait_on_page_locked(page);
                if (PageUptodate(page))
                        goto success;
+       } else if (error == AOP_TRUNCATED_PAGE) {
+               page_cache_release(page);
+               goto retry_find;
        }
 
        /*
@@ -1444,10 +1455,14 @@ page_not_uptodate:
                goto success;
        }
 
-       if (!mapping->a_ops->readpage(file, page)) {
+       error = mapping->a_ops->readpage(file, page);
+       if (!error) {
                wait_on_page_locked(page);
                if (PageUptodate(page))
                        goto success;
+       } else if (error == AOP_TRUNCATED_PAGE) {
+               page_cache_release(page);
+               goto retry_find;
        }
 
        /*
@@ -1470,10 +1485,14 @@ page_not_uptodate:
        }
 
        ClearPageError(page);
-       if (!mapping->a_ops->readpage(file, page)) {
+       error = mapping->a_ops->readpage(file, page);
+       if (!error) {
                wait_on_page_locked(page);
                if (PageUptodate(page))
                        goto success;
+       } else if (error == AOP_TRUNCATED_PAGE) {
+               page_cache_release(page);
+               goto retry_find;
        }
 
        /*
@@ -1934,12 +1953,16 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                status = a_ops->prepare_write(file, page, offset, offset+bytes);
                if (unlikely(status)) {
                        loff_t isize = i_size_read(inode);
+
+                       if (status != AOP_TRUNCATED_PAGE)
+                               unlock_page(page);
+                       page_cache_release(page);
+                       if (status == AOP_TRUNCATED_PAGE)
+                               continue;
                        /*
                         * prepare_write() may have instantiated a few blocks
                         * outside i_size.  Trim these off again.
                         */
-                       unlock_page(page);
-                       page_cache_release(page);
                        if (pos + bytes > isize)
                                vmtruncate(inode, isize);
                        break;
@@ -1952,6 +1975,10 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                                                cur_iov, iov_base, bytes);
                flush_dcache_page(page);
                status = a_ops->commit_write(file, page, offset, offset+bytes);
+               if (status == AOP_TRUNCATED_PAGE) {
+                       page_cache_release(page);
+                       continue;
+               }
                if (likely(copied > 0)) {
                        if (!status)
                                status = copied;