NFS: FS-Cache page management

[pandora-kernel.git] / fs / nfs / file.c

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index d319b49..3523b89 100644 (file)
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -35,6 +35,7 @@
 #include "delegation.h"
 #include "internal.h"
 #include "iostat.h"
+#include "fscache.h"
 
 #define NFSDBG_FACILITY                NFSDBG_FILE
 
@@ -64,11 +65,7 @@ const struct file_operations nfs_file_operations = {
        .write          = do_sync_write,
        .aio_read       = nfs_file_read,
        .aio_write      = nfs_file_write,
-#ifdef CONFIG_MMU
        .mmap           = nfs_file_mmap,
-#else
-       .mmap           = generic_file_mmap,
-#endif
        .open           = nfs_file_open,
        .flush          = nfs_file_flush,
        .release        = nfs_file_release,
@@ -141,9 +138,6 @@ nfs_file_release(struct inode *inode, struct file *filp)
                        dentry->d_parent->d_name.name,
                        dentry->d_name.name);
 
-       /* Ensure that dirty pages are flushed out with the right creds */
-       if (filp->f_mode & FMODE_WRITE)
-               nfs_wb_all(dentry->d_inode);
        nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
        return nfs_release(inode, filp);
 }
@@ -235,7 +229,6 @@ nfs_file_flush(struct file *file, fl_owner_t id)
        struct nfs_open_context *ctx = nfs_file_open_context(file);
        struct dentry   *dentry = file->f_path.dentry;
        struct inode    *inode = dentry->d_inode;
-       int             status;
 
        dprintk("NFS: flush(%s/%s)\n",
                        dentry->d_parent->d_name.name,
@@ -245,11 +238,8 @@ nfs_file_flush(struct file *file, fl_owner_t id)
                return 0;
        nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 
-       /* Ensure that data+attribute caches are up to date after close() */
-       status = nfs_do_fsync(ctx, inode);
-       if (!status)
-               nfs_revalidate_inode(NFS_SERVER(inode), inode);
-       return status;
+       /* Flush writes to the server and return any errors */
+       return nfs_do_fsync(ctx, inode);
 }
 
 static ssize_t
@@ -304,11 +294,13 @@ nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
        dprintk("NFS: mmap(%s/%s)\n",
                dentry->d_parent->d_name.name, dentry->d_name.name);
 
-       status = nfs_revalidate_mapping(inode, file->f_mapping);
+       /* Note: generic_file_mmap() returns ENOSYS on nommu systems
+        *       so we call that before revalidating the mapping
+        */
+       status = generic_file_mmap(file, vma);
        if (!status) {
                vma->vm_ops = &nfs_file_vm_ops;
-               vma->vm_flags |= VM_CAN_NONLINEAR;
-               file_accessed(file);
+               status = nfs_revalidate_mapping(inode, file->f_mapping);
        }
        return status;
 }
@@ -354,7 +346,16 @@ static int nfs_write_begin(struct file *file, struct address_space *mapping,
                file->f_path.dentry->d_name.name,
                mapping->host->i_ino, len, (long long) pos);
 
-       page = __grab_cache_page(mapping, index);
+       /*
+        * Prevent starvation issues if someone is doing a consistency
+        * sync-to-disk
+        */
+       ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
+                       nfs_wait_bit_killable, TASK_KILLABLE);
+       if (ret)
+               return ret;
+
+       page = grab_cache_page_write_begin(mapping, index, flags);
        if (!page)
                return -ENOMEM;
        *pagep = page;
@@ -409,6 +410,13 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
        return copied;
 }
 
+/*
+ * Partially or wholly invalidate a page
+ * - Release the private state associated with a page if undergoing complete
+ *   page invalidation
+ * - Called if either PG_private or PG_fscache is set on the page
+ * - Caller holds page lock
+ */
 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 {
        dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
@@ -417,23 +425,43 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
                return;
        /* Cancel any unstarted writes on this page */
        nfs_wb_page_cancel(page->mapping->host, page);
+
+       nfs_fscache_invalidate_page(page, page->mapping->host);
 }
 
+/*
+ * Attempt to release the private state associated with a page
+ * - Called if either PG_private or PG_fscache is set on the page
+ * - Caller holds page lock
+ * - Return true (may release page) or false (may not)
+ */
 static int nfs_release_page(struct page *page, gfp_t gfp)
 {
        dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 
        /* If PagePrivate() is set, then the page is not freeable */
-       return 0;
+       if (PagePrivate(page))
+               return 0;
+       return nfs_fscache_release_page(page, gfp);
 }
 
+/*
+ * Attempt to clear the private state associated with a page when an error
+ * occurs that requires the cached contents of an inode to be written back or
+ * destroyed
+ * - Called if either PG_private or fscache is set on the page
+ * - Caller holds page lock
+ * - Return 0 if successful, -error otherwise
+ */
 static int nfs_launder_page(struct page *page)
 {
        struct inode *inode = page->mapping->host;
+       struct nfs_inode *nfsi = NFS_I(inode);
 
        dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
                inode->i_ino, (long long)page_offset(page));
 
+       nfs_fscache_wait_on_page_write(nfsi, page);
        return nfs_wb_page(inode, page);
 }
 
@@ -451,8 +479,14 @@ const struct address_space_operations nfs_file_aops = {
        .launder_page = nfs_launder_page,
 };
 
-static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+/*
+ * Notification that a PTE pointing to an NFS page is about to be made
+ * writable, implying that someone is about to modify the page through a
+ * shared-writable mapping
+ */
+static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
+       struct page *page = vmf->page;
        struct file *filp = vma->vm_file;
        struct dentry *dentry = filp->f_path.dentry;
        unsigned pagelen;
@@ -464,6 +498,9 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
                filp->f_mapping->host->i_ino,
                (long long)page_offset(page));
 
+       /* make sure the cache has finished storing the page */
+       nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
+
        lock_page(page);
        mapping = page->mapping;
        if (mapping != dentry->d_inode->i_mapping)
@@ -483,6 +520,8 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
                ret = pagelen;
 out_unlock:
        unlock_page(page);
+       if (ret)
+               ret = VM_FAULT_SIGBUS;
        return ret;
 }