GFS2: Clean up ->page_mkwrite

[pandora-kernel.git] / fs / gfs2 / file.c

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 3b65f67..aa3a4dd 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -366,8 +366,15 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
        unsigned int data_blocks, ind_blocks, rblocks;
        struct gfs2_holder gh;
        struct gfs2_alloc *al;
+       loff_t size;
        int ret;
 
+       /* Wait if fs is frozen. This is racy so we check again later on
+        * and retry if the fs has been frozen after the page lock has
+        * been acquired
+        */
+       vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
        gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
        ret = gfs2_glock_nq(&gh);
        if (ret)
@@ -376,8 +383,15 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
        set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
        set_bit(GIF_SW_PAGED, &ip->i_flags);
 
-       if (!gfs2_write_alloc_required(ip, pos, PAGE_CACHE_SIZE))
+       if (!gfs2_write_alloc_required(ip, pos, PAGE_CACHE_SIZE)) {
+               lock_page(page);
+               if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
+                       ret = -EAGAIN;
+                       unlock_page(page);
+               }
                goto out_unlock;
+       }
+
        ret = -ENOMEM;
        al = gfs2_alloc_get(ip);
        if (al == NULL)
@@ -405,21 +419,29 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
        lock_page(page);
        ret = -EINVAL;
-       last_index = ip->i_inode.i_size >> PAGE_CACHE_SHIFT;
-       if (page->index > last_index)
-               goto out_unlock_page;
+       size = i_size_read(inode);
+       last_index = (size - 1) >> PAGE_CACHE_SHIFT;
+       /* Check page index against inode size */
+       if (size == 0 || (page->index > last_index))
+               goto out_trans_end;
+
+       ret = -EAGAIN;
+       /* If truncated, we must retry the operation, we may have raced
+        * with the glock demotion code.
+        */
+       if (!PageUptodate(page) || page->mapping != inode->i_mapping)
+               goto out_trans_end;
+
+       /* Unstuff, if required, and allocate backing blocks for page */
        ret = 0;
-       if (!PageUptodate(page) || page->mapping != ip->i_inode.i_mapping)
-               goto out_unlock_page;
-       if (gfs2_is_stuffed(ip)) {
+       if (gfs2_is_stuffed(ip))
                ret = gfs2_unstuff_dinode(ip, page);
-               if (ret)
-                       goto out_unlock_page;
-       }
-       ret = gfs2_allocate_page_backing(page);
+       if (ret == 0)
+               ret = gfs2_allocate_page_backing(page);
 
-out_unlock_page:
-       unlock_page(page);
+out_trans_end:
+       if (ret)
+               unlock_page(page);
        gfs2_trans_end(sdp);
 out_trans_fail:
        gfs2_inplace_release(ip);
@@ -431,11 +453,17 @@ out_unlock:
        gfs2_glock_dq(&gh);
 out:
        gfs2_holder_uninit(&gh);
-       if (ret == -ENOMEM)
-               ret = VM_FAULT_OOM;
-       else if (ret)
-               ret = VM_FAULT_SIGBUS;
-       return ret;
+       if (ret == 0) {
+               set_page_dirty(page);
+               /* This check must be post dropping of transaction lock */
+               if (inode->i_sb->s_frozen == SB_UNFROZEN) {
+                       wait_on_page_writeback(page);
+               } else {
+                       ret = -EAGAIN;
+                       unlock_page(page);
+               }
+       }
+       return block_page_mkwrite_return(ret);
 }
 
 static const struct vm_operations_struct gfs2_vm_ops = {