1 files changed, 59 insertions, 42 deletions

diff --git a/fs/affs/file.c b/fs/affs/file.c
index c314a35f0918..6e0c9399200e 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -395,25 +395,33 @@ static int affs_writepage(struct page *page, struct writeback_control *wbc)
 {
         return block_write_full_page(page, affs_get_block, wbc);
 }
+
 static int affs_readpage(struct file *file, struct page *page)
 {
         return block_read_full_page(page, affs_get_block);
 }
-static int affs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
+
+static int affs_write_begin(struct file *file, struct address_space *mapping,
+                        loff_t pos, unsigned len, unsigned flags,
+                        struct page **pagep, void **fsdata)
 {
-        return cont_prepare_write(page, from, to, affs_get_block,
-                &AFFS_I(page->mapping->host)->mmu_private);
+        *pagep = NULL;
+        return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+                                affs_get_block,
+                                &AFFS_I(mapping->host)->mmu_private);
 }
+
 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 {
         return generic_block_bmap(mapping,block,affs_get_block);
 }
+
 const struct address_space_operations affs_aops = {
         .readpage = affs_readpage,
         .writepage = affs_writepage,
         .sync_page = block_sync_page,
-        .prepare_write = affs_prepare_write,
-        .commit_write = generic_commit_write,
+        .write_begin = affs_write_begin,
+        .write_end = generic_write_end,
         .bmap = _affs_bmap
 };
 
@@ -603,54 +611,65 @@ affs_readpage_ofs(struct file *file, struct page *page)
         return err;
 }
 
-static int affs_prepare_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
+static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
+                                loff_t pos, unsigned len, unsigned flags,
+                                struct page **pagep, void **fsdata)
 {
-        struct inode *inode = page->mapping->host;
-        u32 size, offset;
-        u32 tmp;
+        struct inode *inode = mapping->host;
+        struct page *page;
+        pgoff_t index;
         int err = 0;
 
-        pr_debug("AFFS: prepare_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
-        offset = page->index << PAGE_CACHE_SHIFT;
-        if (offset + from > AFFS_I(inode)->mmu_private) {
-                err = affs_extent_file_ofs(inode, offset + from);
+        pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
+        if (pos > AFFS_I(inode)->mmu_private) {
+                /* XXX: this probably leaves a too-big i_size in case of
+                 * failure. Should really be updating i_size at write_end time
+                 */
+                err = affs_extent_file_ofs(inode, pos);
                 if (err)
                         return err;
         }
-        size = inode->i_size;
+
+        index = pos >> PAGE_CACHE_SHIFT;
+        page = __grab_cache_page(mapping, index);
+        if (!page)
+                return -ENOMEM;
+        *pagep = page;
 
         if (PageUptodate(page))
                 return 0;
 
-        if (from) {
-                err = affs_do_readpage_ofs(file, page, 0, from);
-                if (err)
-                        return err;
-        }
-        if (to < PAGE_CACHE_SIZE) {
-                zero_user_page(page, to, PAGE_CACHE_SIZE - to, KM_USER0);
-                if (size > offset + to) {
-                        if (size < offset + PAGE_CACHE_SIZE)
-                                tmp = size & ~PAGE_CACHE_MASK;
-                        else
-                                tmp = PAGE_CACHE_SIZE;
-                        err = affs_do_readpage_ofs(file, page, to, tmp);
-                }
+        /* XXX: inefficient but safe in the face of short writes */
+        err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
+        if (err) {
+                unlock_page(page);
+                page_cache_release(page);
         }
         return err;
 }
 
-static int affs_commit_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
+static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
+                                loff_t pos, unsigned len, unsigned copied,
+                                struct page *page, void *fsdata)
 {
-        struct inode *inode = page->mapping->host;
+        struct inode *inode = mapping->host;
         struct super_block *sb = inode->i_sb;
         struct buffer_head *bh, *prev_bh;
         char *data;
         u32 bidx, boff, bsize;
+        unsigned from, to;
         u32 tmp;
         int written;
 
-        pr_debug("AFFS: commit_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
+        from = pos & (PAGE_CACHE_SIZE - 1);
+        to = pos + len;
+        /*
+         * XXX: not sure if this can handle short copies (len < copied), but
+         * we don't have to, because the page should always be uptodate here,
+         * due to write_begin.
+         */
+
+        pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
         bsize = AFFS_SB(sb)->s_data_blksize;
         data = page_address(page);
 
@@ -748,6 +767,9 @@ done:
         if (tmp > inode->i_size)
                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 
+        unlock_page(page);
+        page_cache_release(page);
+
         return written;
 
 out:
@@ -761,8 +783,8 @@ const struct address_space_operations affs_aops_ofs = {
         .readpage = affs_readpage_ofs,
         //.writepage = affs_writepage_ofs,
         //.sync_page = affs_sync_page_ofs,
-        .prepare_write = affs_prepare_write_ofs,
-        .commit_write = affs_commit_write_ofs
+        .write_begin = affs_write_begin_ofs,
+        .write_end = affs_write_end_ofs
 };
 
 /* Free any preallocated blocks. */
@@ -805,18 +827,13 @@ affs_truncate(struct inode *inode)
         if (inode->i_size > AFFS_I(inode)->mmu_private) {
                 struct address_space *mapping = inode->i_mapping;
                 struct page *page;
-                u32 size = inode->i_size - 1;
+                void *fsdata;
+                u32 size = inode->i_size;
                 int res;
 
-                page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
-                if (!page)
-                        return;
-                size = (size & (PAGE_CACHE_SIZE - 1)) + 1;
-                res = mapping->a_ops->prepare_write(NULL, page, size, size);
+                res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
                 if (!res)
-                        res = mapping->a_ops->commit_write(NULL, page, size, size);
-                unlock_page(page);
-                page_cache_release(page);
+                        res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
                 mark_inode_dirty(inode);
                 return;
         } else if (inode->i_size == AFFS_I(inode)->mmu_private)