[PATCH 04/16] fuse: Prepare to handle multiple pages in writeback

[Maxim Patlasov]

From: Pavel Emelyanov <xe...@openvz.org>

The .writepages callback will issue writeback requests with more than one
page aboard. Make existing end/check code be aware of this.

Signed-off-by: Maxim Patlasov <mpatla...@parallels.com>
---
 fs/fuse/file.c |   24 ++++++++++++++++--------
 1 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index ea70814..90fb235 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -350,7 +350,8 @@ static bool fuse_page_is_writeback(struct inode *inode, 
pgoff_t index)
 
                BUG_ON(req->inode != inode);
                curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
-               if (curr_index == index) {
+               if (curr_index <= index &&
+                   index < curr_index + req->num_pages) {
                        found = true;
                        break;
                }
@@ -1425,7 +1426,10 @@ static ssize_t fuse_direct_write(struct file *file, 
const char __user *buf,
 
 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
 {
-       __free_page(req->pages[0]);
+       int i;
+
+       for (i = 0; i < req->num_pages; i++)
+               __free_page(req->pages[i]);
        fuse_file_put(req->ff, false);
 }
 
@@ -1434,11 +1438,14 @@ static void fuse_writepage_finish(struct fuse_conn *fc, 
struct fuse_req *req)
        struct inode *inode = req->inode;
        struct fuse_inode *fi = get_fuse_inode(inode);
        struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
+       int i;
 
        list_del(&req->writepages_entry);
-       dec_bdi_stat(bdi, BDI_WRITEBACK);
-       dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
-       bdi_writeout_inc(bdi);
+       for (i = 0; i < req->num_pages; i++) {
+               dec_bdi_stat(bdi, BDI_WRITEBACK);
+               dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
+               bdi_writeout_inc(bdi);
+       }
        wake_up(&fi->page_waitq);
 }
 
@@ -1450,14 +1457,15 @@ __acquires(fc->lock)
        struct fuse_inode *fi = get_fuse_inode(req->inode);
        loff_t size = i_size_read(req->inode);
        struct fuse_write_in *inarg = &req->misc.write.in;
+       __u64 data_size = req->num_pages * PAGE_CACHE_SIZE;
 
        if (!fc->connected)
                goto out_free;
 
-       if (inarg->offset + PAGE_CACHE_SIZE <= size) {
-               inarg->size = PAGE_CACHE_SIZE;
+       if (inarg->offset + data_size <= size) {
+               inarg->size = data_size;
        } else if (inarg->offset < size) {
-               inarg->size = size & (PAGE_CACHE_SIZE - 1);
+               inarg->size = size - inarg->offset;
        } else {
                /* Got truncated off completely */
                goto out_free;

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