[PATCH 04/14] fuse: Prepare to handle multiple pages in writeback

From: Maxim V. Patlasov
Date: Fri Jan 25 2013 - 13:21:57 EST


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

Original patch by: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Maxim Patlasov <MPatlasov@xxxxxxxxxxxxx>
---
fs/fuse/file.c | 22 +++++++++++++++-------
1 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 1d76283..b28be33 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -345,7 +345,8 @@ 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;
}
@@ -1295,7 +1296,10 @@ 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);
}

@@ -1304,10 +1308,13 @@ 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);
+ 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);
}
@@ -1320,14 +1327,15 @@ __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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