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fuse: clean up condition for writepage sending

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fuse_writepages_fill uses following construction:

if (wpa && ap->num_pages &&
    (A || B || C)) {
        action;
} else if (wpa && D) {
        if (E) {
                the same action;
        }
}

 - ap->num_pages check is always true and can be removed

 - "if" and "else if" calls the same action and can be merged.

Move checking A, B, C, D, E conditions to a helper, add comments.

Original-patch-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2020-07-14 14:45:41 +02:00
parent b330966f79
commit 6ddf3af93e
1 changed files with 35 additions and 18 deletions
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53
fs/fuse/file.c
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@ -2015,6 +2015,40 @@ static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
return false;
}
static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
struct fuse_args_pages *ap,
struct fuse_fill_wb_data *data)
{
WARN_ON(!ap->num_pages);
/*
* Being under writeback is unlikely but possible. For example direct
* read to an mmaped fuse file will set the page dirty twice; once when
* the pages are faulted with get_user_pages(), and then after the read
* completed.
*/
if (fuse_page_is_writeback(data->inode, page->index))
return true;
/* Reached max pages */
if (ap->num_pages == fc->max_pages)
return true;
/* Reached max write bytes */
if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
return true;
/* Discontinuity */
if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
return true;
/* Need to grow the pages array? If so, did the expansion fail? */
if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
return true;
return false;
}
static int fuse_writepages_fill(struct page *page,
struct writeback_control *wbc, void *_data)
{
@ -2025,7 +2059,6 @@ static int fuse_writepages_fill(struct page *page,
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_conn *fc = get_fuse_conn(inode);
struct page *tmp_page;
bool is_writeback;
int err;
if (!data->ff) {
@ -2035,25 +2068,9 @@ static int fuse_writepages_fill(struct page *page,
goto out_unlock;
}
/*
* Being under writeback is unlikely but possible. For example direct
* read to an mmaped fuse file will set the page dirty twice; once when
* the pages are faulted with get_user_pages(), and then after the read
* completed.
*/
is_writeback = fuse_page_is_writeback(inode, page->index);
if (wpa && ap->num_pages &&
(is_writeback || ap->num_pages == fc->max_pages ||
(ap->num_pages + 1) * PAGE_SIZE > fc->max_write ||
data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)) {
if (wpa && fuse_writepage_need_send(fc, page, ap, data)) {
fuse_writepages_send(data);
data->wpa = NULL;
} else if (wpa && ap->num_pages == data->max_pages) {
if (!fuse_pages_realloc(data)) {
fuse_writepages_send(data);
data->wpa = NULL;
}
}
err = -ENOMEM;