exofs: Optimize read_4_write

Don't attempt a read passed i_size, just zero the page and be
done with it.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
This commit is contained in:
Boaz Harrosh 2010-11-22 18:02:45 +02:00
parent 0a935519cc
commit a8f1418f9e

View File

@ -350,8 +350,10 @@ static int readpage_strip(void *data, struct page *page)
if (!pcol->read_4_write)
unlock_page(page);
EXOFS_DBGMSG("readpage_strip(0x%lx, 0x%lx) empty page,"
" splitting\n", inode->i_ino, page->index);
EXOFS_DBGMSG("readpage_strip(0x%lx) empty page len=%zx "
"read_4_write=%d index=0x%lx end_index=0x%lx "
"splitting\n", inode->i_ino, len,
pcol->read_4_write, page->index, end_index);
return read_exec(pcol);
}
@ -722,11 +724,28 @@ int exofs_write_begin(struct file *file, struct address_space *mapping,
/* read modify write */
if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
loff_t i_size = i_size_read(mapping->host);
pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
size_t rlen;
if (page->index < end_index)
rlen = PAGE_CACHE_SIZE;
else if (page->index == end_index)
rlen = i_size & ~PAGE_CACHE_MASK;
else
rlen = 0;
if (!rlen) {
clear_highpage(page);
SetPageUptodate(page);
goto out;
}
ret = _readpage(page, true);
if (ret) {
/*SetPageError was done by _readpage. Is it ok?*/
unlock_page(page);
EXOFS_DBGMSG("__readpage_filler failed\n");
EXOFS_DBGMSG("__readpage failed\n");
}
}
out: