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>
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index a755523..c8f58a9 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -350,8 +350,10 @@
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 @@
/* 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: