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Message-ID: <527553462.07149@eyou.net>
Date: Thu, 26 Jan 2012 13:04:34 +0800
From: "Li Wang" <liwang@...t.edu.cn>
To: "'Tyler Hicks'" <tyhicks@...onical.com>
Cc: <ecryptfs@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-fsdevel@...r.kernel.org>
Subject: [PATCH v2] eCryptfs: write optimization
Hi,
The new version adds the code to handle short copy issue which may occure
in iov_iter_copy_from_user_atomic(). The idea is to let ecryptfs_write_end() return zero,
therefore, give iov_iter_fault_in_readable() a chance to handle the page fault
for the current iovec, then restart the copy operation.
Cheers,
Li Wang
Signed-off-by: Li Wang <liwang@...t.edu.cn>
Yunchuan Wen <wenyunchuan@...inos.com.cn>
---
fs/ecryptfs/mmap.c | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 6a44148..b3fa499 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -346,7 +346,8 @@ static int ecryptfs_write_begin(struct file *file,
if (prev_page_end_size
>= i_size_read(page->mapping->host)) {
zero_user(page, 0, PAGE_CACHE_SIZE);
- } else {
+ SetPageUptodate(page);
+ } else if (len < PAGE_CACHE_SIZE) {
rc = ecryptfs_decrypt_page(page);
if (rc) {
printk(KERN_ERR "%s: Error decrypting "
@@ -356,8 +357,8 @@ static int ecryptfs_write_begin(struct file *file,
ClearPageUptodate(page);
goto out;
}
+ SetPageUptodate(page);
}
- SetPageUptodate(page);
}
}
/* If creating a page or more of holes, zero them out via truncate.
@@ -512,6 +513,13 @@ static int ecryptfs_write_end(struct file *file,
}
goto out;
}
+ if (!PageUptodate(page)) {
+ if (copied < PAGE_CACHE_SIZE) {
+ rc = 0;
+ goto out;
+ }
+ SetPageUptodate(page);
+ }
/* Fills in zeros if 'to' goes beyond inode size */
rc = fill_zeros_to_end_of_page(page, to);
if (rc) {
--
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