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authorAl Viro <viro@zeniv.linux.org.uk>2016-08-30 03:56:35 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2016-12-10 22:25:18 +0300
commit77469c3f570e329acb631c5c03780eacdca2a534 (patch)
tree56f89cbfd95a55f5d750710d9ca950bf8992fdf1 /fs/9p
parent43388b21e72d36204822bcc3119e42abe6ebceef (diff)
downloadlinux-77469c3f570e329acb631c5c03780eacdca2a534.tar.xz
9p: saner ->write_end() on failing copy into non-uptodate page
If we had a short copy into an uptodate page, there's no reason whatsoever to zero anything; OTOH, if that page had _not_ been uptodate, we must have been trying to overwrite it completely and got a short copy. In that case, overwriting the end with zeroes, marking uptodate and sending to server is just plain wrong. Just unlock, keep it non-uptodate and return 0. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/9p')
-rw-r--r--fs/9p/vfs_addr.c15
1 files changed, 4 insertions, 11 deletions
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 6181ad79e1a5..ff8ece89fb99 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -309,18 +309,10 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
- if (unlikely(copied < len)) {
- /*
- * zero out the rest of the area
- */
- unsigned from = pos & (PAGE_SIZE - 1);
-
- zero_user(page, from + copied, len - copied);
- flush_dcache_page(page);
+ if (unlikely(copied < len && !PageUptodate(page))) {
+ copied = 0;
+ goto out;
}
-
- if (!PageUptodate(page))
- SetPageUptodate(page);
/*
* No need to use i_size_read() here, the i_size
* cannot change under us because we hold the i_mutex.
@@ -330,6 +322,7 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
i_size_write(inode, last_pos);
}
set_page_dirty(page);
+out:
unlock_page(page);
put_page(page);