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authorMiklos Szeredi <mszeredi@suse.cz>2014-09-24 17:09:11 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2014-09-26 21:16:51 -0400
commit2c80929c4c4d54e568b07ab85877d5fd38f4b02f (patch)
treea43d1f9a9706d519a46c1b772b69c8996319961c /fs/fuse
parentb928095b0a7cff7fb9fcf4c706348ceb8ab2c295 (diff)
downloadlinux-2c80929c4c4d54e568b07ab85877d5fd38f4b02f.tar.bz2
fuse: honour max_read and max_write in direct_io mode
The third argument of fuse_get_user_pages() "nbytesp" refers to the number of bytes a caller asked to pack into fuse request. This value may be lesser than capacity of fuse request or iov_iter. So fuse_get_user_pages() must ensure that *nbytesp won't grow. Now, when helper iov_iter_get_pages() performs all hard work of extracting pages from iov_iter, it can be done by passing properly calculated "maxsize" to the helper. The other caller of iov_iter_get_pages() (dio_refill_pages()) doesn't need this capability, so pass LONG_MAX as the maxsize argument here. Fixes: c9c37e2e6378 ("fuse: switch to iov_iter_get_pages()") Reported-by: Werner Baumann <werner.baumann@onlinehome.de> Tested-by: Maxim Patlasov <mpatlasov@parallels.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/file.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 912061ac4baf..caa8d95b24e8 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1305,6 +1305,7 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
size_t start;
ssize_t ret = iov_iter_get_pages(ii,
&req->pages[req->num_pages],
+ *nbytesp - nbytes,
req->max_pages - req->num_pages,
&start);
if (ret < 0)