diff options
| author | Jeff Layton | 2009-07-21 19:42:03 -0400 |
|---|---|---|
| committer | Steve French | 2009-07-22 21:08:00 +0000 |
| commit | 03aa3a49ad3592a9e4e1ab19c6da3e852288caf1 (patch) | |
| tree | eaaa507b6debb862f551d9d3c750b4889e3131ed /fs/cifs | |
| parent | ce6e7fcd43aab1f77e56aa36936dd7d2d05a1ffa (diff) | |
cifs: fix sb->s_maxbytes so that it casts properly to a signed value
This off-by-one bug causes sendfile() to not work properly. When a task
calls sendfile() on a file on a CIFS filesystem, the syscall returns -1
and sets errno to EOVERFLOW.
do_sendfile uses s_maxbytes to verify the returned offset of the file.
The problem there is that this value is cast to a signed value (loff_t).
When this is done on the s_maxbytes value that cifs uses, it becomes
negative and the comparisons against it fail.
Even though s_maxbytes is an unsigned value, it seems that it's not OK
to set it in such a way that it'll end up negative when it's cast to a
signed value. These casts happen in other codepaths besides sendfile
too, but the VFS is a little hard to follow in this area and I can't
be sure if there are other bugs that this will fix.
It's not clear to me why s_maxbytes isn't just declared as loff_t in the
first place, but either way we still need to fix these values to make
sendfile work properly. This is also an opportunity to replace the magic
bit-shift values here with the standard #defines for this.
This fixes the reproducer program I have that does a sendfile and
will probably also fix the situation where apache is serving from a
CIFS share.
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/cifs')
| -rw-r--r-- | fs/cifs/connect.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 9bb5c8750736..fc44d316d0bb 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -2452,10 +2452,10 @@ try_mount_again: tcon->local_lease = volume_info->local_lease; } if (pSesInfo) { - if (pSesInfo->capabilities & CAP_LARGE_FILES) { - sb->s_maxbytes = (u64) 1 << 63; - } else - sb->s_maxbytes = (u64) 1 << 31; /* 2 GB */ + if (pSesInfo->capabilities & CAP_LARGE_FILES) + sb->s_maxbytes = MAX_LFS_FILESIZE; + else + sb->s_maxbytes = MAX_NON_LFS; } /* BB FIXME fix time_gran to be larger for LANMAN sessions */ |