| Message ID | 1234357708-24624-2-git-send-email-jlayton@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
smbfs and ncpfs and fat use iunique but a comment in the kernel source warns about using it since it is slow. Wonder if it is measurably slow? On Wed, Feb 11, 2009 at 7:08 AM, Jeff Layton <jlayton@redhat.com> wrote: > ...to make sure that we get unique inode numbers when we're generating > them on the fly. > >
On Wed, 11 Feb 2009 09:10:35 -0600 Steve French <smfrench@gmail.com> wrote: > smbfs and ncpfs and fat use iunique but a comment in the kernel source warns > about using it since it is slow. Wonder if it is measurably slow? > > On Wed, Feb 11, 2009 at 7:08 AM, Jeff Layton <jlayton@redhat.com> wrote: > > > ...to make sure that we get unique inode numbers when we're generating > > them on the fly. > > > > > > I'm sure there will be some performance impact. If you really want to bench it out correctly, you'll probably need to generate a ton of inodes on a mount so that you can ensure that each hash bucket will have a lot. Ideally you'd also want to make the counter in iunique wrap too so that it has to look for a while for a free inode. In practice, I doubt it'll be noticable -- certainly it should still be faster than a round trip to the server. Even if there is some performance impact though, I think it's still the right thing to do.
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c index 475115c..91d63f3 100644 --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -224,11 +224,12 @@ cifs_new_inode(struct super_block *sb, __u64 *inum) /* * BB: Is i_ino == 0 legal? Here, we assume that it is. If it isn't we * stop passing inum as ptr. Are there sanity checks we can use to - * ensure that the server is really filling in that field? Also, - * if serverino is disabled, perhaps we should be using iunique()? + * ensure that the server is really filling in that field? */ if (inum && (CIFS_SB(sb)->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) inode->i_ino = (unsigned long) *inum; + else + inode->i_ino = iunique(sb, 2); /* * must set this here instead of cifs_alloc_inode since VFS will
...to make sure that we get unique inode numbers when we're generating them on the fly. Signed-off-by: Jeff Layton <jlayton@redhat.com> --- fs/cifs/inode.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)