Re: [PATCH v6 00/27] nfs: Mount API conversion

Scott Mayhew
2019-12-13T21:40:10Z

On Tue, 10 Dec 2019, Schumaker, Anna wrote:

> Hi Scott,
>
> On Tue, 2019-12-10 at 07:30 -0500, Scott Mayhew wrote:
> > Hi Anna, Trond,
> >
> > Here's a set of patches that converts NFS to use the mount API. Note that
> > there are a lot of preliminary patches, some from David and some from Al.
> > The final patch (the one that does the actual conversion) from the David's
> > initial posting has been split into 5 separate patches, and the entire set
> > has been rebased on top of v5.5-rc1.
>
> Thanks for the updated patches! Everything looks okay to me, but I've only
> tested with the legacy mount command. I'm curious if you've tested it using the
> new system?

I've hacked up mount.nfs for testing the new syscalls (for mounting... I
haven't quite figured out remounting yet) here:
https://github.com/scottmayhew/nfs-utils/tree/fscontext

It seems to be working okay, with one exception. If I mount the same
NFS export with the same mount options multiple times, then I get
multiple mounts:

[root@fedora30 ~]# mount.nfs nfs:/export /mnt/t
[root@fedora30 ~]# mount.nfs nfs:/export /mnt/t
[root@fedora30 ~]# grep /mnt/t /proc/mounts
nfs:/export /mnt/t nfs rw,seclabel,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5,clientaddr=192.168.122.239,local_lock=none,addr=192.168.122.3 0 0
nfs:/export /mnt/t nfs rw,seclabel,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5,clientaddr=192.168.122.239,local_lock=none,addr=192.168.122.3 0 0

That doesn't happen with the mount() syscall:

[root@fedora30 ~]# mount.nfs.old nfs:/export /mnt/t
[root@fedora30 ~]# mount.nfs.old nfs:/export /mnt/t
[root@fedora30 ~]# grep /mnt/t /proc/mounts
nfs:/export /mnt/t nfs rw,seclabel,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5,clientaddr=192.168.122.239,local_lock=none,addr=192.168.122.3 0 0

-Scott

>
> Thanks,
> Anna
>
> >
> > Changes since v5:
> > - fixed possible derefence of error pointer in nfs4_validate_fspath()
> > reported by Dan Carpenter
> > - rebased on top of v5.5-rc1
> > Changes since v4:
> > - further split the original "NFS: Add fs_context support" patch (new
> > patch is about 25% smaller than the v4 patch)
> > - fixed NFSv4 referral mounts (broken in the original patch)
> > - fixed leak of nfs_fattr when fs_context is freed
> > Changes since v3:
> > - changed license and copyright text in fs/nfs/fs_context.c
> > Changes since v2:
> > - fixed the conversion of the nconnect= option
> > - added '#if IS_ENABLED(CONFIG_NFS_V4)' around nfs4_parse_monolithic()
> > to avoid unused-function warning when compiling with v4 disabled
> > Chagnes since v1:
> > - split up patch 23 into 4 separate patches
> >
> > -Scott
> >
> > Al Viro (15):
> > saner calling conventions for nfs_fs_mount_common()
> > nfs: stash server into struct nfs_mount_info
> > nfs: lift setting mount_info from nfs4_remote{,_referral}_mount
> > nfs: fold nfs4_remote_fs_type and nfs4_remote_referral_fs_type
> > nfs: don't bother setting/restoring export_path around
> > do_nfs_root_mount()
> > nfs4: fold nfs_do_root_mount/nfs_follow_remote_path
> > nfs: lift setting mount_info from nfs_xdev_mount()
> > nfs: stash nfs_subversion reference into nfs_mount_info
> > nfs: don't bother passing nfs_subversion to ->try_mount() and
> > nfs_fs_mount_common()
> > nfs: merge xdev and remote file_system_type
> > nfs: unexport nfs_fs_mount_common()
> > nfs: don't pass nfs_subversion to ->create_server()
> > nfs: get rid of mount_info ->fill_super()
> > nfs_clone_sb_security(): simplify the check for server bogosity
> > nfs: get rid of ->set_security()
> >
> > David Howells (8):
> > NFS: Move mount parameterisation bits into their own file
> > NFS: Constify mount argument match tables
> > NFS: Rename struct nfs_parsed_mount_data to struct nfs_fs_context
> > NFS: Split nfs_parse_mount_options()
> > NFS: Deindent nfs_fs_context_parse_option()
> > NFS: Add a small buffer in nfs_fs_context to avoid string dup
> > NFS: Do some tidying of the parsing code
> > NFS: Add fs_context support.
> >
> > Scott Mayhew (4):
> > NFS: rename nfs_fs_context pointer arg in a few functions
> > NFS: Convert mount option parsing to use functionality from
> > fs_parser.h
> > NFS: Additional refactoring for fs_context conversion
> > NFS: Attach supplementary error information to fs_context.
> >
> > fs/nfs/Makefile | 2 +-
> > fs/nfs/client.c | 80 +-
> > fs/nfs/fs_context.c | 1424 +++++++++++++++++++++++++
> > fs/nfs/fscache.c | 2 +-
> > fs/nfs/getroot.c | 73 +-
> > fs/nfs/internal.h | 132 +--
> > fs/nfs/namespace.c | 146 ++-
> > fs/nfs/nfs3_fs.h | 2 +-
> > fs/nfs/nfs3client.c | 6 +-
> > fs/nfs/nfs3proc.c | 2 +-
> > fs/nfs/nfs4_fs.h | 9 +-
> > fs/nfs/nfs4client.c | 99 +-
> > fs/nfs/nfs4file.c | 1 +
> > fs/nfs/nfs4namespace.c | 292 +++---
> > fs/nfs/nfs4proc.c | 2 +-
> > fs/nfs/nfs4super.c | 257 ++---
> > fs/nfs/proc.c | 2 +-
> > fs/nfs/super.c | 2217 +++++----------------------------------
> > include/linux/nfs_xdr.h | 9 +-
> > 19 files changed, 2287 insertions(+), 2470 deletions(-)
> > create mode 100644 fs/nfs/fs_context.c
> >