From: David Howells Subject: [PATCH 14/18] xstat: NFS: Use d_automount() rather than abusing follow_link() [ver #6] Date: Thu, 15 Jul 2010 03:17:26 +0100 Message-ID: <20100715021726.5544.59242.stgit@warthog.procyon.org.uk> References: <20100715021709.5544.64506.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org To: viro@ZenIV.linux.org.uk Return-path: In-Reply-To: <20100715021709.5544.64506.stgit@warthog.procyon.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: samba-technical-bounces@lists.samba.org Errors-To: samba-technical-bounces@lists.samba.org List-Id: linux-ext4.vger.kernel.org Make NFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. Signed-off-by: David Howells --- fs/nfs/dir.c | 2 + fs/nfs/inode.c | 1 + fs/nfs/internal.h | 1 + fs/nfs/namespace.c | 87 ++++++++++++++++++++++++---------------------------- 4 files changed, 44 insertions(+), 47 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 782b431..d7e5810 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -927,6 +927,7 @@ const struct dentry_operations nfs_dentry_operations = { .d_revalidate = nfs_lookup_revalidate, .d_delete = nfs_dentry_delete, .d_iput = nfs_dentry_iput, + .d_automount = nfs_d_automount, }; static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) @@ -1002,6 +1003,7 @@ const struct dentry_operations nfs4_dentry_operations = { .d_revalidate = nfs_open_revalidate, .d_delete = nfs_dentry_delete, .d_iput = nfs_dentry_iput, + .d_automount = nfs_d_automount, }; /* diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 8c6de96..f9737bd 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -296,6 +296,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr) inode->i_op = &nfs_mountpoint_inode_operations; inode->i_fop = NULL; set_bit(NFS_INO_MOUNTPOINT, &nfsi->flags); + inode->i_flags |= S_AUTOMOUNT; } } else if (S_ISLNK(inode->i_mode)) inode->i_op = &nfs_symlink_inode_operations; diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index d8bd619..48de6f8 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -238,6 +238,7 @@ extern char *nfs_path(const char *base, const struct dentry *droot, const struct dentry *dentry, char *buffer, ssize_t buflen); +extern struct vfsmount *nfs_d_automount(struct path *path); /* getroot.c */ extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *); diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index db6aa36..bf80079 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -88,9 +88,8 @@ Elong: } /* - * nfs_follow_mountpoint - handle crossing a mountpoint on the server - * @dentry - dentry of mountpoint - * @nd - nameidata info + * nfs_d_automount - Handle crossing a mountpoint on the server + * @path - The mountpoint * * When we encounter a mountpoint on the server, we want to set up * a mountpoint on the client too, to prevent inode numbers from @@ -100,87 +99,81 @@ Elong: * situation, and that different filesystems may want to use * different security flavours. */ -static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) +struct vfsmount *nfs_d_automount(struct path *path) { struct vfsmount *mnt; - struct nfs_server *server = NFS_SERVER(dentry->d_inode); + struct nfs_server *server = NFS_SERVER(path->dentry->d_inode); struct dentry *parent; struct nfs_fh *fh = NULL; struct nfs_fattr *fattr = NULL; int err; - dprintk("--> nfs_follow_mountpoint()\n"); + dprintk("--> nfs_d_automount()\n"); - err = -ESTALE; - if (IS_ROOT(dentry)) - goto out_err; + mnt = ERR_PTR(-ESTALE); + if (IS_ROOT(path->dentry)) + goto out_nofree; - err = -ENOMEM; + mnt = ERR_PTR(-ENOMEM); fh = nfs_alloc_fhandle(); fattr = nfs_alloc_fattr(); if (fh == NULL || fattr == NULL) - goto out_err; + goto out; dprintk("%s: enter\n", __func__); - dput(nd->path.dentry); - nd->path.dentry = dget(dentry); - /* Look it up again */ - parent = dget_parent(nd->path.dentry); + /* Look it up again to get its attributes */ + parent = dget_parent(path->dentry); err = server->nfs_client->rpc_ops->lookup(parent->d_inode, - &nd->path.dentry->d_name, + &path->dentry->d_name, fh, fattr); dput(parent); - if (err != 0) - goto out_err; + if (err != 0) { + mnt = ERR_PTR(err); + goto out; + } if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) - mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry); + mnt = nfs_do_refmount(path->mnt, path->dentry); else - mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, fh, - fattr); - err = PTR_ERR(mnt); + mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr); if (IS_ERR(mnt)) - goto out_err; + goto out; mntget(mnt); - err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE, + err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE, &nfs_automount_list); - if (err < 0) { + switch (err) { + case 0: + dprintk("%s: done, success\n", __func__); + schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); + break; + case -EBUSY: + /* someone else made a mount here whilst we were busy */ mntput(mnt); - if (err == -EBUSY) - goto out_follow; - goto out_err; + dprintk("%s: done, collision\n", __func__); + mnt = NULL; + break; + default: + mntput(mnt); + dprintk("%s: done, error %d\n", __func__, err); + mnt = ERR_PTR(err); + break; } - path_put(&nd->path); - nd->path.mnt = mnt; - nd->path.dentry = dget(mnt->mnt_root); - schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); + out: nfs_free_fattr(fattr); nfs_free_fhandle(fh); - dprintk("%s: done, returned %d\n", __func__, err); - - dprintk("<-- nfs_follow_mountpoint() = %d\n", err); - return ERR_PTR(err); -out_err: - path_put(&nd->path); - goto out; -out_follow: - while (d_mountpoint(nd->path.dentry) && - follow_down(&nd->path)) - ; - err = 0; - goto out; +out_nofree: + dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt); + return mnt; } const struct inode_operations nfs_mountpoint_inode_operations = { - .follow_link = nfs_follow_mountpoint, .getattr = nfs_getattr, }; const struct inode_operations nfs_referral_inode_operations = { - .follow_link = nfs_follow_mountpoint, }; static void nfs_expire_automounts(struct work_struct *work)