From: David Howells Subject: [PATCH 11/12] fsinfo: NFS: Return information through the filesystem info syscall Date: Fri, 20 Nov 2015 14:56:39 +0000 Message-ID: <20151120145639.18930.13368.stgit@warthog.procyon.org.uk> References: <20151120145422.18930.72662.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-afs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@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: arnd@arndb.de Return-path: In-Reply-To: <20151120145422.18930.72662.stgit@warthog.procyon.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Return NFS filesystem information through the filesystem info retrieval system call. This includes the following: (1) information about the capacity and resolution of the inode timestamps; (2) the client hostname as the domain name, setting FSINFO_DOMAIN_NAME; (3) the remote FSID as the volume ID, setting FSINFO_VOLUME_ID; and unless AT_NO_ATTR_SYNC is specified: (4) the statfs information retrieved from the server. Note that the NFS FSID value is *not* returned as the local FSID since the FSID value is a local handle used by NFSD; see the volume ID field instead. Example output: [root@andromeda ~]# ./test-fsinfo /warthog/ fsinfo(/warthog/) = 0 mask : 12f dev : 00:27 fs : type=6969 name=nfs4 ioc : 0 nameln: 255 flags : 1020 times : range=8000000000000000-7fffffffffffffff atime : gran=1e-09s btime : gran=1e-09s ctime : gran=1e-09s mtime : gran=1e-09s blocks: n=503841 fr=48261 av=22645 files : n=32776192 fr=18903243 av=18903243 bsize : 1048576 frsize: 0 volid : 8c494c34 de5688ac 2e61e05d 5f144b8e domain: 'warthog' Note that NFS4 potentially provides a separate value for f_favail that could be provided through this interface. Signed-off-by: David Howells --- fs/nfs/internal.h | 1 + fs/nfs/nfs4super.c | 1 + fs/nfs/super.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 60 insertions(+) diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 56cfde26fb9c..6c7bb9c9e5c6 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -442,6 +442,7 @@ extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio); void nfs_clone_super(struct super_block *, struct nfs_mount_info *); void nfs_umount_begin(struct super_block *); int nfs_statfs(struct dentry *, struct kstatfs *); +int nfs_get_fsinfo(struct dentry *, struct fsinfo *, unsigned); int nfs_show_options(struct seq_file *, struct dentry *); int nfs_show_devname(struct seq_file *, struct dentry *); int nfs_show_path(struct seq_file *, struct dentry *); diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c index 6fb7cb6b3f4b..1c15c5884ac4 100644 --- a/fs/nfs/nfs4super.c +++ b/fs/nfs/nfs4super.c @@ -54,6 +54,7 @@ static const struct super_operations nfs4_sops = { .write_inode = nfs4_write_inode, .drop_inode = nfs_drop_inode, .statfs = nfs_statfs, + .get_fsinfo = nfs_get_fsinfo, .evict_inode = nfs4_evict_inode, .umount_begin = nfs_umount_begin, .show_options = nfs_show_options, diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 383a027de452..bbd33b121b48 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -311,6 +311,7 @@ const struct super_operations nfs_sops = { .write_inode = nfs_write_inode, .drop_inode = nfs_drop_inode, .statfs = nfs_statfs, + .get_fsinfo = nfs_get_fsinfo, .evict_inode = nfs_evict_inode, .umount_begin = nfs_umount_begin, .show_options = nfs_show_options, @@ -494,6 +495,63 @@ int nfs_statfs(struct dentry *dentry, struct kstatfs *buf) EXPORT_SYMBOL_GPL(nfs_statfs); /* + * Read filesystem information. + */ +int nfs_get_fsinfo(struct dentry *dentry, struct fsinfo *f, unsigned flags) +{ + struct nfs_server *server = NFS_SB(dentry->d_sb); + struct nfs_client *client = server->nfs_client; + int ret; + + f->f_bsize = dentry->d_sb->s_blocksize; + f->f_namelen = server->namelen; + + if (client->rpc_ops->version < 4) { + f->f_min_time = 0; + f->f_max_time = U32_MAX; + } else { + f->f_min_time = S64_MIN; + f->f_max_time = S64_MAX; + } + + f->f_atime_gran_exponent = -6; + f->f_ctime_gran_exponent = -6; + f->f_mtime_gran_exponent = -6; + if (client->rpc_ops->version >= 3) { + f->f_atime_gran_exponent = -9; + f->f_ctime_gran_exponent = -9; + f->f_mtime_gran_exponent = -9; + } + + if (client->cl_hostname) { + strncpy(f->f_domain_name, client->cl_hostname, + sizeof(f->f_domain_name)); + f->f_domain_name[sizeof(f->f_domain_name) - 1] = 0; + f->f_mask |= FSINFO_DOMAIN_NAME; + } + + /* Treat the remote FSID as the volume ID since we don't support + * reexportation through NFSD. + */ + memcpy(f->f_volume_id, &server->fsid, + min(sizeof(f->f_volume_id), sizeof(server->fsid))); + f->f_mask |= FSINFO_VOLUME_ID; + + if (flags & AT_NO_ATTR_SYNC) + return 0; + + ret = vfs_get_fsinfo_from_statfs(dentry, f, flags); + if (ret < 0) + return ret; + + /* Don't pass the FSID to userspace since this isn't exportable */ + memset(&f->f_fsid, 0, sizeof(f->f_fsid)); + f->f_mask &= ~FSINFO_FSID; + return 0; +} +EXPORT_SYMBOL_GPL(nfs_get_fsinfo); + +/* * Map the security flavour number to a name */ static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)