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 <dhowells@xxxxxxxxxx>
---
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)
--
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