From: David Howells Subject: [PATCH 10/12] fsinfo: AFS: Return information through the filesystem info syscall Date: Fri, 20 Nov 2015 14:56:26 +0000 Message-ID: <20151120145626.18930.53321.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-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Return AFS 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 cell name as the domain name, setting FSINFO_DOMAIN_NAME; (3) the volume name, setting FSINFO_VOLUME_NAME; (4) the volume ID plus the volume type75 as the volume ID, setting FSINFO_VOLUME_ID; and unless AT_NO_ATTR_SYNC is specified: (5) the statfs information retrieved from the server. Note that no FSID value is 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 /afs fsinfo(/afs) = 0 mask : 1ad dev : 00:24 fs : type=6b414653 name=afs ioc : 0 nameln: 255 flags : 1020 times : range=0-ffffffff atime : gran=1s btime : gran=1s ctime : gran=1s mtime : gran=1s blocks: n=5000 fr=4998 av=4998 bsize : 1024 frsize: 1024 volid : 20000000 00000000 00000000 00000000 volume: 'root.afs' domain: 'cambridge.redhat.com' Possibly I should indicate the length of data stored in the volid field. Signed-off-by: David Howells --- fs/afs/super.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/fs/afs/super.c b/fs/afs/super.c index 1fb4a5129f7d..ca88bb43ee1a 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -37,6 +37,8 @@ static void afs_kill_super(struct super_block *sb); static struct inode *afs_alloc_inode(struct super_block *sb); static void afs_destroy_inode(struct inode *inode); static int afs_statfs(struct dentry *dentry, struct kstatfs *buf); +static int afs_get_fsinfo(struct dentry *dentry, struct fsinfo *f, + unsigned flags); struct file_system_type afs_fs_type = { .owner = THIS_MODULE, @@ -49,6 +51,7 @@ MODULE_ALIAS_FS("afs"); static const struct super_operations afs_super_ops = { .statfs = afs_statfs, + .get_fsinfo = afs_get_fsinfo, .alloc_inode = afs_alloc_inode, .drop_inode = afs_drop_inode, .destroy_inode = afs_destroy_inode, @@ -555,3 +558,39 @@ static int afs_statfs(struct dentry *dentry, struct kstatfs *buf) buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use; return 0; } + +/* + * Read filesystem information. + */ +static int afs_get_fsinfo(struct dentry *dentry, struct fsinfo *f, + unsigned flags) +{ + struct afs_super_info *as = dentry->d_sb->s_fs_info; + int ret; + + f->f_bsize = AFS_BLOCK_SIZE; + f->f_namelen = AFSNAMEMAX - 1; + f->f_min_time = 0; + f->f_max_time = U32_MAX; + + /* Construct a volume ID from the AFS volume ID and type */ + f->f_volume_id[0] = as->volume->vid >> 24; + f->f_volume_id[1] = as->volume->vid >> 16; + f->f_volume_id[2] = as->volume->vid >> 8; + f->f_volume_id[3] = as->volume->vid >> 0; + f->f_volume_id[4] = as->volume->type; + + strcpy(f->f_volume_name, as->volume->vlocation->vldb.name); + strcpy(f->f_domain_name, as->volume->cell->name); + + f->f_mask = FSINFO_VOLUME_ID | FSINFO_VOLUME_NAME | FSINFO_DOMAIN_NAME; + + if (flags & AT_NO_ATTR_SYNC) + return 0; + + ret = vfs_get_fsinfo_from_statfs(dentry, f, flags); + + /* Don't pass the FSID to userspace since this isn't exportable */ + f->f_mask &= ~FSINFO_FSID; + return 0; +}