9p: add 9P2000.L statfs operation

I made a V2 of this patch on top of my patches for VFS switches. The
change was adding v9fs_statfs pointer to v9fs_super_ops_dotl
instead of v9fs_super_ops.

statfs - get file system statistics

size[4] Tstatfs tag[2] fid[4]
size[4] Rstatfs tag[2] type[4] bsize[4] blocks[8] bfree[8] bavail[8]
                files[8] ffree[8] fsid[8] namelen[4]

The statfs message is used to request file system information returned
by the statfs(2) system call, which is used by df(1) to report file
system and disk space usage.

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 38 insertions, 1 deletions

diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index cc3fa8c3aab6..be74d020436e 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -38,6 +38,7 @@
 #include <linux/idr.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/statfs.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 
@@ -214,6 +215,42 @@ v9fs_umount_begin(struct super_block *sb)
         v9fs_session_begin_cancel(v9ses);
 }
 
+static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+        struct v9fs_session_info *v9ses;
+        struct p9_fid *fid;
+        struct p9_rstatfs rs;
+        int res;
+
+        fid = v9fs_fid_lookup(dentry);
+        if (IS_ERR(fid)) {
+                res = PTR_ERR(fid);
+                goto done;
+        }
+
+        v9ses = v9fs_inode2v9ses(dentry->d_inode);
+        if (v9fs_proto_dotl(v9ses)) {
+                res = p9_client_statfs(fid, &rs);
+                if (res == 0) {
+                        buf->f_type = rs.type;
+                        buf->f_bsize = rs.bsize;
+                        buf->f_blocks = rs.blocks;
+                        buf->f_bfree = rs.bfree;
+                        buf->f_bavail = rs.bavail;
+                        buf->f_files = rs.files;
+                        buf->f_ffree = rs.ffree;
+                        buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
+                        buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
+                        buf->f_namelen = rs.namelen;
+                }
+                if (res != -ENOSYS)
+                        goto done;
+        }
+        res = simple_statfs(dentry, buf);
+done:
+        return res;
+}
+
 static const struct super_operations v9fs_super_ops = {
 #ifdef CONFIG_9P_FSCACHE
         .alloc_inode = v9fs_alloc_inode,
@@ -230,7 +267,7 @@ static const struct super_operations v9fs_super_ops_dotl = {
         .alloc_inode = v9fs_alloc_inode,
         .destroy_inode = v9fs_destroy_inode,
 #endif
-        .statfs = simple_statfs,
+        .statfs = v9fs_statfs,
         .clear_inode = v9fs_clear_inode,
         .show_options = generic_show_options,
         .umount_begin = v9fs_umount_begin,