smb3: add mount parm nosparse

To reduce risk of applications breaking that mount to servers
with only partial sparse file support, add optional mount parm
"nosparse" which disables setting files sparse (and thus
will return EOPNOTSUPP on certain fallocate operations).

Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 9d33481..0effc4c 100644 (file)
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -116,7 +116,8 @@ static void cifs_debug_tcon(struct seq_file *m, struct cifs_tcon *tcon)
                tcon->ses->server->ops->dump_share_caps(m, tcon);
        if (tcon->use_witness)
                seq_puts(m, " Witness");
-
+       if (tcon->broken_sparse_sup)
+               seq_puts(m, " nosparse");
        if (tcon->need_reconnect)
                seq_puts(m, "\tDISCONNECTED ");
        seq_putc(m, '\n');

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 2b1a1c0..f539a39 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -582,6 +582,8 @@ cifs_show_options(struct seq_file *s, struct dentry *root)
                seq_puts(s, ",nocase");
        if (tcon->nodelete)
                seq_puts(s, ",nodelete");
+       if (cifs_sb->ctx->no_sparse)
+               seq_puts(s, ",nosparse");
        if (tcon->local_lease)
                seq_puts(s, ",locallease");
        if (tcon->retry)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0b08693..1fd8d6a 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2509,6 +2509,7 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
         */
        tcon->retry = ctx->retry;
        tcon->nocase = ctx->nocase;
+       tcon->broken_sparse_sup = ctx->no_sparse;
        if (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING)
                tcon->nohandlecache = ctx->nohandlecache;
        else

diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index a92e9ee..ca1d695 100644 (file)
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -119,6 +119,7 @@ const struct fs_parameter_spec smb3_fs_parameters[] = {
        fsparam_flag_no("persistenthandles", Opt_persistent),
        fsparam_flag_no("resilienthandles", Opt_resilient),
        fsparam_flag_no("tcpnodelay", Opt_tcp_nodelay),
+       fsparam_flag("nosparse", Opt_nosparse),
        fsparam_flag("domainauto", Opt_domainauto),
        fsparam_flag("rdma", Opt_rdma),
        fsparam_flag("modesid", Opt_modesid),
@@ -943,6 +944,9 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
        case Opt_nolease:
                ctx->no_lease = 1;
                break;
+       case Opt_nosparse:
+               ctx->no_sparse = 1;
+               break;
        case Opt_nodelete:
                ctx->nodelete = 1;
                break;

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index e54090d..6576bb1 100644 (file)
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -62,6 +62,7 @@ enum cifs_param {
        Opt_noblocksend,
        Opt_noautotune,
        Opt_nolease,
+       Opt_nosparse,
        Opt_hard,
        Opt_soft,
        Opt_perm,
@@ -222,6 +223,7 @@ struct smb3_fs_context {
        bool noautotune:1;
        bool nostrictsync:1; /* do not force expensive SMBflush on every sync */
        bool no_lease:1;     /* disable requesting leases */
+       bool no_sparse:1;    /* do not attempt to set files sparse */
        bool fsc:1;     /* enable fscache */
        bool mfsymlinks:1; /* use Minshall+French Symlinks */
        bool multiuser:1;