1 files changed, 33 insertions, 0 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 6c2ddfed2cfc..39aed901514b 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -57,6 +57,7 @@ enum {
         NFSD_Pool_Threads,
         NFSD_Versions,
         NFSD_Ports,
+        NFSD_MaxBlkSize,
         /*
          * The below MUST come last.  Otherwise we leave a hole in nfsd_files[]
          * with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
@@ -82,6 +83,7 @@ static ssize_t write_threads(struct file *file, char *buf, size_t size);
 static ssize_t write_pool_threads(struct file *file, char *buf, size_t size);
 static ssize_t write_versions(struct file *file, char *buf, size_t size);
 static ssize_t write_ports(struct file *file, char *buf, size_t size);
+static ssize_t write_maxblksize(struct file *file, char *buf, size_t size);
 #ifdef CONFIG_NFSD_V4
 static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
@@ -100,6 +102,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
         [NFSD_Pool_Threads] = write_pool_threads,
         [NFSD_Versions] = write_versions,
         [NFSD_Ports] = write_ports,
+        [NFSD_MaxBlkSize] = write_maxblksize,
 #ifdef CONFIG_NFSD_V4
         [NFSD_Leasetime] = write_leasetime,
         [NFSD_RecoveryDir] = write_recoverydir,
@@ -555,6 +558,35 @@ static ssize_t write_ports(struct file *file, char *buf, size_t size)
         return -EINVAL;
 }
 
+int nfsd_max_blksize;
+
+static ssize_t write_maxblksize(struct file *file, char *buf, size_t size)
+{
+        char *mesg = buf;
+        if (size > 0) {
+                int bsize;
+                int rv = get_int(&mesg, &bsize);
+                if (rv)
+                        return rv;
+                /* force bsize into allowed range and
+                 * required alignment.
+                 */
+                if (bsize < 1024)
+                        bsize = 1024;
+                if (bsize > NFSSVC_MAXBLKSIZE)
+                        bsize = NFSSVC_MAXBLKSIZE;
+                bsize &= ~(1024-1);
+                lock_kernel();
+                if (nfsd_serv && nfsd_serv->sv_nrthreads) {
+                        unlock_kernel();
+                        return -EBUSY;
+                }
+                nfsd_max_blksize = bsize;
+                unlock_kernel();
+        }
+        return sprintf(buf, "%d\n", nfsd_max_blksize);
+}
+
 #ifdef CONFIG_NFSD_V4
 extern time_t nfs4_leasetime(void);
 
@@ -620,6 +652,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
                 [NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
                 [NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
                 [NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
+                [NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},
 #ifdef CONFIG_NFSD_V4
                 [NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
                 [NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},