nfs: Add ALLOCATE support

This patch adds support for using the NFS v4.2 operation ALLOCATE to
preallocate data in a file.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

8 files changed, 167 insertions, 1 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 2b48ce58a584..4bffe637ea32 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -192,6 +192,7 @@ void nfs_zap_caches(struct inode *inode)
         nfs_zap_caches_locked(inode);
         spin_unlock(&inode->i_lock);
 }
+EXPORT_SYMBOL_GPL(nfs_zap_caches);
 
 void nfs_zap_mapping(struct inode *inode, struct address_space *mapping)
 {
diff --git a/fs/nfs/nfs42.h b/fs/nfs/nfs42.h
index d10333a197bf..42656a9cf485 100644
--- a/fs/nfs/nfs42.h
+++ b/fs/nfs/nfs42.h
@@ -6,6 +6,7 @@
 #define __LINUX_FS_NFS_NFS4_2_H
 
 /* nfs4.2proc.c */
+int nfs42_proc_allocate(struct file *, loff_t, loff_t);
 loff_t nfs42_proc_llseek(struct file *, loff_t, int);
 
 /* nfs4.2xdr.h */
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 056f5aafecc1..581f34e9d8a0 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -32,6 +32,64 @@ static int nfs42_set_rw_stateid(nfs4_stateid *dst, struct file *file,
         return ret;
 }
 
+static int _nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
+                                 loff_t offset, loff_t len)
+{
+        struct inode *inode = file_inode(filep);
+        struct nfs42_falloc_args args = {
+                .falloc_fh      = NFS_FH(inode),
+                .falloc_offset  = offset,
+                .falloc_length  = len,
+        };
+        struct nfs42_falloc_res res;
+        struct nfs_server *server = NFS_SERVER(inode);
+        int status;
+
+        msg->rpc_argp = &args;
+        msg->rpc_resp = &res;
+
+        status = nfs42_set_rw_stateid(&args.falloc_stateid, filep, FMODE_WRITE);
+        if (status)
+                return status;
+
+        return nfs4_call_sync(server->client, server, msg,
+                              &args.seq_args, &res.seq_res, 0);
+}
+
+static int nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
+                                loff_t offset, loff_t len)
+{
+        struct nfs_server *server = NFS_SERVER(file_inode(filep));
+        struct nfs4_exception exception = { };
+        int err;
+
+        do {
+                err = _nfs42_proc_fallocate(msg, filep, offset, len);
+                if (err == -ENOTSUPP)
+                        return -EOPNOTSUPP;
+                err = nfs4_handle_exception(server, err, &exception);
+        } while (exception.retry);
+
+        return err;
+}
+
+int nfs42_proc_allocate(struct file *filep, loff_t offset, loff_t len)
+{
+        struct rpc_message msg = {
+                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_ALLOCATE],
+        };
+        struct inode *inode = file_inode(filep);
+        int err;
+
+        if (!nfs_server_capable(inode, NFS_CAP_ALLOCATE))
+                return -EOPNOTSUPP;
+
+        err = nfs42_proc_fallocate(&msg, filep, offset, len);
+        if (err == -EOPNOTSUPP)
+                NFS_SERVER(inode)->caps &= ~NFS_CAP_ALLOCATE;
+        return err;
+}
+
 loff_t nfs42_proc_llseek(struct file *filep, loff_t offset, int whence)
 {
         struct inode *inode = file_inode(filep);
diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index c90469b604b8..4248d034479c 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -4,6 +4,12 @@
 #ifndef __LINUX_FS_NFS_NFS4_2XDR_H
 #define __LINUX_FS_NFS_NFS4_2XDR_H
 
+#define encode_fallocate_maxsz          (encode_stateid_maxsz + \
+                                         2 /* offset */ + \
+                                         2 /* length */)
+#define encode_allocate_maxsz           (op_encode_hdr_maxsz + \
+                                         encode_fallocate_maxsz)
+#define decode_allocate_maxsz           (op_decode_hdr_maxsz)
 #define encode_seek_maxsz               (op_encode_hdr_maxsz + \
                                          encode_stateid_maxsz + \
                                          2 /* offset */ + \
@@ -14,6 +20,12 @@
                                          2 /* offset */ + \
                                          2 /* length */)
 
+#define NFS4_enc_allocate_sz            (compound_encode_hdr_maxsz + \
+                                         encode_putfh_maxsz + \
+                                         encode_allocate_maxsz)
+#define NFS4_dec_allocate_sz            (compound_decode_hdr_maxsz + \
+                                         decode_putfh_maxsz + \
+                                         decode_allocate_maxsz)
 #define NFS4_enc_seek_sz                (compound_encode_hdr_maxsz + \
                                          encode_putfh_maxsz + \
                                          encode_seek_maxsz)
@@ -22,6 +34,22 @@
                                          decode_seek_maxsz)
 
 
+static void encode_fallocate(struct xdr_stream *xdr,
+                             struct nfs42_falloc_args *args)
+{
+        encode_nfs4_stateid(xdr, &args->falloc_stateid);
+        encode_uint64(xdr, args->falloc_offset);
+        encode_uint64(xdr, args->falloc_length);
+}
+
+static void encode_allocate(struct xdr_stream *xdr,
+                            struct nfs42_falloc_args *args,
+                            struct compound_hdr *hdr)
+{
+        encode_op_hdr(xdr, OP_ALLOCATE, decode_allocate_maxsz, hdr);
+        encode_fallocate(xdr, args);
+}
+
 static void encode_seek(struct xdr_stream *xdr,
                         struct nfs42_seek_args *args,
                         struct compound_hdr *hdr)
@@ -33,6 +61,24 @@ static void encode_seek(struct xdr_stream *xdr,
 }
 
 /*
+ * Encode ALLOCATE request
+ */
+static void nfs4_xdr_enc_allocate(struct rpc_rqst *req,
+                                  struct xdr_stream *xdr,
+                                  struct nfs42_falloc_args *args)
+{
+        struct compound_hdr hdr = {
+                .minorversion = nfs4_xdr_minorversion(&args->seq_args),
+        };
+
+        encode_compound_hdr(xdr, req, &hdr);
+        encode_sequence(xdr, &args->seq_args, &hdr);
+        encode_putfh(xdr, args->falloc_fh, &hdr);
+        encode_allocate(xdr, args, &hdr);
+        encode_nops(&hdr);
+}
+
+/*
  * Encode SEEK request
  */
 static void nfs4_xdr_enc_seek(struct rpc_rqst *req,
@@ -50,6 +96,11 @@ static void nfs4_xdr_enc_seek(struct rpc_rqst *req,
         encode_nops(&hdr);
 }
 
+static int decode_allocate(struct xdr_stream *xdr, struct nfs42_falloc_res *res)
+{
+        return decode_op_hdr(xdr, OP_ALLOCATE);
+}
+
 static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
 {
         int status;
@@ -73,6 +124,30 @@ out_overflow:
 }
 
 /*
+ * Decode ALLOCATE request
+ */
+static int nfs4_xdr_dec_allocate(struct rpc_rqst *rqstp,
+                                 struct xdr_stream *xdr,
+                                 struct nfs42_falloc_res *res)
+{
+        struct compound_hdr hdr;
+        int status;
+
+        status = decode_compound_hdr(xdr, &hdr);
+        if (status)
+                goto out;
+        status = decode_sequence(xdr, &res->seq_res, rqstp);
+        if (status)
+                goto out;
+        status = decode_putfh(xdr);
+        if (status)
+                goto out;
+        status = decode_allocate(xdr, res);
+out:
+        return status;
+}
+
+/*
  * Decode SEEK request
  */
 static int nfs4_xdr_dec_seek(struct rpc_rqst *rqstp,
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index be6cac37ea10..a08178764cf9 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -226,6 +226,7 @@ int nfs4_replace_transport(struct nfs_server *server,
                                 const struct nfs4_fs_locations *locations);
 
 /* nfs4proc.c */
+extern int nfs4_handle_exception(struct nfs_server *, int, struct nfs4_exception *);
 extern int nfs4_call_sync(struct rpc_clnt *, struct nfs_server *,
                           struct rpc_message *, struct nfs4_sequence_args *,
                           struct nfs4_sequence_res *, int);
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index c51fb4db9bfe..f78e9fd0735a 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -3,6 +3,8 @@
  *
  *  Copyright (C) 1992  Rick Sladkey
  */
+#include <linux/fs.h>
+#include <linux/falloc.h>
 #include <linux/nfs_fs.h>
 #include "internal.h"
 #include "fscache.h"
@@ -134,6 +136,29 @@ static loff_t nfs4_file_llseek(struct file *filep, loff_t offset, int whence)
                 return nfs_file_llseek(filep, offset, whence);
         }
 }
+
+static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t len)
+{
+        struct inode *inode = file_inode(filep);
+        long ret;
+
+        if (!S_ISREG(inode->i_mode))
+                return -EOPNOTSUPP;
+
+        if (mode != 0)
+                return -EOPNOTSUPP;
+
+        ret = inode_newsize_ok(inode, offset + len);
+        if (ret < 0)
+                return ret;
+
+        mutex_lock(&inode->i_mutex);
+        ret = nfs42_proc_allocate(filep, offset, len);
+        mutex_unlock(&inode->i_mutex);
+
+        nfs_zap_caches(inode);
+        return ret;
+}
 #endif /* CONFIG_NFS_V4_2 */
 
 const struct file_operations nfs4_file_operations = {
@@ -155,6 +180,9 @@ const struct file_operations nfs4_file_operations = {
         .flock          = nfs_flock,
         .splice_read    = nfs_file_splice_read,
         .splice_write   = iter_file_splice_write,
+#ifdef CONFIG_NFS_V4_2
+        .fallocate      = nfs42_fallocate,
+#endif /* CONFIG_NFS_V4_2 */
         .check_flags    = nfs_check_flags,
         .setlease       = simple_nosetlease,
 };
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3138913d1cdf..b1b403b0ca0d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -342,7 +342,7 @@ static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
 /* This is the error handling routine for processes that are allowed
  * to sleep.
  */
-static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
+int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
 {
         struct nfs_client *clp = server->nfs_client;
         struct nfs4_state *state = exception->state;
@@ -8424,6 +8424,7 @@ static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
                 | NFS_CAP_POSIX_LOCK
                 | NFS_CAP_STATEID_NFSV41
                 | NFS_CAP_ATOMIC_OPEN_V1
+                | NFS_CAP_ALLOCATE
                 | NFS_CAP_SEEK,
         .init_client = nfs41_init_client,
         .shutdown_client = nfs41_shutdown_client,
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 206c08a60c7f..0a1484561e4b 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -7394,6 +7394,7 @@ struct rpc_procinfo	nfs4_procedures[] = {
 #endif /* CONFIG_NFS_V4_1 */
 #ifdef CONFIG_NFS_V4_2
         PROC(SEEK,              enc_seek,               dec_seek),
+        PROC(ALLOCATE,          enc_allocate,           dec_allocate),
 #endif /* CONFIG_NFS_V4_2 */
 };