nfs: Add DEALLOCATE support

This patch adds support for using the NFS v4.2 operation DEALLOCATE to
punch holes in a file.

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

6 files changed, 89 insertions, 2 deletions

diff --git a/fs/nfs/nfs42.h b/fs/nfs/nfs42.h
index 42656a9cf485..7afb8947dfdf 100644
--- a/fs/nfs/nfs42.h
+++ b/fs/nfs/nfs42.h
@@ -7,6 +7,7 @@
 
 /* nfs4.2proc.c */
 int nfs42_proc_allocate(struct file *, loff_t, loff_t);
+int nfs42_proc_deallocate(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 581f34e9d8a0..cb170722769c 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -90,6 +90,23 @@ int nfs42_proc_allocate(struct file *filep, loff_t offset, loff_t len)
         return err;
 }
 
+int nfs42_proc_deallocate(struct file *filep, loff_t offset, loff_t len)
+{
+        struct rpc_message msg = {
+                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DEALLOCATE],
+        };
+        struct inode *inode = file_inode(filep);
+        int err;
+
+        if (!nfs_server_capable(inode, NFS_CAP_DEALLOCATE))
+                return -EOPNOTSUPP;
+
+        err = nfs42_proc_fallocate(&msg, filep, offset, len);
+        if (err == -EOPNOTSUPP)
+                NFS_SERVER(inode)->caps &= ~NFS_CAP_DEALLOCATE;
+        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 4248d034479c..038a7e1521fa 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -10,6 +10,9 @@
 #define encode_allocate_maxsz           (op_encode_hdr_maxsz + \
                                          encode_fallocate_maxsz)
 #define decode_allocate_maxsz           (op_decode_hdr_maxsz)
+#define encode_deallocate_maxsz         (op_encode_hdr_maxsz + \
+                                         encode_fallocate_maxsz)
+#define decode_deallocate_maxsz         (op_decode_hdr_maxsz)
 #define encode_seek_maxsz               (op_encode_hdr_maxsz + \
                                          encode_stateid_maxsz + \
                                          2 /* offset */ + \
@@ -26,6 +29,12 @@
 #define NFS4_dec_allocate_sz            (compound_decode_hdr_maxsz + \
                                          decode_putfh_maxsz + \
                                          decode_allocate_maxsz)
+#define NFS4_enc_deallocate_sz          (compound_encode_hdr_maxsz + \
+                                         encode_putfh_maxsz + \
+                                         encode_deallocate_maxsz)
+#define NFS4_dec_deallocate_sz          (compound_decode_hdr_maxsz + \
+                                         decode_putfh_maxsz + \
+                                         decode_deallocate_maxsz)
 #define NFS4_enc_seek_sz                (compound_encode_hdr_maxsz + \
                                          encode_putfh_maxsz + \
                                          encode_seek_maxsz)
@@ -50,6 +59,14 @@ static void encode_allocate(struct xdr_stream *xdr,
         encode_fallocate(xdr, args);
 }
 
+static void encode_deallocate(struct xdr_stream *xdr,
+                              struct nfs42_falloc_args *args,
+                              struct compound_hdr *hdr)
+{
+        encode_op_hdr(xdr, OP_DEALLOCATE, decode_deallocate_maxsz, hdr);
+        encode_fallocate(xdr, args);
+}
+
 static void encode_seek(struct xdr_stream *xdr,
                         struct nfs42_seek_args *args,
                         struct compound_hdr *hdr)
@@ -79,6 +96,24 @@ static void nfs4_xdr_enc_allocate(struct rpc_rqst *req,
 }
 
 /*
+ * Encode DEALLOCATE request
+ */
+static void nfs4_xdr_enc_deallocate(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_deallocate(xdr, args, &hdr);
+        encode_nops(&hdr);
+}
+
+/*
  * Encode SEEK request
  */
 static void nfs4_xdr_enc_seek(struct rpc_rqst *req,
@@ -101,6 +136,11 @@ static int decode_allocate(struct xdr_stream *xdr, struct nfs42_falloc_res *res)
         return decode_op_hdr(xdr, OP_ALLOCATE);
 }
 
+static int decode_deallocate(struct xdr_stream *xdr, struct nfs42_falloc_res *res)
+{
+        return decode_op_hdr(xdr, OP_DEALLOCATE);
+}
+
 static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
 {
         int status;
@@ -148,6 +188,30 @@ out:
 }
 
 /*
+ * Decode DEALLOCATE request
+ */
+static int nfs4_xdr_dec_deallocate(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_deallocate(xdr, res);
+out:
+        return status;
+}
+
+/*
  * Decode SEEK request
  */
 static int nfs4_xdr_dec_seek(struct rpc_rqst *rqstp,
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index f78e9fd0735a..8b46389c4c5b 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -145,7 +145,7 @@ static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t
         if (!S_ISREG(inode->i_mode))
                 return -EOPNOTSUPP;
 
-        if (mode != 0)
+        if ((mode != 0) && (mode != (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE)))
                 return -EOPNOTSUPP;
 
         ret = inode_newsize_ok(inode, offset + len);
@@ -153,7 +153,10 @@ static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t
                 return ret;
 
         mutex_lock(&inode->i_mutex);
-        ret = nfs42_proc_allocate(filep, offset, len);
+        if (mode & FALLOC_FL_PUNCH_HOLE)
+                ret = nfs42_proc_deallocate(filep, offset, len);
+        else
+                ret = nfs42_proc_allocate(filep, offset, len);
         mutex_unlock(&inode->i_mutex);
 
         nfs_zap_caches(inode);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index b1b403b0ca0d..e7f8d5ff2581 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -8425,6 +8425,7 @@ static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
                 | NFS_CAP_STATEID_NFSV41
                 | NFS_CAP_ATOMIC_OPEN_V1
                 | NFS_CAP_ALLOCATE
+                | NFS_CAP_DEALLOCATE
                 | 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 0a1484561e4b..03d0fa62a06e 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -7395,6 +7395,7 @@ struct rpc_procinfo	nfs4_procedures[] = {
 #ifdef CONFIG_NFS_V4_2
         PROC(SEEK,              enc_seek,               dec_seek),
         PROC(ALLOCATE,          enc_allocate,           dec_allocate),
+        PROC(DEALLOCATE,        enc_deallocate,         dec_deallocate),
 #endif /* CONFIG_NFS_V4_2 */
 };