enable fallocate punch hole ("fallocate -p") for SMB3

Implement FALLOC_FL_PUNCH_HOLE (which does not change the file size
fortunately so this matches the behavior of the equivalent SMB3
fsctl call) for SMB3 mounts.  This allows "fallocate -p" to work.
It requires that the server support setting files as sparse
(which Windows allows).

Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 0a4a4d7d407e..155347e190f9 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -207,6 +207,19 @@ cifs_statfs(struct dentry *dentry, struct kstatfs *buf)
         return 0;
 }
 
+static long cifs_fallocate(struct file *file, int mode, loff_t off, loff_t len)
+{
+        struct super_block *sb = file->f_path.dentry->d_sb;
+        struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+        struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+        struct TCP_Server_Info *server = tcon->ses->server;
+
+        if (server->ops->fallocate)
+                return server->ops->fallocate(file, tcon, mode, off, len);
+
+        return -EOPNOTSUPP;
+}
+
 static int cifs_permission(struct inode *inode, int mask)
 {
         struct cifs_sb_info *cifs_sb;
@@ -909,6 +922,7 @@ const struct file_operations cifs_file_ops = {
         .unlocked_ioctl = cifs_ioctl,
 #endif /* CONFIG_CIFS_POSIX */
         .setlease = cifs_setlease,
+        .fallocate = cifs_fallocate,
 };
 
 const struct file_operations cifs_file_strict_ops = {
@@ -928,6 +942,7 @@ const struct file_operations cifs_file_strict_ops = {
         .unlocked_ioctl = cifs_ioctl,
 #endif /* CONFIG_CIFS_POSIX */
         .setlease = cifs_setlease,
+        .fallocate = cifs_fallocate,
 };
 
 const struct file_operations cifs_file_direct_ops = {
@@ -948,6 +963,7 @@ const struct file_operations cifs_file_direct_ops = {
 #endif /* CONFIG_CIFS_POSIX */
         .llseek = cifs_llseek,
         .setlease = cifs_setlease,
+        .fallocate = cifs_fallocate,
 };
 
 const struct file_operations cifs_file_nobrl_ops = {
@@ -966,6 +982,7 @@ const struct file_operations cifs_file_nobrl_ops = {
         .unlocked_ioctl = cifs_ioctl,
 #endif /* CONFIG_CIFS_POSIX */
         .setlease = cifs_setlease,
+        .fallocate = cifs_fallocate,
 };
 
 const struct file_operations cifs_file_strict_nobrl_ops = {
@@ -984,6 +1001,7 @@ const struct file_operations cifs_file_strict_nobrl_ops = {
         .unlocked_ioctl = cifs_ioctl,
 #endif /* CONFIG_CIFS_POSIX */
         .setlease = cifs_setlease,
+        .fallocate = cifs_fallocate,
 };
 
 const struct file_operations cifs_file_direct_nobrl_ops = {
@@ -1003,6 +1021,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = {
 #endif /* CONFIG_CIFS_POSIX */
         .llseek = cifs_llseek,
         .setlease = cifs_setlease,
+        .fallocate = cifs_fallocate,
 };
 
 const struct file_operations cifs_dir_ops = {