cifs: add support for FALLOC_FL_COLLAPSE_RANGE

Emulated for SMB3 and later via server side copy
and setsize. Eventually this could be compounded.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 49cdc6e..88a787d 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3688,6 +3688,39 @@ out:
        return rc;
 }
 
+static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
+                           loff_t off, loff_t len)
+{
+       int rc;
+       unsigned int xid;
+       struct cifsFileInfo *cfile = file->private_data;
+       __le64 eof;
+
+       xid = get_xid();
+
+       if (off >= i_size_read(file->f_inode) ||
+           off + len >= i_size_read(file->f_inode)) {
+               rc = -EINVAL;
+               goto out;
+       }
+
+       rc = smb2_copychunk_range(xid, cfile, cfile, off + len,
+                                 i_size_read(file->f_inode) - off - len, off);
+       if (rc < 0)
+               goto out;
+
+       eof = cpu_to_le64(i_size_read(file->f_inode) - len);
+       rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
+                         cfile->fid.volatile_fid, cfile->pid, &eof);
+       if (rc < 0)
+               goto out;
+
+       rc = 0;
+ out:
+       free_xid(xid);
+       return rc;
+}
+
 static loff_t smb3_llseek(struct file *file, struct cifs_tcon *tcon, loff_t offset, int whence)
 {
        struct cifsFileInfo *wrcfile, *cfile = file->private_data;
@@ -3859,6 +3892,8 @@ static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
                return smb3_zero_range(file, tcon, off, len, false);
        } else if (mode == FALLOC_FL_KEEP_SIZE)
                return smb3_simple_falloc(file, tcon, off, len, true);
+       else if (mode == FALLOC_FL_COLLAPSE_RANGE)
+               return smb3_collapse_range(file, tcon, off, len);
        else if (mode == 0)
                return smb3_simple_falloc(file, tcon, off, len, false);