From 30175628bf7f521e9ee31ac98fa6d6fe7441a556 Mon Sep 17 00:00:00 2001
From: Steve French <smfrench@gmail.com>
Date: Sun, 17 Aug 2014 18:16:40 -0500
Subject: [PATCH] [SMB3] Enable fallocate -z support for SMB3 mounts
fallocate -z (FALLOC_FL_ZERO_RANGE) can map to SMB3
FSCTL_SET_ZERO_DATA SMB3 FSCTL but FALLOC_FL_ZERO_RANGE
when called without the FALLOC_FL_KEEPSIZE flag set could want
the file size changed so we can not support that subcase unless
the file is cached (and thus we know the file size).
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
---
fs/cifs/smb2ops.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 101670c2c374..5a48aa290dfe 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1015,6 +1015,56 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
return rc;
}
+static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
+ loff_t offset, loff_t len, bool keep_size)
+{
+ struct inode *inode;
+ struct cifsInodeInfo *cifsi;
+ struct cifsFileInfo *cfile = file->private_data;
+ struct file_zero_data_information fsctl_buf;
+ long rc;
+ unsigned int xid;
+
+ xid = get_xid();
+
+ inode = cfile->dentry->d_inode;
+ cifsi = CIFS_I(inode);
+
+ /* if file not oplocked can't be sure whether asking to extend size */
+ if (!CIFS_CACHE_READ(cifsi))
+ if (keep_size == false)
+ return -EOPNOTSUPP;
+
+ /*
+ * Must check if file sparse since fallocate -z (zero range) assumes
+ * non-sparse allocation
+ */
+ if (!(cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE))
+ return -EOPNOTSUPP;
+
+ /*
+ * need to make sure we are not asked to extend the file since the SMB3
+ * fsctl does not change the file size. In the future we could change
+ * this to zero the first part of the range then set the file size
+ * which for a non sparse file would zero the newly extended range
+ */
+ if (keep_size == false)
+ if (i_size_read(inode) < offset + len)
+ return -EOPNOTSUPP;
+
+ cifs_dbg(FYI, "offset %lld len %lld", offset, len);
+
+ fsctl_buf.FileOffset = cpu_to_le64(offset);
+ fsctl_buf.BeyondFinalZero = cpu_to_le64(offset + len);
+
+ rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
+ cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,
+ true /* is_fctl */, (char *)&fsctl_buf,
+ sizeof(struct file_zero_data_information), NULL, NULL);
+ free_xid(xid);
+ return rc;
+}
+
static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
loff_t offset, loff_t len)
{
@@ -1055,6 +1105,11 @@ static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
/* KEEP_SIZE already checked for by do_fallocate */
if (mode & FALLOC_FL_PUNCH_HOLE)
return smb3_punch_hole(file, tcon, off, len);
+ else if (mode & FALLOC_FL_ZERO_RANGE) {
+ if (mode & FALLOC_FL_KEEP_SIZE)
+ return smb3_zero_range(file, tcon, off, len, true);
+ return smb3_zero_range(file, tcon, off, len, false);
+ }
return -EOPNOTSUPP;
}
--
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