Patch "target/file: Do not return error for UNMAP if length is zero" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    target/file: Do not return error for UNMAP if length is zero

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     target-file-do-not-return-error-for-unmap-if-length-is-zero.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Dec 18 14:47:43 CET 2017
From: Jiang Yi <jiangyilism@gmail.com>
Date: Fri, 11 Aug 2017 11:29:44 +0800
Subject: target/file: Do not return error for UNMAP if length is zero

From: Jiang Yi <jiangyilism@gmail.com>


[ Upstream commit 594e25e73440863981032d76c9b1e33409ceff6e ]

The function fd_execute_unmap() in target_core_file.c calles

ret = file->f_op->fallocate(file, mode, pos, len);

Some filesystems implement fallocate() to return error if
length is zero (e.g. btrfs) but according to SCSI Block
Commands spec UNMAP should return success for zero length.

Signed-off-by: Jiang Yi <jiangyilism@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/target/target_core_file.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -466,6 +466,10 @@ fd_execute_unmap(struct se_cmd *cmd, sec
 	struct inode *inode = file->f_mapping->host;
 	int ret;
 
+	if (!nolb) {
+		return 0;
+	}
+
 	if (cmd->se_dev->dev_attrib.pi_prot_type) {
 		ret = fd_do_prot_unmap(cmd, lba, nolb);
 		if (ret)


Patches currently in stable-queue which might be from jiangyilism@gmail.com are

queue-4.4/target-file-do-not-return-error-for-unmap-if-length-is-zero.patch