From: Anthony Iliopoulos <ailiop@suse.com>
Date: Sun, 19 Apr 2020 16:48:50 -0700
Subject: [PATCH] nvmet: add ns revalidation support
Git-commit: e8cd1ff11d58a21242ea2b85450298f3681768a1
Patch-mainline: v5.8-rc1
References: jsc#SLE-15608

Add support for detecting capacity changes on nvmet blockdev and file
backed namespaces. This allows for emulating and testing online resizing
of nvme devices and filesystems on top.

Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
[chaitanya: Fix comments posted on V1]
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[hch: reuse code a bit more]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/nvme/target/admin-cmd.c   |  5 +++++
 drivers/nvme/target/io-cmd-bdev.c |  5 +++++
 drivers/nvme/target/io-cmd-file.c | 17 +++++++++++++----
 drivers/nvme/target/nvmet.h       |  2 ++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 9d6f75cfa77c..4c79aa804887 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -486,6 +486,11 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 	if (!ns)
 		goto done;
 
+	if (ns->bdev)
+		nvmet_bdev_ns_revalidate(ns);
+	else
+		nvmet_file_ns_revalidate(ns);
+
 	/*
 	 * nuse = ncap = nsze isn't always true, but we have no way to find
 	 * that out from the underlying device.
diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index ea0e596be15d..0427e040e3dd 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -75,6 +75,11 @@ void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
 	}
 }
 
+void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns)
+{
+	ns->size = i_size_read(ns->bdev->bd_inode);
+}
+
 static u16 blk_to_nvme_status(struct nvmet_req *req, blk_status_t blk_sts)
 {
 	u16 status = NVME_SC_SUCCESS;
diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c
index cd5670b83118..f0bd08d86ac0 100644
--- a/drivers/nvme/target/io-cmd-file.c
+++ b/drivers/nvme/target/io-cmd-file.c
@@ -13,6 +13,18 @@
 #define NVMET_MAX_MPOOL_BVEC		16
 #define NVMET_MIN_MPOOL_OBJ		16
 
+int nvmet_file_ns_revalidate(struct nvmet_ns *ns)
+{
+	struct kstat stat;
+	int ret;
+
+	ret = vfs_getattr(&ns->file->f_path, &stat, STATX_SIZE,
+			  AT_STATX_FORCE_SYNC);
+	if (!ret)
+		ns->size = stat.size;
+	return ret;
+}
+
 void nvmet_file_ns_disable(struct nvmet_ns *ns)
 {
 	if (ns->file) {
@@ -30,7 +42,6 @@ void nvmet_file_ns_disable(struct nvmet_ns *ns)
 int nvmet_file_ns_enable(struct nvmet_ns *ns)
 {
 	int flags = O_RDWR | O_LARGEFILE;
-	struct kstat stat;
 	int ret;
 
 	if (!ns->buffered_io)
@@ -43,12 +54,10 @@ int nvmet_file_ns_enable(struct nvmet_ns *ns)
 		return PTR_ERR(ns->file);
 	}
 
-	ret = vfs_getattr(&ns->file->f_path,
-			&stat, STATX_SIZE, AT_STATX_FORCE_SYNC);
+	ret = nvmet_file_ns_revalidate(ns);
 	if (ret)
 		goto err;
 
-	ns->size = stat.size;
 	/*
 	 * i_blkbits can be greater than the universally accepted upper bound,
 	 * so make sure we export a sane namespace lba_shift.
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 421dff3ea143..3d981eb6e100 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -498,6 +498,8 @@ void nvmet_file_ns_disable(struct nvmet_ns *ns);
 u16 nvmet_bdev_flush(struct nvmet_req *req);
 u16 nvmet_file_flush(struct nvmet_req *req);
 void nvmet_ns_changed(struct nvmet_subsys *subsys, u32 nsid);
+void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns);
+int nvmet_file_ns_revalidate(struct nvmet_ns *ns);
 
 static inline u32 nvmet_rw_len(struct nvmet_req *req)
 {
-- 
2.16.4