All of lore.kernel.org
 help / color / mirror / Atom feed
From: Martijn Coenen <maco@android.com>
To: axboe@kernel.dk, hch@lst.de, ming.lei@redhat.com
Cc: narayan@google.com, zezeozue@google.com, maco@google.com,
	kernel-team@android.com, bvanassche@acm.org,
	Chaitanya.Kulkarni@wdc.com, jaegeuk@kernel.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Martijn Coenen <maco@android.com>
Subject: [PATCH v5 10/11] loop: Clean up LOOP_SET_STATUS lo_flags handling
Date: Wed, 13 May 2020 15:38:44 +0200	[thread overview]
Message-ID: <20200513133845.244903-11-maco@android.com> (raw)
In-Reply-To: <20200513133845.244903-1-maco@android.com>

LOOP_SET_STATUS(64) will actually allow some lo_flags to be modified; in
particular, LO_FLAGS_AUTOCLEAR can be set and cleared, whereas
LO_FLAGS_PARTSCAN can be set to request a partition scan. Make this
explicit by updating the UAPI to include the flags that can be
set/cleared using this ioctl.

The implementation can then blindly take over the passed in flags,
and use the previous flags for those flags that can't be set / cleared
using LOOP_SET_STATUS.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martijn Coenen <maco@android.com>
---
 drivers/block/loop.c      | 19 +++++++++++++------
 include/uapi/linux/loop.h | 10 ++++++++--
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 31f10da4945e..13518ba191f5 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1036,9 +1036,7 @@ loop_set_status_from_info(struct loop_device *lo,
 	lo->transfer = xfer->transfer;
 	lo->ioctl = xfer->ioctl;
 
-	if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) !=
-	     (info->lo_flags & LO_FLAGS_AUTOCLEAR))
-		lo->lo_flags ^= LO_FLAGS_AUTOCLEAR;
+	lo->lo_flags = info->lo_flags;
 
 	lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
 	lo->lo_init[0] = info->lo_init[0];
@@ -1323,6 +1321,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 	int err;
 	struct block_device *bdev;
 	kuid_t uid = current_uid();
+	int prev_lo_flags;
 	bool partscan = false;
 	bool size_changed = false;
 
@@ -1359,10 +1358,19 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 		goto out_unfreeze;
 	}
 
+	prev_lo_flags = lo->lo_flags;
+
 	err = loop_set_status_from_info(lo, info);
 	if (err)
 		goto out_unfreeze;
 
+	/* Mask out flags that can't be set using LOOP_SET_STATUS. */
+	lo->lo_flags &= ~LOOP_SET_STATUS_SETTABLE_FLAGS;
+	/* For those flags, use the previous values instead */
+	lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_SETTABLE_FLAGS;
+	/* For flags that can't be cleared, use previous values too */
+	lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_CLEARABLE_FLAGS;
+
 	if (size_changed) {
 		loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
 					   lo->lo_backing_file);
@@ -1377,9 +1385,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 out_unfreeze:
 	blk_mq_unfreeze_queue(lo->lo_queue);
 
-	if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) &&
-	     !(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
-		lo->lo_flags |= LO_FLAGS_PARTSCAN;
+	if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
+	     !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
 		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
 		bdev = lo->lo_device;
 		partscan = true;
diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h
index 080a8df134ef..6b32fee80ce0 100644
--- a/include/uapi/linux/loop.h
+++ b/include/uapi/linux/loop.h
@@ -25,6 +25,12 @@ enum {
 	LO_FLAGS_DIRECT_IO	= 16,
 };
 
+/* LO_FLAGS that can be set using LOOP_SET_STATUS(64) */
+#define LOOP_SET_STATUS_SETTABLE_FLAGS (LO_FLAGS_AUTOCLEAR | LO_FLAGS_PARTSCAN)
+
+/* LO_FLAGS that can be cleared using LOOP_SET_STATUS(64) */
+#define LOOP_SET_STATUS_CLEARABLE_FLAGS (LO_FLAGS_AUTOCLEAR)
+
 #include <asm/posix_types.h>	/* for __kernel_old_dev_t */
 #include <linux/types.h>	/* for __u64 */
 
@@ -37,7 +43,7 @@ struct loop_info {
 	int		   lo_offset;
 	int		   lo_encrypt_type;
 	int		   lo_encrypt_key_size; 	/* ioctl w/o */
-	int		   lo_flags;			/* ioctl r/o */
+	int		   lo_flags;
 	char		   lo_name[LO_NAME_SIZE];
 	unsigned char	   lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
 	unsigned long	   lo_init[2];
@@ -53,7 +59,7 @@ struct loop_info64 {
 	__u32		   lo_number;			/* ioctl r/o */
 	__u32		   lo_encrypt_type;
 	__u32		   lo_encrypt_key_size;		/* ioctl w/o */
-	__u32		   lo_flags;			/* ioctl r/o */
+	__u32		   lo_flags;
 	__u8		   lo_file_name[LO_NAME_SIZE];
 	__u8		   lo_crypt_name[LO_NAME_SIZE];
 	__u8		   lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
-- 
2.26.2.645.ge9eca65c58-goog


  parent reply	other threads:[~2020-05-13 13:39 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-13 13:38 [PATCH v5 00/11] Add a new LOOP_CONFIGURE ioctl Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 01/11] loop: Call loop_config_discard() only after new config is applied Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 02/11] loop: Remove sector_t truncation checks Martijn Coenen
2020-05-13 13:45   ` Christoph Hellwig
2020-05-13 13:38 ` [PATCH v5 03/11] loop: Factor out setting loop device size Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 04/11] loop: Switch to set_capacity_revalidate_and_notify() Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 05/11] loop: Refactor loop_set_status() size calculation Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 06/11] loop: Remove figure_loop_size() Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 07/11] loop: Factor out configuring loop from status Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 08/11] loop: Move loop_set_status_from_info() and friends up Martijn Coenen
2020-05-13 13:38 ` [PATCH v5 09/11] loop: Rework lo_ioctl() __user argument casting Martijn Coenen
2020-05-13 13:38 ` Martijn Coenen [this message]
2020-05-13 13:38 ` [PATCH v5 11/11] loop: Add LOOP_CONFIGURE ioctl Martijn Coenen
2021-06-11 22:54   ` Kristian Klausen
2020-05-21 14:21 ` [PATCH v5 00/11] Add a new " Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200513133845.244903-11-maco@android.com \
    --to=maco@android.com \
    --cc=Chaitanya.Kulkarni@wdc.com \
    --cc=axboe@kernel.dk \
    --cc=bvanassche@acm.org \
    --cc=hch@lst.de \
    --cc=jaegeuk@kernel.org \
    --cc=kernel-team@android.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maco@google.com \
    --cc=ming.lei@redhat.com \
    --cc=narayan@google.com \
    --cc=zezeozue@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.