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From: David Sterba <dsterba@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: David Sterba <dsterba@suse.com>
Subject: [PATCH 5/6] btrfs: add cancelation to resize
Date: Fri, 21 May 2021 14:06:36 +0200	[thread overview]
Message-ID: <6aabd4e1187d0ce49bad7bf7967148a86b4c56d4.1621526221.git.dsterba@suse.com> (raw)
In-Reply-To: <cover.1621526221.git.dsterba@suse.com>

Accept literal string "cancel" as resize operation and interpret that
as a request to cancel the running operation. If it's running, wait
until it finishes current work and return ECANCELED.

Shrinking resize uses relocation to move the chunks away, use the
conditional exclusive operation start and cancelation helpers.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ioctl.c | 47 ++++++++++++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 21 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c75ccadf23dc..8be2ca762894 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1659,6 +1659,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 	char *devstr = NULL;
 	int ret = 0;
 	int mod = 0;
+	bool cancel;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -1667,20 +1668,23 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 	if (ret)
 		return ret;
 
-	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_RESIZE)) {
-		mnt_drop_write_file(file);
-		return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
-	}
-
+	/*
+	 * Read the arguments before checking exclusivity to be able to
+	 * distinguish regular resize and cancel
+	 */
 	vol_args = memdup_user(arg, sizeof(*vol_args));
 	if (IS_ERR(vol_args)) {
 		ret = PTR_ERR(vol_args);
-		goto out;
+		goto out_drop;
 	}
-
 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
-
 	sizestr = vol_args->name;
+	cancel = (strcmp("cancel", sizestr) == 0);
+	ret = exclop_start_or_cancel_reloc(fs_info, BTRFS_EXCLOP_RESIZE, cancel);
+	if (ret)
+		goto out_free;
+	/* Exclusive operation is now claimed */
+
 	devstr = strchr(sizestr, ':');
 	if (devstr) {
 		sizestr = devstr + 1;
@@ -1688,10 +1692,10 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 		devstr = vol_args->name;
 		ret = kstrtoull(devstr, 10, &devid);
 		if (ret)
-			goto out_free;
+			goto out_finish;
 		if (!devid) {
 			ret = -EINVAL;
-			goto out_free;
+			goto out_finish;
 		}
 		btrfs_info(fs_info, "resizing devid %llu", devid);
 	}
@@ -1701,7 +1705,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 		btrfs_info(fs_info, "resizer unable to find device %llu",
 			   devid);
 		ret = -ENODEV;
-		goto out_free;
+		goto out_finish;
 	}
 
 	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
@@ -1709,7 +1713,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 			   "resizer unable to apply on readonly device %llu",
 		       devid);
 		ret = -EPERM;
-		goto out_free;
+		goto out_finish;
 	}
 
 	if (!strcmp(sizestr, "max"))
@@ -1725,13 +1729,13 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 		new_size = memparse(sizestr, &retptr);
 		if (*retptr != '\0' || new_size == 0) {
 			ret = -EINVAL;
-			goto out_free;
+			goto out_finish;
 		}
 	}
 
 	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
 		ret = -EPERM;
-		goto out_free;
+		goto out_finish;
 	}
 
 	old_size = btrfs_device_get_total_bytes(device);
@@ -1739,24 +1743,24 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 	if (mod < 0) {
 		if (new_size > old_size) {
 			ret = -EINVAL;
-			goto out_free;
+			goto out_finish;
 		}
 		new_size = old_size - new_size;
 	} else if (mod > 0) {
 		if (new_size > ULLONG_MAX - old_size) {
 			ret = -ERANGE;
-			goto out_free;
+			goto out_finish;
 		}
 		new_size = old_size + new_size;
 	}
 
 	if (new_size < SZ_256M) {
 		ret = -EINVAL;
-		goto out_free;
+		goto out_finish;
 	}
 	if (new_size > device->bdev->bd_inode->i_size) {
 		ret = -EFBIG;
-		goto out_free;
+		goto out_finish;
 	}
 
 	new_size = round_down(new_size, fs_info->sectorsize);
@@ -1765,7 +1769,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 		trans = btrfs_start_transaction(root, 0);
 		if (IS_ERR(trans)) {
 			ret = PTR_ERR(trans);
-			goto out_free;
+			goto out_finish;
 		}
 		ret = btrfs_grow_device(trans, device, new_size);
 		btrfs_commit_transaction(trans);
@@ -1778,10 +1782,11 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 			"resize device %s (devid %llu) from %llu to %llu",
 			rcu_str_deref(device->name), device->devid,
 			old_size, new_size);
+out_finish:
+	btrfs_exclop_finish(fs_info);
 out_free:
 	kfree(vol_args);
-out:
-	btrfs_exclop_finish(fs_info);
+out_drop:
 	mnt_drop_write_file(file);
 	return ret;
 }
-- 
2.29.2


  parent reply	other threads:[~2021-05-21 12:09 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21 12:06 [PATCH 0/6] Support resize and device delete cancel ops David Sterba
2021-05-21 12:06 ` [PATCH 1/6] btrfs: protect exclusive_operation by super_lock David Sterba
2021-05-21 13:37   ` Josef Bacik
2021-05-21 12:06 ` [PATCH 2/6] btrfs: add cancelable chunk relocation support David Sterba
2021-05-21 13:21   ` Josef Bacik
2021-05-26 22:56     ` David Sterba
2021-06-16 13:54   ` Filipe Manana
2021-06-16 13:55     ` Filipe Manana
2021-06-16 15:53       ` David Sterba
2021-06-16 15:58       ` [PATCH v2] btrfs: add cancellable " David Sterba
2021-06-17  9:18         ` Filipe Manana
2021-05-21 12:06 ` [PATCH 3/6] btrfs: introduce try-lock semantics for exclusive op start David Sterba
2021-05-21 13:38   ` Josef Bacik
2021-05-27  7:43   ` Anand Jain
2021-05-28 12:30     ` David Sterba
2021-05-29 13:48       ` Anand Jain
2021-05-31 18:23         ` David Sterba
2021-05-21 12:06 ` [PATCH 4/6] btrfs: add wrapper for conditional start of exclusive operation David Sterba
2021-05-21 13:29   ` Josef Bacik
2021-05-21 16:45     ` David Sterba
2021-05-26 22:24       ` David Sterba
2021-05-21 12:06 ` David Sterba [this message]
2021-05-21 13:38   ` [PATCH 5/6] btrfs: add cancelation to resize Josef Bacik
2021-05-21 12:06 ` [PATCH 6/6] btrfs: add device delete cancel David Sterba
2021-05-21 13:38   ` Josef Bacik
2021-05-21 12:06 ` [PATCH 1/2] btrfs-progs: device remove: add support for cancel David Sterba
2021-05-21 12:06 ` [PATCH 2/2] btrfs-progs: fi resize: " David Sterba
2021-12-14 14:49 ` [PATCH 0/6] Support resize and device delete cancel ops Anand Jain
2021-12-15 15:13   ` David Sterba

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