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From: David Sterba <dsterba@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: David Sterba <dsterba@suse.com>
Subject: [PATCH 3/6] btrfs: introduce try-lock semantics for exclusive op start
Date: Fri, 21 May 2021 14:06:31 +0200	[thread overview]
Message-ID: <9a99c2204e431bc7a40bd1fb7c26ebb5fa741910.1621526221.git.dsterba@suse.com> (raw)
In-Reply-To: <cover.1621526221.git.dsterba@suse.com>

Add try-lock for exclusive operation start to allow callers to do more
checks. The same operation must already be running. The try-lock and
unlock must pair and are a substitute for btrfs_exclop_start, thus it
must also pair with btrfs_exclop_finish to release the exclop context.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ctree.h |  3 +++
 fs/btrfs/ioctl.c | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3dfc32a3ebab..0dffc06b5ad4 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3231,6 +3231,9 @@ void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
 			       struct btrfs_ioctl_balance_args *bargs);
 bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
 			enum btrfs_exclusive_operation type);
+bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
+				 enum btrfs_exclusive_operation type);
+void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info);
 void btrfs_exclop_finish(struct btrfs_fs_info *fs_info);
 
 /* file.c */
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c4e710ea08ba..cacd6ee17d8e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -371,6 +371,32 @@ bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
+/*
+ * Conditionally allow to enter the exclusive operation in case it's compatible
+ * with the running one.  This must be paired with btrfs_exclop_start_unlock and
+ * btrfs_exclop_finish.
+ *
+ * Compatibility:
+ * - the same type is already running
+ * - not BTRFS_EXCLOP_NONE - this is intentionally incompatible and the caller
+ *   must check the condition first that would allow none -> @type
+ */
+bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info,
+				 enum btrfs_exclusive_operation type)
+{
+	spin_lock(&fs_info->super_lock);
+	if (fs_info->exclusive_operation == type)
+		return true;
+
+	spin_unlock(&fs_info->super_lock);
+	return false;
+}
+
+void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info)
+{
+	spin_unlock(&fs_info->super_lock);
+}
+
 void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
 {
 	spin_lock(&fs_info->super_lock);
-- 
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 ` David Sterba [this message]
2021-05-21 13:38   ` [PATCH 3/6] btrfs: introduce try-lock semantics for exclusive op start 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 ` [PATCH 5/6] btrfs: add cancelation to resize David Sterba
2021-05-21 13:38   ` 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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