* [PATCH v3 0/3] Support adding a device during paused balance
@ 2021-11-25 9:14 Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state Nikolay Borisov
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Nikolay Borisov @ 2021-11-25 9:14 UTC (permalink / raw)
To: linux-btrfs; +Cc: Nikolay Borisov
So here's v3 which takes care of the feedback received in the last round, namely:
- Introduced btrfs_exclop_balance which is used to switch the balance state,
alongside ASSERTS
- Removed unused variable in balance_kthread
Nikolay Borisov (3):
btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state
btrfs: make device add compatible with paused balance in
btrfs_exclop_start_try_lock
btrfs: allow device add if balance is paused
fs/btrfs/ctree.h | 4 ++++
fs/btrfs/ioctl.c | 49 ++++++++++++++++++++++++++++++++++++++++++----
fs/btrfs/volumes.c | 10 ++++++++--
3 files changed, 57 insertions(+), 6 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state
2021-11-25 9:14 [PATCH v3 0/3] Support adding a device during paused balance Nikolay Borisov
@ 2021-11-25 9:14 ` Nikolay Borisov
2021-11-25 15:35 ` David Sterba
2021-11-25 9:14 ` [PATCH v3 2/3] btrfs: make device add compatible with paused balance in btrfs_exclop_start_try_lock Nikolay Borisov
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: Nikolay Borisov @ 2021-11-25 9:14 UTC (permalink / raw)
To: linux-btrfs; +Cc: Nikolay Borisov
Current set of exclusive operation states is not sufficient to handle all
practical use cases. In particular there is a need to be able to add a
device to a filesystem that have paused balance. Currently there is no
way to distinguish between a running and a paused balance. Fix this by
introducing BTRFS_EXCLOP_BALANCE_PAUSED which is going to be set in 2
occasions:
1. When a filesystem is mounted with skip_balance and there is an
unfinished balance it will now be into BALANCE_PAUSED instead of
simply BALANCE state.
2. When a running balance is paused.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/ctree.h | 4 ++++
fs/btrfs/ioctl.c | 23 +++++++++++++++++++++++
fs/btrfs/volumes.c | 10 ++++++++--
3 files changed, 35 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5e29f3fc527d..79a873c6d186 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -613,6 +613,7 @@ enum {
*/
enum btrfs_exclusive_operation {
BTRFS_EXCLOP_NONE,
+ BTRFS_EXCLOP_BALANCE_PAUSED,
BTRFS_EXCLOP_BALANCE,
BTRFS_EXCLOP_DEV_ADD,
BTRFS_EXCLOP_DEV_REMOVE,
@@ -3316,6 +3317,9 @@ 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);
+void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
+ enum btrfs_exclusive_operation op);
+
/* file.c */
int __init btrfs_auto_defrag_init(void);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5263f991ffff..ffe33e853bfa 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -414,6 +414,28 @@ void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");
}
+void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
+ enum btrfs_exclusive_operation op)
+{
+ switch (op) {
+ case BTRFS_EXCLOP_BALANCE_PAUSED:
+ spin_lock(&fs_info->super_lock);
+ ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
+ fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD);
+ fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;
+ spin_unlock(&fs_info->super_lock);
+ break;
+ case BTRFS_EXCLOP_BALANCE:
+ spin_lock(&fs_info->super_lock);
+ ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
+ fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
+ spin_unlock(&fs_info->super_lock);
+ break;
+ default:
+ WARN(1, "BTRFS: invalid balance operation requested\n");
+ }
+}
+
static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
{
struct inode *inode = file_inode(file);
@@ -4062,6 +4084,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
spin_lock(&fs_info->balance_lock);
bctl->flags |= BTRFS_BALANCE_RESUME;
spin_unlock(&fs_info->balance_lock);
+ btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE);
goto do_balance;
}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 45c91a2f172c..8cbc82d49ef0 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4388,8 +4388,10 @@ int btrfs_balance(struct btrfs_fs_info *fs_info,
ret = __btrfs_balance(fs_info);
mutex_lock(&fs_info->balance_mutex);
- if (ret == -ECANCELED && atomic_read(&fs_info->balance_pause_req))
+ if (ret == -ECANCELED && atomic_read(&fs_info->balance_pause_req)) {
btrfs_info(fs_info, "balance: paused");
+ btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);
+ }
/*
* Balance can be canceled by:
*
@@ -4465,6 +4467,10 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
return 0;
}
+ spin_lock(&fs_info->super_lock);
+ ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
+ fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
+ spin_unlock(&fs_info->super_lock);
/*
* A ro->rw remount sequence should continue with the paused balance
* regardless of who pauses it, system or the user as of now, so set
@@ -4533,7 +4539,7 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
* is in a paused state and must have fs_info::balance_ctl properly
* set up.
*/
- if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))
+ if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED))
btrfs_warn(fs_info,
"balance: cannot set exclusive op status, resume manually");
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v3 2/3] btrfs: make device add compatible with paused balance in btrfs_exclop_start_try_lock
2021-11-25 9:14 [PATCH v3 0/3] Support adding a device during paused balance Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state Nikolay Borisov
@ 2021-11-25 9:14 ` Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 3/3] btrfs: allow device add if balance is paused Nikolay Borisov
2021-11-25 15:43 ` [PATCH v3 0/3] Support adding a device during paused balance David Sterba
3 siblings, 0 replies; 6+ messages in thread
From: Nikolay Borisov @ 2021-11-25 9:14 UTC (permalink / raw)
To: linux-btrfs; +Cc: Nikolay Borisov
This is needed to enable device add to work in cases when a file system
has been mounted with 'skip_balance' mount option.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/ioctl.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ffe33e853bfa..ab05319854f8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -387,6 +387,7 @@ bool btrfs_exclop_start(struct btrfs_fs_info *fs_info,
*
* Compatibility:
* - the same type is already running
+ * - when trying to add a device and balance has been paused
* - not BTRFS_EXCLOP_NONE - this is intentionally incompatible and the caller
* must check the condition first that would allow none -> @type
*/
@@ -394,7 +395,9 @@ 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)
+ if (fs_info->exclusive_operation == type ||
+ (fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED &&
+ type == BTRFS_EXCLOP_DEV_ADD))
return true;
spin_unlock(&fs_info->super_lock);
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v3 3/3] btrfs: allow device add if balance is paused
2021-11-25 9:14 [PATCH v3 0/3] Support adding a device during paused balance Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 2/3] btrfs: make device add compatible with paused balance in btrfs_exclop_start_try_lock Nikolay Borisov
@ 2021-11-25 9:14 ` Nikolay Borisov
2021-11-25 15:43 ` [PATCH v3 0/3] Support adding a device during paused balance David Sterba
3 siblings, 0 replies; 6+ messages in thread
From: Nikolay Borisov @ 2021-11-25 9:14 UTC (permalink / raw)
To: linux-btrfs; +Cc: Nikolay Borisov
Currently paused balance precludes adding a device since they are both
considered exclusive ops and we can have at most 1 running at a time.
This is problematic in case a filesystem encounters an ENOSPC situation
while balance is running, in this case the only thing the user can do
is mount the fs with "skip_balance" which pauses balance and delete some
data to free up space for balance. However, it should be possible to add
a new device when balance is paused.
Fix this by allowing device add to proceed when balance is paused.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/ioctl.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ab05319854f8..6d617d2d5fa2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3172,13 +3172,25 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
{
struct btrfs_ioctl_vol_args *vol_args;
+ bool restore_op = false;
int ret;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_ADD))
- return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
+ if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_ADD)) {
+ if (!btrfs_exclop_start_try_lock(fs_info, BTRFS_EXCLOP_DEV_ADD))
+ return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
+
+ /*
+ * We can do the device add because we have a paused balanced,
+ * change the exclusive op type and remember we should bring
+ * back the paused balance
+ */
+ fs_info->exclusive_operation = BTRFS_EXCLOP_DEV_ADD;
+ btrfs_exclop_start_unlock(fs_info);
+ restore_op = true;
+ }
vol_args = memdup_user(arg, sizeof(*vol_args));
if (IS_ERR(vol_args)) {
@@ -3194,7 +3206,10 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
kfree(vol_args);
out:
- btrfs_exclop_finish(fs_info);
+ if (restore_op)
+ btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);
+ else
+ btrfs_exclop_finish(fs_info);
return ret;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state
2021-11-25 9:14 ` [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state Nikolay Borisov
@ 2021-11-25 15:35 ` David Sterba
0 siblings, 0 replies; 6+ messages in thread
From: David Sterba @ 2021-11-25 15:35 UTC (permalink / raw)
To: Nikolay Borisov; +Cc: linux-btrfs
On Thu, Nov 25, 2021 at 11:14:41AM +0200, Nikolay Borisov wrote:
> Current set of exclusive operation states is not sufficient to handle all
> practical use cases. In particular there is a need to be able to add a
> device to a filesystem that have paused balance. Currently there is no
> way to distinguish between a running and a paused balance. Fix this by
> introducing BTRFS_EXCLOP_BALANCE_PAUSED which is going to be set in 2
> occasions:
>
> 1. When a filesystem is mounted with skip_balance and there is an
> unfinished balance it will now be into BALANCE_PAUSED instead of
> simply BALANCE state.
>
> 2. When a running balance is paused.
>
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
> fs/btrfs/ctree.h | 4 ++++
> fs/btrfs/ioctl.c | 23 +++++++++++++++++++++++
> fs/btrfs/volumes.c | 10 ++++++++--
> 3 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 5e29f3fc527d..79a873c6d186 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -613,6 +613,7 @@ enum {
> */
> enum btrfs_exclusive_operation {
> BTRFS_EXCLOP_NONE,
> + BTRFS_EXCLOP_BALANCE_PAUSED,
> BTRFS_EXCLOP_BALANCE,
> BTRFS_EXCLOP_DEV_ADD,
> BTRFS_EXCLOP_DEV_REMOVE,
> @@ -3316,6 +3317,9 @@ 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);
> +void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
> + enum btrfs_exclusive_operation op);
> +
>
> /* file.c */
> int __init btrfs_auto_defrag_init(void);
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 5263f991ffff..ffe33e853bfa 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -414,6 +414,28 @@ void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
> sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");
> }
>
> +void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
> + enum btrfs_exclusive_operation op)
> +{
> + switch (op) {
> + case BTRFS_EXCLOP_BALANCE_PAUSED:
> + spin_lock(&fs_info->super_lock);
> + ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
> + fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD);
> + fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;
> + spin_unlock(&fs_info->super_lock);
> + break;
> + case BTRFS_EXCLOP_BALANCE:
> + spin_lock(&fs_info->super_lock);
> + ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);
> + fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;
> + spin_unlock(&fs_info->super_lock);
> + break;
> + default:
> + WARN(1, "BTRFS: invalid balance operation requested\n");
As the fs_info is available, this shoud use btrfs_warn because it also
prints the uuid/device of the filesytem, otherwise the message is
useless. Also it could contain the number of the operation. I'll fix
that.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3 0/3] Support adding a device during paused balance
2021-11-25 9:14 [PATCH v3 0/3] Support adding a device during paused balance Nikolay Borisov
` (2 preceding siblings ...)
2021-11-25 9:14 ` [PATCH v3 3/3] btrfs: allow device add if balance is paused Nikolay Borisov
@ 2021-11-25 15:43 ` David Sterba
3 siblings, 0 replies; 6+ messages in thread
From: David Sterba @ 2021-11-25 15:43 UTC (permalink / raw)
To: Nikolay Borisov; +Cc: linux-btrfs
On Thu, Nov 25, 2021 at 11:14:40AM +0200, Nikolay Borisov wrote:
>
> So here's v3 which takes care of the feedback received in the last round, namely:
>
> - Introduced btrfs_exclop_balance which is used to switch the balance state,
> alongside ASSERTS
> - Removed unused variable in balance_kthread
>
> Nikolay Borisov (3):
> btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state
> btrfs: make device add compatible with paused balance in
> btrfs_exclop_start_try_lock
> btrfs: allow device add if balance is paused
With the minor message fixup added to misc-next, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-11-25 15:45 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-25 9:14 [PATCH v3 0/3] Support adding a device during paused balance Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 1/3] btrfs: introduce BTRFS_EXCLOP_BALANCE_PAUSED exclusive state Nikolay Borisov
2021-11-25 15:35 ` David Sterba
2021-11-25 9:14 ` [PATCH v3 2/3] btrfs: make device add compatible with paused balance in btrfs_exclop_start_try_lock Nikolay Borisov
2021-11-25 9:14 ` [PATCH v3 3/3] btrfs: allow device add if balance is paused Nikolay Borisov
2021-11-25 15:43 ` [PATCH v3 0/3] Support adding a device during paused balance David Sterba
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