linux.git/fs/btrfs/dev-replace.c, branch v5.1

btrfs: drop the lock on error in btrfs_dev_replace_cancel

2019-02-25T13:13:41+00:00

We should drop the lock on this error path.  This has been found by a
static tool.

The lock needs to be released, it's there to protect access to the
dev_replace members and is not supposed to be left locked. The value of
state that's being switched would need to be artifically changed to an
invalid value so the default: branch is taken.

Fixes: d189dd70e255 ("btrfs: fix use-after-free due to race between replace start and cancel")
CC: stable@vger.kernel.org # 5.0+
Reviewed-by: Anand Jain 
Signed-off-by: Dan Carpenter 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: merge btrfs_find_device and find_device

2019-02-25T13:13:24+00:00

Both btrfs_find_device() and find_device() does the same thing except
that the latter does not take the seed device onto account in the device
scanning context. We can merge them.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: refactor btrfs_find_device() take fs_devices as argument

2019-02-25T13:13:23+00:00

btrfs_find_device() accepts fs_info as an argument and retrieves
fs_devices from fs_info.

Instead use fs_devices, so that this function can be used in non-mount
(during device scanning) context as well.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: Fix typos in comments and strings

2018-12-17T13:51:50+00:00

The typos accumulate over time so once in a while time they get fixed in
a large patch.

Signed-off-by: Andrea Gelmini 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: dev-replace: open code trivial locking helpers

2018-12-17T13:51:45+00:00

The dev-replace locking functions are now trivial wrappers around rw
semaphore that can be used directly everywhere. No functional change.

Signed-off-by: David Sterba

btrfs: dev-replace: remove custom read/write blocking scheme

2018-12-17T13:51:45+00:00

After the rw semaphore has been added, the custom blocking using
::blocking_readers and ::read_lock_wq is redundant.

The blocking logic in __btrfs_map_block is replaced by extending the
time the semaphore is held, that has the same blocking effect on writes
as the previous custom scheme that waited until ::blocking_readers was
zero.

Signed-off-by: David Sterba

btrfs: dev-replace: swich locking to rw semaphore

2018-12-17T13:51:44+00:00

This is the first part of removing the custom locking and waiting scheme
used for device replace. It was probably copied from extent buffer
locking, but there's nothing that would require more than is provided by
the common locking primitives.

The rw spinlock protects waiting tasks counter in case of incompatible
locks and the waitqueue. Same as rw semaphore.

This patch only switches the locking primitive, for better
bisectability.  There should be no functional change other than the
overhead of the locking and potential sleeping instead of spinning when
the lock is contended.

Signed-off-by: David Sterba

btrfs: don't report user-requested cancel as an error

2018-12-17T13:51:36+00:00

As of now only user requested replace cancel can cancel the
replace-scrub so no need to log the error.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: silence warning if replace is canceled

2018-12-17T13:51:35+00:00

When we successfully cancel the device replace, its scrub worker returns
-ECANCELED, which is then passed to btrfs_dev_replace_finishing.

It cleans up based on the returned status and propagates the same
-ECANCELED back the parent function. As of now only user can cancel the
replace-scrub, so its ok to silence the warning here.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: dev-replace: add explicit check for replace result "no error"

2018-12-17T13:51:35+00:00

We recast the replace return status
BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS to 0, to indicate no
error.
And since BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR should also return 0,
which is also declared as 0, so we just return. Instead add it to the if
statement so that there is enough clarity while reading the code.

Signed-off-by: Anand Jain 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba