| Message ID | 1546502498-28070-2-git-send-email-anand.jain@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v13] btrfs: introduce feature to forget a btrfs device | expand |
On Thu, Jan 03, 2019 at 04:01:37PM +0800, Anand Jain wrote: > Support for a new command 'btrfs dev forget [dev]' is proposed here > to undo the effects of 'btrfs dev scan [dev]'. For this purpose > this patch proposes to use ioctl #5 as it was empty. > IOW(BTRFS_IOCTL_MAGIC, 5, ..) > This patch adds new ioctl BTRFS_IOC_FORGET_DEV which can be sent from > the /dev/btrfs-control to forget one or all devices, (devices which are > not mounted) from the btrfs kernel. > > The argument it takes is struct btrfs_ioctl_vol_args, and ::name can be > set to specify the device path. And all unmounted devices can be removed > from the kernel if no device path is provided. > > Again, the devices are removed only if the relevant fsid aren't mounted. > > This new cli can provide.. > . Release of unwanted btrfs_fs_devices and btrfs_devices memory if the > device is not going to be mounted. > . Ability to mount the device in degraded mode when one of the other > device is corrupted like in split brain raid1. > . Running test cases which requires btrfs.ko-reload if the rootfs > is btrfs. > > Signed-off-by: Anand Jain <anand.jain@oracle.com> > Reviewed-by: Nikolay Borisov <nborisov@suse.com> > --- > v12->v13: > btrfs.ko returns error on failing to find the given device. > For no argument (btrfs device scan --forget) if there is > no device to forget then it shall just return success. > v11->v12: fix coding style add spacing before after ":". > v1->v11: Pls ref to the cover-letter. (sorry about that). > > fs/btrfs/super.c | 3 +++ > fs/btrfs/volumes.c | 55 +++++++++++++++++++++++++++++++++++----------- > fs/btrfs/volumes.h | 1 + > include/uapi/linux/btrfs.h | 2 ++ > 4 files changed, 48 insertions(+), 13 deletions(-) > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 33cc9aba9c94..a4e8beec0fc5 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -2247,6 +2247,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, > ret = PTR_ERR_OR_ZERO(device); > mutex_unlock(&uuid_mutex); > break; > + case BTRFS_IOC_FORGET_DEV: > + ret = btrfs_forget_devices(vol->name); > + break; > case BTRFS_IOC_DEVICES_READY: > mutex_lock(&uuid_mutex); > device = btrfs_scan_one_device(vol->name, FMODE_READ, > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 2576b1a379c9..2ab42bfe5d3c 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -734,6 +734,19 @@ static void pending_bios_fn(struct btrfs_work *work) > run_scheduled_bios(device); > } > > +static bool device_path_matched(const char *path, struct btrfs_device *device) > +{ > + int found; > + > + rcu_read_lock(); > + found = strcmp(rcu_str_deref(device->name), path); > + rcu_read_unlock(); > + > + if (!found) > + return true; > + return false; > +} > + > /* > * Search and remove all stale (devices which are not mounted) devices. > * When both inputs are NULL, it will search and release all stale devices. > @@ -742,44 +755,47 @@ static void pending_bios_fn(struct btrfs_work *work) > * skip_dev: Optional. Will skip this device when searching for the stale > * devices. > */ > -static void btrfs_free_stale_devices(const char *path, > +static int btrfs_free_stale_devices(const char *path, > struct btrfs_device *skip_device) > { > struct btrfs_fs_devices *fs_devices, *tmp_fs_devices; > struct btrfs_device *device, *tmp_device; > + int ret; > + > + if (path) > + ret = -ENXIO; > + else > + ret = 0; Can you please split this change to another patch? It's a preparatory work for the new ioctl. The return value meaning should be also documented in the function comment.
On 01/03/2019 11:24 PM, David Sterba wrote: > On Thu, Jan 03, 2019 at 04:01:37PM +0800, Anand Jain wrote: >> Support for a new command 'btrfs dev forget [dev]' is proposed here >> to undo the effects of 'btrfs dev scan [dev]'. For this purpose >> this patch proposes to use ioctl #5 as it was empty. >> IOW(BTRFS_IOCTL_MAGIC, 5, ..) >> This patch adds new ioctl BTRFS_IOC_FORGET_DEV which can be sent from >> the /dev/btrfs-control to forget one or all devices, (devices which are >> not mounted) from the btrfs kernel. >> >> The argument it takes is struct btrfs_ioctl_vol_args, and ::name can be >> set to specify the device path. And all unmounted devices can be removed >> from the kernel if no device path is provided. >> >> Again, the devices are removed only if the relevant fsid aren't mounted. >> >> This new cli can provide.. >> . Release of unwanted btrfs_fs_devices and btrfs_devices memory if the >> device is not going to be mounted. >> . Ability to mount the device in degraded mode when one of the other >> device is corrupted like in split brain raid1. >> . Running test cases which requires btrfs.ko-reload if the rootfs >> is btrfs. >> >> Signed-off-by: Anand Jain <anand.jain@oracle.com> >> Reviewed-by: Nikolay Borisov <nborisov@suse.com> >> --- >> v12->v13: >> btrfs.ko returns error on failing to find the given device. >> For no argument (btrfs device scan --forget) if there is >> no device to forget then it shall just return success. >> v11->v12: fix coding style add spacing before after ":". >> v1->v11: Pls ref to the cover-letter. (sorry about that). >> >> fs/btrfs/super.c | 3 +++ >> fs/btrfs/volumes.c | 55 +++++++++++++++++++++++++++++++++++----------- >> fs/btrfs/volumes.h | 1 + >> include/uapi/linux/btrfs.h | 2 ++ >> 4 files changed, 48 insertions(+), 13 deletions(-) >> >> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c >> index 33cc9aba9c94..a4e8beec0fc5 100644 >> --- a/fs/btrfs/super.c >> +++ b/fs/btrfs/super.c >> @@ -2247,6 +2247,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, >> ret = PTR_ERR_OR_ZERO(device); >> mutex_unlock(&uuid_mutex); >> break; >> + case BTRFS_IOC_FORGET_DEV: >> + ret = btrfs_forget_devices(vol->name); >> + break; >> case BTRFS_IOC_DEVICES_READY: >> mutex_lock(&uuid_mutex); >> device = btrfs_scan_one_device(vol->name, FMODE_READ, >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index 2576b1a379c9..2ab42bfe5d3c 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -734,6 +734,19 @@ static void pending_bios_fn(struct btrfs_work *work) >> run_scheduled_bios(device); >> } >> >> +static bool device_path_matched(const char *path, struct btrfs_device *device) >> +{ >> + int found; >> + >> + rcu_read_lock(); >> + found = strcmp(rcu_str_deref(device->name), path); >> + rcu_read_unlock(); >> + >> + if (!found) >> + return true; >> + return false; >> +} >> + >> /* >> * Search and remove all stale (devices which are not mounted) devices. >> * When both inputs are NULL, it will search and release all stale devices. >> @@ -742,44 +755,47 @@ static void pending_bios_fn(struct btrfs_work *work) >> * skip_dev: Optional. Will skip this device when searching for the stale >> * devices. >> */ >> -static void btrfs_free_stale_devices(const char *path, >> +static int btrfs_free_stale_devices(const char *path, >> struct btrfs_device *skip_device) >> { >> struct btrfs_fs_devices *fs_devices, *tmp_fs_devices; >> struct btrfs_device *device, *tmp_device; >> + int ret; >> + >> + if (path) >> + ret = -ENXIO; >> + else >> + ret = 0; > > Can you please split this change to another patch? It's a preparatory > work for the new ioctl. The return value meaning should be also > documented in the function comment. > Pls find v14. I have also use -ENOENT instead of -ENXIO and documented the return value in the function header.
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 33cc9aba9c94..a4e8beec0fc5 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2247,6 +2247,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, ret = PTR_ERR_OR_ZERO(device); mutex_unlock(&uuid_mutex); break; + case BTRFS_IOC_FORGET_DEV: + ret = btrfs_forget_devices(vol->name); + break; case BTRFS_IOC_DEVICES_READY: mutex_lock(&uuid_mutex); device = btrfs_scan_one_device(vol->name, FMODE_READ, diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 2576b1a379c9..2ab42bfe5d3c 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -734,6 +734,19 @@ static void pending_bios_fn(struct btrfs_work *work) run_scheduled_bios(device); } +static bool device_path_matched(const char *path, struct btrfs_device *device) +{ + int found; + + rcu_read_lock(); + found = strcmp(rcu_str_deref(device->name), path); + rcu_read_unlock(); + + if (!found) + return true; + return false; +} + /* * Search and remove all stale (devices which are not mounted) devices. * When both inputs are NULL, it will search and release all stale devices. @@ -742,44 +755,47 @@ static void pending_bios_fn(struct btrfs_work *work) * skip_dev: Optional. Will skip this device when searching for the stale * devices. */ -static void btrfs_free_stale_devices(const char *path, +static int btrfs_free_stale_devices(const char *path, struct btrfs_device *skip_device) { struct btrfs_fs_devices *fs_devices, *tmp_fs_devices; struct btrfs_device *device, *tmp_device; + int ret; + + if (path) + ret = -ENXIO; + else + ret = 0; list_for_each_entry_safe(fs_devices, tmp_fs_devices, &fs_uuids, fs_list) { + mutex_lock(&fs_devices->device_list_mutex); - if (fs_devices->opened) { - mutex_unlock(&fs_devices->device_list_mutex); - continue; - } list_for_each_entry_safe(device, tmp_device, &fs_devices->devices, dev_list) { - int not_found = 0; if (skip_device && skip_device == device) continue; if (path && !device->name) continue; - - rcu_read_lock(); - if (path) - not_found = strcmp(rcu_str_deref(device->name), - path); - rcu_read_unlock(); - if (not_found) + if (path && !device_path_matched(path, device)) continue; + if (fs_devices->opened) { + if (path) + ret = -EBUSY; + break; + } /* delete the stale device */ fs_devices->num_devices--; list_del(&device->dev_list); btrfs_free_device(device); + ret = 0; if (fs_devices->num_devices == 0) break; } + mutex_unlock(&fs_devices->device_list_mutex); if (fs_devices->num_devices == 0) { btrfs_sysfs_remove_fsid(fs_devices); @@ -787,6 +803,8 @@ static void btrfs_free_stale_devices(const char *path, free_fs_devices(fs_devices); } } + + return ret; } static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, @@ -1451,6 +1469,17 @@ static int btrfs_read_disk_super(struct block_device *bdev, u64 bytenr, return 0; } +int btrfs_forget_devices(const char *path) +{ + int ret; + + mutex_lock(&uuid_mutex); + ret = btrfs_free_stale_devices(strlen(path) ? path : NULL, NULL); + mutex_unlock(&uuid_mutex); + + return ret; +} + /* * Look for a btrfs signature on a device. This may be called out of the mount path * and we are not allowed to call set_blocksize during the scan. The superblock diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index ed806649a473..1e73257e55fb 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -416,6 +416,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, fmode_t flags, void *holder); struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags, void *holder); +int btrfs_forget_devices(const char *path); int btrfs_close_devices(struct btrfs_fs_devices *fs_devices); void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step); void btrfs_assign_next_active_device(struct btrfs_device *device, diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index e0763bc4158e..c195896d478f 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -837,6 +837,8 @@ enum btrfs_err_code { struct btrfs_ioctl_vol_args) #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \ struct btrfs_ioctl_vol_args) +#define BTRFS_IOC_FORGET_DEV _IOW(BTRFS_IOCTL_MAGIC, 5, \ + struct btrfs_ioctl_vol_args) /* trans start and trans end are dangerous, and only for * use by applications that know how to avoid the * resulting deadlocks