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authorDavid Sterba <dsterba@suse.com>2017-03-28 14:44:21 +0200
committerDavid Sterba <dsterba@suse.com>2017-04-18 14:07:25 +0200
commit171938e528079deced3226a17dcab12121312a64 (patch)
treed49869102dade6b05e5736b0df6fd48301e43bb7 /fs/btrfs/ioctl.c
parent48a89bc4f2ceab87bc858a8eb189636b09c846a7 (diff)
btrfs: track exclusive filesystem operation in flags
There are several operations, usually started from ioctls, that cannot run concurrently. The status is tracked in mutually_exclusive_operation_running as an atomic_t. We can easily track the status as one of the per-filesystem flag bits with same synchronization guarantees. The conversion replaces: * atomic_xchg(..., 1) -> test_and_set_bit(FLAG, ...) * atomic_set(..., 0) -> clear_bit(FLAG, ...) Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
-rw-r--r--fs/btrfs/ioctl.c33
1 files changed, 15 insertions, 18 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index dabfc7ac48a6..a29dc3fd7152 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1504,7 +1504,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
if (ret)
return ret;
- if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
+ if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
mnt_drop_write_file(file);
return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
}
@@ -1619,7 +1619,7 @@ out_free:
kfree(vol_args);
out:
mutex_unlock(&fs_info->volume_mutex);
- atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
mnt_drop_write_file(file);
return ret;
}
@@ -2661,7 +2661,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1))
+ if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags))
return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
mutex_lock(&fs_info->volume_mutex);
@@ -2680,7 +2680,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
kfree(vol_args);
out:
mutex_unlock(&fs_info->volume_mutex);
- atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
return ret;
}
@@ -2708,7 +2708,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED)
return -EOPNOTSUPP;
- if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
+ if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
goto out;
}
@@ -2721,7 +2721,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
ret = btrfs_rm_device(fs_info, vol_args->name, 0);
}
mutex_unlock(&fs_info->volume_mutex);
- atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
if (!ret) {
if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
@@ -2752,7 +2752,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
if (ret)
return ret;
- if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
+ if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
goto out_drop_write;
}
@@ -2772,7 +2772,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
btrfs_info(fs_info, "disk deleted %s", vol_args->name);
kfree(vol_args);
out:
- atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
out_drop_write:
mnt_drop_write_file(file);
@@ -4442,13 +4442,11 @@ static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
ret = -EROFS;
goto out;
}
- if (atomic_xchg(
- &fs_info->mutually_exclusive_operation_running, 1)) {
+ if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
} else {
ret = btrfs_dev_replace_by_ioctl(fs_info, p);
- atomic_set(
- &fs_info->mutually_exclusive_operation_running, 0);
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
}
break;
case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
@@ -4643,7 +4641,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
return ret;
again:
- if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
+ if (!test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
mutex_lock(&fs_info->volume_mutex);
mutex_lock(&fs_info->balance_mutex);
need_unlock = true;
@@ -4689,7 +4687,7 @@ again:
}
locked:
- BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));
+ BUG_ON(!test_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
if (arg) {
bargs = memdup_user(arg, sizeof(*bargs));
@@ -4745,11 +4743,10 @@ locked:
do_balance:
/*
- * Ownership of bctl and mutually_exclusive_operation_running
+ * Ownership of bctl and filesystem flag BTRFS_FS_EXCL_OP
* goes to to btrfs_balance. bctl is freed in __cancel_balance,
* or, if restriper was paused all the way until unmount, in
- * free_fs_info. mutually_exclusive_operation_running is
- * cleared in __cancel_balance.
+ * free_fs_info. The flag is cleared in __cancel_balance.
*/
need_unlock = false;
@@ -4769,7 +4766,7 @@ out_unlock:
mutex_unlock(&fs_info->balance_mutex);
mutex_unlock(&fs_info->volume_mutex);
if (need_unlock)
- atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
out:
mnt_drop_write_file(file);
return ret;