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Merge branch 'mutex-ops@next-for-chris' of git://github.com/idryomov/…
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…btrfs-unstable into linus
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Chris Mason committed Jan 22, 2013
2 parents daf2c08 + 25122d1 commit 83bfccb
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Showing 2 changed files with 86 additions and 31 deletions.
107 changes: 79 additions & 28 deletions fs/btrfs/ioctl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1340,7 +1340,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
1)) {
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
mnt_drop_write_file(file);
return -EINPROGRESS;
return -EINVAL;
}

mutex_lock(&root->fs_info->volume_mutex);
Expand Down Expand Up @@ -1446,8 +1446,8 @@ static noinline int btrfs_ioctl_resize(struct file *file,
kfree(vol_args);
out:
mutex_unlock(&root->fs_info->volume_mutex);
mnt_drop_write_file(file);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
mnt_drop_write_file(file);
return ret;
}

Expand Down Expand Up @@ -2186,19 +2186,20 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
struct btrfs_ioctl_defrag_range_args *range;
int ret;

if (btrfs_root_readonly(root))
return -EROFS;
ret = mnt_want_write_file(file);
if (ret)
return ret;

if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1)) {
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
return -EINPROGRESS;
mnt_drop_write_file(file);
return -EINVAL;
}
ret = mnt_want_write_file(file);
if (ret) {
atomic_set(&root->fs_info->mutually_exclusive_operation_running,
0);
return ret;

if (btrfs_root_readonly(root)) {
ret = -EROFS;
goto out;
}

switch (inode->i_mode & S_IFMT) {
Expand Down Expand Up @@ -2250,8 +2251,8 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
ret = -EINVAL;
}
out:
mnt_drop_write_file(file);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
mnt_drop_write_file(file);
return ret;
}

Expand All @@ -2266,7 +2267,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1)) {
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
return -EINPROGRESS;
return -EINVAL;
}

mutex_lock(&root->fs_info->volume_mutex);
Expand Down Expand Up @@ -2303,7 +2304,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
1)) {
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
mnt_drop_write_file(file);
return -EINPROGRESS;
return -EINVAL;
}

mutex_lock(&root->fs_info->volume_mutex);
Expand All @@ -2319,8 +2320,8 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
kfree(vol_args);
out:
mutex_unlock(&root->fs_info->volume_mutex);
mnt_drop_write_file(file);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
mnt_drop_write_file(file);
return ret;
}

Expand Down Expand Up @@ -3440,8 +3441,8 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_ioctl_balance_args *bargs;
struct btrfs_balance_control *bctl;
bool need_unlock; /* for mut. excl. ops lock */
int ret;
int need_to_clear_lock = 0;

if (!capable(CAP_SYS_ADMIN))
return -EPERM;
Expand All @@ -3450,14 +3451,61 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
if (ret)
return ret;

mutex_lock(&fs_info->volume_mutex);
again:
if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
mutex_lock(&fs_info->volume_mutex);
mutex_lock(&fs_info->balance_mutex);
need_unlock = true;
goto locked;
}

/*
* mut. excl. ops lock is locked. Three possibilites:
* (1) some other op is running
* (2) balance is running
* (3) balance is paused -- special case (think resume)
*/
mutex_lock(&fs_info->balance_mutex);
if (fs_info->balance_ctl) {
/* this is either (2) or (3) */
if (!atomic_read(&fs_info->balance_running)) {
mutex_unlock(&fs_info->balance_mutex);
if (!mutex_trylock(&fs_info->volume_mutex))
goto again;
mutex_lock(&fs_info->balance_mutex);

if (fs_info->balance_ctl &&
!atomic_read(&fs_info->balance_running)) {
/* this is (3) */
need_unlock = false;
goto locked;
}

mutex_unlock(&fs_info->balance_mutex);
mutex_unlock(&fs_info->volume_mutex);
goto again;
} else {
/* this is (2) */
mutex_unlock(&fs_info->balance_mutex);
ret = -EINPROGRESS;
goto out;
}
} else {
/* this is (1) */
mutex_unlock(&fs_info->balance_mutex);
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
ret = -EINVAL;
goto out;
}

locked:
BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));

if (arg) {
bargs = memdup_user(arg, sizeof(*bargs));
if (IS_ERR(bargs)) {
ret = PTR_ERR(bargs);
goto out;
goto out_unlock;
}

if (bargs->flags & BTRFS_BALANCE_RESUME) {
Expand All @@ -3477,13 +3525,10 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
bargs = NULL;
}

if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1)) {
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
if (fs_info->balance_ctl) {
ret = -EINPROGRESS;
goto out_bargs;
}
need_to_clear_lock = 1;

bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
if (!bctl) {
Expand All @@ -3504,24 +3549,30 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
}

do_balance:
ret = btrfs_balance(bctl, bargs);
/*
* bctl is freed in __cancel_balance or in free_fs_info if
* restriper was paused all the way until unmount
* Ownership of bctl and mutually_exclusive_operation_running
* 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.
*/
need_unlock = false;

ret = btrfs_balance(bctl, bargs);

if (arg) {
if (copy_to_user(arg, bargs, sizeof(*bargs)))
ret = -EFAULT;
}

out_bargs:
kfree(bargs);
out:
if (need_to_clear_lock)
atomic_set(&root->fs_info->mutually_exclusive_operation_running,
0);
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);
out:
mnt_drop_write_file(file);
return ret;
}
Expand Down
10 changes: 7 additions & 3 deletions fs/btrfs/volumes.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2959,6 +2959,8 @@ static void __cancel_balance(struct btrfs_fs_info *fs_info)
unset_balance_control(fs_info);
ret = del_balance_item(fs_info->tree_root);
BUG_ON(ret);

atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
}

void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
Expand Down Expand Up @@ -3138,8 +3140,10 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
out:
if (bctl->flags & BTRFS_BALANCE_RESUME)
__cancel_balance(fs_info);
else
else {
kfree(bctl);
atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
}
return ret;
}

Expand All @@ -3156,7 +3160,6 @@ static int balance_kthread(void *data)
ret = btrfs_balance(fs_info->balance_ctl, NULL);
}

atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
mutex_unlock(&fs_info->balance_mutex);
mutex_unlock(&fs_info->volume_mutex);

Expand All @@ -3179,7 +3182,6 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
return 0;
}

WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
if (IS_ERR(tsk))
return PTR_ERR(tsk);
Expand Down Expand Up @@ -3233,6 +3235,8 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
btrfs_balance_sys(leaf, item, &disk_bargs);
btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);

WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));

mutex_lock(&fs_info->volume_mutex);
mutex_lock(&fs_info->balance_mutex);

Expand Down

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