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Btrfs: disallow mutually exclusive admin operations from user mode 

Btrfs admin operations that are manually started from user mode
and that cannot be executed at the same time return -EINPROGRESS.
A common way to enter and leave this locked section is introduced
since it used to be specific to the balance operation.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This commit is contained in:
Stefan Behrens 2012-11-05 17:54:08 +01:00 committed by Josef Bacik
parent a2bff64025
commit 5ac00addc7
3 changed files with 40 additions and 17 deletions
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2
fs/btrfs/ctree.h
View File

@ -1527,6 +1527,8 @@ struct btrfs_fs_info {
/* device replace state */
struct btrfs_dev_replace dev_replace;
atomic_t mutually_exclusive_operation_running;
};
/*

53
fs/btrfs/ioctl.c
View File

@ -1317,13 +1317,13 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
mutex_lock(&root->fs_info->volume_mutex);
if (root->fs_info->balance_ctl) {
printk(KERN_INFO "btrfs: balance in progress\n");
ret = -EINVAL;
goto out;
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;
}
mutex_lock(&root->fs_info->volume_mutex);
vol_args = memdup_user(arg, sizeof(*vol_args));
if (IS_ERR(vol_args)) {
ret = PTR_ERR(vol_args);
@ -1419,6 +1419,7 @@ out_free:
kfree(vol_args);
out:
mutex_unlock(&root->fs_info->volume_mutex);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
return ret;
}
@ -2160,9 +2161,17 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
if (btrfs_root_readonly(root))
return -EROFS;
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;
}
ret = mnt_want_write_file(file);
if (ret)
if (ret) {
atomic_set(&root->fs_info->mutually_exclusive_operation_running,
0);
return ret;
}
switch (inode->i_mode & S_IFMT) {
case S_IFDIR:
@ -2214,6 +2223,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
}
out:
mnt_drop_write_file(file);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
return ret;
}
@ -2225,13 +2235,13 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
mutex_lock(&root->fs_info->volume_mutex);
if (root->fs_info->balance_ctl) {
printk(KERN_INFO "btrfs: balance in progress\n");
ret = -EINVAL;
goto out;
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;
}
mutex_lock(&root->fs_info->volume_mutex);
vol_args = memdup_user(arg, sizeof(*vol_args));
if (IS_ERR(vol_args)) {
ret = PTR_ERR(vol_args);
@ -2244,6 +2254,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
kfree(vol_args);
out:
mutex_unlock(&root->fs_info->volume_mutex);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
return ret;
}
@ -2258,13 +2269,13 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
if (root->fs_info->sb->s_flags & MS_RDONLY)
return -EROFS;
mutex_lock(&root->fs_info->volume_mutex);
if (root->fs_info->balance_ctl) {
printk(KERN_INFO "btrfs: balance in progress\n");
ret = -EINVAL;
goto out;
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;
}
mutex_lock(&root->fs_info->volume_mutex);
vol_args = memdup_user(arg, sizeof(*vol_args));
if (IS_ERR(vol_args)) {
ret = PTR_ERR(vol_args);
@ -2277,6 +2288,7 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
kfree(vol_args);
out:
mutex_unlock(&root->fs_info->volume_mutex);
atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
return ret;
}
@ -3319,6 +3331,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
struct btrfs_ioctl_balance_args *bargs;
struct btrfs_balance_control *bctl;
int ret;
int need_to_clear_lock = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@ -3354,10 +3367,13 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
bargs = NULL;
}
if (fs_info->balance_ctl) {
if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
1)) {
pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
ret = -EINPROGRESS;
goto out_bargs;
}
need_to_clear_lock = 1;
bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
if (!bctl) {
@ -3391,6 +3407,9 @@ do_balance:
out_bargs:
kfree(bargs);
out:
if (need_to_clear_lock)
atomic_set(&root->fs_info->mutually_exclusive_operation_running,
0);
mutex_unlock(&fs_info->balance_mutex);
mutex_unlock(&fs_info->volume_mutex);
mnt_drop_write_file(file);

2
fs/btrfs/volumes.c
View File

@ -2952,6 +2952,7 @@ 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);
@ -2974,6 +2975,7 @@ 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);