From 5ac00addc7ac09110995fe967071d191b5981cc1 Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Mon, 5 Nov 2012 17:54:08 +0100 Subject: [PATCH] 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 Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/ioctl.c | 53 +++++++++++++++++++++++++++++++--------------- fs/btrfs/volumes.c | 2 ++ 3 files changed, 40 insertions(+), 17 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 147406d0f9a9..e9dc78014f09 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1527,6 +1527,8 @@ struct btrfs_fs_info { /* device replace state */ struct btrfs_dev_replace dev_replace; + + atomic_t mutually_exclusive_operation_running; }; /* diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index b40b827f93e7..26f46dad3b0e 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -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); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d2c0bccca607..33ca36b37a6a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -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); -- 2.34.1