From 027ed2f0044e95a97ed34db2d55a9ca95ba84385 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 8 Jun 2011 08:27:56 +0000 Subject: Btrfs: avoid stack bloat in btrfs_ioctl_fs_info() The size of struct btrfs_ioctl_fs_info_args is as big as 1KB, so don't declare the variable on stack. Signed-off-by: Li Zefan Reviewed-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/ioctl.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'fs/btrfs/ioctl.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index ac37040e426..b793d112d1f 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2054,29 +2054,34 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg) { - struct btrfs_ioctl_fs_info_args fi_args; + struct btrfs_ioctl_fs_info_args *fi_args; struct btrfs_device *device; struct btrfs_device *next; struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices; + int ret = 0; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - fi_args.num_devices = fs_devices->num_devices; - fi_args.max_id = 0; - memcpy(&fi_args.fsid, root->fs_info->fsid, sizeof(fi_args.fsid)); + fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL); + if (!fi_args) + return -ENOMEM; + + fi_args->num_devices = fs_devices->num_devices; + memcpy(&fi_args->fsid, root->fs_info->fsid, sizeof(fi_args->fsid)); mutex_lock(&fs_devices->device_list_mutex); list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) { - if (device->devid > fi_args.max_id) - fi_args.max_id = device->devid; + if (device->devid > fi_args->max_id) + fi_args->max_id = device->devid; } mutex_unlock(&fs_devices->device_list_mutex); - if (copy_to_user(arg, &fi_args, sizeof(fi_args))) - return -EFAULT; + if (copy_to_user(arg, fi_args, sizeof(*fi_args))) + ret = -EFAULT; - return 0; + kfree(fi_args); + return ret; } static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg) -- cgit v1.2.3-18-g5258 From 8351583e3f6e430ce8f71913909a96ad5cc6a2f6 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 14 Jun 2011 15:16:14 -0400 Subject: Btrfs: protect the pending_snapshots list with trans_lock Currently there is nothing protecting the pending_snapshots list on the transaction. We only hold the directory mutex that we are snapshotting and a read lock on the subvol_sem, so we could race with somebody else creating a snapshot in a different directory and end up with list corruption. So protect this list with the trans_lock. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/ioctl.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/btrfs/ioctl.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index b793d112d1f..a3c4751e07d 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -482,8 +482,10 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry, ret = btrfs_snap_reserve_metadata(trans, pending_snapshot); BUG_ON(ret); + spin_lock(&root->fs_info->trans_lock); list_add(&pending_snapshot->list, &trans->transaction->pending_snapshots); + spin_unlock(&root->fs_info->trans_lock); if (async_transid) { *async_transid = trans->transid; ret = btrfs_commit_transaction_async(trans, -- cgit v1.2.3-18-g5258