From f29efe292198b9dbf67fb79ec9ffb5865ca29fb8 Mon Sep 17 00:00:00 2001 From: Sargun Dhillon Date: Thu, 11 May 2017 21:17:33 +0000 Subject: [PATCH] btrfs: add quota override flag to enable quota override for CAP_SYS_RESOURCE This patch introduces the quota override flag to btrfs_fs_info, and a change to quota limit checking code to temporarily allow for quota to be overridden for processes with CAP_SYS_RESOURCE. It's useful for administrative programs, such as log rotation, that may need to temporarily use more disk space in order to free up a greater amount of overall disk space without yielding more disk space to the rest of userland. Eventually, we may want to add the idea of an operator-specific quota, operator reserved space, or something else to allow for administrative override, but this is perhaps the simplest solution. Signed-off-by: Sargun Dhillon Reviewed-by: David Sterba [ minor changelog edits ] Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/qgroup.c | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 0334452a7be1..aea1b3cee887 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -716,6 +716,8 @@ struct btrfs_delayed_root; #define BTRFS_FS_BTREE_ERR 11 #define BTRFS_FS_LOG1_ERR 12 #define BTRFS_FS_LOG2_ERR 13 +#define BTRFS_FS_QUOTA_OVERRIDE 14 + /* * Indicate that a whole-filesystem exclusive operation is running * (device replace, resize, device add/delete, balance) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index deffbeb74a0b..458fec01d814 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2338,6 +2338,11 @@ static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce) if (num_bytes == 0) return 0; + + if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) && + capable(CAP_SYS_RESOURCE)) + enforce = false; + retry: spin_lock(&fs_info->qgroup_lock); quota_root = fs_info->quota_root; -- 2.20.1