| Message ID | 20180521144515.16501-1-kilobyte@angband.pl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 632e26d6f7ce..b75db9d72106 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2561,7 +2561,8 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp) ret = btrfs_defrag_root(root); break; case S_IFREG: - if (!(file->f_mode & FMODE_WRITE)) { + if (!capable(CAP_SYS_ADMIN) && + inode_permission(inode, MAY_WRITE)) { ret = -EINVAL; goto out; }
Requiring a rw descriptor conflicts both ways with exec, returning ETXTBSY whenever you try to defrag a program that's currently being run, or causing intermittent exec failures on a live system being defragged. As defrag doesn't change the file's contents in any way, there's no reason to consider it a rw operation. Thus, let's check only whether the file could have been opened rw. Such access control is still needed as currently defrag can use extra disk space, and might trigger bugs. Signed-off-by: Adam Borowski <kilobyte@angband.pl> --- fs/btrfs/ioctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)