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Message-ID: <CAOi1vP9Je-DnqUdYcBi_zSDUgj30aYrTeGq1MSwS66E7ptaTSg@mail.gmail.com>
Date: Thu, 15 Dec 2022 14:20:29 +0100
From: Ilya Dryomov <idryomov@...il.com>
To: xiubli@...hat.com
Cc: jlayton@...nel.org, ceph-devel@...r.kernel.org,
mchangir@...hat.com, lhenriques@...e.de, viro@...iv.linux.org.uk,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
stable@...r.kernel.org
Subject: Re: [PATCH v5 1/2] ceph: switch to vfs_inode_has_locks() to fix file
lock bug
On Wed, Dec 14, 2022 at 4:35 AM <xiubli@...hat.com> wrote:
>
> From: Xiubo Li <xiubli@...hat.com>
>
> For the POSIX locks they are using the same owner, which is the
> thread id. And multiple POSIX locks could be merged into single one,
> so when checking whether the 'file' has locks may fail.
>
> For a file where some openers use locking and others don't is a
> really odd usage pattern though. Locks are like stoplights -- they
> only work if everyone pays attention to them.
>
> Just switch ceph_get_caps() to check whether any locks are set on
> the inode. If there are POSIX/OFD/FLOCK locks on the file at the
> time, we should set CHECK_FILELOCK, regardless of what fd was used
> to set the lock.
>
> Cc: stable@...r.kernel.org
> Cc: Jeff Layton <jlayton@...nel.org>
> Fixes: ff5d913dfc71 ("ceph: return -EIO if read/write against filp that lost file locks")
> Reviewed-by: Jeff Layton <jlayton@...nel.org>
> Signed-off-by: Xiubo Li <xiubli@...hat.com>
> ---
> fs/ceph/caps.c | 2 +-
> fs/ceph/locks.c | 4 ----
> fs/ceph/super.h | 1 -
> 3 files changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 065e9311b607..948136f81fc8 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -2964,7 +2964,7 @@ int ceph_get_caps(struct file *filp, int need, int want, loff_t endoff, int *got
>
> while (true) {
> flags &= CEPH_FILE_MODE_MASK;
> - if (atomic_read(&fi->num_locks))
> + if (vfs_inode_has_locks(inode))
> flags |= CHECK_FILELOCK;
> _got = 0;
> ret = try_get_cap_refs(inode, need, want, endoff,
> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
> index 3e2843e86e27..b191426bf880 100644
> --- a/fs/ceph/locks.c
> +++ b/fs/ceph/locks.c
> @@ -32,18 +32,14 @@ void __init ceph_flock_init(void)
>
> static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
> {
> - struct ceph_file_info *fi = dst->fl_file->private_data;
> struct inode *inode = file_inode(dst->fl_file);
> atomic_inc(&ceph_inode(inode)->i_filelock_ref);
> - atomic_inc(&fi->num_locks);
> }
>
> static void ceph_fl_release_lock(struct file_lock *fl)
> {
> - struct ceph_file_info *fi = fl->fl_file->private_data;
> struct inode *inode = file_inode(fl->fl_file);
> struct ceph_inode_info *ci = ceph_inode(inode);
> - atomic_dec(&fi->num_locks);
> if (atomic_dec_and_test(&ci->i_filelock_ref)) {
> /* clear error when all locks are released */
> spin_lock(&ci->i_ceph_lock);
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 14454f464029..e7662ff6f149 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -804,7 +804,6 @@ struct ceph_file_info {
> struct list_head rw_contexts;
>
> u32 filp_gen;
> - atomic_t num_locks;
> };
>
> struct ceph_dir_file_info {
> --
> 2.31.1
>
Hi Xiubo,
You marked this for stable but there is an obvious dependency on
vfs_inode_has_locks() that just got merged for 6.2-rc1. Are you
intending to take it into stable kernels as well?
Thanks,
Ilya
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