> On Jul 6, 2022, at 12:18 AM, NeilBrown <neilb@xxxxxxx> wrote:
>
> When locking a file to access ACLs and xattrs etc, use explicit locking
> with inode_lock() instead of fh_lock(). This means that the calls to
> fh_fill_pre/post_attr() are also explicit which improves readability and
> allows us to place them only where they are needed. Only the xattr
> calls need pre/post information.
>
> When locking a file we don't need I_MUTEX_PARENT as the file is not a
> parent of anything, so we can use inode_lock() directly rather than the
> inode_lock_nested() call that fh_lock() uses.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/nfsd/nfs2acl.c | 6 +++---
> fs/nfsd/nfs3acl.c | 4 ++--
> fs/nfsd/nfs4acl.c | 7 +++----
> fs/nfsd/nfs4state.c | 8 ++++----
> fs/nfsd/vfs.c | 25 ++++++++++++-------------
> 5 files changed, 24 insertions(+), 26 deletions(-)
>
> diff --git a/fs/nfsd/nfs2acl.c b/fs/nfsd/nfs2acl.c
> index b5760801d377..9edd3c1a30fb 100644
> --- a/fs/nfsd/nfs2acl.c
> +++ b/fs/nfsd/nfs2acl.c
> @@ -111,7 +111,7 @@ static __be32 nfsacld_proc_setacl(struct svc_rqst *rqstp)
> if (error)
> goto out_errno;
>
> - fh_lock(fh);
> + inode_lock(inode);
>
> error = set_posix_acl(&init_user_ns, inode, ACL_TYPE_ACCESS,
> argp->acl_access);
> @@ -122,7 +122,7 @@ static __be32 nfsacld_proc_setacl(struct svc_rqst *rqstp)
> if (error)
> goto out_drop_lock;
>
> - fh_unlock(fh);
> + inode_unlock(inode);
>
> fh_drop_write(fh);
>
> @@ -136,7 +136,7 @@ static __be32 nfsacld_proc_setacl(struct svc_rqst *rqstp)
> return rpc_success;
>
> out_drop_lock:
> - fh_unlock(fh);
> + inode_unlock(inode);
> fh_drop_write(fh);
> out_errno:
> resp->status = nfserrno(error);
> diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c
> index 35b2ebda14da..9446c6743664 100644
> --- a/fs/nfsd/nfs3acl.c
> +++ b/fs/nfsd/nfs3acl.c
> @@ -101,7 +101,7 @@ static __be32 nfsd3_proc_setacl(struct svc_rqst *rqstp)
> if (error)
> goto out_errno;
>
> - fh_lock(fh);
> + inode_lock(inode);
>
> error = set_posix_acl(&init_user_ns, inode, ACL_TYPE_ACCESS,
> argp->acl_access);
> @@ -111,7 +111,7 @@ static __be32 nfsd3_proc_setacl(struct svc_rqst *rqstp)
> argp->acl_default);
>
> out_drop_lock:
> - fh_unlock(fh);
> + inode_unlock(inode);
> fh_drop_write(fh);
> out_errno:
> resp->status = nfserrno(error);
> diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
> index 5c9b7e01e8ca..a33cacf62ea0 100644
> --- a/fs/nfsd/nfs4acl.c
> +++ b/fs/nfsd/nfs4acl.c
> @@ -781,19 +781,18 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
> if (host_error < 0)
> goto out_nfserr;
>
> - fh_lock(fhp);
> + inode_lock(inode);
>
> host_error = set_posix_acl(&init_user_ns, inode, ACL_TYPE_ACCESS, pacl);
> if (host_error < 0)
> goto out_drop_lock;
>
> - if (S_ISDIR(inode->i_mode)) {
> + if (S_ISDIR(inode->i_mode))
> host_error = set_posix_acl(&init_user_ns, inode,
> ACL_TYPE_DEFAULT, dpacl);
> - }
>
> out_drop_lock:
> - fh_unlock(fhp);
> + inode_unlock(inode);
>
> posix_acl_release(pacl);
> posix_acl_release(dpacl);
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 9d1a3e131c49..307317ba9aff 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -7322,21 +7322,21 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> static __be32 nfsd_test_lock(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file_lock *lock)
> {
> struct nfsd_file *nf;
> + struct inode *inode = fhp->fh_dentry->d_inode;
I don't think this is correct.
nfsd_file_acquire() calls fh_verify(), which can updated fhp->fh_dentry.
Anyway, is it guaranteed that fh_dentry is not NULL here?
It would be more defensive to set @inode /after/ the call to
nfsd_file_acquire().
> __be32 err;
>
> err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
> if (err)
> return err;
> - fh_lock(fhp); /* to block new leases till after test_lock: */
> - err = nfserrno(nfsd_open_break_lease(fhp->fh_dentry->d_inode,
> - NFSD_MAY_READ));
> + inode_lock(inode); /* to block new leases till after test_lock: */
> + err = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
> if (err)
> goto out;
> lock->fl_file = nf->nf_file;
> err = nfserrno(vfs_test_lock(nf->nf_file, lock));
> lock->fl_file = NULL;
> out:
> - fh_unlock(fhp);
> + inode_unlock(inode);
> nfsd_file_put(nf);
> return err;
> }
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 2ca748aa83bb..2526615285ca 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -444,7 +444,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
> return err;
> }
>
> - fh_lock(fhp);
> + inode_lock(inode);
> if (size_change) {
> /*
> * RFC5661, Section 18.30.4:
> @@ -480,7 +480,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
> host_err = notify_change(&init_user_ns, dentry, iap, NULL);
>
> out_unlock:
> - fh_unlock(fhp);
> + inode_unlock(inode);
> if (size_change)
> put_write_access(inode);
> out:
> @@ -2196,12 +2196,8 @@ nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
> }
>
> /*
> - * Removexattr and setxattr need to call fh_lock to both lock the inode
> - * and set the change attribute. Since the top-level vfs_removexattr
> - * and vfs_setxattr calls already do their own inode_lock calls, call
> - * the _locked variant. Pass in a NULL pointer for delegated_inode,
> - * and let the client deal with NFS4ERR_DELAY (same as with e.g.
> - * setattr and remove).
> + * Pass in a NULL pointer for delegated_inode, and let the client deal
> + * with NFS4ERR_DELAY (same as with e.g. setattr and remove).
> */
> __be32
> nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
> @@ -2217,12 +2213,14 @@ nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
> if (ret)
> return nfserrno(ret);
>
> - fh_lock(fhp);
> + inode_lock(fhp->fh_dentry->d_inode);
> + fh_fill_pre_attrs(fhp);
>
> ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry,
> name, NULL);
>
> - fh_unlock(fhp);
> + fh_fill_post_attrs(fhp);
> + inode_unlock(fhp->fh_dentry->d_inode);
> fh_drop_write(fhp);
>
> return nfsd_xattr_errno(ret);
> @@ -2242,12 +2240,13 @@ nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
> ret = fh_want_write(fhp);
> if (ret)
> return nfserrno(ret);
> - fh_lock(fhp);
> + inode_lock(fhp->fh_dentry->d_inode);
> + fh_fill_pre_attrs(fhp);
>
> ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf,
> len, flags, NULL);
> -
> - fh_unlock(fhp);
> + fh_fill_post_attrs(fhp);
> + inode_unlock(fhp->fh_dentry->d_inode);
> fh_drop_write(fhp);
>
> return nfsd_xattr_errno(ret);
>
>
--
Chuck Lever
