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    SubjectRe: [PATCH 11/12] nfsd: use (un)lock_inode instead of fh_(un)lock
    Date


    > On Jun 13, 2022, at 7:18 PM, NeilBrown <neilb@suse.de> wrote:
    >
    > Except for the xattr changes, these callers don't need to save pre/post
    > attrs, so use a simple lock/unlock.
    >
    > For the xattr changes, make the saving of pre/post explicit rather than
    > requiring a comment.
    >
    > Also many fh_unlock() are not needed.

    This patch does three different (though related) things. I prefer to
    instead see three patches:

    - One that changes the xattr code, as described
    - One that cleans up unneeded fh_unlock calls, with an explanation of
    why that is safe to do
    - One that replaces fh_lock() with inode_lock (or inode_lock_nested,
    see below).


    > Signed-off-by: NeilBrown <neilb@suse.de>
    > ---
    > fs/nfsd/nfs2acl.c | 6 +++---
    > fs/nfsd/nfs3acl.c | 4 ++--
    > fs/nfsd/nfs3proc.c | 4 ----
    > fs/nfsd/nfs4acl.c | 7 +++----
    > fs/nfsd/nfs4proc.c | 2 --
    > fs/nfsd/nfs4state.c | 8 ++++----
    > fs/nfsd/nfsfh.c | 1 -
    > fs/nfsd/nfsfh.h | 8 --------
    > fs/nfsd/vfs.c | 26 ++++++++++++--------------
    > 9 files changed, 24 insertions(+), 42 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);

    fh_lock() uses inode_lock_nested(). If the above hunk is the
    correct substitution, the patch description should explain why
    that is correct. Otherwise, shall we use inode_lock_nested()
    here too?

    Likewise throughout.


    > 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/nfs3proc.c b/fs/nfsd/nfs3proc.c
    > index d85b110d58dd..7bb07c7e6ee8 100644
    > --- a/fs/nfsd/nfs3proc.c
    > +++ b/fs/nfsd/nfs3proc.c
    > @@ -374,7 +374,6 @@ nfsd3_proc_mkdir(struct svc_rqst *rqstp)
    > fh_init(&resp->fh, NFS3_FHSIZE);
    > resp->status = nfsd_create(rqstp, &resp->dirfh, argp->name, argp->len,
    > &argp->attrs, S_IFDIR, 0, &resp->fh);
    > - fh_unlock(&resp->dirfh);
    > return rpc_success;
    > }
    >
    > @@ -449,7 +448,6 @@ nfsd3_proc_mknod(struct svc_rqst *rqstp)
    > type = nfs3_ftypes[argp->ftype];
    > resp->status = nfsd_create(rqstp, &resp->dirfh, argp->name, argp->len,
    > &argp->attrs, type, rdev, &resp->fh);
    > - fh_unlock(&resp->dirfh);
    > out:
    > return rpc_success;
    > }
    > @@ -472,7 +470,6 @@ nfsd3_proc_remove(struct svc_rqst *rqstp)
    > fh_copy(&resp->fh, &argp->fh);
    > resp->status = nfsd_unlink(rqstp, &resp->fh, -S_IFDIR,
    > argp->name, argp->len);
    > - fh_unlock(&resp->fh);
    > return rpc_success;
    > }
    >
    > @@ -493,7 +490,6 @@ nfsd3_proc_rmdir(struct svc_rqst *rqstp)
    > fh_copy(&resp->fh, &argp->fh);
    > resp->status = nfsd_unlink(rqstp, &resp->fh, S_IFDIR,
    > argp->name, argp->len);
    > - fh_unlock(&resp->fh);
    > return rpc_success;
    > }
    >
    > diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
    > index eaa3a0cf38f1..7bcc6dc0f762 100644
    > --- a/fs/nfsd/nfs4acl.c
    > +++ b/fs/nfsd/nfs4acl.c
    > @@ -779,19 +779,18 @@ 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/nfs4proc.c b/fs/nfsd/nfs4proc.c
    > index 79434e29b63f..d6defaf5a77a 100644
    > --- a/fs/nfsd/nfs4proc.c
    > +++ b/fs/nfsd/nfs4proc.c
    > @@ -860,7 +860,6 @@ nfsd4_create(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
    > do_set_nfs4_acl(rqstp, &resfh, create->cr_acl,
    > create->cr_bmval);
    >
    > - fh_unlock(&cstate->current_fh);
    > set_change_info(&create->cr_cinfo, &cstate->current_fh);
    > fh_dup2(&cstate->current_fh, &resfh);
    > out:
    > @@ -1040,7 +1039,6 @@ nfsd4_remove(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
    > status = nfsd_unlink(rqstp, &cstate->current_fh, 0,
    > remove->rm_name, remove->rm_namelen);
    > if (!status) {
    > - fh_unlock(&cstate->current_fh);
    > set_change_info(&remove->rm_cinfo, &cstate->current_fh);
    > }
    > return status;
    > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
    > index 9409a0dc1b76..cb664c61b546 100644
    > --- a/fs/nfsd/nfs4state.c
    > +++ b/fs/nfsd/nfs4state.c
    > @@ -7321,21 +7321,21 @@ 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;
    > __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/nfsfh.c b/fs/nfsd/nfsfh.c
    > index a50db688c60d..ae270e4f921f 100644
    > --- a/fs/nfsd/nfsfh.c
    > +++ b/fs/nfsd/nfsfh.c
    > @@ -685,7 +685,6 @@ fh_put(struct svc_fh *fhp)
    > struct dentry * dentry = fhp->fh_dentry;
    > struct svc_export * exp = fhp->fh_export;
    > if (dentry) {
    > - fh_unlock(fhp);
    > fhp->fh_dentry = NULL;
    > dput(dentry);
    > fh_clear_pre_post_attrs(fhp);
    > diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
    > index ecc57fd3fd67..c5061cdb1016 100644
    > --- a/fs/nfsd/nfsfh.h
    > +++ b/fs/nfsd/nfsfh.h
    > @@ -323,14 +323,6 @@ static inline u64 nfsd4_change_attribute(struct kstat *stat,
    > extern void fh_fill_pre_attrs(struct svc_fh *fhp, bool atomic);
    > extern void fh_fill_post_attrs(struct svc_fh *fhp);
    >
    > -
    > -/*
    > - * Lock a file handle/inode
    > - * NOTE: both fh_lock and fh_unlock are done "by hand" in
    > - * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
    > - * so, any changes here should be reflected there.
    > - */
    > -
    > static inline void
    > fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
    > {
    > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
    > index 4c2e431100ba..f2f4868618bb 100644
    > --- a/fs/nfsd/vfs.c
    > +++ b/fs/nfsd/vfs.c
    > @@ -253,7 +253,6 @@ nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
    > * returned. Otherwise the covered directory is returned.
    > * NOTE: this mountpoint crossing is not supported properly by all
    > * clients and is explicitly disallowed for NFSv3
    > - * NeilBrown <neilb@cse.unsw.edu.au>
    > */
    > __be32
    > nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
    > @@ -434,7 +433,7 @@ 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:
    > @@ -470,7 +469,7 @@ 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:
    > @@ -2123,12 +2122,8 @@ 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)
    > @@ -2144,12 +2139,14 @@ 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, true);
    >
    > 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);
    > @@ -2169,12 +2166,13 @@ 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, true);
    >
    > 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



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