155 lines
5.1 KiB
Diff
155 lines
5.1 KiB
Diff
From 3b7df566d21ac5302a371ca594ce659071abcbeb Mon Sep 17 00:00:00 2001
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Message-Id: <3b7df566d21ac5302a371ca594ce659071abcbeb.1601675152.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 15 Sep 2016 10:51:27 +0200
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Subject: [PATCH 128/333] fs/nfs: turn rmdir_sem into a semaphore
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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The RW semaphore had a reader side which used the _non_owner version
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because it most likely took the reader lock in one thread and released it
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in another which would cause lockdep to complain if the "regular"
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version was used.
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On -RT we need the owner because the rw lock is turned into a rtmutex.
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The semaphores on the hand are "plain simple" and should work as
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expected. We can't have multiple readers but on -RT we don't allow
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multiple readers anyway so that is not a loss.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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fs/nfs/dir.c | 8 ++++++++
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fs/nfs/inode.c | 4 ++++
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fs/nfs/unlink.c | 31 +++++++++++++++++++++++++++----
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include/linux/nfs_fs.h | 4 ++++
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4 files changed, 43 insertions(+), 4 deletions(-)
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diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
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index 4ae726e70d87..c60b20884c45 100644
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--- a/fs/nfs/dir.c
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+++ b/fs/nfs/dir.c
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@@ -1836,7 +1836,11 @@ int nfs_rmdir(struct inode *dir, struct dentry *dentry)
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trace_nfs_rmdir_enter(dir, dentry);
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if (d_really_is_positive(dentry)) {
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+ down(&NFS_I(d_inode(dentry))->rmdir_sem);
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+#else
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down_write(&NFS_I(d_inode(dentry))->rmdir_sem);
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+#endif
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error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
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/* Ensure the VFS deletes this inode */
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switch (error) {
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@@ -1846,7 +1850,11 @@ int nfs_rmdir(struct inode *dir, struct dentry *dentry)
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case -ENOENT:
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nfs_dentry_handle_enoent(dentry);
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}
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+ up(&NFS_I(d_inode(dentry))->rmdir_sem);
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+#else
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up_write(&NFS_I(d_inode(dentry))->rmdir_sem);
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+#endif
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} else
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error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
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trace_nfs_rmdir_exit(dir, dentry, error);
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diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
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index e4cd3a2fe698..6f22c8d65760 100644
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--- a/fs/nfs/inode.c
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+++ b/fs/nfs/inode.c
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@@ -2104,7 +2104,11 @@ static void init_once(void *foo)
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atomic_long_set(&nfsi->nrequests, 0);
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atomic_long_set(&nfsi->commit_info.ncommit, 0);
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atomic_set(&nfsi->commit_info.rpcs_out, 0);
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+ sema_init(&nfsi->rmdir_sem, 1);
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+#else
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init_rwsem(&nfsi->rmdir_sem);
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+#endif
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mutex_init(&nfsi->commit_mutex);
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nfs4_init_once(nfsi);
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}
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diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
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index fd61bf0fce63..ce9100b5604d 100644
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--- a/fs/nfs/unlink.c
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+++ b/fs/nfs/unlink.c
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@@ -52,6 +52,29 @@ static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
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rpc_restart_call_prepare(task);
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}
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+static void nfs_down_anon(struct semaphore *sema)
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+{
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+ down(sema);
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+}
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+
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+static void nfs_up_anon(struct semaphore *sema)
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+{
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+ up(sema);
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+}
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+
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+#else
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+static void nfs_down_anon(struct rw_semaphore *rwsem)
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+{
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+ down_read_non_owner(rwsem);
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+}
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+
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+static void nfs_up_anon(struct rw_semaphore *rwsem)
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+{
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+ up_read_non_owner(rwsem);
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+}
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+#endif
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+
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/**
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* nfs_async_unlink_release - Release the sillydelete data.
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* @task: rpc_task of the sillydelete
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@@ -65,7 +88,7 @@ static void nfs_async_unlink_release(void *calldata)
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struct dentry *dentry = data->dentry;
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struct super_block *sb = dentry->d_sb;
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- up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
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+ nfs_up_anon(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
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d_lookup_done(dentry);
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nfs_free_unlinkdata(data);
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dput(dentry);
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@@ -118,10 +141,10 @@ static int nfs_call_unlink(struct dentry *dentry, struct inode *inode, struct nf
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struct inode *dir = d_inode(dentry->d_parent);
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struct dentry *alias;
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- down_read_non_owner(&NFS_I(dir)->rmdir_sem);
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+ nfs_down_anon(&NFS_I(dir)->rmdir_sem);
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alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
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if (IS_ERR(alias)) {
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- up_read_non_owner(&NFS_I(dir)->rmdir_sem);
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+ nfs_up_anon(&NFS_I(dir)->rmdir_sem);
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return 0;
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}
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if (!d_in_lookup(alias)) {
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@@ -143,7 +166,7 @@ static int nfs_call_unlink(struct dentry *dentry, struct inode *inode, struct nf
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ret = 0;
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spin_unlock(&alias->d_lock);
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dput(alias);
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- up_read_non_owner(&NFS_I(dir)->rmdir_sem);
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+ nfs_up_anon(&NFS_I(dir)->rmdir_sem);
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/*
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* If we'd displaced old cached devname, free it. At that
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* point dentry is definitely not a root, so we won't need
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diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
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index a0831e9d19c9..94b6fefd90b0 100644
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--- a/include/linux/nfs_fs.h
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+++ b/include/linux/nfs_fs.h
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@@ -163,7 +163,11 @@ struct nfs_inode {
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/* Readers: in-flight sillydelete RPC calls */
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/* Writers: rmdir */
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+ struct semaphore rmdir_sem;
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+#else
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struct rw_semaphore rmdir_sem;
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+#endif
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struct mutex commit_mutex;
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#if IS_ENABLED(CONFIG_NFS_V4)
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--
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2.17.1
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