[PATCH v1 03/17] fuse: prepare for readdir passthrough on directories

[Joanne Koong <joannelkoong@gmail.com>]

From: Amir Goldstein <amir73il@gmail.com>

In preparation for readdir passthrough, allow the inode iomode state
to be applicable to directory inodes and prepare the helper
fuse_sync_release() for directories.

Directory inodes will support cached mode, "direct" uncached readdir
mode and readdir passthrough mode, but will not need to wait for
parallel dio like regular files.

Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/fuse/cuse.c   |  2 +-
 fs/fuse/dir.c    |  4 ++--
 fs/fuse/file.c   | 11 ++++++-----
 fs/fuse/fuse_i.h | 12 ++++++------
 fs/fuse/inode.c  |  2 +-
 fs/fuse/iomode.c | 31 ++++++++++++++++++-------------
 6 files changed, 34 insertions(+), 28 deletions(-)

diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index dfcb98a654d8..e168740351a0 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -147,7 +147,7 @@ static int cuse_release(struct inode *inode, struct file *file)
 	struct fuse_file *ff = file->private_data;
 	struct fuse_mount *fm = ff->fm;
 
-	fuse_sync_release(NULL, ff, file->f_flags);
+	fuse_sync_release(NULL, ff, file->f_flags, false);
 	fuse_conn_put(fm->fc);
 
 	return 0;
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index b658b6baf72f..015f0c103d06 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -893,7 +893,7 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir,
 			  &outentry.attr, ATTR_TIMEOUT(&outentry), 0, 0);
 	if (!inode) {
 		flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
-		fuse_sync_release(NULL, ff, flags);
+		fuse_sync_release(NULL, ff, flags, false);
 		fuse_queue_forget(fm->fc, forget, outentry.nodeid, 1);
 		err = -ENOMEM;
 		goto out_err;
@@ -910,7 +910,7 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir,
 	}
 	if (err) {
 		fi = get_fuse_inode(inode);
-		fuse_sync_release(fi, ff, flags);
+		fuse_sync_release(fi, ff, flags, false);
 	} else {
 		if (fm->fc->atomic_o_trunc && trunc)
 			truncate_pagecache(inode, 0);
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f239c8a888cb..3da4ce73e11b 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -285,7 +285,7 @@ static int fuse_open(struct inode *inode, struct file *file)
 		ff = file->private_data;
 		err = fuse_finish_open(inode, file);
 		if (err)
-			fuse_sync_release(fi, ff, file->f_flags);
+			fuse_sync_release(fi, ff, file->f_flags, false);
 		else if (is_truncate)
 			fuse_truncate_update_attr(inode, file);
 	}
@@ -408,10 +408,12 @@ static int fuse_release(struct inode *inode, struct file *file)
 }
 
 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
-		       unsigned int flags)
+		       unsigned int flags, bool isdir)
 {
+	int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
+
 	WARN_ON(refcount_read(&ff->count) > 1);
-	fuse_prepare_release(fi, ff, flags, FUSE_RELEASE, true);
+	fuse_prepare_release(fi, ff, flags, opcode, true);
 	fuse_file_put(ff, true);
 }
 EXPORT_SYMBOL_GPL(fuse_sync_release);
@@ -1456,13 +1458,12 @@ static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
 static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
-	struct fuse_inode *fi = get_fuse_inode(inode);
 
 	if (exclusive) {
 		inode_unlock(inode);
 	} else {
 		/* Allow opens in caching mode after last parallel dio end */
-		fuse_inode_uncached_io_end(fi);
+		fuse_inode_uncached_io_end(inode);
 		inode_unlock_shared(inode);
 	}
 }
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index eb974739dd5e..1c4646ad7c25 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -161,9 +161,6 @@ struct fuse_inode {
 			 * (FUSE_NOWRITE) means more writes are blocked */
 			int writectr;
 
-			/** Number of files/maps using page cache */
-			int iocachectr;
-
 			/* Waitq for writepage completion */
 			wait_queue_head_t page_waitq;
 
@@ -206,6 +203,9 @@ struct fuse_inode {
 	/** Lock to protect write related fields */
 	spinlock_t lock;
 
+	/** Number of files/maps using page cache (negative for passthrough) */
+	int iocachectr;
+
 #ifdef CONFIG_FUSE_DAX
 	/*
 	 * Dax specific inode data
@@ -238,7 +238,7 @@ enum {
 	FUSE_I_BAD,
 	/* Has btime */
 	FUSE_I_BTIME,
-	/* Wants or already has page cache IO */
+	/* Regular file wants or already has page cache IO */
 	FUSE_I_CACHE_IO_MODE,
 	/*
 	 * Client has exclusive access to the inode, either because fs is local
@@ -1192,7 +1192,7 @@ void fuse_file_free(struct fuse_file *ff);
 int fuse_finish_open(struct inode *inode, struct file *file);
 
 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
-		       unsigned int flags);
+		       unsigned int flags, bool isdir);
 
 /**
  * Send RELEASE or RELEASEDIR request
@@ -1542,7 +1542,7 @@ int fuse_fileattr_set(struct mnt_idmap *idmap,
 /* iomode.c */
 int fuse_file_cached_io_open(struct inode *inode, struct fuse_file *ff);
 int fuse_inode_uncached_io_start(struct inode *inode, struct fuse_backing *fb);
-void fuse_inode_uncached_io_end(struct fuse_inode *fi);
+void fuse_inode_uncached_io_end(struct inode *inode);
 
 int fuse_file_io_open(struct file *file, struct inode *inode);
 void fuse_file_io_release(struct fuse_file *ff, struct inode *inode);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 014b9af42909..bdc135f9fe3e 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -192,10 +192,10 @@ static void fuse_evict_inode(struct inode *inode)
 			atomic64_inc(&fc->evict_ctr);
 	}
 	if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
-		WARN_ON(fi->iocachectr != 0);
 		WARN_ON(!list_empty(&fi->write_files));
 		WARN_ON(!list_empty(&fi->queued_writes));
 	}
+	WARN_ON(fi->iocachectr != 0);
 }
 
 static int fuse_reconfigure(struct fs_context *fsc)
diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c
index 6815b4506007..2360b32793c2 100644
--- a/fs/fuse/iomode.c
+++ b/fs/fuse/iomode.c
@@ -15,9 +15,12 @@
 /*
  * Return true if need to wait for new opens in caching mode.
  */
-static inline bool fuse_is_io_cache_wait(struct fuse_inode *fi)
+static inline bool fuse_is_io_cache_wait(struct inode *inode)
 {
-	return READ_ONCE(fi->iocachectr) < 0 && !fuse_inode_backing(fi);
+	struct fuse_inode *fi = get_fuse_inode(inode);
+
+	return S_ISREG(inode->i_mode) &&
+		READ_ONCE(fi->iocachectr) < 0 && !fuse_inode_backing(fi);
 }
 
 /*
@@ -40,10 +43,10 @@ int fuse_file_cached_io_open(struct inode *inode, struct fuse_file *ff)
 	 * Setting the bit advises new direct-io writes to use an exclusive
 	 * lock - without it the wait below might be forever.
 	 */
-	while (fuse_is_io_cache_wait(fi)) {
+	while (fuse_is_io_cache_wait(inode)) {
 		set_bit(FUSE_I_CACHE_IO_MODE, &fi->state);
 		spin_unlock(&fi->lock);
-		wait_event(fi->direct_io_waitq, !fuse_is_io_cache_wait(fi));
+		wait_event(fi->direct_io_waitq, !fuse_is_io_cache_wait(inode));
 		spin_lock(&fi->lock);
 	}
 
@@ -69,8 +72,10 @@ int fuse_file_cached_io_open(struct inode *inode, struct fuse_file *ff)
 }
 
 static void fuse_file_cached_io_release(struct fuse_file *ff,
-					struct fuse_inode *fi)
+					struct inode *inode)
 {
+	struct fuse_inode *fi = get_fuse_inode(inode);
+
 	spin_lock(&fi->lock);
 	WARN_ON(fi->iocachectr <= 0);
 	WARN_ON(ff->iomode != IOM_CACHED);
@@ -141,15 +146,17 @@ static int fuse_file_uncached_io_open(struct inode *inode,
 	return 0;
 }
 
-void fuse_inode_uncached_io_end(struct fuse_inode *fi)
+void fuse_inode_uncached_io_end(struct inode *inode)
 {
+	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_backing *oldfb = NULL;
 
 	spin_lock(&fi->lock);
 	WARN_ON(fi->iocachectr >= 0);
 	fi->iocachectr++;
 	if (!fi->iocachectr) {
-		wake_up(&fi->direct_io_waitq);
+		if (S_ISREG(inode->i_mode))
+			wake_up(&fi->direct_io_waitq);
 		oldfb = fuse_inode_backing_set(fi, NULL);
 	}
 	spin_unlock(&fi->lock);
@@ -159,11 +166,11 @@ void fuse_inode_uncached_io_end(struct fuse_inode *fi)
 
 /* Drop uncached_io reference from passthrough open */
 static void fuse_file_uncached_io_release(struct fuse_file *ff,
-					  struct fuse_inode *fi)
+					  struct inode *inode)
 {
 	WARN_ON(ff->iomode != IOM_UNCACHED);
 	ff->iomode = IOM_NONE;
-	fuse_inode_uncached_io_end(fi);
+	fuse_inode_uncached_io_end(inode);
 }
 
 /*
@@ -267,8 +274,6 @@ int fuse_file_io_open(struct file *file, struct inode *inode)
 /* No more pending io and no new io possible to inode via open/mmapped file */
 void fuse_file_io_release(struct fuse_file *ff, struct inode *inode)
 {
-	struct fuse_inode *fi = get_fuse_inode(inode);
-
 	/*
 	 * Last passthrough file close allows caching inode io mode.
 	 * Last caching file close exits caching inode io mode.
@@ -278,10 +283,10 @@ void fuse_file_io_release(struct fuse_file *ff, struct inode *inode)
 		/* Nothing to do */
 		break;
 	case IOM_UNCACHED:
-		fuse_file_uncached_io_release(ff, fi);
+		fuse_file_uncached_io_release(ff, inode);
 		break;
 	case IOM_CACHED:
-		fuse_file_cached_io_release(ff, fi);
+		fuse_file_cached_io_release(ff, inode);
 		break;
 	}
 }
-- 
2.52.0