+ filemap-assign-current-backing_dev_info-in-generic_perform_write.patch added to mm-unstable branch

+ filemap-assign-current-backing_dev_info-in-generic_perform_write.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: filemap: assign current->backing_dev_info in generic_perform_write
has been added to the -mm mm-unstable branch.  Its filename is
     filemap-assign-current-backing_dev_info-in-generic_perform_write.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/filemap-assign-current-backing_dev_info-in-generic_perform_write.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Christoph Hellwig <hch@lst.de>
Subject: filemap: assign current->backing_dev_info in generic_perform_write
Date: Fri, 19 May 2023 11:35:11 +0200

Move the assignment to current->backing_dev_info from the callers into
generic_perform_write to reduce boiler plate code and reduce the scope to
just around the page dirtying loop.

Link: https://lkml.kernel.org/r/20230519093521.133226-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ceph/file.c |    4 ----
 fs/ext4/file.c |    3 ---
 fs/f2fs/file.c |    2 --
 fs/nfs/file.c  |    5 +----
 mm/filemap.c   |    2 ++
 5 files changed, 3 insertions(+), 13 deletions(-)

--- a/fs/ceph/file.c~filemap-assign-current-backing_dev_info-in-generic_perform_write
+++ a/fs/ceph/file.c
@@ -1791,9 +1791,6 @@ retry_snap:
 	else
 		ceph_start_io_write(inode);
 
-	/* We can write back this queue in page reclaim */
-	current->backing_dev_info = inode_to_bdi(inode);
-
 	if (iocb->ki_flags & IOCB_APPEND) {
 		err = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
 		if (err < 0)
@@ -1938,7 +1935,6 @@ out:
 		ceph_end_io_write(inode);
 out_unlocked:
 	ceph_free_cap_flush(prealloc_cf);
-	current->backing_dev_info = NULL;
 	return written ? written : err;
 }
 
--- a/fs/ext4/file.c~filemap-assign-current-backing_dev_info-in-generic_perform_write
+++ a/fs/ext4/file.c
@@ -29,7 +29,6 @@
 #include <linux/pagevec.h>
 #include <linux/uio.h>
 #include <linux/mman.h>
-#include <linux/backing-dev.h>
 #include "ext4.h"
 #include "ext4_jbd2.h"
 #include "xattr.h"
@@ -285,9 +284,7 @@ static ssize_t ext4_buffered_write_iter(
 	if (ret <= 0)
 		goto out;
 
-	current->backing_dev_info = inode_to_bdi(inode);
 	ret = generic_perform_write(iocb, from);
-	current->backing_dev_info = NULL;
 
 out:
 	inode_unlock(inode);
--- a/fs/f2fs/file.c~filemap-assign-current-backing_dev_info-in-generic_perform_write
+++ a/fs/f2fs/file.c
@@ -4517,9 +4517,7 @@ static ssize_t f2fs_buffered_write_iter(
 	if (iocb->ki_flags & IOCB_NOWAIT)
 		return -EOPNOTSUPP;
 
-	current->backing_dev_info = inode_to_bdi(inode);
 	ret = generic_perform_write(iocb, from);
-	current->backing_dev_info = NULL;
 
 	if (ret > 0) {
 		f2fs_update_iostat(F2FS_I_SB(inode), inode,
--- a/fs/nfs/file.c~filemap-assign-current-backing_dev_info-in-generic_perform_write
+++ a/fs/nfs/file.c
@@ -648,11 +648,8 @@ ssize_t nfs_file_write(struct kiocb *ioc
 	since = filemap_sample_wb_err(file->f_mapping);
 	nfs_start_io_write(inode);
 	result = generic_write_checks(iocb, from);
-	if (result > 0) {
-		current->backing_dev_info = inode_to_bdi(inode);
+	if (result > 0)
 		result = generic_perform_write(iocb, from);
-		current->backing_dev_info = NULL;
-	}
 	nfs_end_io_write(inode);
 	if (result <= 0)
 		goto out;
--- a/mm/filemap.c~filemap-assign-current-backing_dev_info-in-generic_perform_write
+++ a/mm/filemap.c
@@ -3865,6 +3865,7 @@ ssize_t generic_perform_write(struct kio
 	long status = 0;
 	ssize_t written = 0;
 
+	current->backing_dev_info = inode_to_bdi(mapping->host);
 	do {
 		struct page *page;
 		unsigned long offset;	/* Offset into pagecache page */
@@ -3929,6 +3930,7 @@ again:
 
 		balance_dirty_pages_ratelimited(mapping);
 	} while (iov_iter_count(i));
+	current->backing_dev_info = NULL;
 
 	if (!written)
 		return status;
_

Patches currently in -mm which might be from hch@lst.de are

iomap-update-ki_pos-a-little-later-in-iomap_dio_complete.patch
filemap-update-ki_pos-in-generic_perform_write.patch
filemap-assign-current-backing_dev_info-in-generic_perform_write.patch
filemap-add-a-kiocb_write_and_wait-helper.patch
filemap-add-a-kiocb_invalidate_pages-helper.patch
filemap-add-a-kiocb_invalidate_post_write-helper.patch
iomap-update-ki_pos-in-iomap_file_buffered_write.patch
iomap-assign-current-backing_dev_info-in-iomap_file_buffered_write.patch
iomap-use-kiocb_write_and_wait-and-kiocb_invalidate_pages.patch
fs-factor-out-a-direct_write_fallback-helper.patch
fuse-update-ki_pos-in-fuse_perform_write.patch
fuse-drop-redundant-arguments-to-fuse_perform_write.patch
fuse-use-direct_write_fallback.patch
squashfs-dont-include-buffer_headh.patch