[PATCH 03/13] filemap: assign current->backing_dev_info in generic_perform_write

[Christoph Hellwig <hch@lst.de>]

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 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(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index feeb9882ef635a..767f4dfe7def64 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1791,9 +1791,6 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	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 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		ceph_end_io_write(inode);
 out_unlocked:
 	ceph_free_cap_flush(prealloc_cf);
-	current->backing_dev_info = NULL;
 	return written ? written : err;
 }
 
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 50824831d31def..3cb83a3e2e4a2a 100644
--- a/fs/ext4/file.c
+++ b/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(struct kiocb *iocb,
 	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);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 9e3855e43a7a63..7134fe8bd008cb 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4517,9 +4517,7 @@ static ssize_t f2fs_buffered_write_iter(struct kiocb *iocb,
 	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,
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 3cc87ae8473356..e8bb4c48a3210a 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -648,11 +648,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 	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;
diff --git a/mm/filemap.c b/mm/filemap.c
index 4d0ec2fa1c7070..bf693ad1da1ece 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3892,6 +3892,7 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i)
 	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 */
@@ -3956,6 +3957,7 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i)
 
 		balance_dirty_pages_ratelimited(mapping);
 	} while (iov_iter_count(i));
+	current->backing_dev_info = NULL;
 
 	if (!written)
 		return status;
-- 
2.39.2