dax: move writeback calls into the filesystems

Previously calls to dax_writeback_mapping_range() for all DAX filesystems
(ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range().

dax_writeback_mapping_range() needs a struct block_device, and it used
to get that from inode->i_sb->s_bdev.  This is correct for normal inodes
mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
block devices and for XFS real-time files.

Instead, call dax_writeback_mapping_range() directly from the filesystem
->writepages function so that it can supply us with a valid block
device.  This also fixes DAX code to properly flush caches in response
to sync(2).

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ross Zwisler 2016-02-26 15:19:55 -08:00 committed by Linus Torvalds
parent 20a90f5899
commit 7f6d5b529b
7 changed files with 43 additions and 16 deletions

View File

@ -1697,13 +1697,24 @@ static int blkdev_releasepage(struct page *page, gfp_t wait)
return try_to_free_buffers(page);
}
static int blkdev_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
if (dax_mapping(mapping)) {
struct block_device *bdev = I_BDEV(mapping->host);
return dax_writeback_mapping_range(mapping, bdev, wbc);
}
return generic_writepages(mapping, wbc);
}
static const struct address_space_operations def_blk_aops = {
.readpage = blkdev_readpage,
.readpages = blkdev_readpages,
.writepage = blkdev_writepage,
.write_begin = blkdev_write_begin,
.write_end = blkdev_write_end,
.writepages = generic_writepages,
.writepages = blkdev_writepages,
.releasepage = blkdev_releasepage,
.direct_IO = blkdev_direct_IO,
.is_dirty_writeback = buffer_check_dirty_writeback,

View File

@ -484,11 +484,10 @@ static int dax_writeback_one(struct block_device *bdev,
* end]. This is required by data integrity operations to ensure file data is
* on persistent storage prior to completion of the operation.
*/
int dax_writeback_mapping_range(struct address_space *mapping, loff_t start,
loff_t end)
int dax_writeback_mapping_range(struct address_space *mapping,
struct block_device *bdev, struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
struct block_device *bdev = inode->i_sb->s_bdev;
pgoff_t start_index, end_index, pmd_index;
pgoff_t indices[PAGEVEC_SIZE];
struct pagevec pvec;
@ -499,8 +498,11 @@ int dax_writeback_mapping_range(struct address_space *mapping, loff_t start,
if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
return -EIO;
start_index = start >> PAGE_CACHE_SHIFT;
end_index = end >> PAGE_CACHE_SHIFT;
if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL)
return 0;
start_index = wbc->range_start >> PAGE_CACHE_SHIFT;
end_index = wbc->range_end >> PAGE_CACHE_SHIFT;
pmd_index = DAX_PMD_INDEX(start_index);
rcu_read_lock();

View File

@ -876,6 +876,14 @@ ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
static int
ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
#ifdef CONFIG_FS_DAX
if (dax_mapping(mapping)) {
return dax_writeback_mapping_range(mapping,
mapping->host->i_sb->s_bdev,
wbc);
}
#endif
return mpage_writepages(mapping, wbc, ext2_get_block);
}

View File

@ -2478,6 +2478,10 @@ static int ext4_writepages(struct address_space *mapping,
trace_ext4_writepages(inode, wbc);
if (dax_mapping(mapping))
return dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev,
wbc);
/*
* No pages to write? This is mainly a kludge to avoid starting
* a transaction for special inodes like journal inode on last iput()

View File

@ -1208,6 +1208,10 @@ xfs_vm_writepages(
struct writeback_control *wbc)
{
xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
if (dax_mapping(mapping))
return dax_writeback_mapping_range(mapping,
xfs_find_bdev_for_inode(mapping->host), wbc);
return generic_writepages(mapping, wbc);
}

View File

@ -52,6 +52,8 @@ static inline bool dax_mapping(struct address_space *mapping)
{
return mapping->host && IS_DAX(mapping->host);
}
int dax_writeback_mapping_range(struct address_space *mapping, loff_t start,
loff_t end);
struct writeback_control;
int dax_writeback_mapping_range(struct address_space *mapping,
struct block_device *bdev, struct writeback_control *wbc);
#endif

View File

@ -446,7 +446,8 @@ int filemap_write_and_wait(struct address_space *mapping)
{
int err = 0;
if (mapping->nrpages) {
if ((!dax_mapping(mapping) && mapping->nrpages) ||
(dax_mapping(mapping) && mapping->nrexceptional)) {
err = filemap_fdatawrite(mapping);
/*
* Even if the above returned error, the pages may be
@ -482,13 +483,8 @@ int filemap_write_and_wait_range(struct address_space *mapping,
{
int err = 0;
if (dax_mapping(mapping) && mapping->nrexceptional) {
err = dax_writeback_mapping_range(mapping, lstart, lend);
if (err)
return err;
}
if (mapping->nrpages) {
if ((!dax_mapping(mapping) && mapping->nrpages) ||
(dax_mapping(mapping) && mapping->nrexceptional)) {
err = __filemap_fdatawrite_range(mapping, lstart, lend,
WB_SYNC_ALL);
/* See comment of filemap_write_and_wait() */