[PATCH v6 06/15] ext2, dax: introduce ext2_dax_aops

Dan Williams
2018-03-15T16:01:05Z

In preparation for the dax implementation to start associating dax pages
to inodes via page->mapping, we need to provide a 'struct
address_space_operations' instance for dax. Otherwise, direct-I/O
triggers incorrect page cache assumptions and warnings.

Cc: Jan Kara <jack@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
fs/ext2/ext2.h | 1 +
fs/ext2/inode.c | 43 +++++++++++++++++++++++++++----------------
fs/ext2/namei.c | 18 ++----------------
3 files changed, 30 insertions(+), 32 deletions(-)

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 032295e1d386..cc40802ddfa8 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -814,6 +814,7 @@ extern const struct inode_operations ext2_file_inode_operations;
extern const struct file_operations ext2_file_operations;

/* inode.c */
+extern void ext2_set_file_ops(struct inode *inode);
extern const struct address_space_operations ext2_aops;
extern const struct address_space_operations ext2_nobh_aops;
extern const struct iomap_ops ext2_iomap_ops;
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 9b2ac55ac34f..9590712f2f88 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -952,17 +952,16 @@ ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
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);
}

+static int
+ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+ return dax_writeback_mapping_range(mapping,
+ mapping->host->i_sb->s_bdev, wbc);
+}
+
const struct address_space_operations ext2_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
@@ -990,6 +989,13 @@ const struct address_space_operations ext2_nobh_aops = {
.error_remove_page = generic_error_remove_page,
};

+const struct address_space_operations ext2_dax_aops = {
+ .direct_IO = ext2_direct_IO,
+ .writepages = ext2_dax_writepages,
+ .set_page_dirty = noop_set_page_dirty,
+ .invalidatepage = noop_invalidatepage,
+};
+
/*
* Probably it should be a library function... search for first non-zero word
* or memcmp with zero_page, whatever is better for particular architecture.
@@ -1388,6 +1394,18 @@ void ext2_set_inode_flags(struct inode *inode)
inode->i_flags |= S_DAX;
}

+void ext2_set_file_ops(struct inode *inode)
+{
+ inode->i_op = &ext2_file_inode_operations;
+ inode->i_fop = &ext2_file_operations;
+ if (IS_DAX(inode))
+ inode->i_mapping->a_ops = &ext2_dax_aops;
+ else if (test_opt(inode->i_sb, NOBH))
+ inode->i_mapping->a_ops = &ext2_nobh_aops;
+ else
+ inode->i_mapping->a_ops = &ext2_aops;
+}
+
struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
{
struct ext2_inode_info *ei;
@@ -1480,14 +1498,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
ei->i_data[n] = raw_inode->i_block[n];

if (S_ISREG(inode->i_mode)) {
- inode->i_op = &ext2_file_inode_operations;
- if (test_opt(inode->i_sb, NOBH)) {
- inode->i_mapping->a_ops = &ext2_nobh_aops;
- inode->i_fop = &ext2_file_operations;
- } else {
- inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_file_operations;
- }
+ ext2_set_file_ops(inode);
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index e078075dc66f..55f7caadb093 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -107,14 +107,7 @@ static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode
if (IS_ERR(inode))
return PTR_ERR(inode);

- inode->i_op = &ext2_file_inode_operations;
- if (test_opt(inode->i_sb, NOBH)) {
- inode->i_mapping->a_ops = &ext2_nobh_aops;
- inode->i_fop = &ext2_file_operations;
- } else {
- inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_file_operations;
- }
+ ext2_set_file_ops(inode);
mark_inode_dirty(inode);
return ext2_add_nondir(dentry, inode);
}
@@ -125,14 +118,7 @@ static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
if (IS_ERR(inode))
return PTR_ERR(inode);

- inode->i_op = &ext2_file_inode_operations;
- if (test_opt(inode->i_sb, NOBH)) {
- inode->i_mapping->a_ops = &ext2_nobh_aops;
- inode->i_fop = &ext2_file_operations;
- } else {
- inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_file_operations;
- }
+ ext2_set_file_ops(inode);
mark_inode_dirty(inode);
d_tmpfile(dentry, inode);
unlock_new_inode(inode);