[PATCH v3 11/28] iomap: pass readpage operation to read path

Andrey Albershteyn
2023-10-06T18:54:04Z

Preparation for allowing filesystems to provide bio_set and
->submit_io() for read path. This will allow fs to do an additional
processing of ioend on ioend completion.

Make iomap_read_end_io() exportable, so, it can be called back from
filesystem callout after verification is done.

Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>
---
fs/erofs/data.c | 4 ++--
fs/gfs2/aops.c | 4 ++--
fs/iomap/buffered-io.c | 13 ++++++++++---
fs/xfs/xfs_aops.c | 4 ++--
fs/zonefs/file.c | 4 ++--
include/linux/iomap.h | 21 +++++++++++++++++++--
6 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 0c2c99c58b5e..3f5482d6cedb 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -357,12 +357,12 @@ int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
*/
static int erofs_read_folio(struct file *file, struct folio *folio)
{
- return iomap_read_folio(folio, &erofs_iomap_ops);
+ return iomap_read_folio(folio, &erofs_iomap_ops, NULL);
}

static void erofs_readahead(struct readahead_control *rac)
{
- return iomap_readahead(rac, &erofs_iomap_ops);
+ return iomap_readahead(rac, &erofs_iomap_ops, NULL);
}

static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index c26d48355cc2..9c09ff75e586 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -456,7 +456,7 @@ static int gfs2_read_folio(struct file *file, struct folio *folio)

if (!gfs2_is_jdata(ip) ||
(i_blocksize(inode) == PAGE_SIZE && !folio_buffers(folio))) {
- error = iomap_read_folio(folio, &gfs2_iomap_ops);
+ error = iomap_read_folio(folio, &gfs2_iomap_ops, NULL);
} else if (gfs2_is_stuffed(ip)) {
error = stuffed_readpage(ip, &folio->page);
folio_unlock(folio);
@@ -534,7 +534,7 @@ static void gfs2_readahead(struct readahead_control *rac)
else if (gfs2_is_jdata(ip))
mpage_readahead(rac, gfs2_block_map);
else
- iomap_readahead(rac, &gfs2_iomap_ops);
+ iomap_readahead(rac, &gfs2_iomap_ops, NULL);
}

/**
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 644479ccefbd..ca78c7f62527 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -264,7 +264,7 @@ static void iomap_finish_folio_read(struct folio *folio, size_t offset,
folio_unlock(folio);
}

-static void iomap_read_end_io(struct bio *bio)
+void iomap_read_end_io(struct bio *bio)
{
int error = blk_status_to_errno(bio->bi_status);
struct folio_iter fi;
@@ -273,12 +273,14 @@ static void iomap_read_end_io(struct bio *bio)
iomap_finish_folio_read(fi.folio, fi.offset, fi.length, error);
bio_put(bio);
}
+EXPORT_SYMBOL_GPL(iomap_read_end_io);

struct iomap_readpage_ctx {
struct folio *cur_folio;
bool cur_folio_in_bio;
struct bio *bio;
struct readahead_control *rac;
+ const struct iomap_readpage_ops *ops;
};

/**
@@ -402,7 +404,8 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
return pos - orig_pos + plen;
}

-int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
+int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops,
+ const struct iomap_readpage_ops *readpage_ops)
{
struct iomap_iter iter = {
.inode = folio->mapping->host,
@@ -411,6 +414,7 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
};
struct iomap_readpage_ctx ctx = {
.cur_folio = folio,
+ .ops = readpage_ops,
};
int ret;

@@ -468,6 +472,7 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
* iomap_readahead - Attempt to read pages from a file.
* @rac: Describes the pages to be read.
* @ops: The operations vector for the filesystem.
+ * @readpage_ops: Filesystem supplied folio processiong operation
*
* This function is for filesystems to call to implement their readahead
* address_space operation.
@@ -479,7 +484,8 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
* function is called with memalloc_nofs set, so allocations will not cause
* the filesystem to be reentered.
*/
-void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
+void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops,
+ const struct iomap_readpage_ops *readpage_ops)
{
struct iomap_iter iter = {
.inode = rac->mapping->host,
@@ -488,6 +494,7 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
};
struct iomap_readpage_ctx ctx = {
.rac = rac,
+ .ops = readpage_ops,
};

trace_iomap_readahead(rac->mapping->host, readahead_count(rac));
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 465d7630bb21..b413a2dbcc18 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -553,14 +553,14 @@ xfs_vm_read_folio(
struct file *unused,
struct folio *folio)
{
- return iomap_read_folio(folio, &xfs_read_iomap_ops);
+ return iomap_read_folio(folio, &xfs_read_iomap_ops, NULL);
}

STATIC void
xfs_vm_readahead(
struct readahead_control *rac)
{
- iomap_readahead(rac, &xfs_read_iomap_ops);
+ iomap_readahead(rac, &xfs_read_iomap_ops, NULL);
}

static int
diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
index b2c9b35df8f7..29428c012150 100644
--- a/fs/zonefs/file.c
+++ b/fs/zonefs/file.c
@@ -112,12 +112,12 @@ static const struct iomap_ops zonefs_write_iomap_ops = {

static int zonefs_read_folio(struct file *unused, struct folio *folio)
{
- return iomap_read_folio(folio, &zonefs_read_iomap_ops);
+ return iomap_read_folio(folio, &zonefs_read_iomap_ops, NULL);
}

static void zonefs_readahead(struct readahead_control *rac)
{
- iomap_readahead(rac, &zonefs_read_iomap_ops);
+ iomap_readahead(rac, &zonefs_read_iomap_ops, NULL);
}

/*
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 96dd0acbba44..3565c449f3c9 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -262,8 +262,25 @@ int iomap_file_buffered_write_punch_delalloc(struct inode *inode,
struct iomap *iomap, loff_t pos, loff_t length, ssize_t written,
int (*punch)(struct inode *inode, loff_t pos, loff_t length));

-int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
-void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
+struct iomap_readpage_ops {
+ /*
+ * Filesystems wishing to attach private information to a direct io bio
+ * must provide a ->submit_io method that attaches the additional
+ * information to the bio and changes the ->bi_end_io callback to a
+ * custom function. This function should, at a minimum, perform any
+ * relevant post-processing of the bio and end with a call to
+ * iomap_read_end_io.
+ */
+ void (*submit_io)(const struct iomap_iter *iter, struct bio *bio,
+ loff_t file_offset);
+ struct bio_set *bio_set;
+};
+
+void iomap_read_end_io(struct bio *bio);
+int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops,
+ const struct iomap_readpage_ops *readpage_ops);
+void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops,
+ const struct iomap_readpage_ops *readpage_ops);
bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len);
bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
--
2.40.1