Add write_begin and write_end operations to struct iomap_ops to provide
a way of overriding the default behavior of iomap_write_begin and
iomap_write_end. This is needed for implementing data journaling: in
the data journaling case, pages are written into the journal before
being written back to their proper on-disk locations.
Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
Cc: Dave Chinner <dchin...@redhat.com>
---
fs/ext2/inode.c | 2 ++
fs/ext4/inode.c | 2 ++
fs/iomap.c | 62 +++++++++++++++++++++++++++++++++++----------------
fs/xfs/xfs_iomap.c | 2 ++
include/linux/iomap.h | 22 ++++++++++++++++++
5 files changed, 71 insertions(+), 19 deletions(-)
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 9b2ac55ac34f..9b8ea6108b30 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -848,6 +848,8 @@ ext2_iomap_end(struct inode *inode, loff_t offset, loff_t
length,
const struct iomap_ops ext2_iomap_ops = {
.iomap_begin = ext2_iomap_begin,
+ .write_begin = iomap_write_begin,
+ .write_end = iomap_write_end,
.iomap_end = ext2_iomap_end,
};
#else
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c94780075b04..21de1959bc9c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3602,6 +3602,8 @@ static int ext4_iomap_end(struct inode *inode, loff_t
offset, loff_t length,
const struct iomap_ops ext4_iomap_ops = {
.iomap_begin = ext4_iomap_begin,
+ .write_begin = iomap_write_begin,
+ .write_end = iomap_write_end,
.iomap_end = ext4_iomap_end,
};
diff --git a/fs/iomap.c b/fs/iomap.c
index afd163586aa0..27d97a290623 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -108,7 +108,7 @@ iomap_write_failed(struct inode *inode, loff_t pos,
unsigned len)
truncate_pagecache_range(inode, max(pos, i_size), pos + len);
}
-static int
+int
iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned
flags,
struct page **pagep, struct iomap *iomap)
{
@@ -137,8 +137,9 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned
len, unsigned flags,
*pagep = page;
return status;
}
+EXPORT_SYMBOL_GPL(iomap_write_begin);
-static int
+int
iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
unsigned copied, struct page *page)
{
@@ -150,12 +151,19 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned
len,
iomap_write_failed(inode, pos, len);
return ret;
}
+EXPORT_SYMBOL_GPL(iomap_write_end);
+
+struct iomap_write_args {
+ struct iov_iter *iter;
+ const struct iomap_ops *ops;
+};
static loff_t
iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
struct iomap *iomap)
{
- struct iov_iter *i = data;
+ struct iomap_write_args *args = data;
+ struct iov_iter *i = args->iter;
long status = 0;
ssize_t written = 0;
unsigned int flags = AOP_FLAG_NOFS;
@@ -188,7 +196,7 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t
length, void *data,
break;
}
- status = iomap_write_begin(inode, pos, bytes, flags, &page,
+ status = args->ops->write_begin(inode, pos, bytes, flags, &page,
iomap);
if (unlikely(status))
break;
@@ -200,7 +208,7 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t
length, void *data,
flush_dcache_page(page);
- status = iomap_write_end(inode, pos, bytes, copied, page);
+ status = args->ops->write_end(inode, pos, bytes, copied, page);
if (unlikely(status < 0))
break;
copied = status;
@@ -237,10 +245,14 @@ iomap_file_buffered_write(struct kiocb *iocb, struct
iov_iter *iter,
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
loff_t pos = iocb->ki_pos, ret = 0, written = 0;
+ struct iomap_write_args args = {
+ .iter = iter,
+ .ops = ops,
+ };
while (iov_iter_count(iter)) {
ret = iomap_apply(inode, pos, iov_iter_count(iter),
- IOMAP_WRITE, ops, iter, iomap_write_actor);
+ IOMAP_WRITE, ops, &args, iomap_write_actor);
if (ret <= 0)
break;
pos += ret;
@@ -271,6 +283,7 @@ static loff_t
iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
struct iomap *iomap)
{
+ const struct iomap_ops *ops = data;
long status = 0;
ssize_t written = 0;
@@ -286,15 +299,15 @@ iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t
length, void *data,
if (IS_ERR(rpage))
return PTR_ERR(rpage);
- status = iomap_write_begin(inode, pos, bytes,
- AOP_FLAG_NOFS, &page, iomap);
+ status = ops->write_begin(inode, pos, bytes,
+ AOP_FLAG_NOFS, &page, iomap);
put_page(rpage);
if (unlikely(status))
return status;
WARN_ON_ONCE(!PageUptodate(page));
- status = iomap_write_end(inode, pos, bytes, bytes, page);
+ status = ops->write_end(inode, pos, bytes, bytes, page);
if (unlikely(status <= 0)) {
if (WARN_ON_ONCE(status == 0))
return -EIO;
@@ -320,7 +333,7 @@ iomap_file_dirty(struct inode *inode, loff_t pos, loff_t
len,
loff_t ret;
while (len) {
- ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,
+ ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, (void
*)ops,
iomap_dirty_actor);
if (ret <= 0)
return ret;
@@ -333,20 +346,21 @@ iomap_file_dirty(struct inode *inode, loff_t pos, loff_t
len,
EXPORT_SYMBOL_GPL(iomap_file_dirty);
static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
- unsigned bytes, struct iomap *iomap)
+ unsigned bytes, const struct iomap_ops *ops,
+ struct iomap *iomap)
{
struct page *page;
int status;
- status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page,
- iomap);
+ status = ops->write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page,
+ iomap);
if (status)
return status;
zero_user(page, offset, bytes);
mark_page_accessed(page);
- return iomap_write_end(inode, pos, bytes, bytes, page);
+ return ops->write_end(inode, pos, bytes, bytes, page);
}
static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
@@ -359,11 +373,16 @@ static int iomap_dax_zero(loff_t pos, unsigned offset,
unsigned bytes,
offset, bytes);
}
+struct iomap_zero_range_args {
+ const struct iomap_ops *ops;
+ bool *did_zero;
+};
+
static loff_t
iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
void *data, struct iomap *iomap)
{
- bool *did_zero = data;
+ struct iomap_zero_range_args *args = data;
loff_t written = 0;
int status;
@@ -380,15 +399,16 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos,
loff_t count,
if (IS_DAX(inode))
status = iomap_dax_zero(pos, offset, bytes, iomap);
else
- status = iomap_zero(inode, pos, offset, bytes, iomap);
+ status = iomap_zero(inode, pos, offset, bytes,
+ (void *)args->ops, iomap);
if (status < 0)
return status;
pos += bytes;
count -= bytes;
written += bytes;
- if (did_zero)
- *did_zero = true;
+ if (args->did_zero)
+ *args->did_zero = true;
} while (count > 0);
return written;
@@ -398,11 +418,15 @@ int
iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
const struct iomap_ops *ops)
{
+ struct iomap_zero_range_args args = {
+ .ops = ops,
+ .did_zero = did_zero,
+ };
loff_t ret;
while (len > 0) {
ret = iomap_apply(inode, pos, len, IOMAP_ZERO,
- ops, did_zero, iomap_zero_range_actor);
+ ops, &args, iomap_zero_range_actor);
if (ret <= 0)
return ret;
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 66e1edbfb2b2..28b9843e7190 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1181,6 +1181,8 @@ xfs_file_iomap_end(
const struct iomap_ops xfs_iomap_ops = {
.iomap_begin = xfs_file_iomap_begin,
+ .write_begin = iomap_write_begin,
+ .write_end = iomap_write_end,
.iomap_end = xfs_file_iomap_end,
};
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 19a07de28212..423f7ecc1231 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -61,6 +61,8 @@ struct iomap {
#define IOMAP_DIRECT (1 << 4) /* direct I/O */
#define IOMAP_NOWAIT (1 << 5) /* Don't wait for writeback */
+struct page;
+
struct iomap_ops {
/*
* Return the existing mapping at pos, or reserve space starting at
@@ -70,6 +72,21 @@ struct iomap_ops {
int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
unsigned flags, struct iomap *iomap);
+ /*
+ * Begin writing to a page, similar to block_write_begin but in a
+ * mapping returned by iomap_begin. Usually initialized to
+ * iomap_write_begin.
+ */
+ int (*write_begin)(struct inode *inode, loff_t pos, unsigned len,
+ unsigned flags, struct page **pagep,
+ struct iomap *iomap);
+
+ /*
+ * End writing to a page. Usually initialized to iomap_write_end.
+ */
+ int (*write_end)(struct inode *inode, loff_t pos, unsigned len,
+ unsigned copied, struct page *page);
+
/*
* Commit and/or unreserve space previous allocated using iomap_begin.
* Written indicates the length of the successful write operation which
@@ -80,6 +97,11 @@ struct iomap_ops {
ssize_t written, unsigned flags, struct iomap *iomap);
};
+int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
+ unsigned flags, struct page **pagep, struct iomap *iomap);
+int iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
+ unsigned copied, struct page *page);
+
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops);
int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
--
2.14.3
