From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
DAX wants different semantics from any currently-existing ext4
get_block callback. Unlike ext4_get_block_write(), it needs to honour
the 'create' flag, and unlike ext4_get_block(), it needs to be able
to return unwritten extents. So introduce a new ext4_get_block_dax()
which has those semantics. We could also change ext4_get_block_write()
to honour the 'create' flag, but that might have consequences on other
users that I do not currently understand.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
fs/ext4/ext4.h | 2 ++
fs/ext4/file.c | 6 +++---
fs/ext4/inode.c | 11 +++++++++++
3 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d743d93..51c5008 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2274,6 +2274,8 @@ struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
int ext4_get_block_write(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
+int ext4_get_block_dax(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create);
int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index ca5302a..d5219e4 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -207,19 +207,19 @@ static void ext4_end_io_unwritten(struct buffer_head *bh, int uptodate)
static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_fault(vma, vmf, ext4_get_block_write, ext4_end_io_unwritten);
+ return dax_fault(vma, vmf, ext4_get_block_dax, ext4_end_io_unwritten);
}
static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, unsigned int flags)
{
- return dax_pmd_fault(vma, addr, pmd, flags, ext4_get_block_write,
+ return dax_pmd_fault(vma, addr, pmd, flags, ext4_get_block_dax,
ext4_end_io_unwritten);
}
static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_mkwrite(vma, vmf, ext4_get_block_write,
+ return dax_mkwrite(vma, vmf, ext4_get_block_dax,
ext4_end_io_unwritten);
}
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 40e6c66..75146d1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3025,6 +3025,17 @@ static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock,
EXT4_GET_BLOCKS_NO_LOCK);
}
+int ext4_get_block_dax(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ int flags = EXT4_GET_BLOCKS_PRE_IO | EXT4_GET_BLOCKS_UNWRIT_EXT;
+ if (create)
+ flags |= EXT4_GET_BLOCKS_CREATE;
+ ext4_debug("ext4_get_block_dax: inode %lu, create flag %d\n",
+ inode->i_ino, create);
+ return _ext4_get_block(inode, iblock, bh_result, flags);
+}
+
static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
ssize_t size, void *private)
{
--
2.1.4
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