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iomap: generic inline data handling

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Add generic inline data handling by adding a pointer to the inline data
region to struct iomap.  When handling a buffered IOMAP_INLINE write,
iomap_write_begin will copy the current inline data from the inline data
region into the page cache, and iomap_write_end will copy the changes in
the page cache back to the inline data region.

This doesn't cover inline data reads and direct I/O yet because so far,
we have no users.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
[hch: small cleanups to better fit in with other iomap work]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Andreas Gruenbacher 2018-06-19 15:10:56 -07:00 committed by Darrick J. Wong
parent ebf00be37d
commit 19e0c58f65
2 changed files with 56 additions and 7 deletions
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62
fs/iomap.c
View File

@ -103,6 +103,26 @@ iomap_sector(struct iomap *iomap, loff_t pos)
return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
}
static void
iomap_read_inline_data(struct inode *inode, struct page *page,
struct iomap *iomap)
{
size_t size = i_size_read(inode);
void *addr;
if (PageUptodate(page))
return;
BUG_ON(page->index);
BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
addr = kmap_atomic(page);
memcpy(addr, iomap->inline_data, size);
memset(addr + size, 0, PAGE_SIZE - size);
kunmap_atomic(addr);
SetPageUptodate(page);
}
static void
iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
{
@ -133,7 +153,11 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
if (!page)
return -ENOMEM;
status = __block_write_begin_int(page, pos, len, NULL, iomap);
if (iomap->type == IOMAP_INLINE)
iomap_read_inline_data(inode, page, iomap);
else
status = __block_write_begin_int(page, pos, len, NULL, iomap);
if (unlikely(status)) {
unlock_page(page);
put_page(page);
@ -146,14 +170,37 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
return status;
}
static int
iomap_write_end_inline(struct inode *inode, struct page *page,
struct iomap *iomap, loff_t pos, unsigned copied)
{
void *addr;
WARN_ON_ONCE(!PageUptodate(page));
BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
addr = kmap_atomic(page);
memcpy(iomap->inline_data + pos, addr + pos, copied);
kunmap_atomic(addr);
mark_inode_dirty(inode);
__generic_write_end(inode, pos, copied, page);
return copied;
}
static int
iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
unsigned copied, struct page *page)
unsigned copied, struct page *page, struct iomap *iomap)
{
int ret;
ret = generic_write_end(NULL, inode->i_mapping, pos, len,
copied, page, NULL);
if (iomap->type == IOMAP_INLINE) {
ret = iomap_write_end_inline(inode, page, iomap, pos, copied);
} else {
ret = generic_write_end(NULL, inode->i_mapping, pos, len,
copied, page, NULL);
}
if (ret < len)
iomap_write_failed(inode, pos, len);
return ret;
@ -208,7 +255,8 @@ again:
flush_dcache_page(page);
status = iomap_write_end(inode, pos, bytes, copied, page);
status = iomap_write_end(inode, pos, bytes, copied, page,
iomap);
if (unlikely(status < 0))
break;
copied = status;
@ -302,7 +350,7 @@ iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
WARN_ON_ONCE(!PageUptodate(page));
status = iomap_write_end(inode, pos, bytes, bytes, page);
status = iomap_write_end(inode, pos, bytes, bytes, page, iomap);
if (unlikely(status <= 0)) {
if (WARN_ON_ONCE(status == 0))
return -EIO;
@ -354,7 +402,7 @@ static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
zero_user(page, offset, bytes);
mark_page_accessed(page);
return iomap_write_end(inode, pos, bytes, bytes, page);
return iomap_write_end(inode, pos, bytes, bytes, page, iomap);
}
static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,

1
include/linux/iomap.h
View File

@ -55,6 +55,7 @@ struct iomap {
u16 flags; /* flags for mapping */
struct block_device *bdev; /* block device for I/O */
struct dax_device *dax_dev; /* dax_dev for dax operations */
void *inline_data;
};
/*