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authorGao Xiang <hsiangkao@linux.alibaba.com>2021-08-03 19:38:22 +0300
committerDarrick J. Wong <djwong@kernel.org>2021-08-03 19:43:13 +0300
commit69f4a26c1e0c7c5e5e77c5bd7b271743c124c545 (patch)
tree4e944b086cefaeb1145a09dad8c16a72fdff2619 /fs/iomap
parentc1b79f11f4ec27d3b3197a9584950a3be178c717 (diff)
downloadlinux-69f4a26c1e0c7c5e5e77c5bd7b271743c124c545.tar.xz
iomap: support reading inline data from non-zero pos
The existing inline data support only works for cases where the entire file is stored as inline data. For larger files, EROFS stores the initial blocks separately and the remainder of the file ("file tail") adjacent to the inode. Generalise inline data to allow reading the inline file tail. Tails may not cross a page boundary in memory. We currently have no filesystems that support tails and writing, so that case is currently disabled (see iomap_write_begin_inline). Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Diffstat (limited to 'fs/iomap')
-rw-r--r--fs/iomap/buffered-io.c42
-rw-r--r--fs/iomap/direct-io.c10
2 files changed, 36 insertions, 16 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index a463b41c0a16..1d31ff6bfea0 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -205,25 +205,32 @@ struct iomap_readpage_ctx {
struct readahead_control *rac;
};
-static void
-iomap_read_inline_data(struct inode *inode, struct page *page,
+static int iomap_read_inline_data(struct inode *inode, struct page *page,
struct iomap *iomap)
{
- size_t size = i_size_read(inode);
+ size_t size = i_size_read(inode) - iomap->offset;
void *addr;
if (PageUptodate(page))
- return;
+ return 0;
- BUG_ON(page_has_private(page));
- BUG_ON(page->index);
- BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
+ /* inline data must start page aligned in the file */
+ if (WARN_ON_ONCE(offset_in_page(iomap->offset)))
+ return -EIO;
+ if (WARN_ON_ONCE(size > PAGE_SIZE -
+ offset_in_page(iomap->inline_data)))
+ return -EIO;
+ if (WARN_ON_ONCE(size > iomap->length))
+ return -EIO;
+ if (WARN_ON_ONCE(page_has_private(page)))
+ return -EIO;
addr = kmap_atomic(page);
memcpy(addr, iomap->inline_data, size);
memset(addr + size, 0, PAGE_SIZE - size);
kunmap_atomic(addr);
SetPageUptodate(page);
+ return 0;
}
static inline bool iomap_block_needs_zeroing(struct inode *inode,
@@ -246,8 +253,10 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
sector_t sector;
if (iomap->type == IOMAP_INLINE) {
- WARN_ON_ONCE(pos);
- iomap_read_inline_data(inode, page, iomap);
+ int ret = iomap_read_inline_data(inode, page, iomap);
+
+ if (ret)
+ return ret;
return PAGE_SIZE;
}
@@ -581,6 +590,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
return 0;
}
+static int iomap_write_begin_inline(struct inode *inode,
+ struct page *page, struct iomap *srcmap)
+{
+ /* needs more work for the tailpacking case; disable for now */
+ if (WARN_ON_ONCE(srcmap->offset != 0))
+ return -EIO;
+ return iomap_read_inline_data(inode, page, srcmap);
+}
+
static int
iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
struct page **pagep, struct iomap *iomap, struct iomap *srcmap)
@@ -610,7 +628,7 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
}
if (srcmap->type == IOMAP_INLINE)
- iomap_read_inline_data(inode, page, srcmap);
+ status = iomap_write_begin_inline(inode, page, srcmap);
else if (iomap->flags & IOMAP_F_BUFFER_HEAD)
status = __block_write_begin_int(page, pos, len, NULL, srcmap);
else
@@ -663,11 +681,11 @@ static size_t iomap_write_end_inline(struct inode *inode, struct page *page,
void *addr;
WARN_ON_ONCE(!PageUptodate(page));
- BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
+ BUG_ON(!iomap_inline_data_valid(iomap));
flush_dcache_page(page);
addr = kmap_atomic(page);
- memcpy(iomap->inline_data + pos, addr + pos, copied);
+ memcpy(iomap_inline_data(iomap, pos), addr + pos, copied);
kunmap_atomic(addr);
mark_inode_dirty(inode);
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 9398b8c31323..41ccbfc9dc82 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -378,23 +378,25 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
struct iomap_dio *dio, struct iomap *iomap)
{
struct iov_iter *iter = dio->submit.iter;
+ void *inline_data = iomap_inline_data(iomap, pos);
size_t copied;
- BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data));
+ if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap)))
+ return -EIO;
if (dio->flags & IOMAP_DIO_WRITE) {
loff_t size = inode->i_size;
if (pos > size)
- memset(iomap->inline_data + size, 0, pos - size);
- copied = copy_from_iter(iomap->inline_data + pos, length, iter);
+ memset(iomap_inline_data(iomap, size), 0, pos - size);
+ copied = copy_from_iter(inline_data, length, iter);
if (copied) {
if (pos + copied > size)
i_size_write(inode, pos + copied);
mark_inode_dirty(inode);
}
} else {
- copied = copy_to_iter(iomap->inline_data + pos, length, iter);
+ copied = copy_to_iter(inline_data, length, iter);
}
dio->size += copied;
return copied;