Unverified Commit 8d407bb3 authored by Hongbo Li's avatar Hongbo Li Committed by Christian Brauner
Browse files

erofs: hold read context in iomap_iter if needed 



Introduce `struct erofs_iomap_iter_ctx` to hold both `struct page *`
and `void *base`, avoiding bogus use of `kmap_to_page()` in
`erofs_iomap_end()`.

With this change, fiemap and bmap no longer need to read inline data.

Additionally, the upcoming page cache sharing mechanism requires
passing the backing inode pointer to `erofs_iomap_{begin,end}()`, as
I/O accesses must apply to backing inodes rather than anon inodes.

Signed-off-by: default avatarHongbo Li <lihongbo22@huawei.com>
Link: https://patch.msgid.link/20260109102856.598531-3-lihongbo22@huawei.com


Reviewed-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 8806f279

fs/erofs/data.c

+46 −21
Original line number Diff line number Diff line
@@ -266,13 +266,20 @@ void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty) 
	folio_end_read(folio, !(v & BIT(EROFS_ONLINEFOLIO_EIO)));

}



struct erofs_iomap_iter_ctx {

	struct page *page;

	void *base;

};



static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,

		unsigned int flags, struct iomap *iomap, struct iomap *srcmap)

{

	int ret;

	struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);

	struct erofs_iomap_iter_ctx *ctx = iter->private;

	struct super_block *sb = inode->i_sb;

	struct erofs_map_blocks map;

	struct erofs_map_dev mdev;

	int ret;



	map.m_la = offset;

	map.m_llen = length;
@@ -283,7 +290,6 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 
	iomap->offset = map.m_la;

	iomap->length = map.m_llen;

	iomap->flags = 0;

	iomap->private = NULL;

	iomap->addr = IOMAP_NULL_ADDR;

	if (!(map.m_flags & EROFS_MAP_MAPPED)) {

		iomap->type = IOMAP_HOLE;
@@ -309,16 +315,20 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 
	}



	if (map.m_flags & EROFS_MAP_META) {

		void *ptr;

		iomap->type = IOMAP_INLINE;

		/* read context should read the inlined data */

		if (ctx) {

			struct erofs_buf buf = __EROFS_BUF_INITIALIZER;

			void *ptr;



		iomap->type = IOMAP_INLINE;

			ptr = erofs_read_metabuf(&buf, sb, map.m_pa,

						 erofs_inode_in_metabox(inode));

			if (IS_ERR(ptr))

				return PTR_ERR(ptr);

			iomap->inline_data = ptr;

		iomap->private = buf.base;

			ctx->page = buf.page;

			ctx->base = buf.base;

		}

	} else {

		iomap->type = IOMAP_MAPPED;

	}
@@ -328,18 +338,18 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 
static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,

		ssize_t written, unsigned int flags, struct iomap *iomap)

{

	void *ptr = iomap->private;

	struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);

	struct erofs_iomap_iter_ctx *ctx = iter->private;



	if (ptr) {

	if (ctx && ctx->base) {

		struct erofs_buf buf = {

			.page = kmap_to_page(ptr),

			.base = ptr,

			.page = ctx->page,

			.base = ctx->base,

		};



		DBG_BUGON(iomap->type != IOMAP_INLINE);

		erofs_put_metabuf(&buf);

	} else {

		DBG_BUGON(iomap->type == IOMAP_INLINE);

		ctx->base = NULL;

	}

	return written;

}
@@ -369,18 +379,30 @@ int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
 */

static int erofs_read_folio(struct file *file, struct folio *folio)

{

	struct iomap_read_folio_ctx read_ctx = {

		.ops		= &iomap_bio_read_ops,

		.cur_folio	= folio,

	};

	struct erofs_iomap_iter_ctx iter_ctx = {};



	trace_erofs_read_folio(folio, true);



	iomap_bio_read_folio(folio, &erofs_iomap_ops);

	iomap_read_folio(&erofs_iomap_ops, &read_ctx, &iter_ctx);

	return 0;

}



static void erofs_readahead(struct readahead_control *rac)

{

	struct iomap_read_folio_ctx read_ctx = {

		.ops		= &iomap_bio_read_ops,

		.rac		= rac,

	};

	struct erofs_iomap_iter_ctx iter_ctx = {};



	trace_erofs_readahead(rac->mapping->host, readahead_index(rac),

					readahead_count(rac), true);



	iomap_bio_readahead(rac, &erofs_iomap_ops);

	iomap_readahead(&erofs_iomap_ops, &read_ctx, &iter_ctx);

}



static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
@@ -400,9 +422,12 @@ static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 
	if (IS_DAX(inode))

		return dax_iomap_rw(iocb, to, &erofs_iomap_ops);

#endif

	if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev)

	if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev) {

		struct erofs_iomap_iter_ctx iter_ctx = {};



		return iomap_dio_rw(iocb, to, &erofs_iomap_ops,

				    NULL, 0, NULL, 0);

				    NULL, 0, &iter_ctx, 0);

	}

	return filemap_read(iocb, to, 0);

}