Commit 3304b3fe authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'vfs-7.0-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 

Pull vfs iomap updates from Christian Brauner:

 - Erofs page cache sharing preliminaries:

   Plumb a void *private parameter through iomap_read_folio() and
   iomap_readahead() into iomap_iter->private, matching iomap DIO. Erofs
   uses this to replace a bogus kmap_to_page() call, as preparatory work
   for page cache sharing.

 - Fix for invalid folio access:

   Fix an invalid folio access when a folio without iomap_folio_state
   is fully submitted to the IO helper — the helper may call
   folio_end_read() at any time, so ctx->cur_folio must be invalidated
   after full submission.

* tag 'vfs-7.0-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: fix invalid folio access after folio_end_read()
  erofs: hold read context in iomap_iter if needed
  iomap: stash iomap read ctx in the private field of iomap_iter
parents 157d3d6e aa35dd5c

fs/erofs/data.c

+46 −21
Original line number Diff line number Diff line
@@ -267,13 +267,20 @@ 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;
@@ -284,7 +291,6 @@ 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;
@@ -310,16 +316,20 @@ 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;

	}
@@ -329,18 +339,18 @@ 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;

}
@@ -370,18 +380,30 @@ 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)
@@ -401,9 +423,12 @@ 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);

}

fs/fuse/file.c

+2 −2
Original line number Diff line number Diff line
@@ -979,7 +979,7 @@ static int fuse_read_folio(struct file *file, struct folio *folio) 
		return -EIO;

	}



	iomap_read_folio(&fuse_iomap_ops, &ctx);

	iomap_read_folio(&fuse_iomap_ops, &ctx, NULL);

	fuse_invalidate_atime(inode);

	return 0;

}
@@ -1081,7 +1081,7 @@ static void fuse_readahead(struct readahead_control *rac) 
	if (fuse_is_bad(inode))

		return;



	iomap_readahead(&fuse_iomap_ops, &ctx);

	iomap_readahead(&fuse_iomap_ops, &ctx, NULL);

}



static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)

fs/iomap/buffered-io.c

+31 −26
Original line number Diff line number Diff line
@@ -418,8 +418,6 @@ static void iomap_read_init(struct folio *folio) 
	struct iomap_folio_state *ifs = folio->private;



	if (ifs) {

		size_t len = folio_size(folio);



		/*

		 * ifs->read_bytes_pending is used to track how many bytes are

		 * read in asynchronously by the IO helper. We need to track
@@ -427,23 +425,19 @@ static void iomap_read_init(struct folio *folio) 
		 * reading in all the necessary ranges of the folio and can end

		 * the read.

		 *

		 * Increase ->read_bytes_pending by the folio size to start, and

		 * add a +1 bias. We'll subtract the bias and any uptodate /

		 * zeroed ranges that did not require IO in iomap_read_end()

		 * after we're done processing the folio.

		 * Increase ->read_bytes_pending by the folio size to start.

		 * We'll subtract any uptodate / zeroed ranges that did not

		 * require IO in iomap_read_end() after we're done processing

		 * the folio.

		 *

		 * We do this because otherwise, we would have to increment

		 * ifs->read_bytes_pending every time a range in the folio needs

		 * to be read in, which can get expensive since the spinlock

		 * needs to be held whenever modifying ifs->read_bytes_pending.

		 *

		 * We add the bias to ensure the read has not been ended on the

		 * folio when iomap_read_end() is called, even if the IO helper

		 * has already finished reading in the entire folio.

		 */

		spin_lock_irq(&ifs->state_lock);

		WARN_ON_ONCE(ifs->read_bytes_pending != 0);

		ifs->read_bytes_pending = len + 1;

		ifs->read_bytes_pending = folio_size(folio);

		spin_unlock_irq(&ifs->state_lock);

	}

}
@@ -474,11 +468,9 @@ static void iomap_read_end(struct folio *folio, size_t bytes_submitted) 


		/*

		 * Subtract any bytes that were initially accounted to

		 * read_bytes_pending but skipped for IO. The +1 accounts for

		 * the bias we added in iomap_read_init().

		 * read_bytes_pending but skipped for IO.

		 */

		ifs->read_bytes_pending -=

			(folio_size(folio) + 1 - bytes_submitted);

		ifs->read_bytes_pending -= folio_size(folio) - bytes_submitted;



		/*

		 * If !ifs->read_bytes_pending, this means all pending reads by
@@ -492,14 +484,16 @@ static void iomap_read_end(struct folio *folio, size_t bytes_submitted) 
		spin_unlock_irq(&ifs->state_lock);

		if (end_read)

			folio_end_read(folio, uptodate);

	} else if (!bytes_submitted) {

	} else {

		/*

		 * If there were no bytes submitted, this means we are

		 * responsible for unlocking the folio here, since no IO helper

		 * has taken ownership of it. If there were bytes submitted,

		 * then the IO helper will end the read via

		 * iomap_finish_folio_read().

		 * If a folio without an ifs is submitted to the IO helper, the

		 * read must be on the entire folio and the IO helper takes

		 * ownership of the folio. This means we should only enter

		 * iomap_read_end() for the !ifs case if no bytes were submitted

		 * to the IO helper, in which case we are responsible for

		 * unlocking the folio here.

		 */

		WARN_ON_ONCE(bytes_submitted);

		folio_unlock(folio);

	}

}
@@ -511,6 +505,7 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, 
	loff_t pos = iter->pos;

	loff_t length = iomap_length(iter);

	struct folio *folio = ctx->cur_folio;

	size_t folio_len = folio_size(folio);

	size_t poff, plen;

	loff_t pos_diff;

	int ret;
@@ -524,8 +519,7 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, 


	ifs_alloc(iter->inode, folio, iter->flags);



	length = min_t(loff_t, length,

			folio_size(folio) - offset_in_folio(folio, pos));

	length = min_t(loff_t, length, folio_len - offset_in_folio(folio, pos));

	while (length) {

		iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff,

				&plen);
@@ -555,7 +549,15 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, 
						  plen, ret, GFP_NOFS);

			if (ret)

				return ret;



			*bytes_submitted += plen;

			/*

			 * If the entire folio has been read in by the IO

			 * helper, then the helper owns the folio and will end

			 * the read on it.

			 */

			if (*bytes_submitted == folio_len)

				ctx->cur_folio = NULL;

		}



		ret = iomap_iter_advance(iter, plen);
@@ -568,13 +570,14 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, 
}



void iomap_read_folio(const struct iomap_ops *ops,

		struct iomap_read_folio_ctx *ctx)

		struct iomap_read_folio_ctx *ctx, void *private)

{

	struct folio *folio = ctx->cur_folio;

	struct iomap_iter iter = {

		.inode		= folio->mapping->host,

		.pos		= folio_pos(folio),

		.len		= folio_size(folio),

		.private	= private,

	};

	size_t bytes_submitted = 0;

	int ret;
@@ -588,7 +591,8 @@ void iomap_read_folio(const struct iomap_ops *ops, 
	if (ctx->ops->submit_read)

		ctx->ops->submit_read(ctx);



	iomap_read_end(folio, bytes_submitted);

	if (ctx->cur_folio)

		iomap_read_end(ctx->cur_folio, bytes_submitted);

}

EXPORT_SYMBOL_GPL(iomap_read_folio);
@@ -633,13 +637,14 @@ static int iomap_readahead_iter(struct iomap_iter *iter, 
 * the filesystem to be reentered.

 */

void iomap_readahead(const struct iomap_ops *ops,

		struct iomap_read_folio_ctx *ctx)

		struct iomap_read_folio_ctx *ctx, void *private)

{

	struct readahead_control *rac = ctx->rac;

	struct iomap_iter iter = {

		.inode	= rac->mapping->host,

		.pos	= readahead_pos(rac),

		.len	= readahead_length(rac),

		.private = private,

	};

	size_t cur_bytes_submitted;

include/linux/iomap.h

+4 −4
Original line number Diff line number Diff line
@@ -345,9 +345,9 @@ ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, 
		const struct iomap_ops *ops,

		const struct iomap_write_ops *write_ops, void *private);

void iomap_read_folio(const struct iomap_ops *ops,

		struct iomap_read_folio_ctx *ctx);

		struct iomap_read_folio_ctx *ctx, void *private);

void iomap_readahead(const struct iomap_ops *ops,

		struct iomap_read_folio_ctx *ctx);

		struct iomap_read_folio_ctx *ctx, void *private);

bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);

struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len);

bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
@@ -599,7 +599,7 @@ static inline void iomap_bio_read_folio(struct folio *folio, 
		.cur_folio	= folio,

	};



	iomap_read_folio(ops, &ctx);

	iomap_read_folio(ops, &ctx, NULL);

}



static inline void iomap_bio_readahead(struct readahead_control *rac,
@@ -610,7 +610,7 @@ static inline void iomap_bio_readahead(struct readahead_control *rac, 
		.rac		= rac,

	};



	iomap_readahead(ops, &ctx);

	iomap_readahead(ops, &ctx, NULL);

}

#endif /* CONFIG_BLOCK */