Commit 66dabbb6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Andrew Morton
Browse files

mm: return an ERR_PTR from __filemap_get_folio 

Instead of returning NULL for all errors, distinguish between:

 - no entry found and not asked to allocated (-ENOENT)
 - failed to allocate memory (-ENOMEM)
 - would block (-EAGAIN)

so that callers don't have to guess the error based on the passed in
flags.

Also pass through the error through the direct callers: filemap_get_folio,
filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio.

[hch@lst.de: fix null-pointer deref]
  Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de
  Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004
Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nilfs2]
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 48c9d113

fs/afs/dir.c

+5 −5
Original line number Diff line number Diff line
@@ -319,16 +319,16 @@ static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key) 
		struct folio *folio;



		folio = filemap_get_folio(mapping, i);

		if (!folio) {

		if (IS_ERR(folio)) {

			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))

				afs_stat_v(dvnode, n_inval);



			ret = -ENOMEM;

			folio = __filemap_get_folio(mapping,

						    i, FGP_LOCK | FGP_CREAT,

						    mapping->gfp_mask);

			if (!folio)

			if (IS_ERR(folio)) {

				ret = PTR_ERR(folio);

				goto error;

			}

			folio_attach_private(folio, (void *)1);

			folio_unlock(folio);

		}
@@ -524,7 +524,7 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx, 
		 */

		folio = __filemap_get_folio(dir->i_mapping, ctx->pos / PAGE_SIZE,

					    FGP_ACCESSED, 0);

		if (!folio) {

		if (IS_ERR(folio)) {

			ret = afs_bad(dvnode, afs_file_error_dir_missing_page);

			break;

		}

fs/afs/dir_edit.c

+1 −1
Original line number Diff line number Diff line
@@ -115,7 +115,7 @@ static struct folio *afs_dir_get_folio(struct afs_vnode *vnode, pgoff_t index) 
	folio = __filemap_get_folio(mapping, index,

				    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,

				    mapping->gfp_mask);

	if (!folio)

	if (IS_ERR(folio))

		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);

	else if (folio && !folio_test_private(folio))

		folio_attach_private(folio, (void *)1);

fs/afs/write.c

+2 −2
Original line number Diff line number Diff line
@@ -232,7 +232,7 @@ static void afs_kill_pages(struct address_space *mapping, 
		_debug("kill %lx (to %lx)", index, last);



		folio = filemap_get_folio(mapping, index);

		if (!folio) {

		if (IS_ERR(folio)) {

			next = index + 1;

			continue;

		}
@@ -270,7 +270,7 @@ static void afs_redirty_pages(struct writeback_control *wbc, 
		_debug("redirty %llx @%llx", len, start);



		folio = filemap_get_folio(mapping, index);

		if (!folio) {

		if (IS_ERR(folio)) {

			next = index + 1;

			continue;

		}

fs/ext4/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -5395,7 +5395,7 @@ static void ext4_wait_for_tail_page_commit(struct inode *inode) 
	while (1) {

		struct folio *folio = filemap_lock_folio(inode->i_mapping,

				      inode->i_size >> PAGE_SHIFT);

		if (!folio)

		if (IS_ERR(folio))

			return;

		ret = __ext4_journalled_invalidate_folio(folio, offset,

						folio_size(folio) - offset);

fs/ext4/move_extent.c

+4 −4
Original line number Diff line number Diff line
@@ -141,18 +141,18 @@ mext_folio_double_lock(struct inode *inode1, struct inode *inode2, 
	flags = memalloc_nofs_save();

	folio[0] = __filemap_get_folio(mapping[0], index1, fgp_flags,

			mapping_gfp_mask(mapping[0]));

	if (!folio[0]) {

	if (IS_ERR(folio[0])) {

		memalloc_nofs_restore(flags);

		return -ENOMEM;

		return PTR_ERR(folio[0]);

	}



	folio[1] = __filemap_get_folio(mapping[1], index2, fgp_flags,

			mapping_gfp_mask(mapping[1]));

	memalloc_nofs_restore(flags);

	if (!folio[1]) {

	if (IS_ERR(folio[1])) {

		folio_unlock(folio[0]);

		folio_put(folio[0]);

		return -ENOMEM;

		return PTR_ERR(folio[1]);

	}

	/*

	 * __filemap_get_folio() may not wait on folio's writeback if