Merge tag 'ext4_for_linus-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:

- more folio conversion patches

- add support for FS_IOC_GETFSSYSFSPATH

- mballoc cleaups and add more kunit tests

- sysfs cleanups and bug fixes

- miscellaneous bug fixes and cleanups

* tag 'ext4_for_linus-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (40 commits)
ext4: fix error pointer dereference in ext4_mb_load_buddy_gfp()
jbd2: add prefix 'jbd2' for 'shrink_type'
jbd2: use shrink_type type instead of bool type for __jbd2_journal_clean_checkpoint_list()
ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()
ext4: remove calls to to set/clear the folio error flag
ext4: propagate errors from ext4_sb_bread() in ext4_xattr_block_cache_find()
ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()
jbd2: remove redundant assignement to variable err
ext4: remove the redundant folio_wait_stable()
ext4: fix potential unnitialized variable
ext4: convert ac_buddy_page to ac_buddy_folio
ext4: convert ac_bitmap_page to ac_bitmap_folio
ext4: convert ext4_mb_init_cache() to take a folio
ext4: convert bd_buddy_page to bd_buddy_folio
ext4: convert bd_bitmap_page to bd_bitmap_folio
ext4: open coding repeated check in next_linear_group
ext4: use correct criteria name instead stale integer number in comment
ext4: call ext4_mb_mark_free_simple to free continuous bits in found chunk
ext4: add test_mb_mark_used_cost to estimate cost of mb_mark_used
ext4: keep "prefetch_grp" and "nr" consistent
...

fs/ext4/acl.h

···
 static inline int
 ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
 {
-	/* usually, the umask is applied by posix_acl_create(), but if
-	   ext4 ACL support is disabled at compile time, we need to do
-	   it here, because posix_acl_create() will never be called */
-	inode->i_mode &= ~current_umask();
-
 	return 0;
 }
 #endif  /* CONFIG_EXT4_FS_POSIX_ACL */

fs/ext4/ext4.h

···
 #define EXT4_MB_USE_RESERVED		0x2000
 /* Do strict check for free blocks while retrying block allocation */
 #define EXT4_MB_STRICT_CHECK		0x4000
-/* Large fragment size list lookup succeeded at least once for cr = 0 */
+/* Large fragment size list lookup succeeded at least once for
+ * CR_POWER2_ALIGNED */
 #define EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED		0x8000
-/* Avg fragment size rb tree lookup succeeded at least once for cr = 1 */
+/* Avg fragment size rb tree lookup succeeded at least once for
+ * CR_GOAL_LEN_FAST */
 #define EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED		0x00010000
-/* Avg fragment size rb tree lookup succeeded at least once for cr = 1.5 */
+/* Avg fragment size rb tree lookup succeeded at least once for
+ * CR_BEST_AVAIL_LEN */
 #define EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED		0x00020000
 
 struct ext4_allocation_request {

fs/ext4/extents.c

···
 	struct ext4_extent *ex, *abut_ex;
 	ext4_lblk_t ee_block, eof_block;
 	unsigned int ee_len, depth, map_len = map->m_len;
-	int allocated = 0, max_zeroout = 0;
 	int err = 0;
 	int split_flag = EXT4_EXT_DATA_VALID2;
+	int allocated = 0;
+	unsigned int max_zeroout = 0;
 
 	ext_debug(inode, "logical block %llu, max_blocks %u\n",
 		  (unsigned long long)map->m_lblk, map_len);

fs/ext4/file.c

···
 	if (err)
 		goto out_journal;
 	lock_buffer(sbi->s_sbh);
-	strncpy(sbi->s_es->s_last_mounted, cp,
-		sizeof(sbi->s_es->s_last_mounted));
+	strtomem_pad(sbi->s_es->s_last_mounted, cp, 0);
 	ext4_superblock_csum_set(sb);
 	unlock_buffer(sbi->s_sbh);
 	ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
···
 			return ret;
 	}
 
-	filp->f_mode |= FMODE_NOWAIT;
+	filp->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
 	return dquot_file_open(inode, filp);
 }
 

fs/ext4/inode.c

···
 	len = folio_size(folio);
 	if (folio_pos(folio) + len > size &&
 	    !ext4_verity_in_progress(mpd->inode))
-		len = size & ~PAGE_MASK;
+		len = size & (len - 1);
 	err = ext4_bio_write_folio(&mpd->io_submit, folio, len);
 	if (!err)
 		mpd->wbc->nr_to_write--;
···
 
 	if (folio_pos(folio) + len > size &&
 	    !ext4_verity_in_progress(inode))
-		len = size - folio_pos(folio);
+		len = size & (len - 1);
 
 	return ext4_journal_folio_buffers(handle, folio, len);
 }
···
 			mapping_gfp_mask(mapping));
 	if (IS_ERR(folio))
 		return PTR_ERR(folio);
-
-	/* In case writeback began while the folio was unlocked */
-	folio_wait_stable(folio);
 
 #ifdef CONFIG_FS_ENCRYPTION
 	ret = ext4_block_write_begin(folio, pos, len, ext4_da_get_block_prep);
···
 	.bmap			= ext4_bmap,
 	.invalidate_folio	= ext4_invalidate_folio,
 	.release_folio		= ext4_release_folio,
-	.direct_IO		= noop_direct_IO,
 	.migrate_folio		= buffer_migrate_folio,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_folio	= generic_error_remove_folio,
···
 	.bmap			= ext4_bmap,
 	.invalidate_folio	= ext4_journalled_invalidate_folio,
 	.release_folio		= ext4_release_folio,
-	.direct_IO		= noop_direct_IO,
 	.migrate_folio		= buffer_migrate_folio_norefs,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_folio	= generic_error_remove_folio,
···
 	.bmap			= ext4_bmap,
 	.invalidate_folio	= ext4_invalidate_folio,
 	.release_folio		= ext4_release_folio,
-	.direct_IO		= noop_direct_IO,
 	.migrate_folio		= buffer_migrate_folio,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_folio	= generic_error_remove_folio,
···
 
 static const struct address_space_operations ext4_dax_aops = {
 	.writepages		= ext4_dax_writepages,
-	.direct_IO		= noop_direct_IO,
 	.dirty_folio		= noop_dirty_folio,
 	.bmap			= ext4_bmap,
 	.swap_activate		= ext4_iomap_swap_activate,

fs/ext4/ioctl.c

···
 	 */
 	BUILD_BUG_ON(EXT4_LABEL_MAX >= FSLABEL_MAX);
 
-	memset(label, 0, sizeof(label));
 	lock_buffer(sbi->s_sbh);
-	strncpy(label, sbi->s_es->s_volume_name, EXT4_LABEL_MAX);
+	strscpy_pad(label, sbi->s_es->s_volume_name);
 	unlock_buffer(sbi->s_sbh);
 
 	if (copy_to_user(user_label, label, sizeof(label)))

fs/ext4/mballoc-test.c

···
 #define MBT_CTX(_sb) (&MBT_SB(_sb)->mbt_ctx)
 #define MBT_GRP_CTX(_sb, _group) (&MBT_CTX(_sb)->grp_ctx[_group])
 
+static struct inode *mbt_alloc_inode(struct super_block *sb)
+{
+	struct ext4_inode_info *ei;
+
+	ei = kmalloc(sizeof(struct ext4_inode_info), GFP_KERNEL);
+	if (!ei)
+		return NULL;
+
+	INIT_LIST_HEAD(&ei->i_orphan);
+	init_rwsem(&ei->xattr_sem);
+	init_rwsem(&ei->i_data_sem);
+	inode_init_once(&ei->vfs_inode);
+	ext4_fc_init_inode(&ei->vfs_inode);
+
+	return &ei->vfs_inode;
+}
+
+static void mbt_free_inode(struct inode *inode)
+{
+	kfree(EXT4_I(inode));
+}
+
 static const struct super_operations mbt_sops = {
+	.alloc_inode	= mbt_alloc_inode,
+	.free_inode	= mbt_free_inode,
 };
 
 static void mbt_kill_sb(struct super_block *sb)
···
 	ext4_mb_unload_buddy(&e4b);
 }
 
+#define COUNT_FOR_ESTIMATE 100000
+static void test_mb_mark_used_cost(struct kunit *test)
+{
+	struct ext4_buddy e4b;
+	struct super_block *sb = (struct super_block *)test->priv;
+	struct ext4_free_extent ex;
+	int ret;
+	struct test_range ranges[TEST_RANGE_COUNT];
+	int i, j;
+	unsigned long start, end, all = 0;
+
+	/* buddy cache assumes that each page contains at least one block */
+	if (sb->s_blocksize > PAGE_SIZE)
+		kunit_skip(test, "blocksize exceeds pagesize");
+
+	ret = ext4_mb_load_buddy(sb, TEST_GOAL_GROUP, &e4b);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ex.fe_group = TEST_GOAL_GROUP;
+	for (j = 0; j < COUNT_FOR_ESTIMATE; j++) {
+		mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT);
+		start = jiffies;
+		for (i = 0; i < TEST_RANGE_COUNT; i++) {
+			if (ranges[i].len == 0)
+				continue;
+
+			ex.fe_start = ranges[i].start;
+			ex.fe_len = ranges[i].len;
+			ext4_lock_group(sb, TEST_GOAL_GROUP);
+			mb_mark_used(&e4b, &ex);
+			ext4_unlock_group(sb, TEST_GOAL_GROUP);
+		}
+		end = jiffies;
+		all += (end - start);
+
+		for (i = 0; i < TEST_RANGE_COUNT; i++) {
+			if (ranges[i].len == 0)
+				continue;
+
+			ext4_lock_group(sb, TEST_GOAL_GROUP);
+			mb_free_blocks(NULL, &e4b, ranges[i].start,
+				       ranges[i].len);
+			ext4_unlock_group(sb, TEST_GOAL_GROUP);
+		}
+	}
+
+	kunit_info(test, "costed jiffies %lu\n", all);
+	ext4_mb_unload_buddy(&e4b);
+}
+
 static const struct mbt_ext4_block_layout mbt_test_layouts[] = {
 	{
 		.blocksize_bits = 10,
···
 	KUNIT_CASE_PARAM(test_mb_mark_used, mbt_layouts_gen_params),
 	KUNIT_CASE_PARAM(test_mb_free_blocks, mbt_layouts_gen_params),
 	KUNIT_CASE_PARAM(test_mark_diskspace_used, mbt_layouts_gen_params),
+	KUNIT_CASE_PARAM_ATTR(test_mb_mark_used_cost, mbt_layouts_gen_params,
+			      { .speed = KUNIT_SPEED_SLOW }),
 	{}
 };
 

fs/ext4/mballoc.c

···
 		return 0;
 	if (order == MB_NUM_ORDERS(sb))
 		order--;
+	if (WARN_ON_ONCE(order > MB_NUM_ORDERS(sb)))
+		order = MB_NUM_ORDERS(sb) - 1;
 	return order;
 }
 
···
 	 * goal length.
 	 */
 	order = fls(ac->ac_g_ex.fe_len) - 1;
+	if (WARN_ON_ONCE(order - 1 > MB_NUM_ORDERS(ac->ac_sb)))
+		order = MB_NUM_ORDERS(ac->ac_sb);
 	min_order = order - sbi->s_mb_best_avail_max_trim_order;
 	if (min_order < 0)
 		min_order = 0;
···
 }
 
 /*
- * Return next linear group for allocation. If linear traversal should not be
- * performed, this function just returns the same group
+ * Return next linear group for allocation.
  */
 static ext4_group_t
-next_linear_group(struct ext4_allocation_context *ac, ext4_group_t group,
-		  ext4_group_t ngroups)
+next_linear_group(ext4_group_t group, ext4_group_t ngroups)
 {
-	if (!should_optimize_scan(ac))
-		goto inc_and_return;
-
-	if (ac->ac_groups_linear_remaining) {
-		ac->ac_groups_linear_remaining--;
-		goto inc_and_return;
-	}
-
-	return group;
-inc_and_return:
 	/*
 	 * Artificially restricted ngroups for non-extent
 	 * files makes group > ngroups possible on first loop.
···
 {
 	*new_cr = ac->ac_criteria;
 
-	if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) {
-		*group = next_linear_group(ac, *group, ngroups);
+	if (!should_optimize_scan(ac)) {
+		*group = next_linear_group(*group, ngroups);
+		return;
+	}
+
+	/*
+	 * Optimized scanning can return non adjacent groups which can cause
+	 * seek overhead for rotational disks. So try few linear groups before
+	 * trying optimized scan.
+	 */
+	if (ac->ac_groups_linear_remaining) {
+		*group = next_linear_group(*group, ngroups);
+		ac->ac_groups_linear_remaining--;
 		return;
 	}
 
···
 		ext4_mb_choose_next_group_best_avail(ac, new_cr, group);
 	} else {
 		/*
-		 * TODO: For CR=2, we can arrange groups in an rb tree sorted by
-		 * bb_free. But until that happens, we should never come here.
+		 * TODO: For CR_GOAL_LEN_SLOW, we can arrange groups in an
+		 * rb tree sorted by bb_free. But until that happens, we should
+		 * never come here.
 		 */
 		WARN_ON(1);
 	}
···
  * for this page; do not hold this lock when calling this routine!
  */
 
-static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
+static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
 {
 	ext4_group_t ngroups;
 	unsigned int blocksize;
···
 	char *bitmap;
 	struct ext4_group_info *grinfo;
 
-	inode = page->mapping->host;
+	inode = folio->mapping->host;
 	sb = inode->i_sb;
 	ngroups = ext4_get_groups_count(sb);
 	blocksize = i_blocksize(inode);
 	blocks_per_page = PAGE_SIZE / blocksize;
 
-	mb_debug(sb, "init page %lu\n", page->index);
+	mb_debug(sb, "init folio %lu\n", folio->index);
 
 	groups_per_page = blocks_per_page >> 1;
 	if (groups_per_page == 0)
···
 	} else
 		bh = &bhs;
 
-	first_group = page->index * blocks_per_page / 2;
+	first_group = folio->index * blocks_per_page / 2;
 
-	/* read all groups the page covers into the cache */
+	/* read all groups the folio covers into the cache */
 	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
 		if (group >= ngroups)
 			break;
···
 		/*
 		 * If page is uptodate then we came here after online resize
 		 * which added some new uninitialized group info structs, so
-		 * we must skip all initialized uptodate buddies on the page,
+		 * we must skip all initialized uptodate buddies on the folio,
 		 * which may be currently in use by an allocating task.
 		 */
-		if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
+		if (folio_test_uptodate(folio) &&
+				!EXT4_MB_GRP_NEED_INIT(grinfo)) {
 			bh[i] = NULL;
 			continue;
 		}
···
 			err = err2;
 	}
 
-	first_block = page->index * blocks_per_page;
+	first_block = folio->index * blocks_per_page;
 	for (i = 0; i < blocks_per_page; i++) {
 		group = (first_block + i) >> 1;
 		if (group >= ngroups)
···
 		 * above
 		 *
 		 */
-		data = page_address(page) + (i * blocksize);
+		data = folio_address(folio) + (i * blocksize);
 		bitmap = bh[group - first_group]->b_data;
 
 		/*
···
 		if ((first_block + i) & 1) {
 			/* this is block of buddy */
 			BUG_ON(incore == NULL);
-			mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
-				group, page->index, i * blocksize);
+			mb_debug(sb, "put buddy for group %u in folio %lu/%x\n",
+				group, folio->index, i * blocksize);
 			trace_ext4_mb_buddy_bitmap_load(sb, group);
 			grinfo->bb_fragments = 0;
 			memset(grinfo->bb_counters, 0,
···
 		} else {
 			/* this is block of bitmap */
 			BUG_ON(incore != NULL);
-			mb_debug(sb, "put bitmap for group %u in page %lu/%x\n",
-				group, page->index, i * blocksize);
+			mb_debug(sb, "put bitmap for group %u in folio %lu/%x\n",
+				group, folio->index, i * blocksize);
 			trace_ext4_mb_bitmap_load(sb, group);
 
 			/* see comments in ext4_mb_put_pa() */
···
 			incore = data;
 		}
 	}
-	SetPageUptodate(page);
+	folio_mark_uptodate(folio);
 
 out:
 	if (bh) {
···
  * Lock the buddy and bitmap pages. This make sure other parallel init_group
  * on the same buddy page doesn't happen whild holding the buddy page lock.
  * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
- * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
+ * are on the same page e4b->bd_buddy_folio is NULL and return value is 0.
  */
 static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
 		ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
···
 	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
 	int block, pnum, poff;
 	int blocks_per_page;
-	struct page *page;
+	struct folio *folio;
 
-	e4b->bd_buddy_page = NULL;
-	e4b->bd_bitmap_page = NULL;
+	e4b->bd_buddy_folio = NULL;
+	e4b->bd_bitmap_folio = NULL;
 
 	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
 	/*
···
 	block = group * 2;
 	pnum = block / blocks_per_page;
 	poff = block % blocks_per_page;
-	page = find_or_create_page(inode->i_mapping, pnum, gfp);
-	if (!page)
-		return -ENOMEM;
-	BUG_ON(page->mapping != inode->i_mapping);
-	e4b->bd_bitmap_page = page;
-	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
+	folio = __filemap_get_folio(inode->i_mapping, pnum,
+			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	BUG_ON(folio->mapping != inode->i_mapping);
+	e4b->bd_bitmap_folio = folio;
+	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
 
 	if (blocks_per_page >= 2) {
 		/* buddy and bitmap are on the same page */
···
 	}
 
 	/* blocks_per_page == 1, hence we need another page for the buddy */
-	page = find_or_create_page(inode->i_mapping, block + 1, gfp);
-	if (!page)
-		return -ENOMEM;
-	BUG_ON(page->mapping != inode->i_mapping);
-	e4b->bd_buddy_page = page;
+	folio = __filemap_get_folio(inode->i_mapping, block + 1,
+			FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	BUG_ON(folio->mapping != inode->i_mapping);
+	e4b->bd_buddy_folio = folio;
 	return 0;
 }
 
 static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
 {
-	if (e4b->bd_bitmap_page) {
-		unlock_page(e4b->bd_bitmap_page);
-		put_page(e4b->bd_bitmap_page);
+	if (e4b->bd_bitmap_folio) {
+		folio_unlock(e4b->bd_bitmap_folio);
+		folio_put(e4b->bd_bitmap_folio);
 	}
-	if (e4b->bd_buddy_page) {
-		unlock_page(e4b->bd_buddy_page);
-		put_page(e4b->bd_buddy_page);
+	if (e4b->bd_buddy_folio) {
+		folio_unlock(e4b->bd_buddy_folio);
+		folio_put(e4b->bd_buddy_folio);
 	}
 }
 
···
 
 	struct ext4_group_info *this_grp;
 	struct ext4_buddy e4b;
-	struct page *page;
+	struct folio *folio;
 	int ret = 0;
 
 	might_sleep();
···
 		goto err;
 	}
 
-	page = e4b.bd_bitmap_page;
-	ret = ext4_mb_init_cache(page, NULL, gfp);
+	folio = e4b.bd_bitmap_folio;
+	ret = ext4_mb_init_cache(folio, NULL, gfp);
 	if (ret)
 		goto err;
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
 
-	if (e4b.bd_buddy_page == NULL) {
+	if (e4b.bd_buddy_folio == NULL) {
 		/*
 		 * If both the bitmap and buddy are in
 		 * the same page we don't need to force
···
 		goto err;
 	}
 	/* init buddy cache */
-	page = e4b.bd_buddy_page;
-	ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
+	folio = e4b.bd_buddy_folio;
+	ret = ext4_mb_init_cache(folio, e4b.bd_bitmap, gfp);
 	if (ret)
 		goto err;
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
···
 	int block;
 	int pnum;
 	int poff;
-	struct page *page;
+	struct folio *folio;
 	int ret;
 	struct ext4_group_info *grp;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
···
 	e4b->bd_info = grp;
 	e4b->bd_sb = sb;
 	e4b->bd_group = group;
-	e4b->bd_buddy_page = NULL;
-	e4b->bd_bitmap_page = NULL;
+	e4b->bd_buddy_folio = NULL;
+	e4b->bd_bitmap_folio = NULL;
 
 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
 		/*
···
 	pnum = block / blocks_per_page;
 	poff = block % blocks_per_page;
 
-	/* we could use find_or_create_page(), but it locks page
-	 * what we'd like to avoid in fast path ... */
-	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
-	if (page == NULL || !PageUptodate(page)) {
-		if (page)
+	/* Avoid locking the folio in the fast path ... */
+	folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
+	if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+		if (!IS_ERR(folio))
 			/*
-			 * drop the page reference and try
-			 * to get the page with lock. If we
+			 * drop the folio reference and try
+			 * to get the folio with lock. If we
 			 * are not uptodate that implies
-			 * somebody just created the page but
-			 * is yet to initialize the same. So
+			 * somebody just created the folio but
+			 * is yet to initialize it. So
 			 * wait for it to initialize.
 			 */
-			put_page(page);
-		page = find_or_create_page(inode->i_mapping, pnum, gfp);
-		if (page) {
-			if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
-	"ext4: bitmap's paging->mapping != inode->i_mapping\n")) {
+			folio_put(folio);
+		folio = __filemap_get_folio(inode->i_mapping, pnum,
+				FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+		if (!IS_ERR(folio)) {
+			if (WARN_RATELIMIT(folio->mapping != inode->i_mapping,
+	"ext4: bitmap's mapping != inode->i_mapping\n")) {
 				/* should never happen */
-				unlock_page(page);
+				folio_unlock(folio);
 				ret = -EINVAL;
 				goto err;
 			}
-			if (!PageUptodate(page)) {
-				ret = ext4_mb_init_cache(page, NULL, gfp);
+			if (!folio_test_uptodate(folio)) {
+				ret = ext4_mb_init_cache(folio, NULL, gfp);
 				if (ret) {
-					unlock_page(page);
+					folio_unlock(folio);
 					goto err;
 				}
-				mb_cmp_bitmaps(e4b, page_address(page) +
+				mb_cmp_bitmaps(e4b, folio_address(folio) +
 					       (poff * sb->s_blocksize));
 			}
-			unlock_page(page);
+			folio_unlock(folio);
 		}
 	}
-	if (page == NULL) {
-		ret = -ENOMEM;
+	if (IS_ERR(folio)) {
+		ret = PTR_ERR(folio);
 		goto err;
 	}
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
 
-	/* Pages marked accessed already */
-	e4b->bd_bitmap_page = page;
-	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
+	/* Folios marked accessed already */
+	e4b->bd_bitmap_folio = folio;
+	e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
 
 	block++;
 	pnum = block / blocks_per_page;
 	poff = block % blocks_per_page;
 
-	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
-	if (page == NULL || !PageUptodate(page)) {
-		if (page)
-			put_page(page);
-		page = find_or_create_page(inode->i_mapping, pnum, gfp);
-		if (page) {
-			if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
-	"ext4: buddy bitmap's page->mapping != inode->i_mapping\n")) {
+	folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
+	if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+		if (!IS_ERR(folio))
+			folio_put(folio);
+		folio = __filemap_get_folio(inode->i_mapping, pnum,
+				FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+		if (!IS_ERR(folio)) {
+			if (WARN_RATELIMIT(folio->mapping != inode->i_mapping,
+	"ext4: buddy bitmap's mapping != inode->i_mapping\n")) {
 				/* should never happen */
-				unlock_page(page);
+				folio_unlock(folio);
 				ret = -EINVAL;
 				goto err;
 			}
-			if (!PageUptodate(page)) {
-				ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
+			if (!folio_test_uptodate(folio)) {
+				ret = ext4_mb_init_cache(folio, e4b->bd_bitmap,
 							 gfp);
 				if (ret) {
-					unlock_page(page);
+					folio_unlock(folio);
 					goto err;
 				}
 			}
-			unlock_page(page);
+			folio_unlock(folio);
 		}
 	}
-	if (page == NULL) {
-		ret = -ENOMEM;
+	if (IS_ERR(folio)) {
+		ret = PTR_ERR(folio);
 		goto err;
 	}
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		ret = -EIO;
 		goto err;
 	}
 
-	/* Pages marked accessed already */
-	e4b->bd_buddy_page = page;
-	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
+	/* Folios marked accessed already */
+	e4b->bd_buddy_folio = folio;
+	e4b->bd_buddy = folio_address(folio) + (poff * sb->s_blocksize);
 
 	return 0;
 
 err:
-	if (page)
-		put_page(page);
-	if (e4b->bd_bitmap_page)
-		put_page(e4b->bd_bitmap_page);
+	if (!IS_ERR_OR_NULL(folio))
+		folio_put(folio);
+	if (e4b->bd_bitmap_folio)
+		folio_put(e4b->bd_bitmap_folio);
 
 	e4b->bd_buddy = NULL;
 	e4b->bd_bitmap = NULL;
···
 
 static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
 {
-	if (e4b->bd_bitmap_page)
-		put_page(e4b->bd_bitmap_page);
-	if (e4b->bd_buddy_page)
-		put_page(e4b->bd_buddy_page);
+	if (e4b->bd_bitmap_folio)
+		folio_put(e4b->bd_bitmap_folio);
+	if (e4b->bd_buddy_folio)
+		folio_put(e4b->bd_buddy_folio);
 }
 
 
···
 	int ord;
 	int mlen = 0;
 	int max = 0;
-	int cur;
 	int start = ex->fe_start;
 	int len = ex->fe_len;
 	unsigned ret = 0;
 	int len0 = len;
 	void *buddy;
-	bool split = false;
+	int ord_start, ord_end;
 
 	BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
 	BUG_ON(e4b->bd_group != ex->fe_group);
···
 
 	/* let's maintain buddy itself */
 	while (len) {
-		if (!split)
-			ord = mb_find_order_for_block(e4b, start);
+		ord = mb_find_order_for_block(e4b, start);
 
 		if (((start >> ord) << ord) == start && len >= (1 << ord)) {
 			/* the whole chunk may be allocated at once! */
 			mlen = 1 << ord;
-			if (!split)
-				buddy = mb_find_buddy(e4b, ord, &max);
-			else
-				split = false;
+			buddy = mb_find_buddy(e4b, ord, &max);
 			BUG_ON((start >> ord) >= max);
 			mb_set_bit(start >> ord, buddy);
 			e4b->bd_info->bb_counters[ord]--;
···
 		if (ret == 0)
 			ret = len | (ord << 16);
 
-		/* we have to split large buddy */
 		BUG_ON(ord <= 0);
 		buddy = mb_find_buddy(e4b, ord, &max);
 		mb_set_bit(start >> ord, buddy);
 		e4b->bd_info->bb_counters[ord]--;
 
-		ord--;
-		cur = (start >> ord) & ~1U;
-		buddy = mb_find_buddy(e4b, ord, &max);
-		mb_clear_bit(cur, buddy);
-		mb_clear_bit(cur + 1, buddy);
-		e4b->bd_info->bb_counters[ord]++;
-		e4b->bd_info->bb_counters[ord]++;
-		split = true;
+		ord_start = (start >> ord) << ord;
+		ord_end = ord_start + (1 << ord);
+		/* first chunk */
+		if (start > ord_start)
+			ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy,
+						 ord_start, start - ord_start,
+						 e4b->bd_info);
+
+		/* last chunk */
+		if (start + len < ord_end) {
+			ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy,
+						 start + len,
+						 ord_end - (start + len),
+						 e4b->bd_info);
+			break;
+		}
+		len = start + len - ord_end;
+		start = ord_end;
 	}
 	mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
 
···
 	 * double allocate blocks. The reference is dropped
 	 * in ext4_mb_release_context
 	 */
-	ac->ac_bitmap_page = e4b->bd_bitmap_page;
-	get_page(ac->ac_bitmap_page);
-	ac->ac_buddy_page = e4b->bd_buddy_page;
-	get_page(ac->ac_buddy_page);
+	ac->ac_bitmap_folio = e4b->bd_bitmap_folio;
+	folio_get(ac->ac_bitmap_folio);
+	ac->ac_buddy_folio = e4b->bd_buddy_folio;
+	folio_get(ac->ac_buddy_folio);
 	/* store last allocated for subsequent stream allocation */
 	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
 		spin_lock(&sbi->s_md_lock);
···
 		int ret;
 
 		/*
-		 * cr=CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic
+		 * CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic
 		 * search to find large good chunks almost for free. If buddy
 		 * data is not ready, then this optimization makes no sense. But
 		 * we never skip the first block group in a flex_bg, since this
···
 		group = ac->ac_g_ex.fe_group;
 		ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups;
 		prefetch_grp = group;
+		nr = 0;
 
 		for (i = 0, new_cr = cr; i < ngroups; i++,
 		     ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) {
···
 }
 
 static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos)
-__acquires(&EXT4_SB(sb)->s_mb_rb_lock)
 {
 	struct super_block *sb = pde_data(file_inode(seq->file));
 	unsigned long position;
···
 	}
 	if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))
 		sbi->s_mb_prefetch = ext4_get_groups_count(sb);
-	/* now many real IOs to prefetch within a single allocation at cr=0
-	 * given cr=0 is an CPU-related optimization we shouldn't try to
-	 * load too many groups, at some point we should start to use what
-	 * we've got in memory.
+	/*
+	 * now many real IOs to prefetch within a single allocation at
+	 * CR_POWER2_ALIGNED. Given CR_POWER2_ALIGNED is an CPU-related
+	 * optimization we shouldn't try to load too many groups, at some point
+	 * we should start to use what we've got in memory.
 	 * with an average random access time 5ms, it'd take a second to get
 	 * 200 groups (* N with flex_bg), so let's make this limit 4
 	 */
···
 		/* No more items in the per group rb tree
 		 * balance refcounts from ext4_mb_free_metadata()
 		 */
-		put_page(e4b.bd_buddy_page);
-		put_page(e4b.bd_bitmap_page);
+		folio_put(e4b.bd_buddy_folio);
+		folio_put(e4b.bd_bitmap_folio);
 	}
 	ext4_unlock_group(sb, entry->efd_group);
 	ext4_mb_unload_buddy(&e4b);
···
 
 		ext4_mb_put_pa(ac, ac->ac_sb, pa);
 	}
-	if (ac->ac_bitmap_page)
-		put_page(ac->ac_bitmap_page);
-	if (ac->ac_buddy_page)
-		put_page(ac->ac_buddy_page);
+	if (ac->ac_bitmap_folio)
+		folio_put(ac->ac_bitmap_folio);
+	if (ac->ac_buddy_folio)
+		folio_put(ac->ac_buddy_folio);
 	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
 		mutex_unlock(&ac->ac_lg->lg_mutex);
 	ext4_mb_collect_stats(ac);
···
 	ext4_mb_mark_bb(sb, block, 1, true);
 	ar->len = 1;
 
+	*errp = 0;
 	return block;
 }
 
···
 	struct rb_node *parent = NULL, *new_node;
 
 	BUG_ON(!ext4_handle_valid(handle));
-	BUG_ON(e4b->bd_bitmap_page == NULL);
-	BUG_ON(e4b->bd_buddy_page == NULL);
+	BUG_ON(e4b->bd_bitmap_folio == NULL);
+	BUG_ON(e4b->bd_buddy_folio == NULL);
 
 	new_node = &new_entry->efd_node;
 	cluster = new_entry->efd_start_cluster;
···
 		 * otherwise we'll refresh it from
 		 * on-disk bitmap and lose not-yet-available
 		 * blocks */
-		get_page(e4b->bd_buddy_page);
-		get_page(e4b->bd_bitmap_page);
+		folio_get(e4b->bd_buddy_folio);
+		folio_get(e4b->bd_bitmap_folio);
 	}
 	while (*n) {
 		parent = *n;

fs/ext4/mballoc.h

···
 	struct ext4_free_extent ac_f_ex;
 
 	/*
-	 * goal len can change in CR1.5, so save the original len. This is
-	 * used while adjusting the PA window and for accounting.
+	 * goal len can change in CR_BEST_AVAIL_LEN, so save the original len.
+	 * This is used while adjusting the PA window and for accounting.
 	 */
 	ext4_grpblk_t	ac_orig_goal_len;
 
 	__u32 ac_flags;		/* allocation hints */
+	__u32 ac_groups_linear_remaining;
 	__u16 ac_groups_scanned;
-	__u16 ac_groups_linear_remaining;
 	__u16 ac_found;
 	__u16 ac_cX_found[EXT4_MB_NUM_CRS];
 	__u16 ac_tail;
···
 	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
 				 * N > 0, the field stores N, otherwise 0 */
 	__u8 ac_op;		/* operation, for history only */
-	struct page *ac_bitmap_page;
-	struct page *ac_buddy_page;
+	struct folio *ac_bitmap_folio;
+	struct folio *ac_buddy_folio;
 	struct ext4_prealloc_space *ac_pa;
 	struct ext4_locality_group *ac_lg;
 };
···
 #define AC_STATUS_BREAK		3
 
 struct ext4_buddy {
-	struct page *bd_buddy_page;
+	struct folio *bd_buddy_folio;
 	void *bd_buddy;
-	struct page *bd_bitmap_page;
+	struct folio *bd_bitmap_folio;
 	void *bd_bitmap;
 	struct ext4_group_info *bd_info;
 	struct super_block *bd_sb;

fs/ext4/move_extent.c

···
 			continue;
 		if (!buffer_mapped(bh)) {
 			err = ext4_get_block(inode, block, bh, 0);
-			if (err) {
-				folio_set_error(folio);
+			if (err)
 				return err;
-			}
 			if (!buffer_mapped(bh)) {
 				folio_zero_range(folio, block_start, blocksize);
 				set_buffer_uptodate(bh);

fs/ext4/namei.c

···
 	inode = ext4_new_inode_start_handle(idmap, dir, mode,
 					    NULL, 0, NULL,
 					    EXT4_HT_DIR,
-			EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
+			EXT4_MAXQUOTAS_TRANS_BLOCKS(dir->i_sb) +
 			  4 + EXT4_XATTR_TRANS_BLOCKS);
 	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);

fs/ext4/page-io.c

···
 
 		if (bio->bi_status) {
 			int err = blk_status_to_errno(bio->bi_status);
-			folio_set_error(folio);
 			mapping_set_error(folio->mapping, err);
 		}
 		bh = head = folio_buffers(folio);
···
 
 	BUG_ON(!folio_test_locked(folio));
 	BUG_ON(folio_test_writeback(folio));
-
-	folio_clear_error(folio);
 
 	/*
 	 * Comments copied from block_write_full_folio:

fs/ext4/readpage.c

···
 
 				if (ext4_map_blocks(NULL, inode, &map, 0) < 0) {
 				set_error_page:
-					folio_set_error(folio);
 					folio_zero_segment(folio, 0,
 							  folio_size(folio));
 					folio_unlock(folio);

fs/ext4/super.c

···
 {
 	struct ext4_fs_context *ctx = fc->fs_private;
 
-	if (ctx->s_qf_names[qtype])
-		kfree(ctx->s_qf_names[qtype]);
+	kfree(ctx->s_qf_names[qtype]);
 
 	ctx->s_qf_names[qtype] = NULL;
 	ctx->qname_spec |= 1 << qtype;
···
 			param.size = v_len;
 
 			ret = ext4_parse_param(fc, &param);
-			if (param.string)
-				kfree(param.string);
+			kfree(param.string);
 			if (ret < 0)
 				return ret;
 		}
···
 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
 #endif
 	super_set_uuid(sb, es->s_uuid, sizeof(es->s_uuid));
+	super_set_sysfs_name_bdev(sb);
 
 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
 	mutex_init(&sbi->s_orphan_lock);
···
 	if (err)
 		goto failed_mount6;
 
-	err = ext4_register_sysfs(sb);
-	if (err)
-		goto failed_mount7;
-
 	err = ext4_init_orphan_info(sb);
 	if (err)
-		goto failed_mount8;
+		goto failed_mount7;
 #ifdef CONFIG_QUOTA
 	/* Enable quota usage during mount. */
 	if (ext4_has_feature_quota(sb) && !sb_rdonly(sb)) {
 		err = ext4_enable_quotas(sb);
 		if (err)
-			goto failed_mount9;
+			goto failed_mount8;
 	}
 #endif  /* CONFIG_QUOTA */
 
···
 		ext4_msg(sb, KERN_INFO, "recovery complete");
 		err = ext4_mark_recovery_complete(sb, es);
 		if (err)
-			goto failed_mount10;
+			goto failed_mount9;
 	}
 
 	if (test_opt(sb, DISCARD) && !bdev_max_discard_sectors(sb->s_bdev))
···
 	atomic_set(&sbi->s_warning_count, 0);
 	atomic_set(&sbi->s_msg_count, 0);
 
+	/* Register sysfs after all initializations are complete. */
+	err = ext4_register_sysfs(sb);
+	if (err)
+		goto failed_mount9;
+
 	return 0;
 
-failed_mount10:
+failed_mount9:
 	ext4_quotas_off(sb, EXT4_MAXQUOTAS);
-failed_mount9: __maybe_unused
+failed_mount8: __maybe_unused
 	ext4_release_orphan_info(sb);
-failed_mount8:
-	ext4_unregister_sysfs(sb);
-	kobject_put(&sbi->s_kobj);
 failed_mount7:
 	ext4_unregister_li_request(sb);
 failed_mount6:
···
 			__ext4_update_tstamp(&es->s_first_error_time,
 					     &es->s_first_error_time_hi,
 					     sbi->s_first_error_time);
-			strncpy(es->s_first_error_func, sbi->s_first_error_func,
-				sizeof(es->s_first_error_func));
+			strtomem_pad(es->s_first_error_func,
+				     sbi->s_first_error_func, 0);
 			es->s_first_error_line =
 				cpu_to_le32(sbi->s_first_error_line);
 			es->s_first_error_ino =
···
 		__ext4_update_tstamp(&es->s_last_error_time,
 				     &es->s_last_error_time_hi,
 				     sbi->s_last_error_time);
-		strncpy(es->s_last_error_func, sbi->s_last_error_func,
-			sizeof(es->s_last_error_func));
+		strtomem_pad(es->s_last_error_func, sbi->s_last_error_func, 0);
 		es->s_last_error_line = cpu_to_le32(sbi->s_last_error_line);
 		es->s_last_error_ino = cpu_to_le32(sbi->s_last_error_ino);
 		es->s_last_error_block = cpu_to_le64(sbi->s_last_error_block);

fs/ext4/sysfs.c

···
 	attr_trigger_test_error,
 	attr_first_error_time,
 	attr_last_error_time,
+	attr_clusters_in_group,
+	attr_mb_order,
 	attr_feature,
+	attr_pointer_pi,
 	attr_pointer_ui,
 	attr_pointer_ul,
 	attr_pointer_u64,
···
 	int ret;
 
 	ret = kstrtoull(skip_spaces(buf), 0, &val);
-	if (ret || val >= clusters)
+	if (ret || val >= clusters || (s64)val < 0)
 		return -EINVAL;
 
 	atomic64_set(&sbi->s_resv_clusters, val);
···
 #define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size)			\
 	EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)
 
+#define EXT4_RW_ATTR_SBI_PI(_name,_elname)      \
+	EXT4_ATTR_OFFSET(_name, 0644, pointer_pi, ext4_sb_info, _elname)
+
 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)	\
 	EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 
···
 
 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 		 ext4_sb_info, s_inode_readahead_blks);
+EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group,
+		 ext4_sb_info, s_mb_group_prealloc);
+EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order,
+		 ext4_sb_info, s_mb_best_avail_max_trim_order);
 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
-EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 EXT4_RW_ATTR_SBI_UI(mb_max_linear_groups, s_mb_max_linear_groups);
 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
-EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
-EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
-EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
-EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
-EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
-EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
-EXT4_RW_ATTR_SBI_UI(mb_best_avail_max_trim_order, s_mb_best_avail_max_trim_order);
+EXT4_RW_ATTR_SBI_PI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(err_ratelimit_burst, s_err_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 #ifdef CONFIG_EXT4_DEBUG
 EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
 #endif
···
 #define print_tstamp(buf, es, tstamp) \
 	__print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
 
+static ssize_t ext4_generic_attr_show(struct ext4_attr *a,
+				      struct ext4_sb_info *sbi, char *buf)
+{
+	void *ptr = calc_ptr(a, sbi);
+
+	if (!ptr)
+		return 0;
+
+	switch (a->attr_id) {
+	case attr_inode_readahead:
+	case attr_clusters_in_group:
+	case attr_mb_order:
+	case attr_pointer_pi:
+	case attr_pointer_ui:
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr));
+		return sysfs_emit(buf, "%u\n", *((unsigned int *) ptr));
+	case attr_pointer_ul:
+		return sysfs_emit(buf, "%lu\n", *((unsigned long *) ptr));
+	case attr_pointer_u8:
+		return sysfs_emit(buf, "%u\n", *((unsigned char *) ptr));
+	case attr_pointer_u64:
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			return sysfs_emit(buf, "%llu\n", le64_to_cpup(ptr));
+		return sysfs_emit(buf, "%llu\n", *((unsigned long long *) ptr));
+	case attr_pointer_string:
+		return sysfs_emit(buf, "%.*s\n", a->attr_size, (char *) ptr);
+	case attr_pointer_atomic:
+		return sysfs_emit(buf, "%d\n", atomic_read((atomic_t *) ptr));
+	}
+	return 0;
+}
+
 static ssize_t ext4_attr_show(struct kobject *kobj,
 			      struct attribute *attr, char *buf)
 {
 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 						s_kobj);
 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
-	void *ptr = calc_ptr(a, sbi);
 
 	switch (a->attr_id) {
 	case attr_delayed_allocation_blocks:
···
 		return sysfs_emit(buf, "%llu\n",
 				(unsigned long long)
 			percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit));
-	case attr_inode_readahead:
-	case attr_pointer_ui:
-		if (!ptr)
-			return 0;
-		if (a->attr_ptr == ptr_ext4_super_block_offset)
-			return sysfs_emit(buf, "%u\n",
-					le32_to_cpup(ptr));
-		else
-			return sysfs_emit(buf, "%u\n",
-					*((unsigned int *) ptr));
-	case attr_pointer_ul:
-		if (!ptr)
-			return 0;
-		return sysfs_emit(buf, "%lu\n",
-				*((unsigned long *) ptr));
-	case attr_pointer_u8:
-		if (!ptr)
-			return 0;
-		return sysfs_emit(buf, "%u\n",
-				*((unsigned char *) ptr));
-	case attr_pointer_u64:
-		if (!ptr)
-			return 0;
-		if (a->attr_ptr == ptr_ext4_super_block_offset)
-			return sysfs_emit(buf, "%llu\n",
-					le64_to_cpup(ptr));
-		else
-			return sysfs_emit(buf, "%llu\n",
-					*((unsigned long long *) ptr));
-	case attr_pointer_string:
-		if (!ptr)
-			return 0;
-		return sysfs_emit(buf, "%.*s\n", a->attr_size,
-				(char *) ptr);
-	case attr_pointer_atomic:
-		if (!ptr)
-			return 0;
-		return sysfs_emit(buf, "%d\n",
-				atomic_read((atomic_t *) ptr));
 	case attr_feature:
 		return sysfs_emit(buf, "supported\n");
 	case attr_first_error_time:
···
 		return print_tstamp(buf, sbi->s_es, s_last_error_time);
 	case attr_journal_task:
 		return journal_task_show(sbi, buf);
+	default:
+		return ext4_generic_attr_show(a, sbi, buf);
 	}
+}
 
+static ssize_t ext4_generic_attr_store(struct ext4_attr *a,
+				       struct ext4_sb_info *sbi,
+				       const char *buf, size_t len)
+{
+	int ret;
+	unsigned int t;
+	unsigned long lt;
+	void *ptr = calc_ptr(a, sbi);
+
+	if (!ptr)
+		return 0;
+
+	switch (a->attr_id) {
+	case attr_pointer_pi:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if ((int)t < 0)
+			return -EINVAL;
+		*((unsigned int *) ptr) = t;
+		return len;
+	case attr_pointer_ui:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (a->attr_ptr == ptr_ext4_super_block_offset)
+			*((__le32 *) ptr) = cpu_to_le32(t);
+		else
+			*((unsigned int *) ptr) = t;
+		return len;
+	case attr_mb_order:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (t > 64)
+			return -EINVAL;
+		*((unsigned int *) ptr) = t;
+		return len;
+	case attr_clusters_in_group:
+		ret = kstrtouint(skip_spaces(buf), 0, &t);
+		if (ret)
+			return ret;
+		if (t > sbi->s_clusters_per_group)
+			return -EINVAL;
+		*((unsigned int *) ptr) = t;
+		return len;
+	case attr_pointer_ul:
+		ret = kstrtoul(skip_spaces(buf), 0, &lt);
+		if (ret)
+			return ret;
+		*((unsigned long *) ptr) = lt;
+		return len;
+	}
 	return 0;
 }
 
···
 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 						s_kobj);
 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
-	void *ptr = calc_ptr(a, sbi);
-	unsigned long t;
-	int ret;
 
 	switch (a->attr_id) {
 	case attr_reserved_clusters:
 		return reserved_clusters_store(sbi, buf, len);
-	case attr_pointer_ui:
-		if (!ptr)
-			return 0;
-		ret = kstrtoul(skip_spaces(buf), 0, &t);
-		if (ret)
-			return ret;
-		if (a->attr_ptr == ptr_ext4_super_block_offset)
-			*((__le32 *) ptr) = cpu_to_le32(t);
-		else
-			*((unsigned int *) ptr) = t;
-		return len;
-	case attr_pointer_ul:
-		if (!ptr)
-			return 0;
-		ret = kstrtoul(skip_spaces(buf), 0, &t);
-		if (ret)
-			return ret;
-		*((unsigned long *) ptr) = t;
-		return len;
 	case attr_inode_readahead:
 		return inode_readahead_blks_store(sbi, buf, len);
 	case attr_trigger_test_error:
 		return trigger_test_error(sbi, buf, len);
+	default:
+		return ext4_generic_attr_store(a, sbi, buf, len);
 	}
-	return 0;
 }
 
 static void ext4_sb_release(struct kobject *kobj)

fs/ext4/xattr.c

···
 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 				struct ext4_xattr_search *s,
 				handle_t *handle, struct inode *inode,
+				struct inode *new_ea_inode,
 				bool is_block)
 {
 	struct ext4_xattr_entry *last, *next;
···
 	size_t min_offs = s->end - s->base, name_len = strlen(i->name);
 	int in_inode = i->in_inode;
 	struct inode *old_ea_inode = NULL;
-	struct inode *new_ea_inode = NULL;
 	size_t old_size, new_size;
 	int ret;
 
···
 			old_ea_inode = NULL;
 			goto out;
 		}
-	}
-	if (i->value && in_inode) {
-		WARN_ON_ONCE(!i->value_len);
 
-		new_ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
-					i->value, i->value_len);
-		if (IS_ERR(new_ea_inode)) {
-			ret = PTR_ERR(new_ea_inode);
-			new_ea_inode = NULL;
-			goto out;
-		}
-	}
-
-	if (old_ea_inode) {
 		/* We are ready to release ref count on the old_ea_inode. */
 		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
-		if (ret) {
-			/* Release newly required ref count on new_ea_inode. */
-			if (new_ea_inode) {
-				int err;
-
-				err = ext4_xattr_inode_dec_ref(handle,
-							       new_ea_inode);
-				if (err)
-					ext4_warning_inode(new_ea_inode,
-						  "dec ref new_ea_inode err=%d",
-						  err);
-				ext4_xattr_inode_free_quota(inode, new_ea_inode,
-							    i->value_len);
-			}
+		if (ret)
 			goto out;
-		}
 
 		ext4_xattr_inode_free_quota(inode, old_ea_inode,
 					    le32_to_cpu(here->e_value_size));
···
 	ret = 0;
 out:
 	iput(old_ea_inode);
-	iput(new_ea_inode);
 	return ret;
 }
 
···
 	size_t old_ea_inode_quota = 0;
 	unsigned int ea_ino;
 
-
 #define header(x) ((struct ext4_xattr_header *)(x))
+
+	/* If we need EA inode, prepare it before locking the buffer */
+	if (i->value && i->in_inode) {
+		WARN_ON_ONCE(!i->value_len);
+
+		ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
+					i->value, i->value_len);
+		if (IS_ERR(ea_inode)) {
+			error = PTR_ERR(ea_inode);
+			ea_inode = NULL;
+			goto cleanup;
+		}
+	}
 
 	if (s->base) {
 		int offset = (char *)s->here - bs->bh->b_data;
···
 						      EXT4_JTR_NONE);
 		if (error)
 			goto cleanup;
+
 		lock_buffer(bs->bh);
 
 		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
···
 			}
 			ea_bdebug(bs->bh, "modifying in-place");
 			error = ext4_xattr_set_entry(i, s, handle, inode,
-						     true /* is_block */);
+					     ea_inode, true /* is_block */);
 			ext4_xattr_block_csum_set(inode, bs->bh);
 			unlock_buffer(bs->bh);
 			if (error == -EFSCORRUPTED)
···
 		s->end = s->base + sb->s_blocksize;
 	}
 
-	error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
+	error = ext4_xattr_set_entry(i, s, handle, inode, ea_inode,
+				     true /* is_block */);
 	if (error == -EFSCORRUPTED)
 		goto bad_block;
 	if (error)
 		goto cleanup;
 
-	if (i->value && s->here->e_value_inum) {
-		/*
-		 * A ref count on ea_inode has been taken as part of the call to
-		 * ext4_xattr_set_entry() above. We would like to drop this
-		 * extra ref but we have to wait until the xattr block is
-		 * initialized and has its own ref count on the ea_inode.
-		 */
-		ea_ino = le32_to_cpu(s->here->e_value_inum);
-		error = ext4_xattr_inode_iget(inode, ea_ino,
-					      le32_to_cpu(s->here->e_hash),
-					      &ea_inode);
-		if (error) {
-			ea_inode = NULL;
-			goto cleanup;
-		}
-	}
-
 inserted:
 	if (!IS_LAST_ENTRY(s->first)) {
-		new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
-						     &ce);
+		new_bh = ext4_xattr_block_cache_find(inode, header(s->base), &ce);
+		if (IS_ERR(new_bh)) {
+			error = PTR_ERR(new_bh);
+			new_bh = NULL;
+			goto cleanup;
+		}
+
 		if (new_bh) {
 			/* We found an identical block in the cache. */
 			if (new_bh == bs->bh)
···
 						      ENTRY(header(s->base)+1));
 			if (error)
 				goto getblk_failed;
+			if (ea_inode) {
+				/* Drop the extra ref on ea_inode. */
+				error = ext4_xattr_inode_dec_ref(handle,
+								 ea_inode);
+				if (error)
+					ext4_warning_inode(ea_inode,
+							   "dec ref error=%d",
+							   error);
+				iput(ea_inode);
+				ea_inode = NULL;
+			}
 
 			lock_buffer(new_bh);
 			error = ext4_journal_get_create_access(handle, sb,
···
 
 cleanup:
 	if (ea_inode) {
-		int error2;
+		if (error) {
+			int error2;
 
-		error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
-		if (error2)
-			ext4_warning_inode(ea_inode, "dec ref error=%d",
-					   error2);
-
-		/* If there was an error, revert the quota charge. */
-		if (error)
+			error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+			if (error2)
+				ext4_warning_inode(ea_inode, "dec ref error=%d",
+						   error2);
 			ext4_xattr_inode_free_quota(inode, ea_inode,
 						    i_size_read(ea_inode));
+		}
 		iput(ea_inode);
 	}
 	if (ce)
···
 {
 	struct ext4_xattr_ibody_header *header;
 	struct ext4_xattr_search *s = &is->s;
+	struct inode *ea_inode = NULL;
 	int error;
 
 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
 		return -ENOSPC;
 
-	error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
-	if (error)
+	/* If we need EA inode, prepare it before locking the buffer */
+	if (i->value && i->in_inode) {
+		WARN_ON_ONCE(!i->value_len);
+
+		ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
+					i->value, i->value_len);
+		if (IS_ERR(ea_inode))
+			return PTR_ERR(ea_inode);
+	}
+	error = ext4_xattr_set_entry(i, s, handle, inode, ea_inode,
+				     false /* is_block */);
+	if (error) {
+		if (ea_inode) {
+			int error2;
+
+			error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+			if (error2)
+				ext4_warning_inode(ea_inode, "dec ref error=%d",
+						   error2);
+
+			ext4_xattr_inode_free_quota(inode, ea_inode,
+						    i_size_read(ea_inode));
+			iput(ea_inode);
+		}
 		return error;
+	}
 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
 	if (!IS_LAST_ENTRY(s->first)) {
 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
···
 		header->h_magic = cpu_to_le32(0);
 		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
 	}
+	iput(ea_inode);
 	return 0;
 }
 
···
  *
  * Find an identical extended attribute block.
  *
- * Returns a pointer to the block found, or NULL if such a block was
- * not found or an error occurred.
+ * Returns a pointer to the block found, or NULL if such a block was not
+ * found, or an error pointer if an error occurred while reading ea block.
  */
 static struct buffer_head *
 ext4_xattr_block_cache_find(struct inode *inode,
···
 
 		bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
 		if (IS_ERR(bh)) {
-			if (PTR_ERR(bh) == -ENOMEM)
-				return NULL;
-			bh = NULL;
-			EXT4_ERROR_INODE(inode, "block %lu read error",
-					 (unsigned long)ce->e_value);
+			if (PTR_ERR(bh) != -ENOMEM)
+				EXT4_ERROR_INODE(inode, "block %lu read error",
+						 (unsigned long)ce->e_value);
+			mb_cache_entry_put(ea_block_cache, ce);
+			return bh;
 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
 			*pce = ce;
 			return bh;

fs/jbd2/checkpoint.c

···
 
 /* Checkpoint list management */
 
-enum shrink_type {SHRINK_DESTROY, SHRINK_BUSY_STOP, SHRINK_BUSY_SKIP};
-
 /*
  * journal_shrink_one_cp_list
  *
···
  * Called with j_list_lock held.
  */
 static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
-						enum shrink_type type,
+						enum jbd2_shrink_type type,
 						bool *released)
 {
 	struct journal_head *last_jh;
···
 		jh = next_jh;
 		next_jh = jh->b_cpnext;
 
-		if (type == SHRINK_DESTROY) {
+		if (type == JBD2_SHRINK_DESTROY) {
 			ret = __jbd2_journal_remove_checkpoint(jh);
 		} else {
 			ret = jbd2_journal_try_remove_checkpoint(jh);
 			if (ret < 0) {
-				if (type == SHRINK_BUSY_SKIP)
+				if (type == JBD2_SHRINK_BUSY_SKIP)
 					continue;
 				break;
 			}
···
 		tid = transaction->t_tid;
 
 		freed = journal_shrink_one_cp_list(transaction->t_checkpoint_list,
-						   SHRINK_BUSY_SKIP, &released);
+						   JBD2_SHRINK_BUSY_SKIP, &released);
 		nr_freed += freed;
 		(*nr_to_scan) -= min(*nr_to_scan, freed);
 		if (*nr_to_scan == 0)
···
  * journal_clean_checkpoint_list
  *
  * Find all the written-back checkpoint buffers in the journal and release them.
- * If 'destroy' is set, release all buffers unconditionally.
+ * If 'type' is JBD2_SHRINK_DESTROY, release all buffers unconditionally. If
+ * 'type' is JBD2_SHRINK_BUSY_STOP, will stop release buffers if encounters a
+ * busy buffer. To avoid wasting CPU cycles scanning the buffer list in some
+ * cases, don't pass JBD2_SHRINK_BUSY_SKIP 'type' for this function.
  *
  * Called with j_list_lock held.
  */
-void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
+void __jbd2_journal_clean_checkpoint_list(journal_t *journal,
+					  enum jbd2_shrink_type type)
 {
 	transaction_t *transaction, *last_transaction, *next_transaction;
-	enum shrink_type type;
 	bool released;
+
+	WARN_ON_ONCE(type == JBD2_SHRINK_BUSY_SKIP);
 
 	transaction = journal->j_checkpoint_transactions;
 	if (!transaction)
 		return;
 
-	type = destroy ? SHRINK_DESTROY : SHRINK_BUSY_STOP;
 	last_transaction = transaction->t_cpprev;
 	next_transaction = transaction;
 	do {
···
 			spin_unlock(&journal->j_list_lock);
 			break;
 		}
-		__jbd2_journal_clean_checkpoint_list(journal, true);
+		__jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_DESTROY);
 		spin_unlock(&journal->j_list_lock);
 		cond_resched();
 	}

fs/jbd2/commit.c

···
 	 * frees some memory
 	 */
 	spin_lock(&journal->j_list_lock);
-	__jbd2_journal_clean_checkpoint_list(journal, false);
+	__jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_BUSY_STOP);
 	spin_unlock(&journal->j_list_lock);
 
 	jbd2_debug(3, "JBD2: commit phase 1\n");
···
 	J_ASSERT(commit_transaction->t_nr_buffers <=
 		 atomic_read(&commit_transaction->t_outstanding_credits));
 
-	err = 0;
 	bufs = 0;
 	descriptor = NULL;
 	while (commit_transaction->t_buffers) {

include/linux/jbd2.h

···
 extern void jbd2_journal_commit_transaction(journal_t *);
 
 /* Checkpoint list management */
-void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy);
+enum jbd2_shrink_type {JBD2_SHRINK_DESTROY, JBD2_SHRINK_BUSY_STOP, JBD2_SHRINK_BUSY_SKIP};
+
+void __jbd2_journal_clean_checkpoint_list(journal_t *journal, enum jbd2_shrink_type type);
 unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, unsigned long *nr_to_scan);
 int __jbd2_journal_remove_checkpoint(struct journal_head *);
 int jbd2_journal_try_remove_checkpoint(struct journal_head *jh);