Commit 4a622e4d authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: fix FS_IOC_GETFSMAP handling 



The original implementation ext4's FS_IOC_GETFSMAP handling only
worked when the range of queried blocks included at least one free
(unallocated) block range.  This is because how the metadata blocks
were emitted was as a side effect of ext4_mballoc_query_range()
calling ext4_getfsmap_datadev_helper(), and that function was only
called when a free block range was identified.  As a result, this
caused generic/365 to fail.

Fix this by creating a new function ext4_getfsmap_meta_helper() which
gets called so that blocks before the first free block range in a
block group can get properly reported.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
parent 40eb3104

fs/ext4/fsmap.c

+53 −1
Original line number Diff line number Diff line
@@ -185,6 +185,56 @@ static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr) 
	return fmr->fmr_physical + fmr->fmr_length;

}



static int ext4_getfsmap_meta_helper(struct super_block *sb,

				     ext4_group_t agno, ext4_grpblk_t start,

				     ext4_grpblk_t len, void *priv)

{

	struct ext4_getfsmap_info *info = priv;

	struct ext4_fsmap *p;

	struct ext4_fsmap *tmp;

	struct ext4_sb_info *sbi = EXT4_SB(sb);

	ext4_fsblk_t fsb, fs_start, fs_end;

	int error;



	fs_start = fsb = (EXT4_C2B(sbi, start) +

			  ext4_group_first_block_no(sb, agno));

	fs_end = fs_start + EXT4_C2B(sbi, len);



	/* Return relevant extents from the meta_list */

	list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {

		if (p->fmr_physical < info->gfi_next_fsblk) {

			list_del(&p->fmr_list);

			kfree(p);

			continue;

		}

		if (p->fmr_physical <= fs_start ||

		    p->fmr_physical + p->fmr_length <= fs_end) {

			/* Emit the retained free extent record if present */

			if (info->gfi_lastfree.fmr_owner) {

				error = ext4_getfsmap_helper(sb, info,

							&info->gfi_lastfree);

				if (error)

					return error;

				info->gfi_lastfree.fmr_owner = 0;

			}

			error = ext4_getfsmap_helper(sb, info, p);

			if (error)

				return error;

			fsb = p->fmr_physical + p->fmr_length;

			if (info->gfi_next_fsblk < fsb)

				info->gfi_next_fsblk = fsb;

			list_del(&p->fmr_list);

			kfree(p);

			continue;

		}

	}

	if (info->gfi_next_fsblk < fsb)

		info->gfi_next_fsblk = fsb;



	return 0;

}





/* Transform a blockgroup's free record into a fsmap */

static int ext4_getfsmap_datadev_helper(struct super_block *sb,

					ext4_group_t agno, ext4_grpblk_t start,
@@ -539,6 +589,7 @@ static int ext4_getfsmap_datadev(struct super_block *sb, 
		error = ext4_mballoc_query_range(sb, info->gfi_agno,

				EXT4_B2C(sbi, info->gfi_low.fmr_physical),

				EXT4_B2C(sbi, info->gfi_high.fmr_physical),

				ext4_getfsmap_meta_helper,

				ext4_getfsmap_datadev_helper, info);

		if (error)

			goto err;
@@ -560,7 +611,8 @@ static int ext4_getfsmap_datadev(struct super_block *sb, 


	/* Report any gaps at the end of the bg */

	info->gfi_last = true;

	error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);

	error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster + 1,

					     0, info);

	if (error)

		goto err;

fs/ext4/mballoc.c

+14 −4
Original line number Diff line number Diff line
@@ -6999,13 +6999,14 @@ int 
ext4_mballoc_query_range(

	struct super_block		*sb,

	ext4_group_t			group,

	ext4_grpblk_t			start,

	ext4_grpblk_t			first,

	ext4_grpblk_t			end,

	ext4_mballoc_query_range_fn	meta_formatter,

	ext4_mballoc_query_range_fn	formatter,

	void				*priv)

{

	void				*bitmap;

	ext4_grpblk_t			next;

	ext4_grpblk_t			start, next;

	struct ext4_buddy		e4b;

	int				error;
@@ -7016,10 +7017,19 @@ ext4_mballoc_query_range( 


	ext4_lock_group(sb, group);



	start = max(e4b.bd_info->bb_first_free, start);

	start = max(e4b.bd_info->bb_first_free, first);

	if (end >= EXT4_CLUSTERS_PER_GROUP(sb))

		end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;



	if (meta_formatter && start != first) {

		if (start > end)

			start = end;

		ext4_unlock_group(sb, group);

		error = meta_formatter(sb, group, first, start - first,

				       priv);

		if (error)

			goto out_unload;

		ext4_lock_group(sb, group);

	}

	while (start <= end) {

		start = mb_find_next_zero_bit(bitmap, end + 1, start);

		if (start > end)

fs/ext4/mballoc.h

+1 −0
Original line number Diff line number Diff line
@@ -259,6 +259,7 @@ ext4_mballoc_query_range( 
	ext4_group_t			agno,

	ext4_grpblk_t			start,

	ext4_grpblk_t			end,

	ext4_mballoc_query_range_fn	meta_formatter,

	ext4_mballoc_query_range_fn	formatter,

	void				*priv);