Commit 9da33619 authored by Namjae Jeon's avatar Namjae Jeon
Browse files

exfat: fix soft lockup in exfat_clear_bitmap 



bitmap clear loop will take long time in __exfat_free_cluster()
if data size of file/dir enty is invalid.
If cluster bit in bitmap is already clear, stop clearing bitmap go to
out of loop.

Fixes: 31023864 ("exfat: add fat entry operations")
Reported-by: default avatarKun Hu &lt;huk23@m.fudan.edu.cn&gt;, Jiaji Qin <jjtan24@m.fudan.edu.cn>
Reviewed-by: default avatarSungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
parent 6697f819

fs/exfat/balloc.c

+8 −2
Original line number Diff line number Diff line
@@ -141,7 +141,7 @@ int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync) 
	return 0;

}



void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)

int exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)

{

	int i, b;

	unsigned int ent_idx;
@@ -150,13 +150,17 @@ void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync) 
	struct exfat_mount_options *opts = &sbi->options;



	if (!is_valid_cluster(sbi, clu))

		return;

		return -EIO;



	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);

	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);

	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);



	if (!test_bit_le(b, sbi->vol_amap[i]->b_data))

		return -EIO;



	clear_bit_le(b, sbi->vol_amap[i]->b_data);



	exfat_update_bh(sbi->vol_amap[i], sync);



	if (opts->discard) {
@@ -171,6 +175,8 @@ void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync) 
			opts->discard = 0;

		}

	}



	return 0;

}



/*

fs/exfat/exfat_fs.h

+1 −1
Original line number Diff line number Diff line
@@ -456,7 +456,7 @@ int exfat_count_num_clusters(struct super_block *sb, 
int exfat_load_bitmap(struct super_block *sb);

void exfat_free_bitmap(struct exfat_sb_info *sbi);

int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync);

void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync);

int exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync);

unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu);

int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);

int exfat_trim_fs(struct inode *inode, struct fstrim_range *range);

fs/exfat/fatent.c

+7 −4
Original line number Diff line number Diff line
@@ -175,6 +175,7 @@ static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain 
		BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu));



	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {

		int err;

		unsigned int last_cluster = p_chain->dir + p_chain->size - 1;

		do {

			bool sync = false;
@@ -189,7 +190,9 @@ static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain 
				cur_cmap_i = next_cmap_i;

			}



			exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));

			err = exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));

			if (err)

				break;

			clu++;

			num_clusters++;

		} while (num_clusters < p_chain->size);
@@ -210,12 +213,13 @@ static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain 
				cur_cmap_i = next_cmap_i;

			}



			exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));

			if (exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))))

				break;

			clu = n_clu;

			num_clusters++;



			if (err)

				goto dec_used_clus;

				break;



			if (num_clusters >= sbi->num_clusters - EXFAT_FIRST_CLUSTER) {

				/*
@@ -229,7 +233,6 @@ static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain 
		} while (clu != EXFAT_EOF_CLUSTER);

	}



dec_used_clus:

	sbi->used_clusters -= num_clusters;

	return 0;

}