From 5c2d728507299f84631ab8020d6f0f98f2cb8fc2 Mon Sep 17 00:00:00 2001 From: Hyeongseok Kim Date: Tue, 2 Mar 2021 14:05:20 +0900 Subject: [Backport 5c2d72850729] exfat: introduce bitmap_lock for cluster bitmap access s_lock which is for protecting concurrent access of file operations is too huge for cluster bitmap protection, so introduce a new bitmap_lock to narrow the lock range if only need to access cluster bitmap. Signed-off-by: Hyeongseok Kim Acked-by: Sungjong Seo Signed-off-by: Namjae Jeon --- src/exfat_fs.h | 1 + src/fatent.c | 37 +++++++++++++++++++++++++++++-------- src/super.c | 1 + 3 files changed, 31 insertions(+), 8 deletions(-) diff --git a/src/exfat_fs.h b/src/exfat_fs.h index fa21421a14d9e047add5b9b03c0970b4fd4d7522..e05e0a3152c0e5c415bd042e40d680194f02b49e 100644 --- a/src/exfat_fs.h +++ b/src/exfat_fs.h @@ -238,6 +238,7 @@ struct exfat_sb_info { unsigned int used_clusters; /* number of used clusters */ struct mutex s_lock; /* superblock lock */ + struct mutex bitmap_lock; /* bitmap lock */ struct exfat_mount_options options; struct nls_table *nls_io; /* Charset used for input and display */ struct ratelimit_state ratelimit; diff --git a/src/fatent.c b/src/fatent.c index 7b2e8af17193bfffe00b4e0b8b88cccb34b1970a..fd6c7fd127620fc405cff2b5ae2d6fae5be25422 100644 --- a/src/fatent.c +++ b/src/fatent.c @@ -151,13 +151,14 @@ int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain, return 0; } -int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) +/* This function must be called with bitmap_lock held */ +static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) { - unsigned int num_clusters = 0; - unsigned int clu; struct super_block *sb = inode->i_sb; struct exfat_sb_info *sbi = EXFAT_SB(sb); int cur_cmap_i, next_cmap_i; + unsigned int num_clusters = 0; + unsigned int clu; /* invalid cluster number */ if (p_chain->dir == EXFAT_FREE_CLUSTER || @@ -230,6 +231,17 @@ int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) return 0; } +int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) +{ + int ret = 0; + + mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock); + ret = __exfat_free_cluster(inode, p_chain); + mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock); + + return ret; +} + int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, unsigned int *ret_clu) { @@ -328,6 +340,8 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, if (num_alloc > total_cnt - sbi->used_clusters) return -ENOSPC; + mutex_lock(&sbi->bitmap_lock); + hint_clu = p_chain->dir; /* find new cluster */ if (hint_clu == EXFAT_EOF_CLUSTER) { @@ -338,8 +352,10 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, } hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); - if (hint_clu == EXFAT_EOF_CLUSTER) - return -ENOSPC; + if (hint_clu == EXFAT_EOF_CLUSTER) { + ret = -ENOSPC; + goto unlock; + } } /* check cluster validation */ @@ -349,8 +365,10 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, hint_clu = EXFAT_FIRST_CLUSTER; if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { if (exfat_chain_cont_cluster(sb, p_chain->dir, - num_clusters)) - return -EIO; + num_clusters)) { + ret = -EIO; + goto unlock; + } p_chain->flags = ALLOC_FAT_CHAIN; } } @@ -400,6 +418,7 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, sbi->used_clusters += num_clusters; p_chain->size += num_clusters; + mutex_unlock(&sbi->bitmap_lock); return 0; } @@ -419,7 +438,9 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, } free_cluster: if (num_clusters) - exfat_free_cluster(inode, p_chain); + __exfat_free_cluster(inode, p_chain); +unlock: + mutex_unlock(&sbi->bitmap_lock); return ret; } diff --git a/src/super.c b/src/super.c index c6d8d2e534865236d16386575627e0a442a8db52..d38d17a77e76c45a006abeae532a6ae3170529d7 100644 --- a/src/super.c +++ b/src/super.c @@ -752,6 +752,7 @@ static int exfat_init_fs_context(struct fs_context *fc) return -ENOMEM; mutex_init(&sbi->s_lock); + mutex_init(&sbi->bitmap_lock); ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); -- 2.31.1