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exfat: introduce bitmap_lock for cluster bitmap access

Browse source 
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 <hyeongseok@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
This commit is contained in:
Hyeongseok Kim 2021-03-25 08:09:50 +09:00 • committed by Namjae Jeon
commit 7646a7516d
3 changed files with 32 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

1
exfat_fs.h
View file

@ -247,6 +247,7 @@ 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;

37
fatent.c
View file

@ -159,13 +159,14 @@ 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 ||
@ -238,6 +239,17 @@ dec_used_clus:
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)
{
@ -336,6 +348,8 @@ 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) {
@ -346,8 +360,10 @@ 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 */
@ -357,8 +373,10 @@ 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;
}
}
@ -408,6 +426,7 @@ 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;
}
@ -427,7 +446,9 @@ 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;
}

2
super.c
View file

@ -902,6 +902,7 @@ static int exfat_fill_super(struct super_block *sb, void *data, int silent)
return -ENOMEM;
mutex_init(&sbi->s_lock);
mutex_init(&sbi->bitmap_lock);
sb->s_fs_info = sbi;
ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
@ -1046,6 +1047,7 @@ 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);