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exfat: support dynamic allocate bh for exfat_entry_set_cache 

[ Upstream commit a3ff29a95f ]

In special cases, a file or a directory may occupied more than 19
directory entries, pre-allocating 3 bh is not enough. Such as
  - Support vendor secondary directory entry in the future.
  - Since file directory entry is damaged, the SecondaryCount
    field is bigger than 18.

So this commit supports dynamic allocation of bh.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Yuezhang Mo 2022-11-09 13:50:22 +08:00 committed by Greg Kroah-Hartman
parent b4dc693b29
commit 92dcd7d6c6
2 changed files with 19 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
fs/exfat/dir.c
View File

@ -618,6 +618,10 @@ int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
bforget(es->bh[i]);
else
brelse(es->bh[i]);
if (IS_DYNAMIC_ES(es))
kfree(es->bh);
kfree(es);
return err;
}
@ -853,6 +857,7 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
/* byte offset in sector */
off = EXFAT_BLK_OFFSET(byte_offset, sb);
es->start_off = off;
es->bh = es->__bh;
/* sector offset in cluster */
sec = EXFAT_B_TO_BLK(byte_offset, sb);
@ -872,6 +877,16 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
es->num_entries = num_entries;
num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
if (num_bh > ARRAY_SIZE(es->__bh)) {
es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_KERNEL);
if (!es->bh) {
brelse(bh);
kfree(es);
return NULL;
}
es->bh[0] = bh;
}
for (i = 1; i < num_bh; i++) {
/* get the next sector */
if (exfat_is_last_sector_in_cluster(sbi, sec)) {

5
fs/exfat/exfat_fs.h
View File

@ -170,10 +170,13 @@ struct exfat_entry_set_cache {
bool modified;
unsigned int start_off;
int num_bh;
struct buffer_head *bh[DIR_CACHE_SIZE];
struct buffer_head *__bh[DIR_CACHE_SIZE];
struct buffer_head **bh;
unsigned int num_entries;
};
#define IS_DYNAMIC_ES(es) ((es)->__bh != (es)->bh)
struct exfat_dir_entry {
struct exfat_chain dir;
int entry;