From a3ff29a95fde16906304455aa8c0bd84eb770258 Mon Sep 17 00:00:00 2001 From: Yuezhang Mo Date: Wed, 9 Nov 2022 13:50:22 +0800 Subject: [PATCH] exfat: support dynamic allocate bh for exfat_entry_set_cache 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 Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon --- fs/exfat/dir.c | 15 +++++++++++++++ fs/exfat/exfat_fs.h | 5 ++++- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index 30d0ac43b66c..03e9c9e3966e 100644 --- a/fs/exfat/dir.c +++ b/fs/exfat/dir.c @@ -615,6 +615,10 @@ 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; } @@ -847,6 +851,7 @@ 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); @@ -866,6 +871,16 @@ 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)) { diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index af55018ff22e..82395ae80dba 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -185,11 +185,14 @@ struct exfat_entry_set_cache { struct super_block *sb; 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; bool modified; }; +#define IS_DYNAMIC_ES(es) ((es)->__bh != (es)->bh) + struct exfat_dir_entry { struct exfat_chain dir; int entry;