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authorTetsuhiro Kohada <kohada.tetsuhiro@dc.mitsubishielectric.co.jp>2020-05-20 10:56:41 +0300
committerNamjae Jeon <namjae.jeon@samsung.com>2020-06-09 10:49:05 +0300
commit943af1fdacfebe4ff13430655abc460a5e1072f7 (patch)
treef11c323bba0aae808b76cc1a9cbedf107faeddd0 /fs/exfat/dir.c
parented0f84d30ba65f44bed2739572c7ab0fdeed4004 (diff)
downloadlinux-943af1fdacfebe4ff13430655abc460a5e1072f7.tar.xz
exfat: optimize dir-cache
Optimize directory access based on exfat_entry_set_cache. - Hold bh instead of copied d-entry. - Modify bh->data directly instead of the copied d-entry. - Write back the retained bh instead of rescanning the d-entry-set. And - Remove unused cache related definitions. Signed-off-by: Tetsuhiro Kohada <kohada.tetsuhiro@dc.mitsubishielectric.co.jp> Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Diffstat (limited to 'fs/exfat/dir.c')
-rw-r--r--fs/exfat/dir.c197
1 files changed, 75 insertions, 122 deletions
diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index b5a237c33d50..2902d285bf20 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -32,35 +32,30 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
struct exfat_chain *p_dir, int entry, unsigned short *uniname)
{
int i;
- struct exfat_dentry *ep;
struct exfat_entry_set_cache *es;
- es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES, &ep);
+ es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
if (!es)
return;
- if (es->num_entries < 3)
- goto free_es;
-
- ep += 2;
-
/*
* First entry : file entry
* Second entry : stream-extension entry
* Third entry : first file-name entry
* So, the index of first file-name dentry should start from 2.
*/
- for (i = 2; i < es->num_entries; i++, ep++) {
+ for (i = 2; i < es->num_entries; i++) {
+ struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
+
/* end of name entry */
if (exfat_get_entry_type(ep) != TYPE_EXTEND)
- goto free_es;
+ break;
exfat_extract_uni_name(ep, uniname);
uniname += EXFAT_FILE_NAME_LEN;
}
-free_es:
- kfree(es);
+ exfat_free_dentry_set(es, false);
}
/* read a directory entry from the opened directory */
@@ -590,62 +585,33 @@ int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
return 0;
}
-int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
- struct exfat_entry_set_cache *es, int sync)
+void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
{
- struct exfat_sb_info *sbi = EXFAT_SB(sb);
- struct buffer_head *bh;
- sector_t sec = es->sector;
- unsigned int off = es->offset;
- int chksum_type = CS_DIR_ENTRY, i, num_entries = es->num_entries;
- unsigned int buf_off = (off - es->offset);
- unsigned int remaining_byte_in_sector, copy_entries, clu;
+ int chksum_type = CS_DIR_ENTRY, i;
unsigned short chksum = 0;
+ struct exfat_dentry *ep;
- for (i = 0; i < num_entries; i++) {
- chksum = exfat_calc_chksum_2byte(&es->entries[i], DENTRY_SIZE,
- chksum, chksum_type);
+ for (i = 0; i < es->num_entries; i++) {
+ ep = exfat_get_dentry_cached(es, i);
+ chksum = exfat_calc_chksum_2byte(ep, DENTRY_SIZE, chksum,
+ chksum_type);
chksum_type = CS_DEFAULT;
}
+ ep = exfat_get_dentry_cached(es, 0);
+ ep->dentry.file.checksum = cpu_to_le16(chksum);
+ es->modified = true;
+}
- es->entries[0].dentry.file.checksum = cpu_to_le16(chksum);
+void exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
+{
+ int i;
- while (num_entries) {
- /* write per sector base */
- remaining_byte_in_sector = (1 << sb->s_blocksize_bits) - off;
- copy_entries = min_t(int,
- EXFAT_B_TO_DEN(remaining_byte_in_sector),
- num_entries);
- bh = sb_bread(sb, sec);
- if (!bh)
- goto err_out;
- memcpy(bh->b_data + off,
- (unsigned char *)&es->entries[0] + buf_off,
- EXFAT_DEN_TO_B(copy_entries));
- exfat_update_bh(sb, bh, sync);
- brelse(bh);
- num_entries -= copy_entries;
-
- if (num_entries) {
- /* get next sector */
- if (exfat_is_last_sector_in_cluster(sbi, sec)) {
- clu = exfat_sector_to_cluster(sbi, sec);
- if (es->alloc_flag == ALLOC_NO_FAT_CHAIN)
- clu++;
- else if (exfat_get_next_cluster(sb, &clu))
- goto err_out;
- sec = exfat_cluster_to_sector(sbi, clu);
- } else {
- sec++;
- }
- off = 0;
- buf_off += EXFAT_DEN_TO_B(copy_entries);
- }
+ for (i = 0; i < es->num_bh; i++) {
+ if (es->modified)
+ exfat_update_bh(es->sb, es->bh[i], sync);
+ brelse(es->bh[i]);
}
-
- return 0;
-err_out:
- return -EIO;
+ kfree(es);
}
static int exfat_walk_fat_chain(struct super_block *sb,
@@ -820,34 +786,40 @@ static bool exfat_validate_entry(unsigned int type,
}
}
+struct exfat_dentry *exfat_get_dentry_cached(
+ struct exfat_entry_set_cache *es, int num)
+{
+ int off = es->start_off + num * DENTRY_SIZE;
+ struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
+ char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
+
+ return (struct exfat_dentry *)p;
+}
+
/*
* Returns a set of dentries for a file or dir.
*
- * Note that this is a copy (dump) of dentries so that user should
- * call write_entry_set() to apply changes made in this entry set
- * to the real device.
+ * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
+ * User should call exfat_get_dentry_set() after setting 'modified' to apply
+ * changes made in this entry set to the real device.
*
* in:
* sb+p_dir+entry: indicates a file/dir
* type: specifies how many dentries should be included.
- * out:
- * file_ep: will point the first dentry(= file dentry) on success
* return:
* pointer of entry set on success,
* NULL on failure.
*/
struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
- struct exfat_chain *p_dir, int entry, unsigned int type,
- struct exfat_dentry **file_ep)
+ struct exfat_chain *p_dir, int entry, unsigned int type)
{
- int ret;
+ int ret, i, num_bh;
unsigned int off, byte_offset, clu = 0;
- unsigned int entry_type;
sector_t sec;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_entry_set_cache *es;
- struct exfat_dentry *ep, *pos;
- unsigned char num_entries;
+ struct exfat_dentry *ep;
+ int num_entries;
enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
struct buffer_head *bh;
@@ -861,11 +833,18 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
if (ret)
return NULL;
+ es = kzalloc(sizeof(*es), GFP_KERNEL);
+ if (!es)
+ return NULL;
+ es->sb = sb;
+ es->modified = false;
+
/* byte offset in cluster */
byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
/* byte offset in sector */
off = EXFAT_BLK_OFFSET(byte_offset, sb);
+ es->start_off = off;
/* sector offset in cluster */
sec = EXFAT_B_TO_BLK(byte_offset, sb);
@@ -873,72 +852,46 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
bh = sb_bread(sb, sec);
if (!bh)
- return NULL;
-
- ep = (struct exfat_dentry *)(bh->b_data + off);
- entry_type = exfat_get_entry_type(ep);
+ goto free_es;
+ es->bh[es->num_bh++] = bh;
- if (entry_type != TYPE_FILE && entry_type != TYPE_DIR)
- goto release_bh;
+ ep = exfat_get_dentry_cached(es, 0);
+ if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+ goto free_es;
num_entries = type == ES_ALL_ENTRIES ?
ep->dentry.file.num_ext + 1 : type;
- es = kmalloc(struct_size(es, entries, num_entries), GFP_KERNEL);
- if (!es)
- goto release_bh;
-
es->num_entries = num_entries;
- es->sector = sec;
- es->offset = off;
- es->alloc_flag = p_dir->flags;
-
- pos = &es->entries[0];
-
- while (num_entries) {
- if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
- goto free_es;
- /* copy dentry */
- memcpy(pos, ep, sizeof(struct exfat_dentry));
-
- if (--num_entries == 0)
- break;
-
- if (((off + DENTRY_SIZE) & (sb->s_blocksize - 1)) <
- (off & (sb->s_blocksize - 1))) {
- /* get the next sector */
- if (exfat_is_last_sector_in_cluster(sbi, sec)) {
- if (es->alloc_flag == ALLOC_NO_FAT_CHAIN)
- clu++;
- else if (exfat_get_next_cluster(sb, &clu))
- goto free_es;
- sec = exfat_cluster_to_sector(sbi, clu);
- } else {
- sec++;
- }
-
- brelse(bh);
- bh = sb_bread(sb, sec);
- if (!bh)
+ num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
+ for (i = 1; i < num_bh; i++) {
+ /* get the next sector */
+ if (exfat_is_last_sector_in_cluster(sbi, sec)) {
+ if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
+ clu++;
+ else if (exfat_get_next_cluster(sb, &clu))
goto free_es;
- off = 0;
- ep = (struct exfat_dentry *)bh->b_data;
+ sec = exfat_cluster_to_sector(sbi, clu);
} else {
- ep++;
- off += DENTRY_SIZE;
+ sec++;
}
- pos++;
+
+ bh = sb_bread(sb, sec);
+ if (!bh)
+ goto free_es;
+ es->bh[es->num_bh++] = bh;
}
- if (file_ep)
- *file_ep = &es->entries[0];
- brelse(bh);
+ /* validiate cached dentries */
+ for (i = 1; i < num_entries; i++) {
+ ep = exfat_get_dentry_cached(es, i);
+ if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+ goto free_es;
+ }
return es;
free_es:
- kfree(es);
-release_bh:
- brelse(bh);
+ exfat_free_dentry_set(es, false);
return NULL;
}