| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Wed, 8 Apr 2020 19:44:46 +0900
From: Wang Shilong <wangshilong1991@...il.com>
To: linux-ext4@...r.kernel.org
Cc: lixi@....com, adilger@...ger.ca, sihara@....com,
Wang Shilong <wshilong@....com>
Subject: [RFC PATCH 18/46] e2fsck: optimize the inserting of dir_info_db
From: Li Xi <lixi@....com>
Binary search is now used when inserting an dir info to the array.
Memmove is now used when moving array. Both of them improves
the performance of inserting.
This patch is also a prepartion for the merging of two dir db
arrays.
Signed-off-by: Li Xi <lixi@....com>
Signed-off-by: Wang Shilong <wshilong@....com>
---
e2fsck/dirinfo.c | 154 +++++++++++++++++++++++++++++------------------
1 file changed, 96 insertions(+), 58 deletions(-)
diff --git a/e2fsck/dirinfo.c b/e2fsck/dirinfo.c
index cceadac3..c5183261 100644
--- a/e2fsck/dirinfo.c
+++ b/e2fsck/dirinfo.c
@@ -7,6 +7,7 @@
#undef DIRINFO_DEBUG
+#include <assert.h>
#include "config.h"
#include "e2fsck.h"
#include <sys/stat.h>
@@ -122,6 +123,89 @@ static void setup_db(e2fsck_t ctx)
"directory map");
}
+/*
+ * Return the min index that has ino larger or equal to @ino
+ * If not found, return -1
+ */
+static int e2fsck_dir_info_min_larger_equal(struct dir_info_db *dir_info,
+ ext2_ino_t ino)
+{
+ int low = 0;
+ int high = dir_info->count - 1;
+ int mid;
+ int tmp_ino;
+ int index = -1;
+
+ while (low <= high) {
+ mid = (low + high) / 2;
+ tmp_ino = dir_info->array[mid].ino;
+ if (ino == tmp_ino) {
+ return mid;
+ } else if (ino < tmp_ino) {
+ /*
+ * The mid ino is larger than @ino, remember the index
+ * here so we won't miss this ino
+ */
+ index = mid;
+ high = mid - 1;
+ } else {
+ low = mid + 1;
+ }
+ }
+ return index;
+}
+
+/*
+ *
+ * Insert an inode into the sorted array. The array should have at least one
+ * free slot.
+ *
+ * Normally, add_dir_info is called with each inode in
+ * sequential order; but once in a while (like when pass 3
+ * needs to recreate the root directory or lost+found
+ * directory) it is called out of order. In those cases, we
+ * need to move the dir_info entries down to make room, since
+ * the dir_info array needs to be sorted by inode number for
+ * get_dir_info()'s sake.
+ */
+static void e2fsck_insert_dir_info(struct dir_info_db *dir_info, ext2_ino_t ino, ext2_ino_t parent)
+{
+ int index;
+ struct dir_info *dir;
+ int dir_size = sizeof(*dir);
+ struct dir_info *array = dir_info->array;
+ int array_count = dir_info->count;
+
+ /*
+ * Removing this check won't break anything. But since seqential ino
+ * inserting happens a lot, this check avoids binary search.
+ */
+ if (array_count == 0 || array[array_count - 1].ino < ino) {
+ dir = &array[array_count];
+ dir_info->count++;
+ goto out;
+ }
+
+ index = e2fsck_dir_info_min_larger_equal(dir_info, ino);
+ if (index >= 0 && array[index].ino == ino) {
+ dir = &array[index];
+ goto out;
+ }
+ if (index < 0) {
+ dir = &array[array_count];
+ dir_info->count++;
+ goto out;
+ }
+
+ dir = &array[index];
+ memmove((char *)dir + dir_size, dir, dir_size * (array_count - index));
+ dir_info->count++;
+out:
+ dir->ino = ino;
+ dir->dotdot = parent;
+ dir->parent = parent;
+}
+
/*
* This subroutine is called during pass1 to create a directory info
* entry. During pass1, the passed-in parent is 0; it will get filled
@@ -171,30 +255,7 @@ void e2fsck_add_dir_info(e2fsck_t ctx, ext2_ino_t ino, ext2_ino_t parent)
}
#endif
- /*
- * Normally, add_dir_info is called with each inode in
- * sequential order; but once in a while (like when pass 3
- * needs to recreate the root directory or lost+found
- * directory) it is called out of order. In those cases, we
- * need to move the dir_info entries down to make room, since
- * the dir_info array needs to be sorted by inode number for
- * get_dir_info()'s sake.
- */
- if (ctx->dir_info->count &&
- ctx->dir_info->array[ctx->dir_info->count-1].ino >= ino) {
- for (i = ctx->dir_info->count-1; i > 0; i--)
- if (ctx->dir_info->array[i-1].ino < ino)
- break;
- dir = &ctx->dir_info->array[i];
- if (dir->ino != ino)
- for (j = ctx->dir_info->count++; j > i; j--)
- ctx->dir_info->array[j] = ctx->dir_info->array[j-1];
- } else
- dir = &ctx->dir_info->array[ctx->dir_info->count++];
-
- dir->ino = ino;
- dir->dotdot = parent;
- dir->parent = parent;
+ e2fsck_insert_dir_info(ctx->dir_info, ino, parent);
}
/*
@@ -204,7 +265,7 @@ void e2fsck_add_dir_info(e2fsck_t ctx, ext2_ino_t ino, ext2_ino_t parent)
static struct dir_info *e2fsck_get_dir_info(e2fsck_t ctx, ext2_ino_t ino)
{
struct dir_info_db *db = ctx->dir_info;
- int low, high, mid;
+ int index;
if (!db)
return 0;
@@ -245,43 +306,20 @@ static struct dir_info *e2fsck_get_dir_info(e2fsck_t ctx, ext2_ino_t ino)
if (db->last_lookup && db->last_lookup->ino == ino)
return db->last_lookup;
- low = 0;
- high = ctx->dir_info->count-1;
- if (ino == ctx->dir_info->array[low].ino) {
-#ifdef DIRINFO_DEBUG
- printf("(%d,%d,%d)\n", ino,
- ctx->dir_info->array[low].dotdot,
- ctx->dir_info->array[low].parent);
-#endif
- return &ctx->dir_info->array[low];
- }
- if (ino == ctx->dir_info->array[high].ino) {
-#ifdef DIRINFO_DEBUG
- printf("(%d,%d,%d)\n", ino,
- ctx->dir_info->array[high].dotdot,
- ctx->dir_info->array[high].parent);
-#endif
- return &ctx->dir_info->array[high];
- }
+ index = e2fsck_dir_info_min_larger_equal(ctx->dir_info, ino);
+ if (index < 0)
+ return NULL;
- while (low < high) {
- mid = (low+high)/2;
- if (mid == low || mid == high)
- break;
- if (ino == ctx->dir_info->array[mid].ino) {
+ assert(ino <= ctx->dir_info->array[index].ino);
+ if (ino == ctx->dir_info->array[index].ino) {
#ifdef DIRINFO_DEBUG
- printf("(%d,%d,%d)\n", ino,
- ctx->dir_info->array[mid].dotdot,
- ctx->dir_info->array[mid].parent);
+ printf("(%d,%d,%d)\n", ino,
+ ctx->dir_info->array[index].dotdot,
+ ctx->dir_info->array[index].parent);
#endif
- return &ctx->dir_info->array[mid];
- }
- if (ino < ctx->dir_info->array[mid].ino)
- high = mid;
- else
- low = mid;
+ return &ctx->dir_info->array[index];
}
- return 0;
+ return NULL;
}
static void e2fsck_put_dir_info(e2fsck_t ctx EXT2FS_NO_TDB_UNUSED,
--
2.25.2
Powered by blists - more mailing lists