linux-kernel - [PATCH 3/3] fs/ntfs3: Always use binary search with entry search

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Message-Id: <20210902154050.5075-4-kari.argillander@gmail.com>
Date:   Thu,  2 Sep 2021 18:40:50 +0300
From:   Kari Argillander <kari.argillander@...il.com>
To:     Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
        ntfs3@...ts.linux.dev
Cc:     Kari Argillander <kari.argillander@...il.com>,
        linux-kernel@...r.kernel.org, Joe Perches <joe@...ches.com>
Subject: [PATCH 3/3] fs/ntfs3: Always use binary search with entry search

We do not have any reason to keep old linear search in. Before this was
used for error path or if table was so big that it cannot be allocated.
Current binary search implementation won't need error path. Remove old
references to linear entry search.

Signed-off-by: Kari Argillander <kari.argillander@...il.com>
---
 fs/ntfs3/index.c | 50 ++++++------------------------------------------
 fs/ntfs3/ntfs.h  |  3 ---
 2 files changed, 6 insertions(+), 47 deletions(-)

diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index e336d5645628..9f79cff7d09e 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -672,22 +672,16 @@ static struct NTFS_DE *hdr_find_e(const struct ntfs_index *indx,
 				  const struct INDEX_HDR *hdr, const void *key,
 				  size_t key_len, const void *ctx, int *diff)
 {
-	struct NTFS_DE *e;
+	struct NTFS_DE *e, *found = NULL;
 	NTFS_CMP_FUNC cmp = indx->cmp;
+	int min_idx = 0, mid_idx, max_idx = 0;
+	int diff2;
+	int table_size = 8;
 	u32 e_size, e_key_len;
 	u32 end = le32_to_cpu(hdr->used);
 	u32 off = le32_to_cpu(hdr->de_off);
-
-#ifdef NTFS3_INDEX_BINARY_SEARCH
-	struct NTFS_DE *found = NULL;
-	int min_idx = 0, mid_idx, max_idx = 0;
-	int table_size = 8;
-	int diff2;
 	u16 offs[128];
 
-	if (end > 0x10000)
-		goto next;
-
 fill_table:
 	if (off + sizeof(struct NTFS_DE) > end)
 		return NULL;
@@ -721,7 +715,8 @@ static struct NTFS_DE *hdr_find_e(const struct ntfs_index *indx,
 				return NULL;
 
 			max_idx = 0;
-			table_size = min(table_size * 2, 128);
+			table_size = min(table_size * 2,
+					 (int)ARRAY_SIZE(offs));
 			goto fill_table;
 		}
 	} else if (diff2 < 0) {
@@ -745,39 +740,6 @@ static struct NTFS_DE *hdr_find_e(const struct ntfs_index *indx,
 	e = Add2Ptr(hdr, offs[mid_idx]);
 
 	goto binary_search;
-#endif
-
-next:
-	/*
-	 * Entries index are sorted.
-	 * Enumerate all entries until we find entry
-	 * that is <= to the search value.
-	 */
-	if (off + sizeof(struct NTFS_DE) > end)
-		return NULL;
-
-	e = Add2Ptr(hdr, off);
-	e_size = le16_to_cpu(e->size);
-
-	if (e_size < sizeof(struct NTFS_DE) || off + e_size > end)
-		return NULL;
-
-	off += e_size;
-
-	e_key_len = le16_to_cpu(e->key_size);
-
-	*diff = (*cmp)(key, key_len, e + 1, e_key_len, ctx);
-	if (!*diff)
-		return e;
-
-	if (*diff <= 0)
-		return e;
-
-	if (de_is_last(e)) {
-		*diff = 1;
-		return e;
-	}
-	goto next;
 }
 
 /*
diff --git a/fs/ntfs3/ntfs.h b/fs/ntfs3/ntfs.h
index 6bb3e595263b..a7e1b7cc7a14 100644
--- a/fs/ntfs3/ntfs.h
+++ b/fs/ntfs3/ntfs.h
@@ -12,9 +12,6 @@
 
 /* TODO: Check 4K MFT record and 512 bytes cluster. */
 
-/* Activate this define to use binary search in indexes. */
-#define NTFS3_INDEX_BINARY_SEARCH
-
 /* Check each run for marked clusters. */
 #define NTFS3_CHECK_FREE_CLST
 
-- 
2.25.1