linux-ext4 - [PATCH v2 3/3] ext2: optimize ext2_xattr

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Date:   Tue, 28 May 2019 10:59:47 +0800
From:   Chengguang Xu <cgxu519@...o.com.cn>
To:     jack@...e.com
Cc:     linux-ext4@...r.kernel.org, Chengguang Xu <cgxu519@...o.com.cn>
Subject: [PATCH v2 3/3] ext2: optimize ext2_xattr_get()

Since xattr entry names are sorted, we don't have
to continue when current entry name is greater than
target.

Signed-off-by: Chengguang Xu <cgxu519@...o.com.cn>
---
v1->v2:
- Introduce new helper for xattr entry comparison

 fs/ext2/xattr.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 59356cd2a842..839e71e78673 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -199,7 +199,7 @@ ext2_xattr_get(struct inode *inode, int name_index, const char *name,
 	struct ext2_xattr_entry *entry;
 	size_t name_len, size;
 	char *end;
-	int error;
+	int error, not_found;
 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 
 	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
@@ -238,10 +238,14 @@ ext2_xattr_get(struct inode *inode, int name_index, const char *name,
 		if (!ext2_xattr_entry_valid(entry, end,
 		    inode->i_sb->s_blocksize))
 			goto bad_block;
-		if (name_index == entry->e_name_index &&
-		    name_len == entry->e_name_len &&
-		    memcmp(name, entry->e_name, name_len) == 0)
+
+		not_found = ext2_xattr_cmp_entry(name_index, name_len, name,
+						 entry);
+		if (!not_found)
 			goto found;
+		if (not_found < 0)
+			break;
+
 		entry = EXT2_XATTR_NEXT(entry);
 	}
 	if (ext2_xattr_cache_insert(ea_block_cache, bh))
-- 
2.20.1