linux-ext4.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "zhangyi (F)" <yi.zhang@huawei.com>
To: <linux-ext4@vger.kernel.org>
Cc: <tytso@mit.edu>, <jack@suse.cz>, <adilger.kernel@dilger.ca>,
	<yi.zhang@huawei.com>, <miaoxie@huawei.com>
Subject: [PATCH v2 2/2] ext4: cleanup bh release code in ext4_ind_remove_space()
Date: Fri, 15 Mar 2019 15:10:13 +0800	[thread overview]
Message-ID: <1552633813-42832-3-git-send-email-yi.zhang@huawei.com> (raw)
In-Reply-To: <1552633813-42832-1-git-send-email-yi.zhang@huawei.com>

Currently, we are releasing the indirect buffer where we are done with
it in ext4_ind_remove_space(), so we can see the brelse() and
BUFFER_TRACE() everywhere. It seems fragile and hard to read, and we
may probably forget to release the buffer some day. This patch do some
cleanup stuff, put all the releasing code together to the end of this
function.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
---
 fs/ext4/indirect.c | 47 ++++++++++++++++++++++-------------------------
 1 file changed, 22 insertions(+), 25 deletions(-)

diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 9e96a0b..e1801b2 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -1219,6 +1219,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 	ext4_lblk_t offsets[4], offsets2[4];
 	Indirect chain[4], chain2[4];
 	Indirect *partial, *partial2;
+	Indirect *p = NULL, *p2 = NULL;
 	ext4_lblk_t max_block;
 	__le32 nr = 0, nr2 = 0;
 	int n = 0, n2 = 0;
@@ -1260,7 +1261,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 		}
 
 
-		partial = ext4_find_shared(inode, n, offsets, chain, &nr);
+		partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
 		if (nr) {
 			if (partial == chain) {
 				/* Shared branch grows from the inode */
@@ -1285,13 +1286,11 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 				partial->p + 1,
 				(__le32 *)partial->bh->b_data+addr_per_block,
 				(chain+n-1) - partial);
-			BUFFER_TRACE(partial->bh, "call brelse");
-			brelse(partial->bh);
 			partial--;
 		}
 
 end_range:
-		partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
+		partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
 		if (nr2) {
 			if (partial2 == chain2) {
 				/*
@@ -1321,16 +1320,14 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 					   (__le32 *)partial2->bh->b_data,
 					   partial2->p,
 					   (chain2+n2-1) - partial2);
-			BUFFER_TRACE(partial2->bh, "call brelse");
-			brelse(partial2->bh);
 			partial2--;
 		}
 		goto do_indirects;
 	}
 
 	/* Punch happened within the same level (n == n2) */
-	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
-	partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
+	partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
+	partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
 
 	/* Free top, but only if partial2 isn't its subtree. */
 	if (nr) {
@@ -1387,15 +1384,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 					   partial->p + 1,
 					   partial2->p,
 					   (chain+n-1) - partial);
-			while (partial > chain) {
-				BUFFER_TRACE(partial->bh, "call brelse");
-				brelse(partial->bh);
-			}
-			while (partial2 > chain2) {
-				BUFFER_TRACE(partial2->bh, "call brelse");
-				brelse(partial2->bh);
-			}
-			return 0;
+			goto cleanup;
 		}
 
 		/*
@@ -1410,8 +1399,6 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 					   partial->p + 1,
 					   (__le32 *)partial->bh->b_data+addr_per_block,
 					   (chain+n-1) - partial);
-			BUFFER_TRACE(partial->bh, "call brelse");
-			brelse(partial->bh);
 			partial--;
 		}
 		if (partial2 > chain2 && depth2 <= depth) {
@@ -1419,11 +1406,21 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 					   (__le32 *)partial2->bh->b_data,
 					   partial2->p,
 					   (chain2+n2-1) - partial2);
-			BUFFER_TRACE(partial2->bh, "call brelse");
-			brelse(partial2->bh);
 			partial2--;
 		}
 	}
+
+cleanup:
+	while (p && p > chain) {
+		BUFFER_TRACE(p->bh, "call brelse");
+		brelse(p->bh);
+		p--;
+	}
+	while (p2 && p2 > chain2) {
+		BUFFER_TRACE(p2->bh, "call brelse");
+		brelse(p2->bh);
+		p2--;
+	}
 	return 0;
 
 do_indirects:
@@ -1431,7 +1428,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 	switch (offsets[0]) {
 	default:
 		if (++n >= n2)
-			return 0;
+			break;
 		nr = i_data[EXT4_IND_BLOCK];
 		if (nr) {
 			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
@@ -1439,7 +1436,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 		}
 	case EXT4_IND_BLOCK:
 		if (++n >= n2)
-			return 0;
+			break;
 		nr = i_data[EXT4_DIND_BLOCK];
 		if (nr) {
 			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
@@ -1447,7 +1444,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 		}
 	case EXT4_DIND_BLOCK:
 		if (++n >= n2)
-			return 0;
+			break;
 		nr = i_data[EXT4_TIND_BLOCK];
 		if (nr) {
 			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
@@ -1456,5 +1453,5 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 	case EXT4_TIND_BLOCK:
 		;
 	}
-	return 0;
+	goto cleanup;
 }
-- 
2.7.4


  parent reply	other threads:[~2019-03-15  7:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-15  7:10 [PATCH v2 0/2] ext4: fix buffer references leak problem zhangyi (F)
2019-03-15  7:10 ` [PATCH v2 1/2] ext4: brelse all indirect buffer in ext4_ind_remove_space() zhangyi (F)
2019-03-18 11:08   ` Jan Kara
2019-03-23 15:53   ` Theodore Ts'o
2019-03-15  7:10 ` zhangyi (F) [this message]
2019-03-18 11:10   ` [PATCH v2 2/2] ext4: cleanup bh release code " Jan Kara
2019-03-23 15:58   ` Theodore Ts'o

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1552633813-42832-3-git-send-email-yi.zhang@huawei.com \
    --to=yi.zhang@huawei.com \
    --cc=adilger.kernel@dilger.ca \
    --cc=jack@suse.cz \
    --cc=linux-ext4@vger.kernel.org \
    --cc=miaoxie@huawei.com \
    --cc=tytso@mit.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).