linux-ext4 - [PATCH] jbd2: Create proc entry with bdevname+i

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 8 Sep 2008 16:31:14 -0700
From:	Joel Becker <Joel.Becker@...cle.com>
To:	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Cc:	ocfs2-devel@....oracle.com, mfasheh@...e.com,
	sunil.mushran@...cle.com
Subject: [PATCH] jbd2: Create proc entry with bdevname+i_ino.

jbd2 currently creates statistics files for each loaded journal in
/proc/fs/jbd2/<bdevname>.  ocfs2 loads multiple journals when recovering
other nodes, and the multiple journals on a given bdev collide in the
proc namespace.

This patch changes the location to /proc/fs/jbd2/<bdevname>-<i_ino> as
proposed by Jan Kara.  ocfs2 can load multiple journals safely without
collision.  There are, to my knowledge, no programmatic users, so the
name change shouldn't (haha) cause any problems.

ocfs2 has 64bit inode numbers, so a collision could theoretically happen
with inodes above 32bits, but ocfs2 journals are generally created at
the front of the volume during mkfs(8).  In addition, ocfs2 restricts
inodes to 32bits unless the 'inode64' option is specified.

Signed-off-by: Joel Becker <joel.becker@...cle.com>
---
 fs/jbd2/journal.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8207a01..18d3063 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -901,9 +901,11 @@ static struct proc_dir_entry *proc_jbd2_stats;
 
 static void jbd2_stats_proc_init(journal_t *journal)
 {
-	char name[BDEVNAME_SIZE];
+	char dname[BDEVNAME_SIZE];
+	char name[NAME_MAX];
 
-	bdevname(journal->j_dev, name);
+	bdevname(journal->j_dev, dname);
+	snprintf(name, NAME_MAX, "%s-%lu", dname, journal->j_inode->i_ino);
 	journal->j_proc_entry = proc_mkdir(name, proc_jbd2_stats);
 	if (journal->j_proc_entry) {
 		proc_create_data("history", S_IRUGO, journal->j_proc_entry,
@@ -915,9 +917,11 @@ static void jbd2_stats_proc_init(journal_t *journal)
 
 static void jbd2_stats_proc_exit(journal_t *journal)
 {
-	char name[BDEVNAME_SIZE];
+	char dname[BDEVNAME_SIZE];
+	char name[NAME_MAX];
 
-	bdevname(journal->j_dev, name);
+	bdevname(journal->j_dev, dname);
+	snprintf(name, NAME_MAX, "%s-%lu", dname, journal->j_inode->i_ino);
 	remove_proc_entry("info", journal->j_proc_entry);
 	remove_proc_entry("history", journal->j_proc_entry);
 	remove_proc_entry(name, proc_jbd2_stats);
-- 
1.5.6.3


-- 

None of our men are "experts."  We have most unfortunately found
it necessary to get rid of a man as soon as he thinks himself an
expert -- because no one ever considers himself expert if he really
knows his job.  A man who knows a job sees so much more to be done
than he has done, that he is always pressing forward and never
gives up an instant of thought to how good and how efficient he is.
Thinking always ahead, thinking always of trying to do more, brings
a state of mind in which nothing is impossible. The moment one gets
into the "expert" state of mind a great number of things become
impossible.
	- From Henry Ford Sr., "My Life and Work"

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@...cle.com
Phone: (650) 506-8127
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html