[NILFS users] nilfs_cleanerd on root partition

[Ryusuke Konishi]

On Mon, 22 Jun 2009 01:05:10 +0900 (JST), Ryusuke Konishi wrote:
> Hi,
> On Sun, 21 Jun 2009 17:37:08 +0300, Sami Liedes wrote:
> > On Sun, Jun 21, 2009 at 05:02:34PM +0300, Sami Liedes wrote:
> > > You say I should start the cleanerd by running
> > > 
> > >  # nilfs_cleanerd /dev/sdb1 /
> > > 
> > > However nothing in the output of `nilfs_cleanerd -h' indicates
> > > anything of the second parameter (mount point). Looking at the source,
> > > that's how mount.nilfs2 runs it too, and that's exactly the case where
> > > it fails.
> > 
> > OK, I debugged a bit and figured out what the real problem is. It's
> > the fact that nilfs_find_fs() is too strict about the mount points
> > being the same. Namely, it considers /media/lacie and /media/lacie/ to
> > be different mount points (it merely does a strcmp()).
> >
> > /proc/mounts always uses the former syntax, so if the mount command is
> > something like `mount /dev/mapper/lacie /media/lacie/ -t nilfs2', the
> > cleanerd is not started because mount passes "/media/lacie/" as the
> > mount point, and nilfs_find_fs() expects it to not have the last
> > slash.
> > 
> > 	Sami
> 
> Grr, that's an elementary and influential bug.  Okay, I'll fix it.
> 
> Sami, thank you for finding this!
> 
> Cheers,
> Ryusuke Konishi

The following patch will fix this.  I've pushed it to the git repo,
too.

Regards,
Ryusuke Konishi
---
 lib/nilfs.c |   29 +++++++++++++++++++++++++----
 1 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/lib/nilfs.c b/lib/nilfs.c
index 15ee98f..9c80538 100644
--- a/lib/nilfs.c
+++ b/lib/nilfs.c
@@ -147,14 +147,27 @@ static int nilfs_find_fs(struct nilfs *nilfs, const char *dev, const char *dir,
 	size_t len;
 	int ret, n;
 	char canonical[PATH_MAX + 2];
+	char *cdev = NULL, *cdir = NULL;
 
-	if (dev && myrealpath(dev, canonical, sizeof(canonical)))
-		dev = canonical;
+	ret = -1;
+	if (dev && myrealpath(dev, canonical, sizeof(canonical))) {
+		cdev = strdup(canonical);
+		if (!cdev)
+			goto failed;
+		dev = cdev;
+	}
+
+	if (dir && myrealpath(dir, canonical, sizeof(canonical))) {
+		cdir = strdup(canonical);
+		if (!cdir)
+			goto failed_dev;
+		dir = cdir;
+	}
 
 	fp = fopen(PROCMOUNTS, "r");
 	if (fp == NULL)
-		return -1;
-	ret = -1;
+		goto failed_dir;
+
 	while (fgets(line, sizeof(line), fp) != NULL) {
 		n = tokenize(line, mntent, NMNTFLDS);
 		assert(n == NMNTFLDS);
@@ -181,6 +194,14 @@ static int nilfs_find_fs(struct nilfs *nilfs, const char *dev, const char *dir,
 		}
 	}
 	fclose(fp);
+
+ failed_dir:
+	free(cdir);
+
+ failed_dev:
+	free(cdev);
+
+ failed:
 	return ret;
 }
 
-- 
1.6.2