e4defrag doesn't work on root filesystem

Hi,

I'm playing with e4defrag from e2frprogs git, and I've run into a bug. When I try to defragment files on my root filesystem, it refuses to acknowledge that the filesystem is ext4. I believe the problem is that it checks the filesystem type by parsing /etc/mtab, but the root filesystem shows up there like this:

rootfs on / type rootfs (rw)
/dev/root on / type ext4 (rw,noatime,barrier=1,data=ordered)

so it gets confused by the bogus first entry. It works just fine on other ext4 filesystems I have.

(If this is the wrong mailing list, I apologize; I couldn't find one for e2fsprogs, so I thought this was the next best thing.)

--Ravi
--

Quoted 11 lines · Ravi Pinjala

Hi,

I'm playing with e4defrag from e2frprogs git, and I've run into a bug. When I try to defragment files on my root filesystem, it refuses to acknowledge that the filesystem is ext4. I believe the problem is that it checks the filesystem type by parsing /etc/mtab, but the root filesystem shows up there like this:

rootfs on / type rootfs (rw)
/dev/root on / type ext4 (rw,noatime,barrier=1,data=ordered)

Quoted 9 lines

so it gets confused by the bogus first entry. It works just fine on other ext4 filesystems I have.

(If this is the wrong mailing list, I apologize; I couldn't find one for e2fsprogs, so I thought this was the next best thing.)

--Ravi

This list is a fine place to report it, thanks.

In is_ext4() it does a statfs on the file, and checks that the magic is EXT4,
but then that's the same as ext2 and ext3 unfortunately ....

It later does getmntent for the actual fs type, but fails, as you said.

Does this fix it for you?

=========

Skip "rootfs" entry when checking for ext4 filesystem.

Signed-off-by Eric Sandeen <[email protected]>

---

misc/e4defrag.c +2 -0

index 82e3868..0d04df9 100644
@@ -430,6 +430,8 @@ static int is_ext4(const char *file)
    }
 
    while ((mnt = getmntent(fp)) != NULL) {
+        if (mnt->mnt_fsname[0] != '/')
+            continue;
        len = strlen(mnt->mnt_dir);
        ret = memcmp(file_path, mnt->mnt_dir, len);
        if (ret != 0)

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