Le 23/06/2014 13:16, Karel Zak a écrit :
On Tue, Jun 17, 2014 at 10:16:54PM +0200, arnaud.mouiche@xxxxxxxxx wrote:
From: Arnaud Mouiche <arnaud.mouiche@xxxxxxxxxxx>
find_identical_file() may squash files with identical contents, but
different uid/gid or mode.
here is a test script to show the problem (to run as root):
without this patch, the output is
-rw-r--r-- 1 root root 4 janv. 1 1970 a
-rw-r--r-- 1 root root 4 janv. 1 1970 b
-rw-r--r-- 1 root root 4 janv. 1 1970 c
whereas the expected result should be
-rw-r--r-- 1 root root 4 janv. 1 1970 a
-rw------- 1 root root 4 janv. 1 1970 b
-rw-r--r-- 1 daemon root 4 janv. 1 1970 c
Strange.
- if (orig->size == new->size && orig->path) {
+ if (orig->size == new->size &&
+ orig->uid == new->uid &&
+ orig->gid == new->gid &&
+ orig->mode == new->mode &&
+ orig->path) {
if (!orig->flags)
mdfile(orig);
if (!new->flags)
I don't think this is right solution. The content de-duplication code
has to be independent on file name, uid/gid and mode. The
de-duplication does not mean that info about the file has been
removed from the cramfs image.
The filesystem still contains file specific inode. So if you see a
different filename then you have to see a different uid/gid too.
(I guess.)
Karel
You are right,
The issue is in the linux kernel code indeed (fs/cramfs/inode.c)
on line 37
/* These two macros may change in future, to provide better st_ino
semantics. */
#define CRAMINO(x) (((x)->offset && (x)->size)?(x)->offset<<2:1)
#define OFFSET(x) ((x)->i_ino)
for linux, the inode of an entry is equal to the data offset.
2 files which have been squashed through the "eliminate_doubles" process
(mkfs.cramfs) have identical inode number under linux,
whatever the mode, uid or gid is.
so forget about my patch, I need for find a patch for the FS mainling list
Arnaud
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