Re: [PATCH 15/31] e2fsck: Teach EA refcounting code to handle 48bit block addresses

Darrick J. Wong
2013-10-07T18:37:50Z

On Mon, Oct 07, 2013 at 05:30:17PM +0200, Lukáš Czerner wrote:
> On Mon, 30 Sep 2013, Darrick J. Wong wrote:
>
> > Date: Mon, 30 Sep 2013 18:28:18 -0700
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > To: tytso@mit.edu, darrick.wong@oracle.com
> > Cc: linux-ext4@vger.kernel.org
> > Subject: [PATCH 15/31] e2fsck: Teach EA refcounting code to handle 48bit block
> > addresses
>
> Did you meant to say 64bit ?

Yep.

>
> >
> > The extended attribute refcounting code only accepts blk_t, which is dangerous
> > because EA blocks can exist at high addresses (> 2^32) as well. Therefore,
> > widen the block fields to 64 bits.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> > e2fsck/e2fsck.h | 12 ++++++------
> > e2fsck/ea_refcount.c | 36 ++++++++++++++++++------------------
> > 2 files changed, 24 insertions(+), 24 deletions(-)
> >
> >
> > diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
> > index 13d70f1..f1df525 100644
> > --- a/e2fsck/e2fsck.h
> > +++ b/e2fsck/e2fsck.h
> > @@ -432,17 +432,17 @@ extern struct dx_dir_info *e2fsck_dx_dir_info_iter(e2fsck_t ctx, int *control);
> > /* ea_refcount.c */
> > extern errcode_t ea_refcount_create(int size, ext2_refcount_t *ret);
> > extern void ea_refcount_free(ext2_refcount_t refcount);
> > -extern errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
> > +extern errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk64_t blk,
> > int *ret);
> > extern errcode_t ea_refcount_increment(ext2_refcount_t refcount,
> > - blk_t blk, int *ret);
> > + blk64_t blk, int *ret);
> > extern errcode_t ea_refcount_decrement(ext2_refcount_t refcount,
> > - blk_t blk, int *ret);
> > + blk64_t blk, int *ret);
> > extern errcode_t ea_refcount_store(ext2_refcount_t refcount,
> > - blk_t blk, int count);
> > -extern blk_t ext2fs_get_refcount_size(ext2_refcount_t refcount);
> > + blk64_t blk, int count);
> > +extern blk64_t ext2fs_get_refcount_size(ext2_refcount_t refcount);
> > extern void ea_refcount_intr_begin(ext2_refcount_t refcount);
> > -extern blk_t ea_refcount_intr_next(ext2_refcount_t refcount, int *ret);
> > +extern blk64_t ea_refcount_intr_next(ext2_refcount_t refcount, int *ret);
> >
> > /* ehandler.c */
> > extern const char *ehandler_operation(const char *op);
> > diff --git a/e2fsck/ea_refcount.c b/e2fsck/ea_refcount.c
> > index e66e636..bcce6a0 100644
> > --- a/e2fsck/ea_refcount.c
> > +++ b/e2fsck/ea_refcount.c
> > @@ -25,14 +25,14 @@
> > * checked, its bit is set in the block_ea_map bitmap.
> > */
> > struct ea_refcount_el {
> > - blk_t ea_blk;
> > + blk64_t ea_blk;
> > int ea_count;
> > };
> >
> > struct ea_refcount {
> > - blk_t count;
> > - blk_t size;
> > - blk_t cursor;
> > + blk64_t count;
> > + blk64_t size;
> > + blk64_t cursor;
>
> I am not sure if we really need count, size and cursor to be blk_t
> let alone blk64_t. It's a bit misleading because AFAICT those
> variable does not represent block numbers at all. Maybe it should be
> changed to something less confusing, preferably matching the actual
> xattr implementation ?

Oops, I got a little too s/blk_t/blk64_t/ happy there. Those could be __u32, I
think. Or unsigned long.

--D
>
> Thanks!
> -Lukas
>
> > struct ea_refcount_el *list;
> > };
> >
> > @@ -111,11 +111,11 @@ static void refcount_collapse(ext2_refcount_t refcount)
> > * specified position.
> > */
> > static struct ea_refcount_el *insert_refcount_el(ext2_refcount_t refcount,
> > - blk_t blk, int pos)
> > + blk64_t blk, int pos)
> > {
> > struct ea_refcount_el *el;
> > errcode_t retval;
> > - blk_t new_size = 0;
> > + blk64_t new_size = 0;
> > int num;
> >
> > if (refcount->count >= refcount->size) {
> > @@ -153,7 +153,7 @@ static struct ea_refcount_el *insert_refcount_el(ext2_refcount_t refcount,
> > * and we can't find an entry, create one in the sorted list.
> > */
> > static struct ea_refcount_el *get_refcount_el(ext2_refcount_t refcount,
> > - blk_t blk, int create)
> > + blk64_t blk, int create)
> > {
> > int low, high, mid;
> >
> > @@ -206,7 +206,7 @@ retry:
> > return 0;
> > }
> >
> > -errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
> > +errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk64_t blk,
> > int *ret)
> > {
> > struct ea_refcount_el *el;
> > @@ -220,7 +220,7 @@ errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
> > return 0;
> > }
> >
> > -errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk_t blk, int *ret)
> > +errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk64_t blk, int *ret)
> > {
> > struct ea_refcount_el *el;
> >
> > @@ -234,7 +234,7 @@ errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk_t blk, int *ret)
> > return 0;
> > }
> >
> > -errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk_t blk, int *ret)
> > +errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk64_t blk, int *ret)
> > {
> > struct ea_refcount_el *el;
> >
> > @@ -249,7 +249,7 @@ errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk_t blk, int *ret)
> > return 0;
> > }
> >
> > -errcode_t ea_refcount_store(ext2_refcount_t refcount, blk_t blk, int count)
> > +errcode_t ea_refcount_store(ext2_refcount_t refcount, blk64_t blk, int count)
> > {
> > struct ea_refcount_el *el;
> >
> > @@ -263,7 +263,7 @@ errcode_t ea_refcount_store(ext2_refcount_t refcount, blk_t blk, int count)
> > return 0;
> > }
> >
> > -blk_t ext2fs_get_refcount_size(ext2_refcount_t refcount)
> > +blk64_t ext2fs_get_refcount_size(ext2_refcount_t refcount)
> > {
> > if (!refcount)
> > return 0;
> > @@ -277,7 +277,7 @@ void ea_refcount_intr_begin(ext2_refcount_t refcount)
> > }
> >
> >
> > -blk_t ea_refcount_intr_next(ext2_refcount_t refcount,
> > +blk64_t ea_refcount_intr_next(ext2_refcount_t refcount,
> > int *ret)
> > {
> > struct ea_refcount_el *list;
> > @@ -370,7 +370,7 @@ int main(int argc, char **argv)
> > int i = 0;
> > ext2_refcount_t refcount;
> > int size, arg;
> > - blk_t blk;
> > + blk64_t blk;
> > errcode_t retval;
> >
> > while (1) {
> > @@ -394,7 +394,7 @@ int main(int argc, char **argv)
> > printf("Freeing refcount\n");
> > break;
> > case BCODE_STORE:
> > - blk = (blk_t) bcode_program[i++];
> > + blk = (blk64_t) bcode_program[i++];
> > arg = bcode_program[i++];
> > printf("Storing blk %u with value %d\n", blk, arg);
> > retval = ea_refcount_store(refcount, blk, arg);
> > @@ -403,7 +403,7 @@ int main(int argc, char **argv)
> > "while storing blk %u", blk);
> > break;
> > case BCODE_FETCH:
> > - blk = (blk_t) bcode_program[i++];
> > + blk = (blk64_t) bcode_program[i++];
> > retval = ea_refcount_fetch(refcount, blk, &arg);
> > if (retval)
> > com_err("ea_refcount_fetch", retval,
> > @@ -413,7 +413,7 @@ int main(int argc, char **argv)
> > blk, arg);
> > break;
> > case BCODE_INCR:
> > - blk = (blk_t) bcode_program[i++];
> > + blk = (blk64_t) bcode_program[i++];
> > retval = ea_refcount_increment(refcount, blk, &arg);
> > if (retval)
> > com_err("ea_refcount_increment", retval,
> > @@ -423,7 +423,7 @@ int main(int argc, char **argv)
> > blk, arg);
> > break;
> > case BCODE_DECR:
> > - blk = (blk_t) bcode_program[i++];
> > + blk = (blk64_t) bcode_program[i++];
> > retval = ea_refcount_decrement(refcount, blk, &arg);
> > if (retval)
> > com_err("ea_refcount_decrement", retval,
> >
> > --
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