[PATCH] resize_reiserfs may use invalid bitmap blocks

[PATCH] resize_reiserfs may use invalid bitmap blocks

[Jeff Mahoney]

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Another problem in reiserfs_resize:

This time it's the writing of the new bitmaps. It writes them outside of
~ journal control, which is fine. It does it synchronously, and if the
transaction following it doesn't complete, then the new bitmaps aren't
used anyway.

However, it doesn't check to see if the writing of the new bitmap blocks
succeeded, so the bitmaps may contain invalid data later on.

Attached is a patch that checks the error status of the bitmap block and
returns -EIO as appropriate.

- -Jeff

- --
Jeff Mahoney
SuSE Labs
jeffm@suse.com
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diff -u linux-2.6.5.kgdb/fs/reiserfs/resize.c linux-2.6.5.kgdb.afs/fs/reiserfs/resize.c
--- linux-2.6.5.kgdb/fs/reiserfs/resize.c	2004-04-03 22:36:55.000000000 -0500
+++ linux-2.6.5.kgdb.afs/fs/reiserfs/resize.c	2004-04-19 15:01:44.923208976 -0400
 -113,6 +117,11 @@
 	    memset (bitmap, 0, sizeof (struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
 	    for (i = 0; i < bmap_nr; i++)
 		bitmap[i] = SB_AP_BITMAP(s)[i];
+
+	    /* This doesn't go through the journal, but it doesn't have to.
+	     * The changes are still atomic: We're synced up when the journal
+	     * transaction begins, and the new bitmaps don't matter if the
+	     * transaction fails. */
 	    for (i = bmap_nr; i < bmap_nr_new; i++) {
 		bitmap[i].bh = sb_getblk(s, i * s->s_blocksize * 8);
 		memset(bitmap[i].bh->b_data, 0, sb_blocksize(sb));
@@ -121,6 +130,10 @@
 		set_buffer_uptodate(bitmap[i].bh);
 		mark_buffer_dirty(bitmap[i].bh) ;
 		sync_dirty_buffer(bitmap[i].bh);
+		if (!buffer_uptodate (bitmap[i].bh)) {
+		    vfree (bitmap);
+		    return -EIO;
+		}
 		// update bitmap_info stuff
 		bitmap[i].first_zero_hint=1;
 		bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;