Messages in this thread Patch in this message |  | | Date | Thu, 26 Apr 2001 01:51:11 -0400 | From | Chris Mason <> | Subject | [PATCH] reiserfs highmem bug on tail reads |
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Ok, so all the reiserfs tail bugs weren't quite fixed yet, the last tail fix can cause problems with highmem turned on. Both bugs are in fs/reiserfs/inode.c:_get_block_create_0
When reading the tail in, if the buffer was already up to date, we skip the disk i/o and return. But the cleanup code assumes the page was kmap'd, which isn't right.
Also, there was a chance to double kmap the page if kmap scheduled a nd the tree balanced while we slept. This bug has been there for a long time.
Anyway, this was tested with Andrea's HIGHMEM_DEBUG_MERE_MORTALS patch to force highmem on my 128MB machine. It works for me, but more testers are always good.
-chris
against 2.4.4-pre6, should work against 2.4.3 or higher.
diff -Nru a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c --- a/fs/reiserfs/inode.c Wed Apr 25 23:15:14 2001 +++ b/fs/reiserfs/inode.c Wed Apr 25 23:15:14 2001 @@ -374,9 +374,11 @@ ** sure we need to. But, this means the item might move if ** kmap schedules */ - p = (char *)kmap(bh_result->b_page) ; - if (fs_changed (fs_gen, inode->i_sb) && item_moved (&tmp_ih, &path)) { - goto research; + if (!p) { + p = (char *)kmap(bh_result->b_page) ; + if (fs_changed (fs_gen, inode->i_sb) && item_moved (&tmp_ih, &path)) { + goto research; + } } p += offset ; memset (p, 0, inode->i_sb->s_blocksize); @@ -420,14 +422,15 @@ ih = get_ih (&path); } while (1); + flush_dcache_page(bh_result->b_page) ; + kunmap(bh_result->b_page) ; + finished: pathrelse (&path); bh_result->b_blocknr = 0 ; bh_result->b_dev = inode->i_dev; mark_buffer_uptodate (bh_result, 1); bh_result->b_state |= (1UL << BH_Mapped); - flush_dcache_page(bh_result->b_page) ; - kunmap(bh_result->b_page) ; return 0; }
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