Messages in this thread Patch in this message |  | | Date | Tue, 20 Aug 2002 15:59:49 +0200 | From | Christoph Hellwig <> | Subject | Re: [bkpatch-2.5.7] Detect get_block() errors in block_read_full_page() |
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Marcelo,
any chance you could review the below patch for -pre5?
From: Anton Altaparmakov <aia21@cus.cam.ac.uk> To: torvalds@transmeta.com Cc: linux-kernel@vger.kernel.org, andrea@suse.de Subject: [bkpatch-2.5.7] Detect get_block() errors in block_read_full_page() Date: Sat, 23 Mar 2002 14:36:44 +0000 (GMT)
Linus,
Below patch causes errors from get_block() in block_read_full_page() to be detected and handled properly (by setting page error flag). Without the patch the page (or parts of the page) will contain random data on get_block() failing without any form of error being signalled which can be catastrophic for filesystems using block_read_full_page() for accessing their metadata. And for normal data it would mean the user would see random data instead of what they expected.
The patch works for me and the changes have been blessed by Andrea Arcangeli.
Please apply.
Best regards,
Anton -- Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @) Linux NTFS maintainer / WWW: http://linux-ntfs.sf.net/ ICQ: 8561279 / WWW: http://www-stu.christs.cam.ac.uk/~aia21/
---------snip---------- # This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.537 -> 1.538 # fs/buffer.c 1.69 -> 1.70 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 02/03/23 aia21@cam.ac.uk 1.538 # Detect get_block() error return in fs/buffer.c::block_read_full_page() and # set page error and don't set page uptodate. # -------------------------------------------- # diff -Nru a/fs/buffer.c b/fs/buffer.c --- a/fs/buffer.c Sat Mar 23 14:23:26 2002 +++ b/fs/buffer.c Sat Mar 23 14:23:26 2002 @@ -795,8 +795,11 @@ unlock_buffer(bh); tmp = bh->b_this_page; while (tmp != bh) { - if (buffer_async(tmp) && buffer_locked(tmp)) - goto still_busy; + if (buffer_locked(tmp)) { + if (buffer_async(tmp)) + goto still_busy; + } else if (!buffer_uptodate(tmp)) + SetPageError(page); tmp = tmp->b_this_page; } @@ -1716,7 +1719,7 @@ if (!buffer_mapped(bh)) { if (iblock < lblock) { if (get_block(inode, iblock, bh, 0)) - continue; + SetPageError(page); } if (!buffer_mapped(bh)) { memset(kmap(page) + i*blocksize, 0, blocksize); @@ -1736,10 +1739,11 @@ if (!nr) { /* - * all buffers are uptodate - we can set the page - * uptodate as well. + * All buffers are uptodate - we can set the page uptodate + * as well. But not if get_block() returned an error. */ - SetPageUptodate(page); + if (!PageError(page)) + SetPageUptodate(page); UnlockPage(page); return 0; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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