[PATCH 09/13] xfs: add CRC checks to the AGI

Christoph Hellwig
2009-02-10T20:30:17Z

[-- Attachment #1: xfs-agi-crc --]
[-- Type: text/plain, Size: 5249 bytes --]

[hch: minor adaptions]

Signed-off-by: Dave Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: xfs/fs/xfs/xfs_ag.h
===================================================================
--- xfs.orig/fs/xfs/xfs_ag.h 2009-02-09 19:15:46.916949727 +0100
+++ xfs/fs/xfs/xfs_ag.h 2009-02-09 19:15:48.966944136 +0100
@@ -126,6 +126,8 @@ typedef struct xfs_agi {
* still being referenced.
*/
__be32 agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
+ __be32 agi_crc; /* crc of agi sector */
+ uuid_t agi_uuid; /* uuid of filesystem */
} xfs_agi_t;

#define XFS_AGI_MAGICNUM 0x00000001
@@ -139,6 +141,9 @@ typedef struct xfs_agi {
#define XFS_AGI_NEWINO 0x00000100
#define XFS_AGI_DIRINO 0x00000200
#define XFS_AGI_UNLINKED 0x00000400
+/*
+ * XXX(hch): update for the CRC additions? It's unused anyway..
+ */
#define XFS_AGI_NUM_BITS 11
#define XFS_AGI_ALL_BITS ((1 << XFS_AGI_NUM_BITS) - 1)

@@ -147,6 +152,7 @@ typedef struct xfs_agi {
#define XFS_AGI_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
#define XFS_BUF_TO_AGI(bp) ((xfs_agi_t *)XFS_BUF_PTR(bp))

+extern void xfs_agi_calc_crc(struct xfs_buf *bp);
extern int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
xfs_agnumber_t agno, struct xfs_buf **bpp);

Index: xfs/fs/xfs/xfs_fsops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_fsops.c 2009-02-09 19:15:46.917943848 +0100
+++ xfs/fs/xfs/xfs_fsops.c 2009-02-09 19:15:48.966944136 +0100
@@ -245,6 +245,10 @@ xfs_growfs_data_private(
agi->agi_dirino = cpu_to_be32(NULLAGINO);
for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
+ if (xfs_sb_version_hascrc(&mp->m_sb)) {
+ uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_uuid);
+ xfs_buf_set_io_callback(bp, xfs_agi_calc_crc);
+ }
error = xfs_bwrite(mp, bp);
if (error) {
goto error0;
Index: xfs/fs/xfs/xfs_ialloc.c
===================================================================
--- xfs.orig/fs/xfs/xfs_ialloc.c 2009-02-09 19:05:48.022069819 +0100
+++ xfs/fs/xfs/xfs_ialloc.c 2009-02-09 19:15:48.968944600 +0100
@@ -40,6 +40,7 @@
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_bmap.h"
+#include "xfs_cksum.h"

/*
@@ -1455,6 +1456,24 @@ xfs_check_agi_unlinked(
#endif

/*
+ * Calculate CRC on AGI and stuff it into the structure.
+ *
+ * We CRC the entire AGI sector, not just the bits we use so that changes
+ * in structure size as features are included do not invalidate CRCs.
+ *
+ * We get called here just before the AGI is written to disk. We should
+ * also do some validity checking here.
+ */
+void
+xfs_agi_calc_crc(
+ xfs_buf_t *bp)
+{
+ xfs_update_cksum(XFS_BUF_PTR(bp), XFS_BUF_SIZE(bp),
+ offsetof(struct xfs_agi, agi_crc));
+
+}
+
+/*
* Read in the allocation group header (inode allocation section)
*/
int
@@ -1464,6 +1483,7 @@ xfs_read_agi(
xfs_agnumber_t agno, /* allocation group number */
struct xfs_buf **bpp) /* allocation group hdr buf */
{
+ struct xfs_buf *bp;
struct xfs_agi *agi; /* allocation group header */
int agi_ok; /* agi is consistent */
int error;
@@ -1472,12 +1492,28 @@ xfs_read_agi(

error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
- XFS_FSS_TO_BB(mp, 1), 0, bpp);
+ XFS_FSS_TO_BB(mp, 1), 0, &bp);
if (error)
return error;

- ASSERT(*bpp && !XFS_BUF_GETERROR(*bpp));
- agi = XFS_BUF_TO_AGI(*bpp);
+ ASSERT(bp && !XFS_BUF_GETERROR(bp));
+ agi = XFS_BUF_TO_AGI(bp);
+
+ /*
+ * Validate the CRC of the AGI block only if the block is clean (i.e.
+ * it just came from disk) and we have CRCs enabled.
+ */
+ if (xfs_sb_version_hascrc(&mp->m_sb) &&
+ !(XFS_BUF_ISWRITE(bp) || XFS_BUF_ISDELAYWRITE(bp))) {
+ if (!xfs_verify_cksum(XFS_BUF_PTR(bp), XFS_BUF_SIZE(bp),
+ offsetof(struct xfs_agi, agi_crc)) ||
+ !uuid_equal(&agi->agi_uuid, &mp->m_sb.sb_uuid)) {
+ XFS_CORRUPTION_ERROR("xfs_read_agi crc",
+ XFS_ERRLEVEL_LOW, mp, agi);
+ xfs_trans_brelse(tp, bp);
+ return XFS_ERROR(EFSCORRUPTED);
+ }
+ }

/*
* Validate the magic number of the agi block.
@@ -1489,13 +1525,18 @@ xfs_read_agi(
XFS_RANDOM_IALLOC_READ_AGI))) {
XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,
mp, agi);
- xfs_trans_brelse(tp, *bpp);
+ xfs_trans_brelse(tp, bp);
return XFS_ERROR(EFSCORRUPTED);
}

- XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGI, XFS_AGI_REF);
+ XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGI, XFS_AGI_REF);

xfs_check_agi_unlinked(agi);
+
+ if (xfs_sb_version_hascrc(&mp->m_sb))
+ xfs_buf_set_io_callback(bp, xfs_agi_calc_crc);
+
+ *bpp = bp;
return 0;
}

Index: xfs/fs/xfs/xfs_log_recover.c
===================================================================
--- xfs.orig/fs/xfs/xfs_log_recover.c 2009-02-09 19:15:46.924974841 +0100
+++ xfs/fs/xfs/xfs_log_recover.c 2009-02-09 19:15:48.970972860 +0100
@@ -1996,6 +1996,9 @@ xlog_recover_do_reg_buffer(
case XFS_AGF_MAGIC:
xfs_agf_calc_crc(bp);
break;
+ case XFS_AGI_MAGIC:
+ xfs_agi_calc_crc(bp);
+ break;
default:
break;