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xfs: add CRC checks to the AGFL 

Add CRC checks, location information and a magic number to the AGFL.
Previously the AGFL was just a block containing nothing but the
free block pointers.  The new AGFL has a real header with the usual
boilerplate instead, so that we can verify it's not corrupted and
written into the right place.

[dchinner@redhat.com] Added LSN field, reworked significantly to fit
into new verifier structure and growfs structure, enabled full
verifier functionality now there is a header to verify and we can
guarantee an initialised AGFL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This commit is contained in:
Christoph Hellwig 2013-04-03 16:11:14 +11:00 committed by Ben Myers
parent 4e0e6040c4
commit 77c95bba01
5 changed files with 124 additions and 49 deletions
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25
fs/xfs/xfs_ag.h
View File

@ -30,6 +30,7 @@ struct xfs_trans;
#define XFS_AGF_MAGIC 0x58414746 /* 'XAGF' */
#define XFS_AGI_MAGIC 0x58414749 /* 'XAGI' */
#define XFS_AGFL_MAGIC 0x5841464c /* 'XAFL' */
#define XFS_AGF_VERSION 1
#define XFS_AGI_VERSION 1
@ -190,11 +191,31 @@ extern const struct xfs_buf_ops xfs_agi_buf_ops;
*/
#define XFS_AGFL_DADDR(mp) ((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
#define XFS_AGFL_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
#define XFS_AGFL_SIZE(mp) ((mp)->m_sb.sb_sectsize / sizeof(xfs_agblock_t))
#define XFS_BUF_TO_AGFL(bp) ((xfs_agfl_t *)((bp)->b_addr))
#define XFS_BUF_TO_AGFL_BNO(mp, bp) \
(xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
&(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \
(__be32 *)(bp)->b_addr)
/*
* Size of the AGFL. For CRC-enabled filesystes we steal a couple of
* slots in the beginning of the block for a proper header with the
* location information and CRC.
*/
#define XFS_AGFL_SIZE(mp) \
(((mp)->m_sb.sb_sectsize - \
(xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
sizeof(struct xfs_agfl) : 0)) / \
sizeof(xfs_agblock_t))
typedef struct xfs_agfl {
__be32 agfl_bno[1]; /* actually XFS_AGFL_SIZE(mp) */
__be32 agfl_magicnum;
__be32 agfl_seqno;
uuid_t agfl_uuid;
__be64 agfl_lsn;
__be32 agfl_crc;
__be32 agfl_bno[]; /* actually XFS_AGFL_SIZE(mp) */
} xfs_agfl_t;
/*

129
fs/xfs/xfs_alloc.c
View File

@ -432,53 +432,84 @@ xfs_alloc_fixup_trees(
return 0;
}
static void
static bool
xfs_agfl_verify(
struct xfs_buf *bp)
{
#ifdef WHEN_CRCS_COME_ALONG
/*
* we cannot actually do any verification of the AGFL because mkfs does
* not initialise the AGFL to zero or NULL. Hence the only valid part of
* the AGFL is what the AGF says is active. We can't get to the AGF, so
* we can't verify just those entries are valid.
*
* This problem goes away when the CRC format change comes along as that
* requires the AGFL to be initialised by mkfs. At that point, we can
* verify the blocks in the agfl -active or not- lie within the bounds
* of the AG. Until then, just leave this check ifdef'd out.
*/
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
int agfl_ok = 1;
int i;
if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_uuid))
return false;
if (be32_to_cpu(agfl->agfl_magicnum) != XFS_AGFL_MAGIC)
return false;
/*
* during growfs operations, the perag is not fully initialised,
* so we can't use it for any useful checking. growfs ensures we can't
* use it by using uncached buffers that don't have the perag attached
* so we can detect and avoid this problem.
*/
if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
return false;
for (i = 0; i < XFS_AGFL_SIZE(mp); i++) {
if (be32_to_cpu(agfl->agfl_bno[i]) == NULLAGBLOCK ||
if (be32_to_cpu(agfl->agfl_bno[i]) != NULLAGBLOCK &&
be32_to_cpu(agfl->agfl_bno[i]) >= mp->m_sb.sb_agblocks)
agfl_ok = 0;
return false;
}
if (!agfl_ok) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, agfl);
xfs_buf_ioerror(bp, EFSCORRUPTED);
}
#endif
}
static void
xfs_agfl_write_verify(
struct xfs_buf *bp)
{
xfs_agfl_verify(bp);
return true;
}
static void
xfs_agfl_read_verify(
struct xfs_buf *bp)
{
xfs_agfl_verify(bp);
struct xfs_mount *mp = bp->b_target->bt_mount;
int agfl_ok = 1;
/*
* There is no verification of non-crc AGFLs because mkfs does not
* initialise the AGFL to zero or NULL. Hence the only valid part of the
* AGFL is what the AGF says is active. We can't get to the AGF, so we
* can't verify just those entries are valid.
*/
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
agfl_ok = xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
offsetof(struct xfs_agfl, agfl_crc));
agfl_ok = agfl_ok && xfs_agfl_verify(bp);
if (!agfl_ok) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
xfs_buf_ioerror(bp, EFSCORRUPTED);
}
}
static void
xfs_agfl_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_buf_log_item *bip = bp->b_fspriv;
/* no verification of non-crc AGFLs */
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (!xfs_agfl_verify(bp)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
xfs_buf_ioerror(bp, EFSCORRUPTED);
return;
}
if (bip)
XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
offsetof(struct xfs_agfl, agfl_crc));
}
const struct xfs_buf_ops xfs_agfl_buf_ops = {
@ -1984,18 +2015,18 @@ xfs_alloc_get_freelist(
int btreeblk) /* destination is a AGF btree */
{
xfs_agf_t *agf; /* a.g. freespace structure */
xfs_agfl_t *agfl; /* a.g. freelist structure */
xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */
xfs_agblock_t bno; /* block number returned */
__be32 *agfl_bno;
int error;
int logflags;
xfs_mount_t *mp; /* mount structure */
xfs_mount_t *mp = tp->t_mountp;
xfs_perag_t *pag; /* per allocation group data */
agf = XFS_BUF_TO_AGF(agbp);
/*
* Freelist is empty, give up.
*/
agf = XFS_BUF_TO_AGF(agbp);
if (!agf->agf_flcount) {
*bnop = NULLAGBLOCK;
return 0;
@ -2003,15 +2034,17 @@ xfs_alloc_get_freelist(
/*
* Read the array of free blocks.
*/
mp = tp->t_mountp;
if ((error = xfs_alloc_read_agfl(mp, tp,
be32_to_cpu(agf->agf_seqno), &agflbp)))
error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
&agflbp);
if (error)
return error;
agfl = XFS_BUF_TO_AGFL(agflbp);
/*
* Get the block number and update the data structures.
*/
bno = be32_to_cpu(agfl->agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
be32_add_cpu(&agf->agf_flfirst, 1);
xfs_trans_brelse(tp, agflbp);
if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp))
@ -2104,12 +2137,13 @@ xfs_alloc_put_freelist(
int btreeblk) /* block came from a AGF btree */
{
xfs_agf_t *agf; /* a.g. freespace structure */
xfs_agfl_t *agfl; /* a.g. free block array */
__be32 *blockp;/* pointer to array entry */
int error;
int logflags;
xfs_mount_t *mp; /* mount structure */
xfs_perag_t *pag; /* per allocation group data */
__be32 *agfl_bno;
int startoff;
agf = XFS_BUF_TO_AGF(agbp);
mp = tp->t_mountp;
@ -2117,7 +2151,6 @@ xfs_alloc_put_freelist(
if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
be32_to_cpu(agf->agf_seqno), &agflbp)))
return error;
agfl = XFS_BUF_TO_AGFL(agflbp);
be32_add_cpu(&agf->agf_fllast, 1);
if (be32_to_cpu(agf->agf_fllast) == XFS_AGFL_SIZE(mp))
agf->agf_fllast = 0;
@ -2138,13 +2171,17 @@ xfs_alloc_put_freelist(
xfs_alloc_log_agf(tp, agbp, logflags);
ASSERT(be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp));
blockp = &agfl->agfl_bno[be32_to_cpu(agf->agf_fllast)];
agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
*blockp = cpu_to_be32(bno);
startoff = (char *)blockp - (char *)agflbp->b_addr;
xfs_alloc_log_agf(tp, agbp, logflags);
xfs_trans_log_buf(tp, agflbp,
(int)((xfs_caddr_t)blockp - (xfs_caddr_t)agfl),
(int)((xfs_caddr_t)blockp - (xfs_caddr_t)agfl +
sizeof(xfs_agblock_t) - 1));
xfs_trans_buf_set_type(tp, agflbp, XFS_BLF_AGFL_BUF);
xfs_trans_log_buf(tp, agflbp, startoff,
startoff + sizeof(xfs_agblock_t) - 1);
return 0;
}

4
fs/xfs/xfs_buf_item.h
View File

@ -46,13 +46,15 @@ extern kmem_zone_t *xfs_buf_item_zone;
*/
#define XFS_BLF_BTREE_BUF (1<<5)
#define XFS_BLF_AGF_BUF (1<<6)
#define XFS_BLF_AGFL_BUF (1<<7)
#define XFS_BLF_TYPE_MASK \
(XFS_BLF_UDQUOT_BUF | \
XFS_BLF_PDQUOT_BUF | \
XFS_BLF_GDQUOT_BUF | \
XFS_BLF_BTREE_BUF | \
XFS_BLF_AGF_BUF)
XFS_BLF_AGF_BUF | \
XFS_BLF_AGFL_BUF)
#define XFS_BLF_CHUNK 128
#define XFS_BLF_SHIFT 7

5
fs/xfs/xfs_fsops.c
View File

@ -268,6 +268,11 @@ xfs_growfs_data_private(
}
agfl = XFS_BUF_TO_AGFL(bp);
if (xfs_sb_version_hascrc(&mp->m_sb)) {
agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
agfl->agfl_seqno = cpu_to_be32(agno);
uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_uuid);
}
for (bucket = 0; bucket < XFS_AGFL_SIZE(mp); bucket++)
agfl->agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);

10
fs/xfs/xfs_log_recover.c
View File

@ -1961,6 +1961,16 @@ xlog_recover_do_reg_buffer(
}
bp->b_ops = &xfs_agf_buf_ops;
break;
case XFS_BLF_AGFL_BUF:
if (!xfs_sb_version_hascrc(&mp->m_sb))
break;
if (*(__be32 *)bp->b_addr != cpu_to_be32(XFS_AGFL_MAGIC)) {
xfs_warn(mp, "Bad AGFL block magic!");
ASSERT(0);
break;
}
bp->b_ops = &xfs_agfl_buf_ops;
break;
default:
break;
}