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authorDavid Chinner <dgc@sgi.com>2008-03-06 13:45:50 +1100
committerLachlan McIlroy <lachlan@redback.melbourne.sgi.com>2008-04-10 16:25:15 +1000
commitee1c090825bf2f1cb9712489c234eabf69a9a78f (patch)
treec261cbeeda46937e6c65994b4348227505665f66 /fs/xfs/xfs_mount.c
parent6211870992502efdccf9cd6bae155c83277835fa (diff)
downloadop-kernel-dev-ee1c090825bf2f1cb9712489c234eabf69a9a78f.zip
op-kernel-dev-ee1c090825bf2f1cb9712489c234eabf69a9a78f.tar.gz
[XFS] Fix superblock features2 field alignment problem
Due to the xfs_dsb_t structure not being 64 bit aligned, the last field of the on-disk superblock can vary in location This causes problems when the filesystem gets moved to a different platform, or there is a 32 bit userspace and 64 bit kernel. This patch detects the defect at mount time, logs a warning such as: XFS: correcting sb_features alignment problem in dmesg and corrects the problem so that everything is OK. it also blacklists the bad field in the superblock so it does not get used for something else later on. SGI-PV: 977636 SGI-Modid: xfs-linux-melb:xfs-kern:30539a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_mount.c')
-rw-r--r--fs/xfs/xfs_mount.c34
1 files changed, 28 insertions, 6 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 99bab1e..4e93c02 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -44,7 +44,7 @@
#include "xfs_quota.h"
#include "xfs_fsops.h"
-STATIC void xfs_mount_log_sbunit(xfs_mount_t *, __int64_t);
+STATIC void xfs_mount_log_sb(xfs_mount_t *, __int64_t);
STATIC int xfs_uuid_mount(xfs_mount_t *);
STATIC void xfs_uuid_unmount(xfs_mount_t *mp);
STATIC void xfs_unmountfs_wait(xfs_mount_t *);
@@ -119,6 +119,7 @@ static const struct {
{ offsetof(xfs_sb_t, sb_logsectsize),0 },
{ offsetof(xfs_sb_t, sb_logsunit), 0 },
{ offsetof(xfs_sb_t, sb_features2), 0 },
+ { offsetof(xfs_sb_t, sb_bad_features2), 0 },
{ sizeof(xfs_sb_t), 0 }
};
@@ -449,6 +450,7 @@ xfs_sb_from_disk(
to->sb_logsectsize = be16_to_cpu(from->sb_logsectsize);
to->sb_logsunit = be32_to_cpu(from->sb_logsunit);
to->sb_features2 = be32_to_cpu(from->sb_features2);
+ to->sb_bad_features2 = be32_to_cpu(from->sb_bad_features2);
}
/*
@@ -970,6 +972,26 @@ xfs_mountfs(
xfs_mount_common(mp, sbp);
/*
+ * Check for a bad features2 field alignment. This happened on
+ * some platforms due to xfs_sb_t not being 64bit size aligned
+ * when sb_features was added and hence the compiler put it in
+ * the wrong place.
+ *
+ * If we detect a bad field, we or the set bits into the existing
+ * features2 field in case it has already been modified and we
+ * don't want to lose any features. Zero the bad one and mark
+ * the two fields as needing updates once the transaction subsystem
+ * is online.
+ */
+ if (xfs_sb_has_bad_features2(sbp)) {
+ cmn_err(CE_WARN,
+ "XFS: correcting sb_features alignment problem");
+ sbp->sb_features2 |= sbp->sb_bad_features2;
+ sbp->sb_bad_features2 = 0;
+ update_flags |= XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2;
+ }
+
+ /*
* Check if sb_agblocks is aligned at stripe boundary
* If sb_agblocks is NOT aligned turn off m_dalign since
* allocator alignment is within an ag, therefore ag has
@@ -1159,11 +1181,10 @@ xfs_mountfs(
}
/*
- * If fs is not mounted readonly, then update the superblock
- * unit and width changes.
+ * If fs is not mounted readonly, then update the superblock changes.
*/
if (update_flags && !(mp->m_flags & XFS_MOUNT_RDONLY))
- xfs_mount_log_sbunit(mp, update_flags);
+ xfs_mount_log_sb(mp, update_flags);
/*
* Initialise the XFS quota management subsystem for this mount
@@ -1878,13 +1899,14 @@ xfs_uuid_unmount(
* be altered by the mount options. Only the first superblock is updated.
*/
STATIC void
-xfs_mount_log_sbunit(
+xfs_mount_log_sb(
xfs_mount_t *mp,
__int64_t fields)
{
xfs_trans_t *tp;
- ASSERT(fields & (XFS_SB_UNIT|XFS_SB_WIDTH|XFS_SB_UUID));
+ ASSERT(fields & (XFS_SB_UNIT | XFS_SB_WIDTH | XFS_SB_UUID |
+ XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2));
tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
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