On Sat, Feb 16, 2008 at 02:34:08AM +0100, Jan Derfinak wrote:
> Hello.
>
> I found following problem with xfs_info (xfs_grows -p xfs_info) command:
>
> # mkfs.xfs -f /dev/loop0
> meta-data=/dev/loop0 isize=256 agcount=4, agsize=32000 blks
> = sectsz=512 attr=2
> data = bsize=4096 blocks=128000, imaxpct=25
> = sunit=0 swidth=0 blks
> naming =version 2 bsize=4096
> log =internal log bsize=4096 blocks=1200, version=2
> = sectsz=512 sunit=0 blks, lazy-count=1
> realtime =none extsz=4096 blocks=0, rtextents=0
> # mount /dev/loop0 /mnt/usb
> # xfs_info /mnt/usb
> meta-data=/dev/loop0 isize=256 agcount=4, agsize=32000 blks
> = sectsz=512 attr=0
> data = bsize=4096 blocks=128000, imaxpct=25
> = sunit=0 swidth=0 blks
> naming =version 2 bsize=4096
> log =internal bsize=4096 blocks=1200, version=2
> = sectsz=512 sunit=0 blks, lazy-count=0
> realtime =none extsz=4096 blocks=0, rtextents=0
>
> Can somebody explain the difference in attr and lazy-count parameters?
> Which output is the right one?
.....
> # xfs_db -r /dev/loop0
> xfs_db> sb
> xfs_db> print
....
> features2 = 0
That's why.
I've been meaning to push out a patch to fix this - just haven't
had time. The patch below should fix the problem - mkfs.xfs is writing
the features2 field to the wrong location in the superblock, and
this patch detects and corrects it. You'll probably see the output:
XFS: correcting sb_features alignment problem
in dmesg when you first mount the filesystem with the patched
kernel, and then it won't appear again (unless you mkfs it again).
Cheers,
Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group
---
fs/xfs/xfs_mount.c | 34 ++++++++++++++++++++++++++++------
fs/xfs/xfs_sb.h | 37 ++++++++++++++++++++++++++++++++++---
2 files changed, 62 insertions(+), 9 deletions(-)
Index: 2.6.x-xfs-new/fs/xfs/xfs_mount.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_mount.c 2007-11-22 10:25:25.590278381
+1100
+++ 2.6.x-xfs-new/fs/xfs/xfs_mount.c 2007-11-22 10:31:27.891999961 +1100
@@ -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 }
};
@@ -455,6 +456,7 @@ 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);
}
/*
@@ -976,6 +978,26 @@ 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
@@ -1165,11 +1187,10 @@ 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
@@ -1884,13 +1905,14 @@ 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,
Index: 2.6.x-xfs-new/fs/xfs/xfs_sb.h
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_sb.h 2007-11-22 10:25:25.598277360 +1100
+++ 2.6.x-xfs-new/fs/xfs/xfs_sb.h 2007-11-22 10:31:27.891999961 +1100
@@ -89,6 +89,7 @@ struct xfs_mount;
/*
* Superblock - in core version. Must match the ondisk version below.
+ * Must be padded to 64 bit alignment.
*/
typedef struct xfs_sb {
__uint32_t sb_magicnum; /* magic number == XFS_SB_MAGIC */
@@ -145,10 +146,21 @@ typedef struct xfs_sb {
__uint16_t sb_logsectsize; /* sector size for the log, bytes */
__uint32_t sb_logsunit; /* stripe unit size for the log */
__uint32_t sb_features2; /* additional feature bits */
+
+ /*
+ * bad features2 field as a result of failing to pad the sb
+ * structure to 64 bits. Some machines will be using this field
+ * for features2 bits. Easiest just to mark it bad and not use
+ * it for anything else.
+ */
+ __uint32_t sb_bad_features2;
+
+ /* must be padded to 64 bit alignment */
} xfs_sb_t;
/*
- * Superblock - on disk version. Must match the in core version below.
+ * Superblock - on disk version. Must match the in core version above.
+ * Must be padded to 64 bit alignment.
*/
typedef struct xfs_dsb {
__be32 sb_magicnum; /* magic number == XFS_SB_MAGIC */
@@ -205,6 +217,15 @@ typedef struct xfs_dsb {
__be16 sb_logsectsize; /* sector size for the log, bytes */
__be32 sb_logsunit; /* stripe unit size for the log */
__be32 sb_features2; /* additional feature bits */
+ /*
+ * bad features2 field as a result of failing to pad the sb
+ * structure to 64 bits. Some machines will be using this field
+ * for features2 bits. Easiest just to mark it bad and not use
+ * it for anything else.
+ */
+ __be32 sb_bad_features2;
+
+ /* must be padded to 64 bit alignment */
} xfs_dsb_t;
/*
@@ -223,7 +244,7 @@ typedef enum {
XFS_SBS_GQUOTINO, XFS_SBS_QFLAGS, XFS_SBS_FLAGS, XFS_SBS_SHARED_VN,
XFS_SBS_INOALIGNMT, XFS_SBS_UNIT, XFS_SBS_WIDTH, XFS_SBS_DIRBLKLOG,
XFS_SBS_LOGSECTLOG, XFS_SBS_LOGSECTSIZE, XFS_SBS_LOGSUNIT,
- XFS_SBS_FEATURES2,
+ XFS_SBS_FEATURES2, XFS_SBS_BAD_FEATURES2,
XFS_SBS_FIELDCOUNT
} xfs_sb_field_t;
@@ -248,13 +269,15 @@ typedef enum {
#define XFS_SB_IFREE XFS_SB_MVAL(IFREE)
#define XFS_SB_FDBLOCKS XFS_SB_MVAL(FDBLOCKS)
#define XFS_SB_FEATURES2 XFS_SB_MVAL(FEATURES2)
+#define XFS_SB_BAD_FEATURES2 XFS_SB_MVAL(BAD_FEATURES2)
#define XFS_SB_NUM_BITS ((int)XFS_SBS_FIELDCOUNT)
#define XFS_SB_ALL_BITS ((1LL << XFS_SB_NUM_BITS) - 1)
#define XFS_SB_MOD_BITS \
(XFS_SB_UUID | XFS_SB_ROOTINO | XFS_SB_RBMINO | XFS_SB_RSUMINO | \
XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO | XFS_SB_GQUOTINO | \
XFS_SB_QFLAGS | XFS_SB_SHARED_VN | XFS_SB_UNIT | XFS_SB_WIDTH | \
- XFS_SB_ICOUNT | XFS_SB_IFREE | XFS_SB_FDBLOCKS | XFS_SB_FEATURES2)
+ XFS_SB_ICOUNT | XFS_SB_IFREE | XFS_SB_FDBLOCKS | XFS_SB_FEATURES2 | \
+ XFS_SB_BAD_FEATURES2)
/*
@@ -297,6 +320,14 @@ static inline int xfs_sb_good_version(xf
}
#endif /* __KERNEL__ */
+/*
+ * Detect a bad features2 field
+ */
+static inline int xfs_sb_has_bad_features2(xfs_sb_t *sbp)
+{
+ return (sbp->sb_bad_features2 != 0);
+}
+
#define XFS_SB_VERSION_TONEW(v) xfs_sb_version_tonew(v)
static inline unsigned xfs_sb_version_tonew(unsigned v)
{
|