From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 20 Feb 2008 06:09:41 -0800 (PST) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m1KE9YtG017452 for ; Wed, 20 Feb 2008 06:09:36 -0800 Received: from sandeen.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 558D5E73FA4 for ; Wed, 20 Feb 2008 06:09:59 -0800 (PST) Received: from sandeen.net (sandeen.net [209.173.210.139]) by cuda.sgi.com with ESMTP id Dn3sxARfhYYbvI5e for ; Wed, 20 Feb 2008 06:09:59 -0800 (PST) Message-ID: <47BC34B4.8000609@sandeen.net> Date: Wed, 20 Feb 2008 08:09:56 -0600 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: [patch] detect and correct bad features2 superblock field References: <20080220054041.GM155407@sgi.com> In-Reply-To: <20080220054041.GM155407@sgi.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: David Chinner Cc: xfs-dev , xfs-oss David Chinner wrote: > There is a bug in mkfs.xfs that can result in writing the features2 > field in the superblock to the wrong location. This only occurs > on some architectures, typically those with 32 bit userspace and > 64 bit kernels. > > 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. Looks good to me, thanks for fixing it up properly. You can add Reviewed-by: or Acked-by: or whatever is appropriate... Eric Sandeen Thanks, -Eric > Signed-off-by: Dave Chinner > --- > 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) > { > >