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[PATCH 04/30] xfs: split dquot buffer operations out

To: xfs@xxxxxxxxxxx
Subject: [PATCH 04/30] xfs: split dquot buffer operations out
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Wed, 30 Oct 2013 15:30:55 +1100
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1383107481-28937-1-git-send-email-david@xxxxxxxxxxxxx>
References: <1383107481-28937-1-git-send-email-david@xxxxxxxxxxxxx>
From: Dave Chinner <dchinner@xxxxxxxxxx>

Parts of userspace want to be able to read and modify dquot buffers
(e.g. xfs_db) so we need to split out the reading and writing of
these buffers so it is easy to shared code with libxfs in userspace.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
 include/libxfs.h       |   9 ++
 libxfs/Makefile        |   1 +
 libxfs/xfs_dquot_buf.c | 273 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 libxfs/xfs_dquot_buf.c

diff --git a/include/libxfs.h b/include/libxfs.h
index 835ba37..f10ab59 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -216,6 +216,15 @@ typedef struct xfs_mount {
        xfs_dablk_t             m_dirdatablk;   /* blockno of dir data v2 */
        xfs_dablk_t             m_dirleafblk;   /* blockno of dir non-data v2 */
        xfs_dablk_t             m_dirfreeblk;   /* blockno of dirfreeindex v2 */
+
+       /*
+        * anonymous struct to allow xfs_dquot_buf.c to compile.
+        * Pointer is always null in userspace, so code does not use it at all
+        */
+       struct {
+               int     qi_dqperchunk;
+       }                       *m_quotainfo;
+
 } xfs_mount_t;
 
 /*
diff --git a/libxfs/Makefile b/libxfs/Makefile
index f0cbae3..4522218 100644
--- a/libxfs/Makefile
+++ b/libxfs/Makefile
@@ -29,6 +29,7 @@ CFILES = cache.c \
        xfs_dir2_leaf.c \
        xfs_dir2_node.c \
        xfs_dir2_sf.c \
+       xfs_dquot_buf.c \
        xfs_ialloc.c \
        xfs_inode_buf.c \
        xfs_inode_fork.c \
diff --git a/libxfs/xfs_dquot_buf.c b/libxfs/xfs_dquot_buf.c
new file mode 100644
index 0000000..620d9d3
--- /dev/null
+++ b/libxfs/xfs_dquot_buf.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * Copyright (c) 2013 Red Hat, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+
+int
+xfs_calc_dquots_per_chunk(
+       struct xfs_mount        *mp,
+       unsigned int            nbblks) /* basic block units */
+{
+       unsigned int    ndquots;
+
+       ASSERT(nbblks > 0);
+       ndquots = BBTOB(nbblks);
+       do_div(ndquots, sizeof(xfs_dqblk_t));
+
+       return ndquots;
+}
+
+/*
+ * Do some primitive error checking on ondisk dquot data structures.
+ */
+int
+xfs_dqcheck(
+       struct xfs_mount *mp,
+       xfs_disk_dquot_t *ddq,
+       xfs_dqid_t       id,
+       uint             type,    /* used only when IO_dorepair is true */
+       uint             flags,
+       char             *str)
+{
+       xfs_dqblk_t      *d = (xfs_dqblk_t *)ddq;
+       int             errs = 0;
+
+       /*
+        * We can encounter an uninitialized dquot buffer for 2 reasons:
+        * 1. If we crash while deleting the quotainode(s), and those blks got
+        *    used for user data. This is because we take the path of regular
+        *    file deletion; however, the size field of quotainodes is never
+        *    updated, so all the tricks that we play in itruncate_finish
+        *    don't quite matter.
+        *
+        * 2. We don't play the quota buffers when there's a quotaoff logitem.
+        *    But the allocation will be replayed so we'll end up with an
+        *    uninitialized quota block.
+        *
+        * This is all fine; things are still consistent, and we haven't lost
+        * any quota information. Just don't complain about bad dquot blks.
+        */
+       if (ddq->d_magic != cpu_to_be16(XFS_DQUOT_MAGIC)) {
+               if (flags & XFS_QMOPT_DOWARN)
+                       xfs_alert(mp,
+                       "%s : XFS dquot ID 0x%x, magic 0x%x != 0x%x",
+                       str, id, be16_to_cpu(ddq->d_magic), XFS_DQUOT_MAGIC);
+               errs++;
+       }
+       if (ddq->d_version != XFS_DQUOT_VERSION) {
+               if (flags & XFS_QMOPT_DOWARN)
+                       xfs_alert(mp,
+                       "%s : XFS dquot ID 0x%x, version 0x%x != 0x%x",
+                       str, id, ddq->d_version, XFS_DQUOT_VERSION);
+               errs++;
+       }
+
+       if (ddq->d_flags != XFS_DQ_USER &&
+           ddq->d_flags != XFS_DQ_PROJ &&
+           ddq->d_flags != XFS_DQ_GROUP) {
+               if (flags & XFS_QMOPT_DOWARN)
+                       xfs_alert(mp,
+                       "%s : XFS dquot ID 0x%x, unknown flags 0x%x",
+                       str, id, ddq->d_flags);
+               errs++;
+       }
+
+       if (id != -1 && id != be32_to_cpu(ddq->d_id)) {
+               if (flags & XFS_QMOPT_DOWARN)
+                       xfs_alert(mp,
+                       "%s : ondisk-dquot 0x%p, ID mismatch: "
+                       "0x%x expected, found id 0x%x",
+                       str, ddq, id, be32_to_cpu(ddq->d_id));
+               errs++;
+       }
+
+       if (!errs && ddq->d_id) {
+               if (ddq->d_blk_softlimit &&
+                   be64_to_cpu(ddq->d_bcount) >
+                               be64_to_cpu(ddq->d_blk_softlimit)) {
+                       if (!ddq->d_btimer) {
+                               if (flags & XFS_QMOPT_DOWARN)
+                                       xfs_alert(mp,
+                       "%s : Dquot ID 0x%x (0x%p) BLK TIMER NOT STARTED",
+                                       str, (int)be32_to_cpu(ddq->d_id), ddq);
+                               errs++;
+                       }
+               }
+               if (ddq->d_ino_softlimit &&
+                   be64_to_cpu(ddq->d_icount) >
+                               be64_to_cpu(ddq->d_ino_softlimit)) {
+                       if (!ddq->d_itimer) {
+                               if (flags & XFS_QMOPT_DOWARN)
+                                       xfs_alert(mp,
+                       "%s : Dquot ID 0x%x (0x%p) INODE TIMER NOT STARTED",
+                                       str, (int)be32_to_cpu(ddq->d_id), ddq);
+                               errs++;
+                       }
+               }
+               if (ddq->d_rtb_softlimit &&
+                   be64_to_cpu(ddq->d_rtbcount) >
+                               be64_to_cpu(ddq->d_rtb_softlimit)) {
+                       if (!ddq->d_rtbtimer) {
+                               if (flags & XFS_QMOPT_DOWARN)
+                                       xfs_alert(mp,
+                       "%s : Dquot ID 0x%x (0x%p) RTBLK TIMER NOT STARTED",
+                                       str, (int)be32_to_cpu(ddq->d_id), ddq);
+                               errs++;
+                       }
+               }
+       }
+
+       if (!errs || !(flags & XFS_QMOPT_DQREPAIR))
+               return errs;
+
+       if (flags & XFS_QMOPT_DOWARN)
+               xfs_notice(mp, "Re-initializing dquot ID 0x%x", id);
+
+       /*
+        * Typically, a repair is only requested by quotacheck.
+        */
+       ASSERT(id != -1);
+       ASSERT(flags & XFS_QMOPT_DQREPAIR);
+       memset(d, 0, sizeof(xfs_dqblk_t));
+
+       d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
+       d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
+       d->dd_diskdq.d_flags = type;
+       d->dd_diskdq.d_id = cpu_to_be32(id);
+
+       if (xfs_sb_version_hascrc(&mp->m_sb)) {
+               uuid_copy(&d->dd_uuid, &mp->m_sb.sb_uuid);
+               xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
+                                XFS_DQUOT_CRC_OFF);
+       }
+
+       return errs;
+}
+
+STATIC bool
+xfs_dquot_buf_verify_crc(
+       struct xfs_mount        *mp,
+       struct xfs_buf          *bp)
+{
+       struct xfs_dqblk        *d = (struct xfs_dqblk *)bp->b_addr;
+       int                     ndquots;
+       int                     i;
+
+       if (!xfs_sb_version_hascrc(&mp->m_sb))
+               return true;
+
+       /*
+        * if we are in log recovery, the quota subsystem has not been
+        * initialised so we have no quotainfo structure. In that case, we need
+        * to manually calculate the number of dquots in the buffer.
+        */
+       if (mp->m_quotainfo)
+               ndquots = mp->m_quotainfo->qi_dqperchunk;
+       else
+               ndquots = xfs_calc_dquots_per_chunk(mp,
+                                       XFS_BB_TO_FSB(mp, bp->b_length));
+
+       for (i = 0; i < ndquots; i++, d++) {
+               if (!xfs_verify_cksum((char *)d, sizeof(struct xfs_dqblk),
+                                XFS_DQUOT_CRC_OFF))
+                       return false;
+               if (!uuid_equal(&d->dd_uuid, &mp->m_sb.sb_uuid))
+                       return false;
+       }
+       return true;
+}
+
+STATIC bool
+xfs_dquot_buf_verify(
+       struct xfs_mount        *mp,
+       struct xfs_buf          *bp)
+{
+       struct xfs_dqblk        *d = (struct xfs_dqblk *)bp->b_addr;
+       xfs_dqid_t              id = 0;
+       int                     ndquots;
+       int                     i;
+
+       /*
+        * if we are in log recovery, the quota subsystem has not been
+        * initialised so we have no quotainfo structure. In that case, we need
+        * to manually calculate the number of dquots in the buffer.
+        */
+       if (mp->m_quotainfo)
+               ndquots = mp->m_quotainfo->qi_dqperchunk;
+       else
+               ndquots = xfs_calc_dquots_per_chunk(mp, bp->b_length);
+
+       /*
+        * On the first read of the buffer, verify that each dquot is valid.
+        * We don't know what the id of the dquot is supposed to be, just that
+        * they should be increasing monotonically within the buffer. If the
+        * first id is corrupt, then it will fail on the second dquot in the
+        * buffer so corruptions could point to the wrong dquot in this case.
+        */
+       for (i = 0; i < ndquots; i++) {
+               struct xfs_disk_dquot   *ddq;
+               int                     error;
+
+               ddq = &d[i].dd_diskdq;
+
+               if (i == 0)
+                       id = be32_to_cpu(ddq->d_id);
+
+               error = xfs_dqcheck(mp, ddq, id + i, 0, XFS_QMOPT_DOWARN,
+                                      "xfs_dquot_buf_verify");
+               if (error)
+                       return false;
+       }
+       return true;
+}
+
+static void
+xfs_dquot_buf_read_verify(
+       struct xfs_buf  *bp)
+{
+       struct xfs_mount        *mp = bp->b_target->bt_mount;
+
+       if (!xfs_dquot_buf_verify_crc(mp, bp) || !xfs_dquot_buf_verify(mp, bp)) 
{
+               XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, 
bp->b_addr);
+               xfs_buf_ioerror(bp, EFSCORRUPTED);
+       }
+}
+
+/*
+ * we don't calculate the CRC here as that is done when the dquot is flushed to
+ * the buffer after the update is done. This ensures that the dquot in the
+ * buffer always has an up-to-date CRC value.
+ */
+void
+xfs_dquot_buf_write_verify(
+       struct xfs_buf  *bp)
+{
+       struct xfs_mount        *mp = bp->b_target->bt_mount;
+
+       if (!xfs_dquot_buf_verify(mp, bp)) {
+               XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, 
bp->b_addr);
+               xfs_buf_ioerror(bp, EFSCORRUPTED);
+               return;
+       }
+}
+
+const struct xfs_buf_ops xfs_dquot_buf_ops = {
+       .verify_read = xfs_dquot_buf_read_verify,
+       .verify_write = xfs_dquot_buf_write_verify,
+};
+
-- 
1.8.4.rc3

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