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authorDave Chinner <dchinner@redhat.com>2012-10-09 14:50:52 +1100
committerBen Myers <bpm@sgi.com>2012-11-02 15:42:35 -0500
commit1375cb65e87b327a8dd4f920c3e3d837fb40e9c2 (patch)
tree65864cb563db56e2bb8fe2e63f2c21d4e61a01c4
parente04426b9202bccd4cfcbc70b2fa2aeca1c86d8f5 (diff)
downloadop-kernel-dev-1375cb65e87b327a8dd4f920c3e3d837fb40e9c2.zip
op-kernel-dev-1375cb65e87b327a8dd4f920c3e3d837fb40e9c2.tar.gz
xfs: growfs: don't read garbage for new secondary superblocks
When updating new secondary superblocks in a growfs operation, the superblock buffer is read from the newly grown region of the underlying device. This is not guaranteed to be zero, so violates the underlying assumption that the unused parts of superblocks are zero filled. Get a new buffer for these secondary superblocks to ensure that the unused regions are zero filled correctly. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
-rw-r--r--fs/xfs/xfs_fsops.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index c25b094..4beaede 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -399,9 +399,26 @@ xfs_growfs_data_private(
/* update secondary superblocks. */
for (agno = 1; agno < nagcount; agno++) {
- error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
+ error = 0;
+ /*
+ * new secondary superblocks need to be zeroed, not read from
+ * disk as the contents of the new area we are growing into is
+ * completely unknown.
+ */
+ if (agno < oagcount) {
+ error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
XFS_FSS_TO_BB(mp, 1), 0, &bp);
+ } else {
+ bp = xfs_trans_get_buf(NULL, mp->m_ddev_targp,
+ XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+ XFS_FSS_TO_BB(mp, 1), 0);
+ if (bp)
+ xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
+ else
+ error = ENOMEM;
+ }
+
if (error) {
xfs_warn(mp,
"error %d reading secondary superblock for ag %d",
@@ -423,7 +440,7 @@ xfs_growfs_data_private(
break; /* no point in continuing */
}
}
- return 0;
+ return error;
error0:
xfs_trans_cancel(tp, XFS_TRANS_ABORT);
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