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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 /fs/xfs/xfs_fsops.c
parente04426b9202bccd4cfcbc70b2fa2aeca1c86d8f5 (diff)
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>
Diffstat (limited to 'fs/xfs/xfs_fsops.c')
-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 c25b094efbf..4beaede4327 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);