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79 lines
3.3 KiB
79 lines
3.3 KiB
commit cbca895541facb3a1a00fd0fe6614301a64c0e3a |
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Author: Eric Sandeen <sandeen@redhat.com> |
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Date: Fri Sep 23 09:16:52 2016 +1000 |
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xfs_copy: Fix meta UUID handling on multiple copies |
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Zorro reported that when making multiple copies of a V5 |
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filesystem with xfs_copy while generating new UUIDs, all |
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but the first copy were corrupt. |
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Upon inspection, the corruption was related to incorrect UUIDs; |
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the original UUID, as stamped into every metadata structure, |
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was not preserved in the sb_meta_uuid field of the superblock |
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on any but the first copy. |
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This happened because sb_update_uuid was using the UUID present in |
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the ag_hdr structure as the unchanging meta-uuid which is to match |
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existing structures, but it also /updates/ that UUID with the |
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new identifying UUID present in tcarg. So the newly-generated |
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UUIDs moved transitively from tcarg->uuid to ag_hdr->xfs_sb->sb_uuid |
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to ag_hdr->xfs_sb->sb_meta_uuid each time the function got called. |
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Fix this by looking instead to the unchanging, original UUID |
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present in the xfs_sb_t we are given, which reflects the original |
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filesystem's metadata UUID, and copy /that/ UUID into each target |
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filesystem's meta_uuid field. |
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Most of this patch is changing comments and re-ordering tests |
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to match; the functional change is to simply use the *sb rather |
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than the *ag_hdr to identify the proper metadata UUID. |
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Reported-and-tested-by: Zorro Lang <zlang@redhat.com> |
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Signed-off-by: Eric Sandeen <sandeen@redhat.com> |
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Reviewed-by: Dave Chinner <dchinner@redhat.com> |
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Signed-off-by: Dave Chinner <david@fromorbit.com> |
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diff --git a/copy/xfs_copy.c b/copy/xfs_copy.c |
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index 3c8998c..22ded6b 100644 |
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--- a/copy/xfs_copy.c |
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+++ b/copy/xfs_copy.c |
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@@ -494,27 +494,29 @@ write_wbuf(void) |
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void |
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sb_update_uuid( |
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- xfs_sb_t *sb, |
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- ag_header_t *ag_hdr, |
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- thread_args *tcarg) |
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+ xfs_sb_t *sb, /* Original fs superblock */ |
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+ ag_header_t *ag_hdr, /* AG hdr to update for this copy */ |
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+ thread_args *tcarg) /* Args for this thread, with UUID */ |
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{ |
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/* |
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* If this filesystem has CRCs, the original UUID is stamped into |
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- * all metadata. If we are changing the UUID in the copy, we need |
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- * to copy the original UUID into the meta_uuid slot and set the |
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- * set the incompat flag if that hasn't already been done. |
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+ * all metadata. If we don't have an existing meta_uuid field in the |
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+ * the original filesystem and we are changing the UUID in this copy, |
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+ * we must copy the original sb_uuid to the sb_meta_uuid slot and set |
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+ * the incompat flag for the feature on this copy. |
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*/ |
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- if (!uuid_equal(&tcarg->uuid, &ag_hdr->xfs_sb->sb_uuid) && |
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- xfs_sb_version_hascrc(sb) && !xfs_sb_version_hasmetauuid(sb)) { |
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+ if (xfs_sb_version_hascrc(sb) && !xfs_sb_version_hasmetauuid(sb) && |
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+ !uuid_equal(&tcarg->uuid, &sb->sb_uuid)) { |
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__be32 feat; |
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feat = be32_to_cpu(ag_hdr->xfs_sb->sb_features_incompat); |
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feat |= XFS_SB_FEAT_INCOMPAT_META_UUID; |
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ag_hdr->xfs_sb->sb_features_incompat = cpu_to_be32(feat); |
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platform_uuid_copy(&ag_hdr->xfs_sb->sb_meta_uuid, |
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- &ag_hdr->xfs_sb->sb_uuid); |
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+ &sb->sb_uuid); |
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} |
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+ /* Copy the (possibly new) fs-identifier UUID into sb_uuid */ |
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platform_uuid_copy(&ag_hdr->xfs_sb->sb_uuid, &tcarg->uuid); |
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/* We may have changed the UUID, so update the superblock CRC */
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