LU-11625 ofd: handle upgraded filter_fid properly

[fs/lustre-release.git] / lustre / include / uapi / linux / lustre / lustre_user.h

diff --git a/lustre/include/uapi/linux/lustre/lustre_user.h b/lustre/include/uapi/linux/lustre/lustre_user.h
index 7997d39..a747e45 100644 (file)
--- a/lustre/include/uapi/linux/lustre/lustre_user.h
+++ b/lustre/include/uapi/linux/lustre/lustre_user.h
@@ -201,15 +201,47 @@ struct ost_layout {
        __u32   ol_comp_id;
 } __attribute__((packed));
 
-/* keep this one for compatibility */
-struct filter_fid_old {
-       struct lu_fid   ff_parent;
-       __u64           ff_objid;
-       __u64           ff_seq;
+/* The filter_fid structure has changed several times over its lifetime.
+ * For a long time "trusted.fid" held the MDT inode parent FID/IGIF and
+ * stripe_index and the "self FID" (objid/seq) to be able to recover the
+ * OST objects in case of corruption.  With the move to 2.4 and OSD-API for
+ * the OST, the "trusted.lma" xattr was added to the OST objects to store
+ * the "self FID" to be consistent with the MDT on-disk format, and the
+ * filter_fid only stored the MDT inode parent FID and stripe index.
+ *
+ * In 2.10, the addition of PFL composite layouts required more information
+ * to be stored into the filter_fid in order to be able to identify which
+ * component the OST object belonged.  As well, the stripe size may vary
+ * between components, so it was no longer safe to assume the stripe size
+ * or stripe_count of a file.  This is also more robust for plain layouts.
+ *
+ * For ldiskfs OSTs that were formatted with 256-byte inodes, there is not
+ * enough space to store both the filter_fid and LMA in the inode, so they
+ * are packed into struct lustre_ost_attrs on disk in trusted.lma to avoid
+ * an extra seek for every OST object access.
+ *
+ * In 2.11, FLR mirror layouts also need to store the layout version and
+ * range so that writes to old versions of the layout are not allowed.
+ * That ensures that mirrored objects are not modified by evicted clients,
+ * and ensures that the components are correctly marked stale on the MDT.
+ */
+struct filter_fid_18_23 {
+       struct lu_fid           ff_parent;      /* stripe_idx in f_ver */
+       __u64                   ff_objid;
+       __u64                   ff_seq;
+};
+
+struct filter_fid_24_29 {
+       struct lu_fid           ff_parent;      /* stripe_idx in f_ver */
+};
+
+struct filter_fid_210 {
+       struct lu_fid           ff_parent;      /* stripe_idx in f_ver */
+       struct ost_layout       ff_layout;
 };
 
 struct filter_fid {
-       struct lu_fid           ff_parent;
+       struct lu_fid           ff_parent;      /* stripe_idx in f_ver */
        struct ost_layout       ff_layout;
        __u32                   ff_layout_version;
        __u32                   ff_range; /* range of layout version that