LU-5549 mdc: cl_default_mds_easize not refreshed

[fs/lustre-release.git] / lustre / include / obd.h

diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index 3f3d2fa..de554b8 100644 (file)
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -205,23 +205,59 @@ enum {
         NUM_SYNC_ON_CANCEL_STATES
 };
 
+/*
+ * Limit reply buffer size for striping data to one x86_64 page. This
+ * value is chosen to fit the striping data for common use cases while
+ * staying well below the limit at which the buffer must be backed by
+ * vmalloc(). Excessive use of vmalloc() may cause spinlock contention
+ * on the MDS.
+ */
+#define OBD_MAX_DEFAULT_EA_SIZE                4096
+#define OBD_MAX_DEFAULT_COOKIE_SIZE    4096
+
 struct mdc_rpc_lock;
 struct obd_import;
 struct client_obd {
        struct rw_semaphore      cl_sem;
-        struct obd_uuid          cl_target_uuid;
-        struct obd_import       *cl_import; /* ptlrpc connection state */
+       struct obd_uuid          cl_target_uuid;
+       struct obd_import       *cl_import; /* ptlrpc connection state */
        size_t                   cl_conn_count;
-       /* max_mds_easize is purely a performance thing so we don't have to
-        * call obd_size_diskmd() all the time. */
+
+       /* Cache maximum and default values for easize and cookiesize. This is
+        * strictly a performance optimization to minimize calls to
+        * obd_size_diskmd(). The default values are used to calculate the
+        * initial size of a request buffer. The ptlrpc layer will resize the
+        * buffer as needed to accommodate a larger reply from the
+        * server. The default values should be small enough to avoid wasted
+        * memory and excessive use of vmalloc(), yet large enough to avoid
+        * reallocating the buffer in the common use case. */
+
+       /* Default EA size for striping attributes. It is initialized at
+        * mount-time based on the default stripe width of the filesystem,
+        * then it tracks the largest observed EA size advertised by
+        * the MDT, up to a maximum value of OBD_MAX_DEFAULT_EA_SIZE. */
        __u32                    cl_default_mds_easize;
+
+       /* Maximum possible EA size computed at mount-time based on
+        * the number of OSTs in the filesystem. May be increased at
+        * run-time if a larger observed size is advertised by the MDT. */
        __u32                    cl_max_mds_easize;
+
+       /* Default cookie size for llog cookies (see struct llog_cookie). It is
+        * initialized to zero at mount-time, then it tracks the largest
+        * observed cookie size advertised by the MDT, up to a maximum value of
+        * OBD_MAX_DEFAULT_COOKIE_SIZE. Note that llog_cookies are not
+        * used by clients communicating with MDS versions 2.4.0 and later.*/
        __u32                    cl_default_mds_cookiesize;
+
+       /* Maximum possible cookie size computed at mount-time based on
+        * the number of OSTs in the filesystem. May be increased at
+        * run-time if a larger observed size is advertised by the MDT. */
        __u32                    cl_max_mds_cookiesize;
 
-        enum lustre_sec_part     cl_sp_me;
-        enum lustre_sec_part     cl_sp_to;
-        struct sptlrpc_flavor    cl_flvr_mgc;   /* fixed flavor of mgc->mgs */
+       enum lustre_sec_part     cl_sp_me;
+       enum lustre_sec_part     cl_sp_to;
+       struct sptlrpc_flavor    cl_flvr_mgc; /* fixed flavor of mgc->mgs */
 
        /* the grant values are protected by loi_list_lock below */
        unsigned long            cl_dirty_pages;      /* all _dirty_ in pages */
@@ -834,6 +870,9 @@ struct md_op_data {
        /* File object data version for HSM release, on client */
        __u64                   op_data_version;
        struct lustre_handle    op_lease_handle;
+
+       /* default stripe offset */
+       __u32                   op_default_stripe_offset;
 };
 
 struct md_callback {