LU-10092 pcc: Non-blocking PCC caching

[fs/lustre-release.git] / lustre / utils / liblustreapi_hsm.c

diff --git a/lustre/utils/liblustreapi_hsm.c b/lustre/utils/liblustreapi_hsm.c
index 39624f2..c8a68ef 100644 (file)
--- a/lustre/utils/liblustreapi_hsm.c
+++ b/lustre/utils/liblustreapi_hsm.c
@@ -1140,7 +1140,37 @@ int llapi_hsm_action_begin(struct hsm_copyaction_private **phcp,
                        goto err_out;
        } else if (hai->hai_action == HSMA_REMOVE) {
                /* Since remove is atomic there is no need to send an
-                * initial MDS_HSM_PROGRESS RPC. */
+                * initial MDS_HSM_PROGRESS RPC.
+                * RW-PCC uses Lustre HSM mechanism for data synchronization.
+                * At the beginning of RW-PCC attach, the client tries to
+                * exclusively open the file by using a lease lock. A
+                * successful lease open ensures that the current attach
+                * process is the unique opener for the file.
+                * After taking the lease, the file data is then copied from
+                * OSTs into PCC and then the client closes the lease with
+                * with a PCC attach intent.
+                * However, for a file with HSM exists, archived state (i.e. a
+                * cached file just was detached from PCC and restore into
+                * OST), a HSM REMOVE request may delete the above PCC copy
+                * during RW-PCC attach wrongly.
+                * Thus, a open/close on the corresponding Lustre file is added
+                * for HSMA_REMOVE here to solve this conflict.
+                */
+               fd = ct_open_by_fid(hcp->ct_priv, &hai->hai_fid,
+                               O_RDONLY | O_NOATIME | O_NOFOLLOW | O_NONBLOCK);
+               if (fd < 0) {
+                       rc = fd;
+                       /* ignore the error in case of Remove Archive on Last
+                        * Unlink (RAoLU).
+                        */
+                       if (rc == -ENOENT) {
+                               rc = 0;
+                               goto out_log;
+                       }
+                       goto err_out;
+               }
+
+               hcp->source_fd = fd;
                goto out_log;
        }