Handle write-perm on LOCATE correctly (#233)

LinearTapeFileSystem · Dec 9, 2020 · fffa125 · fffa125
1 parent be1b873
commit fffa125
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Showing 5 changed files with 30 additions and 3 deletions.
diff --git a/messages/internal_error/root.txt b/messages/internal_error/root.txt
@@ -251,6 +251,7 @@ root:table {
  I1198E:string{ "The tape is already removed." }
  I1199E:string{ "You need to move tape to a storage slot first before the operation." }
  I1200E:string{ "The operation needs to be started again." }
+ I1201E:string{ "Locate returns write-perm error." }
 
  // Special error codes
  I9997E:string{ "Child process error (ltfsck/mkltfs): %s (%d)." }

diff --git a/messages/libltfs/root.txt b/messages/libltfs/root.txt
@@ -808,6 +808,7 @@ v
  17264I:string { "The index on %s is newer, but MAM shows a permanent write error happened on %s." }
  17265I:string { "Skip writing the index because of %s." }
  17266I:string { "Skip setting the append only mode because the drive doesn't seem to support it." }
+ 17267E:string { "Locate command returns write-perm error (%d). Replace a return code to %d." }
 
  // For Debug 19999I:string { "%s %s %d." }
 

diff --git a/src/libltfs/arch/errormap.c b/src/libltfs/arch/errormap.c
@@ -286,6 +286,7 @@ static struct error_map fuse_error_list[] = {
  { LTFS_TAPE_REMOVED, "I1198E", EIDRM},
  { LTFS_NEED_MOVE, "I1199E", EINVAL},
  { LTFS_NEED_START_OVER, "I1200E", EINVAL},
+ { LTFS_LOCATE_ERROR, "I1201E", EIO},
 
  { EDEV_NO_SENSE, "D0000E", EIO},
  { EDEV_OVERRUN, "D0002E", EIO},

diff --git a/src/libltfs/ltfs_error.h b/src/libltfs/ltfs_error.h
@@ -257,6 +257,7 @@
 #define LTFS_TAPE_REMOVED 1198 /* The tape is already removed */
 #define LTFS_NEED_MOVE 1199 /* Need to move tape to a storage slot first before the operation */
 #define LTFS_NEED_START_OVER 1200 /* Need operation needs to be started again */
+#define LTFS_LOCATE_ERROR 1201 /* Locate returns write-perm error */
 
 #define LTFS_ERR_MAX 19999
 

diff --git a/src/libltfs/tape.c b/src/libltfs/tape.c
@@ -851,6 +851,7 @@ int tape_seek_append_position(struct device_data *dev, tape_partition_t prt, boo
  if (ret < 0) {
  ltfsmsg(LTFS_ERR, 12033E, ret);
  dev->write_error = true;
+
  return ret;
  }
 
@@ -996,7 +997,7 @@ int tape_rewind(struct device_data *dev)
  */
 int tape_seek(struct device_data *dev, struct tc_position *pos)
 {
- int ret;
+ int ret = 0;
 
  CHECK_ARG_NULL(dev, -LTFS_NULL_ARG);
  CHECK_ARG_NULL(pos, -LTFS_NULL_ARG);
@@ -1016,8 +1017,14 @@ int tape_seek(struct device_data *dev, struct tc_position *pos)
  ltfs_mutex_unlock(&dev->read_only_flag_mutex);
  }
  }
- else {
- ret = 0;
+
+ if (IS_WRITE_PERM(-ret)) {
+ /*
+ * LOCATE command must not return a WRITE_PERM related error.
+ * LOCATE is actually read operation, it doesn't make sense to return a WRITE_PERM at all.
+ */
+ ltfsmsg(LTFS_ERR, 17267E, ret, -LTFS_LOCATE_ERROR);
+ ret = -LTFS_LOCATE_ERROR;
  }
 
  if (ret == 0 && (dev->position.partition != pos->partition ||
@@ -1051,6 +1058,14 @@ int tape_seek_eod(struct device_data *dev, tape_partition_t partition)
  ret = dev->backend->locate(dev->backend_data, seekpos, &dev->position);
  if (ret < 0) {
  ltfsmsg(LTFS_ERR, 12039E, ret);
+ if (IS_WRITE_PERM(-ret)) {
+ /*
+ * LOCATE command must not return a WRITE_PERM related error.
+ * LOCATE is actually read operation, it doesn't make sense to return a WRITE_PERM at all.
+ */
+ ltfsmsg(LTFS_ERR, 17267E, ret, -LTFS_LOCATE_ERROR);
+ ret = -LTFS_LOCATE_ERROR;
+ }
  return ret;
  }
 
@@ -1547,6 +1562,14 @@ int tape_unformat(struct device_data *dev)
  ret = dev->backend->locate(dev->backend_data, bom, &dev->position);
  if (ret < 0) {
  ltfsmsg(LTFS_ERR, 12054E, ret);
+ if (IS_WRITE_PERM(-ret)) {
+ /*
+ * LOCATE command must not return a WRITE_PERM related error.
+ * LOCATE is actually read operation, it doesn't make sense to return a WRITE_PERM at all.
+ */
+ ltfsmsg(LTFS_ERR, 17267E, ret, -LTFS_LOCATE_ERROR);
+ ret = -LTFS_LOCATE_ERROR;
+ }
  return ret;
  }