[PATCH 1/5] metadump: sanitise write_buf/index return values

[Dave Chinner <david@xxxxxxxxxxxxx>]

From: Dave Chinner <dchinner@xxxxxxxxxx>

Write_buf/write_index use confusing boolean values for return,
meaning that it's hard to tell what the correct error return is
supposed to be.  Convert them to return zero on success or a
negative errno otherwise so that it's clear what the error case is.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
 db/metadump.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/db/metadump.c b/db/metadump.c
index 117dc42..4104fcb 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -145,6 +145,8 @@ print_progress(const char *fmt, ...)
  * even if the dump is exactly aligned, the last index will be full of
  * zeros. If the last index entry is non-zero, the dump is incomplete.
  * Correspondingly, the last chunk will have a count < num_indicies.
+ *
+ * Return 0 for success, -1 for failure.
  */
 
 static int
@@ -156,12 +158,12 @@ write_index(void)
        metablock->mb_count = cpu_to_be16(cur_index);
        if (fwrite(metablock, (cur_index + 1) << BBSHIFT, 1, outf) != 1) {
                print_warning("error writing to file: %s", strerror(errno));
-               return 0;
+               return -errno;
        }
 
        memset(block_index, 0, num_indicies * sizeof(__be64));
        cur_index = 0;
-       return 1;
+       return 0;
 }
 
 static int
@@ -171,6 +173,7 @@ write_buf(
        char            *data;
        __int64_t       off;
        int             i;
+       int             ret;
 
        /*
         * Run the write verifier to recalculate the buffer CRCs and check
@@ -184,7 +187,7 @@ write_buf(
        _("%s: write verifer failed on bno 0x%llx/0x%x\n"),
                                __func__, (long long)buf->bp->b_bn,
                                buf->bp->b_bcount);
-                       return buf->bp->b_error;
+                       return -buf->bp->b_error;
                }
        }
 
@@ -194,11 +197,12 @@ write_buf(
                block_index[cur_index] = cpu_to_be64(off);
                memcpy(&block_buffer[cur_index << BBSHIFT], data, BBSIZE);
                if (++cur_index == num_indicies) {
-                       if (!write_index())
-                               return 0;
+                       ret = write_index();
+                       if (ret)
+                               return ret;
                }
        }
-       return !seenint();
+       return seenint() ? -EINTR : 0;
 }
 
 
@@ -227,7 +231,7 @@ scan_btree(
                rval = !stop_on_read_error;
                goto pop_out;
        }
-       if (!write_buf(iocur_top))
+       if (write_buf(iocur_top))
                goto pop_out;
 
        if (!(*func)(iocur_top->data, agno, agbno, level - 1, btype, arg))
@@ -1439,7 +1443,7 @@ process_bmbt_reclist(
 
                                default: ;
                            }
-                       if (!write_buf(iocur_top)) {
+                       if (write_buf(iocur_top)) {
                                pop_cur();
                                return 0;
                        }
@@ -1748,7 +1752,7 @@ copy_inode_chunk(
                xfs_dinode_calc_crc(mp, dip);
        }
 skip_processing:
-       if (!write_buf(iocur_top))
+       if (write_buf(iocur_top))
                goto pop_out;
 
        inodes_copied += XFS_INODES_PER_CHUNK;
@@ -1866,7 +1870,7 @@ scan_ag(
                if (stop_on_read_error)
                        goto pop_out;
        } else {
-               if (!write_buf(iocur_top))
+               if (write_buf(iocur_top))
                        goto pop_out;
        }
 
@@ -1881,7 +1885,7 @@ scan_ag(
                if (stop_on_read_error)
                        goto pop_out;
        } else {
-               if (!write_buf(iocur_top))
+               if (write_buf(iocur_top))
                        goto pop_out;
        }
 
@@ -1896,7 +1900,7 @@ scan_ag(
                if (stop_on_read_error)
                        goto pop_out;
        } else {
-               if (!write_buf(iocur_top))
+               if (write_buf(iocur_top))
                        goto pop_out;
        }
 
@@ -1910,7 +1914,7 @@ scan_ag(
                if (stop_on_read_error)
                        goto pop_out;
        } else {
-               if (!write_buf(iocur_top))
+               if (write_buf(iocur_top))
                        goto pop_out;
        }
 
@@ -2015,7 +2019,7 @@ copy_log(void)
                print_warning("cannot read log");
                return !stop_on_read_error;
        }
-       return write_buf(iocur_top);
+       return !write_buf(iocur_top);
 }
 
 static int
@@ -2121,7 +2125,7 @@ metadump_f(
 
        /* write the remaining index */
        if (!exitcode)
-               exitcode = !write_index();
+               exitcode = write_index() < 0;
 
        if (progress_since_warning)
                fputc('\n', (outf == stdout) ? stderr : stdout);
-- 
1.8.4.rc3