Seeking file data and holes
       Since version 3.1, Linux supports the following additional values
       for whence:

       SEEK_DATA
              Adjust the file offset to the next location in the file
              greater than or equal to offset containing data.  If
              offset points to data, then the file offset is set to
              offset.

       SEEK_HOLE
              Adjust the file offset to the next hole in the file
              greater than or equal to offset.  If offset points into
              the middle of a hole, then the file offset is set to
              offset.  If there is no hole past offset, then the file
              offset is adjusted to the end of the file (i.e., there is
              an implicit hole at the end of any file).

This is probably what's needed to disable lseek:

diff --git a/src/copy.c b/src/copy.c
index cb9018f93..2a4ccc061 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -502,7 +502,7 @@ write_zeros (int fd, off_t n_bytes)
   return true;
 }

-#ifdef SEEK_HOLE
+#if 0
 /* Perform an efficient extent copy, if possible.  This avoids
    the overhead of detecting holes in hole-introducing/preserving
    copy, and thus makes copying sparse files much more efficient.
@@ -1095,7 +1095,7 @@ infer_scantype (int fd, struct stat const *sb,
          && ST_NBLOCKS (*sb) < sb->st_size / ST_NBLOCKSIZE))
     return PLAIN_SCANTYPE;

-#ifdef SEEK_HOLE
+#if 0
   scan_inference->ext_start = lseek (fd, 0, SEEK_DATA);
   if (0 <= scan_inference->ext_start)
     return LSEEK_SCANTYPE;
@@ -1377,7 +1377,7 @@ copy_reg (char const *src_name, char const *dst_name,
       off_t n_read;
       bool wrote_hole_at_eof = false;
       if (! (
-#ifdef SEEK_HOLE
+#if 0
              scantype == LSEEK_SCANTYPE
              ? lseek_copy (source_desc, dest_desc, buf, buf_size, hole_size,
                            scan_inference.ext_start, src_open_sb.st_size,
diff --git a/tests/seek-data-capable b/tests/seek-data-capable
index cc6372214..6e7a9ec1e 100644
--- a/tests/seek-data-capable
+++ b/tests/seek-data-capable
@@ -1,5 +1,7 @@
 import sys, os, errno, platform

+sys.exit(1)
+
 # Pass an _empty_ file
 if len(sys.argv) != 2:
     sys.exit(1)

In reply to @janne.hess:helsinki-systems.de

This is probably what's needed to disable lseek:

diff --git a/src/copy.c b/src/copy.c
index cb9018f93..2a4ccc061 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -502,7 +502,7 @@ write_zeros (int fd, off_t n_bytes)
   return true;
 }

-#ifdef SEEK_HOLE
+#if 0
 /* Perform an efficient extent copy, if possible.  This avoids
    the overhead of detecting holes in hole-introducing/preserving
    copy, and thus makes copying sparse files much more efficient.
@@ -1095,7 +1095,7 @@ infer_scantype (int fd, struct stat const *sb,
          && ST_NBLOCKS (*sb) < sb->st_size / ST_NBLOCKSIZE))
     return PLAIN_SCANTYPE;

-#ifdef SEEK_HOLE
+#if 0
   scan_inference->ext_start = lseek (fd, 0, SEEK_DATA);
   if (0 <= scan_inference->ext_start)
     return LSEEK_SCANTYPE;
@@ -1377,7 +1377,7 @@ copy_reg (char const *src_name, char const *dst_name,
       off_t n_read;
       bool wrote_hole_at_eof = false;
       if (! (
-#ifdef SEEK_HOLE
+#if 0
              scantype == LSEEK_SCANTYPE
              ? lseek_copy (source_desc, dest_desc, buf, buf_size, hole_size,
                            scan_inference.ext_start, src_open_sb.st_size,
diff --git a/tests/seek-data-capable b/tests/seek-data-capable
index cc6372214..6e7a9ec1e 100644
--- a/tests/seek-data-capable
+++ b/tests/seek-data-capable
@@ -1,5 +1,7 @@
 import sys, os, errno, platform

+sys.exit(1)
+
 # Pass an _empty_ file
 if len(sys.argv) != 2:
     sys.exit(1)

In reply to @vcunat:matrix.org
I also confirm that this patch fixes peertube build, atop staging-next. (same machine: all ext4 on LVM, x86_64-linux)

In reply to @janne.hess:helsinki-systems.de
Also, is your /tmp on tmpfs?

In reply to @janne.hess:helsinki-systems.de
Awesome! Thank you. The build fails because presumably a file is broken, right? It's not because cp fails in the build process?

I haven't poked into details of the error. It looks like it attempts some tests after build and those all end with

Error: The service is no longer running

In reply to @vcunat:matrix.org
No, it's all ext4 on LVM.

In reply to @janne.hess:helsinki-systems.de
Because that's one big difference between us. For you, it's the same filesystem, for me it's not