diff --git a/remotefilelog/debugcommands.py b/remotefilelog/debugcommands.py
--- a/remotefilelog/debugcommands.py
+++ b/remotefilelog/debugcommands.py
@@ -18,6 +18,7 @@
     shallowrepo,
     shallowutil,
 )
+from .repack import repacklockvfs
 from .lz4wrapper import lz4decompress
 import hashlib, os, time
 
@@ -361,7 +362,7 @@
 def debugwaitonrepack(repo):
     while True:
         try:
-            with extutil.fcntllock(repo.svfs, 'repacklock', ''):
+            with extutil.fcntllock(repacklockvfs(repo), 'repacklock', ''):
                 return
         except error.LockHeld:
             time.sleep(0.1)
diff --git a/remotefilelog/repack.py b/remotefilelog/repack.py
--- a/remotefilelog/repack.py
+++ b/remotefilelog/repack.py
@@ -9,6 +9,7 @@
     policy,
     scmutil,
     util,
+    vfs,
 )
 from mercurial.node import (
     nullid,
@@ -412,7 +413,7 @@
     def run(self, targetdata, targethistory):
         ledger = repackledger()
 
-        with fcntllock(self.repo.svfs, "repacklock",
+        with fcntllock(repacklockvfs(self.repo), "repacklock",
                        _('repacking %s') % self.repo.origroot):
             self.repo.hook('prerepack')
 
@@ -739,3 +740,14 @@
         self.historyrepacked = False
         # If garbage collected
         self.gced = False
+
+def repacklockvfs(repo):
+    if util.safehasattr(repo, 'name'):
+        # Lock in the shared cache so repacks across multiple copies of the same
+        # repo are coordinated.
+        sharedcachepath = shallowutil.getcachepackpath(
+            repo,
+            constants.FILEPACK_CATEGORY)
+        return vfs.vfs(sharedcachepath)
+    else:
+        return repo.svfs
diff --git a/tests/test-remotefilelog-bgprefetch.t b/tests/test-remotefilelog-bgprefetch.t
--- a/tests/test-remotefilelog-bgprefetch.t
+++ b/tests/test-remotefilelog-bgprefetch.t
@@ -111,6 +111,7 @@
   $TESTTMP/hgcache/master/packs/94d53eef9e622533aec1fc6d8053cb086e785d21.histpack
   $TESTTMP/hgcache/master/packs/f3644bc7773e8289deda7f765138120c838f4e6e.dataidx
   $TESTTMP/hgcache/master/packs/f3644bc7773e8289deda7f765138120c838f4e6e.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # background prefetch with repack on update when wcprevset configured
@@ -146,6 +147,7 @@
   $TESTTMP/hgcache/master/packs/27c52c105a1ddf8c75143a6b279b04c24b1f4bee.histpack
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.dataidx
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Ensure that file 'w' was prefetched - it was not part of the update operation and therefore
@@ -197,6 +199,7 @@
   $TESTTMP/hgcache/master/packs/27c52c105a1ddf8c75143a6b279b04c24b1f4bee.histpack
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.dataidx
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Ensure that file 'w' was prefetched - it was not part of the commit operation and therefore
@@ -288,6 +291,7 @@
   $TESTTMP/hgcache/master/packs/27c52c105a1ddf8c75143a6b279b04c24b1f4bee.histpack
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.dataidx
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Ensure that files were prefetched
@@ -331,6 +335,7 @@
   $TESTTMP/hgcache/master/packs/27c52c105a1ddf8c75143a6b279b04c24b1f4bee.histpack
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.dataidx
   $TESTTMP/hgcache/master/packs/8299d5a1030f073f4adbb3b6bd2ad3bdcc276df0.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Ensure that files were prefetched
diff --git a/tests/test-remotefilelog-gc.t b/tests/test-remotefilelog-gc.t
--- a/tests/test-remotefilelog-gc.t
+++ b/tests/test-remotefilelog-gc.t
@@ -94,6 +94,7 @@
   $TESTTMP/hgcache/master/packs/8d3499c65d926e4f107cf03c6b0df833222025b4.histpack
   $TESTTMP/hgcache/master/packs/9c7046f8cad0417c39aa7c03ce13e0ba991306c2.dataidx
   $TESTTMP/hgcache/master/packs/9c7046f8cad0417c39aa7c03ce13e0ba991306c2.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Test that warning is displayed when there are no valid repos in repofile
diff --git a/tests/test-remotefilelog-lfs.t b/tests/test-remotefilelog-lfs.t
--- a/tests/test-remotefilelog-lfs.t
+++ b/tests/test-remotefilelog-lfs.t
@@ -100,6 +100,7 @@
   $TESTTMP/hgcache/master/packs/8f2de7e341fbe688326386a45a3a7082d9f56871.histpack
   $TESTTMP/hgcache/master/packs/fd280cbfab2f4047961d1ec5f7858e763ac985ab.dataidx
   $TESTTMP/hgcache/master/packs/fd280cbfab2f4047961d1ec5f7858e763ac985ab.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
   $ cp -R . ../shallow2
@@ -237,6 +238,7 @@
   $TESTTMP/hgcache/master/packs/bf634767241b49b174b18732f92c6653ff966751.histpack
   $TESTTMP/hgcache/master/packs/faa267575712c2ee0a4ff7e9c09bf75e10055c04.dataidx
   $TESTTMP/hgcache/master/packs/faa267575712c2ee0a4ff7e9c09bf75e10055c04.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
   $ hg log -p -r ::tip -T '{rev}:{node} {desc}\n'
diff --git a/tests/test-remotefilelog-repack-fast.t b/tests/test-remotefilelog-repack-fast.t
--- a/tests/test-remotefilelog-repack-fast.t
+++ b/tests/test-remotefilelog-repack-fast.t
@@ -54,6 +54,7 @@
   $TESTTMP/hgcache/master/packs/276d308429d0303762befa376788300f0310f90e.histpack
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Test that the packs are readonly
@@ -62,6 +63,7 @@
   -r--r--r--     172 276d308429d0303762befa376788300f0310f90e.histpack
   -r--r--r--    1074 8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   -r--r--r--      69 8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  -rw-r--r--       0 repacklock
 
 # Test that the data in the new packs is accessible
   $ hg cat -r . x
@@ -85,6 +87,7 @@
   $TESTTMP/hgcache/master/packs/276d308429d0303762befa376788300f0310f90e.histpack
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
   $ hg repack --traceback
@@ -94,6 +97,7 @@
   $TESTTMP/hgcache/master/packs/077e7ce5dfe862dc40cc8f3c9742d96a056865f2.histpack
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.dataidx
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Verify all the file data is still available
@@ -113,6 +117,7 @@
   $TESTTMP/hgcache/master/packs/077e7ce5dfe862dc40cc8f3c9742d96a056865f2.histpack
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.dataidx
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Run two repacks at once
@@ -137,6 +142,7 @@
   $TESTTMP/hgcache/master/packs/077e7ce5dfe862dc40cc8f3c9742d96a056865f2.histpack
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.dataidx
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
   $ hg repack --background
@@ -148,6 +154,7 @@
   $TESTTMP/hgcache/master/packs/094b530486dad4427a0faf6bcbc031571b99ca24.histpack
   $TESTTMP/hgcache/master/packs/8fe685c56f6f7edf550bfcec74eeecc5f3c2ba15.dataidx
   $TESTTMP/hgcache/master/packs/8fe685c56f6f7edf550bfcec74eeecc5f3c2ba15.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Test debug commands
@@ -224,6 +231,7 @@
   e8fdf7ae22b772dcc291f905b9c6e5f381d28739.datapack
   ebbd7411e00456c0eec8d1150a77e2b3ef490f3f.histidx
   ebbd7411e00456c0eec8d1150a77e2b3ef490f3f.histpack
+  repacklock
   $ hg debughistorypack $TESTTMP/hgcache/master/packs/*.histidx
   
   x
diff --git a/tests/test-remotefilelog-repack.t b/tests/test-remotefilelog-repack.t
--- a/tests/test-remotefilelog-repack.t
+++ b/tests/test-remotefilelog-repack.t
@@ -49,6 +49,7 @@
   $TESTTMP/hgcache/master/packs/276d308429d0303762befa376788300f0310f90e.histpack
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Test that the packs are readonly
@@ -57,6 +58,7 @@
   -r--r--r--     172 276d308429d0303762befa376788300f0310f90e.histpack
   -r--r--r--    1074 8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   -r--r--r--      69 8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  -rw-r--r--       0 repacklock
 
 # Test that the data in the new packs is accessible
   $ hg cat -r . x
@@ -80,6 +82,7 @@
   $TESTTMP/hgcache/master/packs/276d308429d0303762befa376788300f0310f90e.histpack
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # First assert that with --packsonly, the loose object will be ignored:
@@ -92,6 +95,7 @@
   $TESTTMP/hgcache/master/packs/276d308429d0303762befa376788300f0310f90e.histpack
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.dataidx
   $TESTTMP/hgcache/master/packs/8e25dec685d5e0bb1f1b39df3acebda0e0d75c6e.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
   $ hg repack --traceback
@@ -101,6 +105,7 @@
   $TESTTMP/hgcache/master/packs/077e7ce5dfe862dc40cc8f3c9742d96a056865f2.histpack
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.dataidx
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Verify all the file data is still available
@@ -120,6 +125,7 @@
   $TESTTMP/hgcache/master/packs/077e7ce5dfe862dc40cc8f3c9742d96a056865f2.histpack
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.dataidx
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Run two repacks at once
@@ -144,6 +150,7 @@
   $TESTTMP/hgcache/master/packs/077e7ce5dfe862dc40cc8f3c9742d96a056865f2.histpack
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.dataidx
   $TESTTMP/hgcache/master/packs/935861cae0be6ce41a0d47a529e4d097e9e68a69.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
   $ hg repack --background
@@ -155,6 +162,7 @@
   $TESTTMP/hgcache/master/packs/094b530486dad4427a0faf6bcbc031571b99ca24.histpack
   $TESTTMP/hgcache/master/packs/8fe685c56f6f7edf550bfcec74eeecc5f3c2ba15.dataidx
   $TESTTMP/hgcache/master/packs/8fe685c56f6f7edf550bfcec74eeecc5f3c2ba15.datapack
+  $TESTTMP/hgcache/master/packs/repacklock
   $TESTTMP/hgcache/repos
 
 # Test debug commands
@@ -231,6 +239,7 @@
   e8fdf7ae22b772dcc291f905b9c6e5f381d28739.datapack
   ebbd7411e00456c0eec8d1150a77e2b3ef490f3f.histidx
   ebbd7411e00456c0eec8d1150a77e2b3ef490f3f.histpack
+  repacklock
   $ hg debughistorypack $TESTTMP/hgcache/master/packs/*.histidx
   
   x