lfs: fix the stall and corruption issue when concurrently uploading blobs
We've avoided the issue up to this point by gating worker usage with an
experimental config. See 10e62d5efa73, and the thread linked there for some of
the initial diagnosis, but essentially some data was being read from the blob
before an error occurred and `keepalive` retried, but didn't rewind the file
pointer. So the leading data was lost from the blob on the server, and the
connection stalled, trying to send more data than available.
In trying to recreate this, I was unable to do so uploading from Windows to
CentOS 7. But it reproduced every time going from CentOS 7 to another CentOS 7
over https.
I found recent fixes in the FaceBook repo to address this[1][2]. The commit
message for the first is:
The KeepAlive HTTP implementation is bugged in it's retry logic, it supports
reading from a file pointer, but doesn't support rewinding of the seek cursor
when it performs a retry. So it can happen that an upload fails for whatever
reason and will then 'hang' on the retry event.
The sequence of events that get triggered are:
- Upload file A, goes OK. Keep-Alive caches connection.
- Upload file B, fails due to (for example) failing Keep-Alive, but LFS file
pointer has been consumed for the upload and fd has been closed.
- Retry for file B starts, sets the Content-Length properly to the expected
file size, but since file pointer has been consumed no data will be uploaded,
causing the server to wait for the uploaded data until either client or
server reaches a timeout, making it seem as our mercurial process hangs.
This is just a stop-gap measure to prevent this behavior from blocking Mercurial
(LFS has retry logic). A proper solutions need to be build on top of this
stop-gap measure: for upload from file pointers, we should support fseek() on
the interface. Since we expect to consume the whole file always anyways, this
should be safe. This way we can seek back to the beginning on a retry.
I ported those two patches, and it works. But I see that `url._sendfile()` does
a rewind on `httpsendfile` objects[3], so maybe it's better to keep this all in
one place and avoid a second seek. We may still want the first FaceBook patch
as extra protection for this problem in general. The other two uses of
`httpsendfile` are in the wire protocol to upload bundles, and to upload
largefiles. Neither of these appear to use a worker, and I'm not sure why
workers seem to trigger this, or if this could have happened without a worker.
Since `httpsendfile` already has a `close()` method, that is dropped. That
class also explicitly says there's no `__len__` attribute, so that is removed
too. The override for `read()` is necessary to avoid the progressbar usage per
file.
[1] https://github.com/facebookexperimental/eden/commit/c350d6536d90c044c837abdd3675185644481469
[2] https://github.com/facebookexperimental/eden/commit/77f0d3fd0415e81b63e317e457af9c55c46103ee
[3] https://www.mercurial-scm.org/repo/hg/file/5.2.2/mercurial/url.py#l176
Differential Revision: https://phab.mercurial-scm.org/D7962
#require serve
Create a repo with whitespace only changes
$ hg init repo-with-whitespace
$ cd repo-with-whitespace
$ cat > foo << EOF
> line 0
> line 1
> line 2
> line 3
> EOF
$ hg -q commit -A -m 'commit 0'
$ cat > foo << EOF
> line 0
> line 1 modified by 1
> line 2
> line 3
> EOF
$ hg commit -m 'commit 1'
$ cat > foo << EOF
> line 0
> line 1 modified by 1
> line 2
> line 3
> EOF
$ hg commit -m 'commit 2 (leading whitespace on line 2)'
$ cat > foo << EOF
> line 0
> line 1 modified by 1
> line 2
> EOF
Need to use printf to avoid check-code complaining about trailing whitespace.
$ printf 'line 3 \n' >> foo
$ hg commit -m 'commit 3 (trailing whitespace on line 3)'
$ cat > foo << EOF
> line 0
> line 1 modified by 1
> line 2
> EOF
$ printf 'line 3 \n' >> foo
$ hg commit -m 'commit 4 (intra whitespace on line 0)'
$ cat > foo << EOF
> line 0
>
> line 1 modified by 1
> line 2
> EOF
$ printf 'line 3 \n' >> foo
$ hg commit -m 'commit 5 (add blank line between line 0 and 1)'
$ cat > foo << EOF
> line 0
>
>
> line 1 modified by 1
> line 2
> EOF
$ printf 'line 3 \n' >> foo
$ hg commit -m 'commit 6 (add another blank line between line 0 and 1)'
$ hg log -G -T '{rev}:{node|short} {desc}'
@ 6:9d1b2c7db017 commit 6 (add another blank line between line 0 and 1)
|
o 5:400ef1d40470 commit 5 (add blank line between line 0 and 1)
|
o 4:08adbe269f24 commit 4 (intra whitespace on line 0)
|
o 3:dcb62cfbfc9b commit 3 (trailing whitespace on line 3)
|
o 2:6bdb694e7b8c commit 2 (leading whitespace on line 2)
|
o 1:23e1e37387dc commit 1
|
o 0:b9c578134d72 commit 0
$ hg serve -p $HGPORT -d --pid-file hg.pid
$ cat hg.pid >> $DAEMON_PIDS
$ hg serve --config annotate.ignorews=true -p $HGPORT1 -d --pid-file hg.pid
$ cat hg.pid >> $DAEMON_PIDS
$ cd ..
Annotate works
$ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 4 (intra whitespace on line 0)",
"line": "line 0\n",
"lineno": 1,
"node": "08adbe269f24cf22d975eadeec16790c5b22f558",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 2 (leading whitespace on line 2)",
"line": " line 2\n",
"lineno": 5,
"node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 3 (trailing whitespace on line 3)",
"line": "line 3 \n",
"lineno": 6,
"node": "dcb62cfbfc9b3ab995a5cbbaff6e1971c3e4f865",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}
annotate.ignorews=1 config option is honored
$ get-with-headers.py --json $LOCALIP:$HGPORT1 'json-annotate/9d1b2c7db017/foo'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 0\n",
"lineno": 1,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": " line 2\n",
"lineno": 5,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 3 \n",
"lineno": 6,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}
ignorews=1 query string argument enables whitespace skipping
$ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignorews=1'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 0\n",
"lineno": 1,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": " line 2\n",
"lineno": 5,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 3 \n",
"lineno": 6,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}
ignorews=0 query string argument disables when config defaults to enabled
$ get-with-headers.py --json $LOCALIP:$HGPORT1 'json-annotate/9d1b2c7db017/foo?ignorews=0'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 4 (intra whitespace on line 0)",
"line": "line 0\n",
"lineno": 1,
"node": "08adbe269f24cf22d975eadeec16790c5b22f558",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 2 (leading whitespace on line 2)",
"line": " line 2\n",
"lineno": 5,
"node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 3 (trailing whitespace on line 3)",
"line": "line 3 \n",
"lineno": 6,
"node": "dcb62cfbfc9b3ab995a5cbbaff6e1971c3e4f865",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}
ignorewsamount=1 query string enables whitespace amount skipping
$ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignorewsamount=1'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 0\n",
"lineno": 1,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 2 (leading whitespace on line 2)",
"line": " line 2\n",
"lineno": 5,
"node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 3 \n",
"lineno": 6,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}
ignorewseol=1 query string enables whitespace end of line skipping
$ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignorewseol=1'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 4 (intra whitespace on line 0)",
"line": "line 0\n",
"lineno": 1,
"node": "08adbe269f24cf22d975eadeec16790c5b22f558",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 2 (leading whitespace on line 2)",
"line": " line 2\n",
"lineno": 5,
"node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 0",
"line": "line 3 \n",
"lineno": 6,
"node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}
ignoreblanklines=1 query string enables whitespace blank line skipping
$ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignoreblanklines=1'
200 Script output follows
{
"abspath": "foo",
"annotate": [
{
"abspath": "foo",
"author": "test",
"desc": "commit 4 (intra whitespace on line 0)",
"line": "line 0\n",
"lineno": 1,
"node": "08adbe269f24cf22d975eadeec16790c5b22f558",
"revdate": [
0.0,
0
],
"targetline": 1
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 5 (add blank line between line 0 and 1)",
"line": "\n",
"lineno": 2,
"node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 6 (add another blank line between line 0 and 1)",
"line": "\n",
"lineno": 3,
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 1",
"line": "line 1 modified by 1\n",
"lineno": 4,
"node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
"revdate": [
0.0,
0
],
"targetline": 2
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 2 (leading whitespace on line 2)",
"line": " line 2\n",
"lineno": 5,
"node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
"revdate": [
0.0,
0
],
"targetline": 3
},
{
"abspath": "foo",
"author": "test",
"desc": "commit 3 (trailing whitespace on line 3)",
"line": "line 3 \n",
"lineno": 6,
"node": "dcb62cfbfc9b3ab995a5cbbaff6e1971c3e4f865",
"revdate": [
0.0,
0
],
"targetline": 4
}
],
"author": "test",
"children": [],
"date": [
0.0,
0
],
"desc": "commit 6 (add another blank line between line 0 and 1)",
"node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
"parents": [
"400ef1d404706cfb48afd2b78ce6addf641ced25"
],
"permissions": ""
}