strange write proxy error

I use Debian (apache 2.2.16 and subversion 1.6.12), here is my
stripped apache config file:

        <Directory />
                Options FollowSymLinks
                AllowOverride None
        </Directory>
        <Directory /var/www/>
                Options Indexes FollowSymLinks MultiViews
                AllowOverride None
                Order allow,deny
                allow from all
        </Directory>

        <Location /repo/svn>
            DAV svn
            SVNParentPath /srv/repo/svn
            SVNListParentPath on
            AuthzSVNAccessFile /srv/repo/repo_svn.authz
            SVNMasterURI https://192.168.30.123/repo/svn
        </Location>

When I commit with write proxy, the write proxy OPTIONS and PROPFIND
command is OK,
but MKACTIVITY failed stupidly after not found directory
'/var/www/repo' (it do not care about
Location /repo/svn), see the following strace log:

PROPFIND is OK:

stat64("/var/www/repo/svn/CRM30", 0xbfe1862c) = -1 ENOENT (No such
file or directory)
lstat64("/var", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat64("/var/www", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat64("/var/www/repo", 0xbfe1862c)    = -1 ENOENT (No such file or directory)
semop(5242880, {{0, -1, SEM_UNDO}}, 1)  = 0
semop(5242880, {{0, 1, SEM_UNDO}}, 1)   = 0
semop(5242880, {{0, -1, SEM_UNDO}}, 1)  = 0
gettimeofday({1332742488, 746294}, NULL) = 0
semop(5242880, {{0, 1, SEM_UNDO}}, 1)   = 0
gettimeofday({1332742488, 746413}, NULL) = 0
write(2, "[Mon Mar 26 08:14:48 2012] [info] [client 192.168.10.16]
Access granted: 'cauchy' PROPFIND CRM30:/\n", 99) = 99
open("/srv/repo/svn/CRM30/db/current", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 14
fcntl64(14, F_GETFD)                    = 0x1 (flags FD_CLOEXEC)
fcntl64(14, F_SETFD, FD_CLOEXEC)        = 0
read(14, "5\n", 4096)                   = 2
close(14)                               = 0
lstat64("/srv/repo/svn/CRM30/db/revs/0/5", {st_mode=S_IFREG|0644,
st_size=569, ...}) = 0
open("/srv/repo/svn/CRM30/db/revs/0/5", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 14
fcntl64(14, F_GETFD)                    = 0x1 (flags FD_CLOEXEC)
fcntl64(14, F_SETFD, FD_CLOEXEC)        = 0
_llseek(14, 385, [385], SEEK_SET)       = 0
read(14, "id: 0.0.r5/385\ntype: dir\npred: 0.0.r4/393\ncount: 5\ntext:
5 230 142 142 7460f6ac294ff24ea4fdba089e9ff07e\ncpath: /\ncopyroot: 0
/\n\n0-2.0.t4-4 modify-file true false /.gitignore\n\n\n385 513\n",
4096) = 184
close(14)                               = 0
lstat64("/srv/repo/svn/CRM30/db/revs/0/5", {st_mode=S_IFREG|0644,
st_size=569, ...}) = 0
open("/srv/repo/svn/CRM30/db/revs/0/5", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 14
fcntl64(14, F_GETFD)                    = 0x1 (flags FD_CLOEXEC)
fcntl64(14, F_SETFD, FD_CLOEXEC)        = 0
_llseek(14, 385, [385], SEEK_SET)       = 0
read(14, "id: 0.0.r5/385\ntype: dir\npred: 0.0.r4/393\ncount: 5\ntext:
5 230 142 142 7460f6ac294ff24ea4fdba089e9ff07e\ncpath: /\ncopyroot: 0
/\n\n0-2.0.t4-4 modify-file true false /.gitignore\n\n\n385 513\n",
4096) = 184
close(14)                               = 0
writev(12, [{"\27\3\1\1\0\340\360\27\33\22\365\262\271Y\r\204\0267\205\320\22\320mI\305\320>\375\215\251\215~jfz\266\340\n\21\4m(o\213|\372\37\236iy\243\365-\346<\377\207\210\235\340tB\227\203\34\36!_\"\224J~\241\222\2\371\357\366\6\360\rA\267\306\350\322\266\246=\300\35\320\241\240\253h\327\312(\v\351:\177\265\355Z\230W\0068j\302\361Oy\300\370\216@\324\31\35\3632\311O\226\303#iu\211\0270\211+\24r\364\377I\1\350{\237\360`m9XVb\356\251\24'\220\203\302\0ic\343\270$\331\253A\223y'\371\276\24\341z%VS\20\300[un
\332Jz@\223\256%\237\5!R\251<\274\5\307\364M\251j\203\340\203\365\357\210\317
\260%\26\260w\225\204\320R\270R\233\317o\27.\225@\343;&\7\16\275\274\200\30\236\211\317St!V{\2\215\375d*+\1\265"...,
954}], 1) = 954
gettimeofday({1332742488, 749526}, NULL) = 0
write(9, "192.168.10.16 - cauchy [26/Mar/2012:08:14:48 +0200]
\"PROPFIND /repo/svn/CRM30 HTTP/1.1\" 207 954 \"-\" \"SVN/1.6.12
(r955767) neon/0.29.3\"\n", 135) = 135

MKACTIVITY failed stupidly

poll([{fd=12, events=POLLIN}], 1, 5000) = 1 ([{fd=12, revents=POLLIN}])
read(12, "\27\3\1\2P\242\334%y\251u\246\335S\246TF\r$\362\372\250[\250\3\313\324\324BdI\256x\177l\32kQ\312\302\323\312\271\266]\210<\206\243\0\340W\246\37\353\335\317\240lU\2\331\0308\277FLDl\33\333\350\321\22\223\351O\371\240F\353\364\324z>\230\360'\371\250\254\233\330X\37\321\342\262\343@\251\310\36\217\353\250\320\37l\2672\264\336b'`\262\305-\317}\257+~\333L2:p7\356\6\340\344\276\221<7\350\372\10\312\366\6\6\312\357\306\314\375\200N\331\237\374\205\362\6c\277\360&\362,\27\214X|\237\302\376\276R\0060!\276\275\365\356\t\310se\202\303~\246ta\353\273\325E\220\267JPp\27O\346~\337\335\224\235\316\257\2657C\3535e\372fe\236\344\366\352n\243\264\267#
p\306y\277=\20:\311\322F\10\244\207_\272\217\2567\260w\246\33\363s0#\357\t"...,
8000) = 597
gettimeofday({1332742488, 750067}, NULL) = 0
gettimeofday({1332742488, 750130}, NULL) = 0
write(2, "[Mon Mar 26 08:14:48 2012] [info] Subsequent (No.4) HTTPS
request received for child 0 (server 192.168.10.16:443)\n", 114) = 114
gettimeofday({1332742488, 750282}, NULL) = 0
gettimeofday({1332742488, 750406}, NULL) = 0
stat64("/var/www/repo/svn/CRM30/!svn/act/4bd03ee2-0018-490c-9801-baf5208bbde6",
0xbfe1862c) = -1 ENOENT (No such file or directory)
lstat64("/var", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat64("/var/www", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat64("/var/www/repo", 0xbfe1862c)    = -1 ENOENT (No such file or directory)
semop(5242880, {{0, -1, SEM_UNDO}}, 1)  = 0
semop(5242880, {{0, 1, SEM_UNDO}}, 1)   = 0
semop(5242880, {{0, -1, SEM_UNDO}}, 1)  = 0
gettimeofday({1332742488, 750930}, NULL) = 0
semop(5242880, {{0, 1, SEM_UNDO}}, 1)   = 0
gettimeofday({1332742488, 751049}, NULL) = 0
write(2, "[Mon Mar 26 08:14:48 2012] [info] [client 192.168.10.16]
Access granted: 'cauchy' MKACTIVITY CRM30:\n", 100) = 100
writev(12, [{"\27\3\1\0\320{\2044\205Jn\253el\2258\231\235\220
\362\277\246,\24\214\220.\360\333\333.K(\213\222\374\364=\375\330\24\337%\10\346\307\243\367m6\37\307WvV\377\2544\303\257r*\330^d\36\240>\306\210\361\372Y\207ggZ#\31\365\36G\332\333\344$T\230\24j\351\337\302\275\335N,tg\2229my/%\t\177\340\203rF\21K\5=\334\203\267\225q\20\330\311\244\235\243\243?\372\305\250\340\6\213\261m\20\364\260\276\344Zt[\216?\0\232|\235<p\362=\23b\324\7z\333L\232BL|\301\306@\5\373\252,D\207\314KC0\26\3069]_\32\277\256\251]\305)\304\242\265\264\17(\n\375<\234\263\210\22p\316a\311\362\306\373\243z\27\3\1\1@\251\342\301\334\217\\L\31\340\276\250b\236\21\0345sev\236\251\347\254M
6\370\315\240\200\205\377\20\25L\277d\314"..., 538}], 1) = 538
gettimeofday({1332742488, 756541}, NULL) = 0
write(9, "192.168.10.16 - cauchy [26/Mar/2012:08:14:48 +0200]
\"MKACTIVITY /repo/svn/CRM30/!svn/act/4bd03ee2-0018-490c-9801-baf5208bbde6
HTTP/1.1\" 405 538 \"-\" \"SVN/1.6.12 (r955767) neon/0.29.3\"\n", 183)
= 183
gettimeofday({1332742488, 756725}, NULL) = 0
times({tms_utime=6, tms_stime=2, tms_cutime=0, tms_cstime=0}) = 1286221687
gettimeofday({1332742488, 756821}, NULL) = 0
poll([{fd=12, events=POLLIN}], 1, 5000) = 1 ([{fd=12, revents=POLLIN}])
read(12, "\25\3\1\0000g,\353\300o\246\3560\6\260\226\2\261\226d\27u\246\201\323\274U_\35\320\377\327\211tD\356V\326q}\344\354,%\331\324J\253k\32\243\357=",
8000) = 53
gettimeofday({1332742488, 757051}, NULL) = 0
gettimeofday({1332742488, 757208}, NULL) = 0
writev(12, [{"\25\3\1\0
\305F\233A\304\256\363c\303\355\377'\236w~!\23\331\202)\211~\274=\3005
\216\230w\340m", 37}], 1) = 37
gettimeofday({1332742488, 757421}, NULL) = 0
write(2, "[Mon Mar 26 08:14:48 2012] [info] [client 192.168.10.16]
Connection closed to child 0 with standard shutdown (server
192.168.10.16:443)\n", 136) = 136
shutdown(12, 1 /* send */)              = -1 ENOTCONN (Transport
endpoint is not connected)
close(12)                               = 0

Thanks for some help.

--
Dongsheng