Hi all, I have discovered a problem with webdav. If multiple processes or threads are writing to unique files in the same folder on a webdav server using LOCKS, intermittent webdav errors will occur during the UNLOCK request. Server configuration: Centos 5.5. Tested with Apache/2.2.3, Apache/2.2.17 and Apache/2.3.8. I have a custom application that uses libcurl to upload files to a webdav server. However, I have reproduced the same problem using cadaver, a simple script and a locally hosted Apache webdav server. The error occurs during an UNLOCK. A 400 (bad request) is returned. Once this failure occurs, the file remains locked. I used several methods over several days to ensure the LOCK/PUT/UNLOCK sequences being issued are valid and contain the correct lock token (wireshark, added custom logging to dav, etc.). I used a patched version of cadaver that adds scripting ability so I could automate the test. Here is what the test does: One shell script is repeatedly running this: 1. LOCK webdav/test/a.bin 2. PUT a.bin webdav/test/a.bin 3. UNLOCK webdav/test/a.bin At the same time, a second shell script is repeatedly running this (same webdav folder, but accessing a different file): 1. LOCK webdav/test/b.bin 2. PUT b.bin webdav/test/b.bin 3. UNLOCK webdav/test/b.bin The test repeats anywhere from a few times to several hundred times before the failure occurs. Below is the output from cadaver at the failure point: Locking `webdav/test/a.bin': succeeded. Lock token <opaquelocktoken:7ca6e55d-1bf6-4ce0-a8a4-7d97117db8af>: Depth infinity on `http://localhost:81/webdav/test/a.bin' Scope: exclusive Type: write Timeout: infinite Owner: Uploading a.bin to `/webdav/test/a.bin': [.......... succeeded. Unlocking `webdav/test/a.bin': failed: 400 Bad Request At the failure point, this message is in the Apache error_log: (11)Resource temporarily unavailable: The locktoken specified in the "Lock-Token:" header is invalid because this resource has no outstanding locks. [400, #0] I tried adding additional debug messages to dav, but have not been able to track down why the lock is not valid. I also tried to make a debug build of Apache so I could use gdb to help debug at least one of the scripts to better understand the flow of the lock data, but was unable to get debug symbols in the binary (I used the --enable-maintainer-mode configure option). I'll wait a few days to hear back before submitting a bug. Regards, Mike --------------------------------------------------------------------- The official User-To-User support forum of the Apache HTTP Server Project. See <URL:http://httpd.apache.org/userslist.html> for more info. To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx " from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
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