I'm trying to setup nginx to return a 503 if a particular file exists (probably something like "upgrading"). I'm trying to use the try_files directive, but when it finds the /upgrading.html file, it serves it rather than following the directive. Why is that?

location / {
    try_files /upgrading.html @keepgoing;
}

location = /upgrading.html {
    return 503;
}

location @keepgoing {
    #do stuff here to do whatever I would normally do...
}

In the log when I turn on debugging I see the following:

3388    2010/07/01 19:44:21 [debug] 76327#0: *8 test location: "/"
3389    2010/07/01 19:44:21 [debug] 76327#0: *8 using configuration "/"
3390    2010/07/01 19:44:21 [debug] 76327#0: *8 http cl:-1 max:52428800
3391    2010/07/01 19:44:21 [debug] 76327#0: *8 generic phase: 2
3392    2010/07/01 19:44:21 [debug] 76327#0: *8 post rewrite phase: 3
3393    2010/07/01 19:44:21 [debug] 76327#0: *8 generic phase: 4
3394    2010/07/01 19:44:21 [debug] 76327#0: *8 generic phase: 5
3395    2010/07/01 19:44:21 [debug] 76327#0: *8 access phase: 6
3396    2010/07/01 19:44:21 [debug] 76327#0: *8 access phase: 7
3397    2010/07/01 19:44:21 [debug] 76327#0: *8 post access phase: 8
3398    2010/07/01 19:44:21 [debug] 76327#0: *8 try files phase: 9
3399    2010/07/01 19:44:21 [debug] 76327#0: *8 try to use file: "/upgrading.html" "/usr/local/nginx/html/upgrading.html"
3400    2010/07/01 19:44:21 [debug] 76327#0: *8 try file uri: "/upgrading.html"
3401    2010/07/01 19:44:21 [debug] 76327#0: *8 content phase: 10
3402    2010/07/01 19:44:21 [debug] 76327#0: *8 content phase: 11
3403    2010/07/01 19:44:21 [debug] 76327#0: *8 content phase: 12
3404    2010/07/01 19:44:21 [debug] 76327#0: *8 http filename: "/usr/local/nginx/html/upgrading.html"

Seems like it can't find the directive, but it's there, so not sure what I'm doing wrong.

Also, more generally, is this an acceptable approach to solving this problem? Other ways to do it?