Unix & Linux

Are there any drawbacks from using mount –bind as a substitute for symbolic links?

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Symlinks have limitations in how functions like ls, mv, and cp can operate on them because unlike shell initiated commands like cd, these functions do not have information about how the user accessed the directory with respect to the logical path (see related post). It seems like using the mount --bind option instead can get an around this, offering increased functionality and compatibility with samba and other file servers because the mounted directory will then have two independent physical paths, instead of a link.

How do pdflush, kjournald, swapd, etc interoperate?

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Recently saw a question that sparked this thought. Couldn’t really find an answer here or via the Google machine. Basically, I’m interested in knowing how the kernel I/O architecture is layered. For example, does kjournald dispatch to pdflush or the other way around? My assumption is that pdflush (being more generic to mass storage I/O) would sit at a lower level and trigger the SCSI/ATA/whatever commands necessary to actually perform the writes, and kjournald handles higher level filesystem data structures before writing. I could see it the other way around as well, though, with kjournald directly interfacing with the filesystem data structures and pdflush waking up every now and then to write dirty pagecache pages to the device through kjournald. It’s also possible that the two don’t interact at all for some other reason.

Simple way to create a tunnel from one local port to another?

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I have a development server, which is only accessible from 127.0.0.1:8000, not 192.168.1.x:8000. As a quick hack, is there a way to set up something to listen on another port (say, 8001) so that from the local network I could connect 192.168.1.x:8001 and it would tunnel the traffic between the client and 127.0.0.1:8000?