Messages in this thread | | | From | Neil Brown <> | Date | Thu, 15 Dec 2005 14:14:06 +1100 | Subject | sysfs question: how to map major:minor to name under /sys |
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Hi, I have a question about sysfs related usage.
Suppose I have a major:minor number for a block device - maybe from fstat of a filedescriptor I was given, or stat of a name in /dev. How do I find the directory in /sys/block that contains relevant information?
It seems to me that there is no direct way, and maybe there should be. (I can do a find of 'dev' file and compare, which is fine in a one-off shell script, but sub-optimal in general).
The most obvious solution would be to have a directory somewhere full of symlinks: /sys/block_dev/8:0 -> ../block/sda or whatever. Is this reasonable? Should I try it?
The particular case that I am interested in involves md. In this case I can find the right /sys/block/mdX entry easily enough because I *know* how the names are generated. However when a block device is added to an array, it gets an entry like /sys/block/md4/md/dev-sda I would like to be able to easily find that given just the information that 8:0 was added. If the above directory of symlinks existed, I could readlink the relevant entry, take the basename, and add "md/dev-" to front of that.
Comments?
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