add an option for rules to be run after a device is created

Stefanos Harhalakis

author

2006-01-04 14:20 UTC #0 lore raw

Hi there,

I'm using udev and I'd like to make a suggestion. I have these rules:

BUS="ide", KERNEL="*[!0-9]", PROGRAM="/etc/udev/scripts/get_serial %k", RESULT="WD-WMAEH1157379", SYMLINK="disk/root"
BUS="ide", KERNEL="*[0-9]", PROGRAM="/etc/udev/scripts/get_serial %k", RESULT="WD-WMAEH1157379", SYMLINK="disk/root%n"

which call a script that return the hard disk serial number using hdparm. I'm using this rule to find the root disk and enable its swap partition without knowing the device name.

The problem is that the get_serial script is run before (for
example) /dev/hda is created and hdparm cannot find the device (/dev is a tmpfs). This can be solved by running udevstart twice but I believe that there can be a better solution.

I suggest you add an option that would mark rules to be examined *after* the
device is created. This can be thought as a class of 'second pass' rules. Another solution is to delay the symlink rules but this may produce incompatibilities or other problems.

I'm using udev 0.79, kernel 2.6.15.

Thanks in advace,

<<V13>>

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Kay Sievers

2006-01-04 14:49 UTC #1 lore raw

Quoted 9 lines · Stefanos Harhalakis

Hi there,
I'm using udev and I'd like to make a suggestion. I have these rules:
BUS="ide", KERNEL="*[!0-9]", PROGRAM="/etc/udev/scripts/get_serial %k", RESULT="WD-WMAEH1157379", SYMLINK="disk/root"
BUS="ide", KERNEL="*[0-9]", PROGRAM="/etc/udev/scripts/get_serial %k", RESULT="WD-WMAEH1157379", SYMLINK="disk/root%n"

Quoted 8 lines

which call a script that return the hard disk serial number using hdparm. I'm using this rule to find the root disk and enable its swap partition without knowing the device name.
The problem is that the get_serial script is run before (for
example) /dev/hda is created and hdparm cannot find the device (/dev is a tmpfs). This can be solved by running udevstart twice but I believe that there can be a better solution.

Use the persistent disk links in /dev/disk/, they will just work.

Kay

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Stefanos Harhalakis

author

2006-01-04 15:37 UTC #2 lore raw

In reply to Stefanos Harhalakis

Quoted 14 lines · Kay Sievers

Quoted 13 lines · Stefanos Harhalakis
Hi there,
I'm using udev and I'd like to make a suggestion. I have these rules:
BUS="ide", KERNEL="*[!0-9]", PROGRAM="/etc/udev/scripts/get_serial %k", RESULT="WD-WMAEH1157379", SYMLINK="disk/root"
BUS="ide", KERNEL="*[0-9]", PROGRAM="/etc/udev/scripts/get_serial %k", RESULT="WD-WMAEH1157379", SYMLINK="disk/root%n"
which call a script that return the hard disk serial number using hdparm. I'm using this rule to find the root disk and enable its swap partition without knowing the device name.

Quoted 6 lines

Quoted 4 lines
The problem is that the get_serial script is run before (for
example) /dev/hda is created and hdparm cannot find the device (/dev is a tmpfs). This can be solved by running udevstart twice but I believe that there can be a better solution.
Use the persistent disk links in /dev/disk/, they will just work.

I'm sorry about this. It seems that all I wanted was the %N ($tempnode), which I just found because of your reply.

Thanks a lot for your time!

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