strange interaction between open and cwd

[Cameron Simpson]

On 05May2010 13:23, Baz Walter <bazwal at ftml.net> wrote:
| here's what i get on my system, where '/dev/sda1' and '/dev/sda6'
| are mounted at '/boot' and '/home' respectively:
| 
| >>> os.stat('/').st_ino
| 2L
| >>> os.stat('/usr').st_ino
| 212993L
| >>> os.stat('/boot').st_ino
| 2L
| >>> os.stat('/home').st_ino
| 2L
| >>>
| 
| if the algorithm is climbing up from '/home/baz/tmp/xxx', what does
| it do when it searches os.listdir('../../../..')? how can it tell
| whether 'boot' or 'home' is the correct next parent if it only
| checks the inode number? i think the algorithm would at least need
| to take account of changes in the current device id. not sure
| whether that would be enough to cover all cases, though.

Look at the st_rdev field (== the device holding this inode).
When that changes, you've crossed a mount mount point.
-- 
Cameron Simpson <cs at zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

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