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udev-node: simplify the example of race

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This commit is contained in:
Yu Watanabe 2021-09-12 16:05:51 +09:00
parent de829ff593
commit 3df566a667
1 changed files with 5 additions and 5 deletions
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src/udev/udev-node.c
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@ -272,14 +272,14 @@ static int update_timestamp(sd_device *dev, const char *path, struct stat *prev)
/* Even if a symlink in the stack directory is created/removed, the mtime of the directory may
* not be changed. Why? Let's consider the following situation. For simplicity, let's assume
* there exist three udev workers (A, B, and C) and all of them calls link_update() for the
* same devlink simultaneously.
* there exist two udev workers (A and B) and all of them calls link_update() for the same
* devlink simultaneously.
*
* 1. B creates/removes a symlink in the stack directory.
* 1. A creates/removes a symlink in the stack directory.
* 2. A calls the first stat() in the loop of link_update().
* 3. A calls link_find_prioritized().
* 4. C creates/removes another symlink in the stack directory, so the result of the step 3 is outdated.
* 5. B and C finish link_update().
* 4. B creates/removes another symlink in the stack directory, so the result of the step 3 is outdated.
* 5. B finishes link_update().
* 6. A creates/removes devlink according to the outdated result in the step 3.
* 7. A calls the second stat() in the loop of link_update().
*