Messages in this thread | | | Date | Sun, 7 Oct 2007 15:20:19 -0400 | From | Erez Zadok <> | Subject | msync(2) bug(?), returns AOP_WRITEPAGE_ACTIVATE to userland |
| |
According to vfs.txt, ->writepage() may return AOP_WRITEPAGE_ACTIVATE back to the VFS/VM. Indeed some filesystems such as tmpfs can return AOP_WRITEPAGE_ACTIVATE; and stackable file systems (e.g., Unionfs) also return AOP_WRITEPAGE_ACTIVATE if the lower f/s returned it.
Anyway, some Ubuntu users of Unionfs reported that msync(2) sometimes returns AOP_WRITEPAGE_ACTIVATE (decimal 524288) back to userland. Therefore, some user programs fail, esp. if they're written such as this:
err = msync(...); if (err != 0) // fail
They temporarily fixed the specific program in question (apt-get) to check
if (err < 0) // fail
Is this a bug indeed, or are user programs supposed to handle AOP_WRITEPAGE_ACTIVATE (I hope not the latter). If it's a kernel bug, what should the kernel return: a zero, or an -errno (and which one)?
Thanks, Erez. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |