Messages in this thread | | | Date | Wed, 23 Nov 2011 12:30:43 +0800 | From | Cong Wang <> | Subject | Re: [V2 PATCH] tmpfs: add fallocate support |
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于 2011年11月23日 06:06, Andrew Morton 写道: > On Fri, 18 Nov 2011 18:39:50 +0800 > Cong Wang<amwang@redhat.com> wrote: > >> It seems that systemd needs tmpfs to support fallocate, >> see http://lkml.org/lkml/2011/10/20/275. This patch adds >> fallocate support to tmpfs. >> >> As we already have shmem_truncate_range(), it is also easy >> to add FALLOC_FL_PUNCH_HOLE support too. >> >> >> ... >> >> +static long shmem_fallocate(struct file *file, int mode, >> + loff_t offset, loff_t len) >> +{ >> + struct inode *inode = file->f_path.dentry->d_inode; >> + pgoff_t start = offset>> PAGE_CACHE_SHIFT; >> + pgoff_t end = DIV_ROUND_UP((offset + len), PAGE_CACHE_SIZE); >> + pgoff_t index = start; >> + loff_t i_size = i_size_read(inode); >> + struct page *page = NULL; >> + int ret = 0; >> + >> + mutex_lock(&inode->i_mutex); > > It would be saner and less racy-looking to read i_size _after_ taking > i_mutex. > > And if you do that, there's no need to use i_size_read() - just a plain > old > > i_size = inode->i_size; > > is OK.
Fair enough, I will fix that in V3.
Thanks, Andrew! -- 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/
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