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SubjectRe: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing
2008/1/12, Peter Zijlstra <a.p.zijlstra@chello.nl>:
>
> On Fri, 2008-01-11 at 03:44 +0300, Anton Salikhmetov wrote:
>
> > +/*
> > + * Update the ctime and mtime stamps after checking if they are to be updated.
> > + */
> > +void mapped_file_update_time(struct file *file)
> > +{
> > + if (test_and_clear_bit(AS_MCTIME, &file->f_mapping->flags)) {
> > + get_file(file);
> > + file_update_time(file);
> > + fput(file);
> > + }
> > +}
> > +
>
> I don't think you need the get/put file stuff here, because
>
> > @@ -87,6 +87,8 @@ long do_fsync(struct file *file, int datasync)
> > goto out;
> > }
> >
> > + mapped_file_update_time(file);
> > +
> > ret = filemap_fdatawrite(mapping);
> >
> > /*
>
> at this call-site we already hold an extra reference on the file, and
>
> > @@ -74,14 +79,17 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
> > break;
> > }
> > file = vma->vm_file;
> > - if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) {
> > - get_file(file);
> > - up_read(&mm->mmap_sem);
> > - error = do_fsync(file, 0);
> > - fput(file);
> > - if (error)
> > - return error;
> > - down_read(&mm->mmap_sem);
> > + if (file && (vma->vm_flags & VM_SHARED)) {
> > + mapped_file_update_time(file);
> > + if (flags & MS_SYNC) {
> > + get_file(file);
> > + up_read(&mm->mmap_sem);
> > + error = do_fsync(file, 0);
> > + fput(file);
> > + if (error)
> > + return error;
> > + down_read(&mm->mmap_sem);
> > + }
> > }
> >
> > start = vma->vm_end;
>
> here we hold the mmap_sem so the vma reference on the file can't go
> away.

These get_file() and fput() calls were in the sys_msync() function form before
all my changes. I did not add them here.

>
>


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