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    SubjectRe: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing
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    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.



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