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    SubjectRe: [PATCH] update ctime and mtime for mmaped write
    On Wed, 2007-02-21 at 18:51 +0100, Miklos Szeredi wrote:
    > From: Miklos Szeredi <>
    > This patch makes writing to shared memory mappings update st_ctime and
    > st_mtime as defined by SUSv3:
    > The st_ctime and st_mtime fields of a file that is mapped with
    > MAP_SHARED and PROT_WRITE shall be marked for update at some point
    > in the interval between a write reference to the mapped region and
    > the next call to msync() with MS_ASYNC or MS_SYNC for that portion
    > of the file by any process. If there is no such call and if the
    > underlying file is modified as a result of a write reference, then
    > these fields shall be marked for update at some time after the
    > write reference.
    > A new address_space flag is introduced: AS_CMTIME. This is set each
    > time a page is dirtied through a userspace memory mapping. This
    > includes write accesses via get_user_pages().
    > Note, the flag is set unconditionally, even if the page is already
    > dirty. This is important, because the page might have been dirtied
    > earlier by a non-mmap write.
    > This flag is checked in msync() and __fput(), and if set, the file
    > times are updated and the flag is cleared

    Why not also check inside vfs_getattr?


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