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    SubjectRe: [PATCH] don't allow sys_readahead() on files opened with O_DIRECT
    Christoph Hellwig wrote:
    > your check is wrong, it's testing whether the filesystem supports O_DIRECT, not
    > whether sys_readahead is used on a file descriptor that has been opened with O_DIRECT

    D'oh! You're right.

    Jan

    do_readahead() doesn't make sense if the file is opened with O_DIRECT,
    since only the page cache is stuffed but never used.

    Signed-off-by: Jan Blunck <j.blunck@tu-harburg.de>

    mm/filemap.c | 3 ++-
    1 files changed, 2 insertions(+), 1 deletion(-)

    Index: experimental-um/mm/filemap.c
    ===================================================================
    --- experimental-um.orig/mm/filemap.c
    +++ experimental-um/mm/filemap.c
    @@ -1110,7 +1110,8 @@ static ssize_t
    do_readahead(struct address_space *mapping, struct file *filp,
    unsigned long index, unsigned long nr)
    {
    - if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage)
    + if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage
    + || (filp->f_flags & O_DIRECT))
    return -EINVAL;

    force_page_cache_readahead(mapping, filp, index,
    \
     
     \ /
      Last update: 2005-06-06 14:49    [W:0.029 / U:0.932 seconds]
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