• Al Viro's avatar
    make nfs_atomic_open() call d_drop() on all ->open_context() errors. · d20cb71d
    Al Viro authored
    In "NFSv4: Move dentry instantiation into the NFSv4-specific atomic open code"
    unconditional d_drop() after the ->open_context() had been removed.  It had
    been correct for success cases (there ->open_context() itself had been doing
    dcache manipulations), but not for error ones.  Only one of those (ENOENT)
    got a compensatory d_drop() added in that commit, but in fact it should've
    been done for all errors.  As it is, the case of O_CREAT non-exclusive open
    on a hashed negative dentry racing with e.g. symlink creation from another
    client ended up with ->open_context() getting an error and proceeding to
    call nfs_lookup().  On a hashed dentry, which would've instantly triggered
    BUG_ON() in d_materialise_unique() (or, these days, its equivalent in
    d_splice_alias()).
    
    Cc: stable@vger.kernel.org # v3.10+
    Tested-by: default avatarOleg Drokin <green@linuxhacker.ru>
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
    Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
    d20cb71d
dir.c 63.3 KB