flag which protects it from to be processed by pdflush's writeback
mechanism. this allows us to work locking problem with lustre_fwrite()
around
- MDS sets I_SKIP_PDFLUSH flag on 'last record' file
- filter_prep() sets I_SKIP_PDFLUSH flag
- inode-protection-from-pdflush.patch has been included in kgdb-2.5.73
series