On Jul. 20, 2010, 20:30 +0300, "William A. (Andy) Adamson" <androsadamson@xxxxxxxxx> wrote: > Trond and Fred informed me that kfree under a spin lock is actually > OK. So, maybe these patches aren't needed. > > On the other hand, with these patches we don't hold the spin lock over > function calls which to my mind is easier to read. Also, the > free_layout/free_lseg layoutdriver calls may do more than call kfree. I'm all for that. Just document they must not block. If we ever see that as a requirement we can then change the caller to drop the spin lock before calling the free method. Beny > > At least, we should document what we expect from the > free_layout/free_lseg - e.g. no side affects that conflict with being > called under a spinlock.. > > -->Andy > > On Tue, Jul 20, 2010 at 1:01 PM, <andros@xxxxxxxxxx> wrote: >> >> Fix kfree under spin lock >> >> Both put_lseg and put_layout are called under the inode i_lock where the >> last reference will end up freeing structures. >> >> I know there has been a lot of churn in this code, but free'ing under the >> spin lock is a no-no. >> In this patch I refactor the layout allocation, combining it with the >> layout segment lookup code. The new function, pnfs_get_layout_segment takes >> inode spin lock, and looks to see if the requested range is serviced by an >> existing layout segment. If the layout has not been allocated, allocate it. >> If a layout segement is found, reference it and give up the lock. If no >> layout segment is found, reference the layout for the layoutget call and >> give up the lock. >> >> 0001-SQUASHME-pnfs-submit-alloc-layout-don-t-call-put_lay.patch >> 0002-SQUASHME-pnfs-submit-use-atomic_dec_and_lock-for-lay.patch >> >> Fix the put_lseg under spin lock. >> 0003-SQUASHME-pnfs-submit-don-t-call-put_lseg-under-spin-.patch >> >> Cleanup. >> 0004-SQUASHME-pnfs-submit-pnfs_release_layout-just-use-in.patch >> 0005-SQUASHME-pnfs-submit-fix-has_layout-compile-error.patch >> >> Tests: >> CONFIG_NFS_V4_1 set: >> Connectathon tests pass against GFS2 and pyNFS file layout servers. >> >> CONFIG_NFS_V4_1 not set: >> Connectathon tests pass. >> >> -->Andy >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
