/* * Asynchronous I/O daemons for client nfs. * They do read-ahead and write-behind operations on the block I/O cache. * Returns if we hit the timeout defined by the iodmaxidle sysctl. */ static void nfssvc_iod(void *instance) { struct buf *bp; struct nfsmount *nmp; int myiod, timo; int error = 0; mtx_lock(&nfs_iod_mtx); myiod = (int *)instance - nfs_asyncdaemon; /* * Main loop */ for (;;) { while (((nmp = nfs_iodmount[myiod]) == NULL) || !TAILQ_FIRST(&nmp->nm_bufq)) { if (myiod >= nfs_iodmax) goto finish; if (nmp) nmp->nm_bufqiods--; if (nfs_iodwant[myiod] == NFSIOD_NOT_AVAILABLE) nfs_iodwant[myiod] = NFSIOD_AVAILABLE; nfs_iodmount[myiod] = NULL; /* * Always keep at least nfs_iodmin kthreads. */ timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz; error = msleep(&nfs_iodwant[myiod], &nfs_iod_mtx, PWAIT | PCATCH, "-", timo); if (error) { nmp = nfs_iodmount[myiod]; /* * Rechecking the nm_bufq closes a rare race where the * nfsiod is woken up at the exact time the idle timeout * fires */ if (nmp && TAILQ_FIRST(&nmp->nm_bufq)) error = 0; break; } } if (error) break; while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) { int giant_locked = 0; /* Take one off the front of the list */ TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist); nmp->nm_bufqlen--; if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) { nmp->nm_bufqwant = 0; wakeup(&nmp->nm_bufq); } mtx_unlock(&nfs_iod_mtx); if (NFS_ISV4(bp->b_vp)) { giant_locked = 1; mtx_lock(&Giant); } if (bp->b_flags & B_DIRECT) { KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set")); (void)nfs_doio_directwrite(bp); } else { if (bp->b_iocmd == BIO_READ) (void) nfs_doio(bp->b_vp, bp, bp->b_rcred, NULL); else (void) nfs_doio(bp->b_vp, bp, bp->b_wcred, NULL); } if (giant_locked) mtx_unlock(&Giant); mtx_lock(&nfs_iod_mtx); /* * If there are more than one iod on this mount, then defect * so that the iods can be shared out fairly between the mounts */ if (nfs_defect && nmp->nm_bufqiods > 1) { NFS_DPF(ASYNCIO, ("nfssvc_iod: iod %d defecting from mount %p\n", myiod, nmp)); nfs_iodmount[myiod] = NULL; nmp->nm_bufqiods--; break; } } } finish: nfs_asyncdaemon[myiod] = 0; if (nmp) nmp->nm_bufqiods--; nfs_iodwant[myiod] = NFSIOD_NOT_AVAILABLE; nfs_iodmount[myiod] = NULL; /* Someone may be waiting for the last nfsiod to terminate. */ if (--nfs_numasync == 0) wakeup(&nfs_numasync); mtx_unlock(&nfs_iod_mtx); if ((error == 0) || (error == EWOULDBLOCK)) kproc_exit(0); /* Abnormal termination */ kproc_exit(1); }
/* * Asynchronous I/O daemons for client nfs. * They do read-ahead and write-behind operations on the block I/O cache. * Returns if we hit the timeout defined by the iodmaxidle sysctl. */ static void nfssvc_iod(void *instance) { struct buf *bp; struct nfsmount *nmp; int myiod, timo; int error = 0; mtx_lock(&Giant); myiod = (int *)instance - nfs_asyncdaemon; /* * Main loop */ for (;;) { while (((nmp = nfs_iodmount[myiod]) == NULL || !TAILQ_FIRST(&nmp->nm_bufq)) && error == 0) { if (myiod >= nfs_iodmax) goto finish; if (nmp) nmp->nm_bufqiods--; nfs_iodwant[myiod] = curthread->td_proc; nfs_iodmount[myiod] = NULL; /* * Always keep at least nfs_iodmin kthreads. */ timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz; error = tsleep((caddr_t)&nfs_iodwant[myiod], PWAIT | PCATCH, "nfsidl", timo); } if (error) break; while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) { /* Take one off the front of the list */ TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist); nmp->nm_bufqlen--; if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) { nmp->nm_bufqwant = 0; wakeup(&nmp->nm_bufq); } if (bp->b_iocmd == BIO_READ) (void) nfs_doio(bp, bp->b_rcred, NULL); else (void) nfs_doio(bp, bp->b_wcred, NULL); /* * If there are more than one iod on this mount, then defect * so that the iods can be shared out fairly between the mounts */ if (nfs_defect && nmp->nm_bufqiods > 1) { NFS_DPF(ASYNCIO, ("nfssvc_iod: iod %d defecting from mount %p\n", myiod, nmp)); nfs_iodmount[myiod] = NULL; nmp->nm_bufqiods--; break; } } } finish: nfs_asyncdaemon[myiod] = 0; if (nmp) nmp->nm_bufqiods--; nfs_iodwant[myiod] = NULL; nfs_iodmount[myiod] = NULL; nfs_numasync--; if ((error == 0) || (error == EWOULDBLOCK)) kthread_exit(0); /* Abnormal termination */ kthread_exit(1); }