1 /* 2 * Copyright (c) 1991 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)lfs_bio.c 7.16 (Berkeley) 08/26/92 8 */ 9 10 #include <sys/param.h> 11 #include <sys/proc.h> 12 #include <sys/buf.h> 13 #include <sys/vnode.h> 14 #include <sys/resourcevar.h> 15 #include <sys/mount.h> 16 17 #include <ufs/ufs/quota.h> 18 #include <ufs/ufs/inode.h> 19 #include <ufs/ufs/ufsmount.h> 20 21 #include <ufs/lfs/lfs.h> 22 #include <ufs/lfs/lfs_extern.h> 23 24 /* 25 * LFS block write function. 26 * 27 * XXX 28 * No write cost accounting is done. 29 * This is almost certainly wrong for synchronous operations and NFS. 30 */ 31 int lfs_allclean_wakeup; /* Cleaner wakeup address. */ 32 int locked_queue_count; /* XXX Count of locked-down buffers. */ 33 int lfs_writing; /* Set if already kicked off a writer 34 because of buffer space */ 35 #define WRITE_THRESHHOLD ((nbuf >> 2) - 10) 36 #define WAIT_THRESHHOLD ((nbuf >> 1) - 10) 37 38 int 39 lfs_bwrite(ap) 40 struct vop_bwrite_args /* { 41 struct buf *a_bp; 42 } */ *ap; 43 { 44 register struct buf *bp = ap->a_bp; 45 struct lfs *fs; 46 struct inode *ip; 47 int s; 48 49 /* 50 * Set the delayed write flag and use reassignbuf to move the buffer 51 * from the clean list to the dirty one. 52 * 53 * Set the B_LOCKED flag and unlock the buffer, causing brelse to move 54 * the buffer onto the LOCKED free list. This is necessary, otherwise 55 * getnewbuf() would try to reclaim the buffers using bawrite, which 56 * isn't going to work. 57 */ 58 if (!(bp->b_flags & B_LOCKED)) { 59 fs = VFSTOUFS(bp->b_vp->v_mount)->um_lfs; 60 if (!LFS_FITS(fs, fsbtodb(fs, 1)) && !IS_IFILE(bp)) { 61 bp->b_flags |= B_INVAL; 62 brelse(bp); 63 wakeup(&lfs_allclean_wakeup); 64 return (ENOSPC); 65 } 66 ip = VTOI((bp)->b_vp); 67 if (!(ip->i_flag & IMOD)) 68 ++fs->lfs_uinodes; 69 ip->i_flag |= IMOD | ICHG | IUPD; \ 70 fs->lfs_avail -= fsbtodb(fs, 1); 71 ++locked_queue_count; 72 bp->b_flags |= B_DELWRI | B_LOCKED; 73 bp->b_flags &= ~(B_READ | B_ERROR); 74 s = splbio(); 75 reassignbuf(bp, bp->b_vp); 76 splx(s); 77 } 78 brelse(bp); 79 return (0); 80 } 81 82 /* 83 * XXX 84 * This routine flushes buffers out of the B_LOCKED queue when LFS has too 85 * many locked down. Eventually the pageout daemon will simply call LFS 86 * when pages need to be reclaimed. Note, we have one static count of locked 87 * buffers, so we can't have more than a single file system. To make this 88 * work for multiple file systems, put the count into the mount structure. 89 */ 90 void 91 lfs_flush() 92 { 93 register struct mount *mp; 94 95 if (lfs_writing) 96 return; 97 lfs_writing = 1; 98 mp = rootfs; 99 do { 100 /* The lock check below is to avoid races with unmount. */ 101 if (mp->mnt_stat.f_type == MOUNT_LFS && 102 (mp->mnt_flag & (MNT_MLOCK|MNT_RDONLY|MNT_UNMOUNT)) == 0 && 103 !((((struct ufsmount *)mp->mnt_data))->ufsmount_u.lfs)->lfs_dirops ) { 104 /* 105 * We set the queue to 0 here because we are about to 106 * write all the dirty buffers we have. If more come 107 * in while we're writing the segment, they may not 108 * get written, so we want the count to reflect these 109 * new writes after the segwrite completes. 110 */ 111 lfs_segwrite(mp, 0); 112 } 113 mp = mp->mnt_next; 114 } while (mp != rootfs); 115 lfs_writing = 0; 116 } 117 118 int 119 lfs_check(vp, blkno) 120 struct vnode *vp; 121 daddr_t blkno; 122 { 123 extern int lfs_allclean_wakeup; 124 int error; 125 126 if (incore(vp, blkno)) 127 return (0); 128 if (locked_queue_count > WRITE_THRESHHOLD) 129 lfs_flush(); 130 if (locked_queue_count > WAIT_THRESHHOLD) 131 error = tsleep(&lfs_allclean_wakeup, PCATCH | PUSER, 132 "buffers", NULL); 133 return (error); 134 } 135