diff options
Diffstat (limited to 'ext2fs/pokel.c')
| -rw-r--r-- | ext2fs/pokel.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/ext2fs/pokel.c b/ext2fs/pokel.c new file mode 100644 index 00000000..85b4d2d1 --- /dev/null +++ b/ext2fs/pokel.c @@ -0,0 +1,172 @@ +/* A data structure to remember modifications to a memory region + + Copyright (C) 1995 Free Software Foundation, Inc. + + Written by Miles Bader <miles@gnu.ai.mit.edu> + + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + The GNU Hurd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include "ext2fs.h" + +void +pokel_init (struct pokel *pokel, struct pager *pager, void *image) +{ + pokel->lock = SPIN_LOCK_INITIALIZER; + pokel->pokes = NULL; + pokel->free_pokes = NULL; + pokel->pager = pager; + pokel->image = image; +} + +/* Clean up any state associated with POKEL (but don't free POKEL). */ +void +pokel_finalize (struct pokel *pokel) +{ + struct poke *pl, *next; + for (pl = pokel->pokes; pl; pl = next) + { + next = pl->next; + free (pl); + } + for (pl = pokel->free_pokes; pl; pl = next) + { + next = pl->next; + free (pl); + } +} + +/* Remember that data here on the disk has been modified. */ +void +pokel_add (struct pokel *pokel, void *loc, vm_size_t length) +{ + struct poke *pl; + vm_offset_t offset = trunc_page (loc - pokel->image); + vm_offset_t end = round_page (loc + length - pokel->image); + + ext2_debug ("adding %p[%ul] (range 0x%x to 0x%x)", loc, length, offset, end); + + spin_lock (&pokel->lock); + + pl = pokel->pokes; + while (pl != NULL) + { + vm_offset_t p_offs = pl->offset; + vm_size_t p_end = p_offs + pl->length; + + if (p_offs == offset && p_end == end) + break; + else if (p_end >= offset && end >= p_offs) + { + pl->offset = offset < p_offs ? offset : p_offs; + pl->length = (end > p_end ? end : p_end) - pl->offset; + ext2_debug ("extended 0x%x[%ul] to 0x%x[%ul]", + p_offs, p_end - p_offs, pl->offset, pl->length); + break; + } + + pl = pl->next; + } + + if (pl == NULL) + { + pl = pokel->free_pokes; + if (pl == NULL) + { + pl = malloc (sizeof (struct poke)); + assert (pl); + } + else + pokel->free_pokes = pl->next; + pl->offset = offset; + pl->length = end - offset; + pl->next = pokel->pokes; + pokel->pokes = pl; + } + + spin_unlock (&pokel->lock); +} + +/* Move all pending pokes from POKEL into its free list. If SYNC is true, + otherwise do nothing. */ +void +_pokel_exec (struct pokel *pokel, int sync, int wait) +{ + struct poke *pl, *pokes, *last = NULL; + + spin_lock (&pokel->lock); + pokes = pokel->pokes; + pokel->pokes = NULL; + spin_unlock (&pokel->lock); + + for (pl = pokes; pl; last = pl, pl = pl->next) + if (sync) + { + ext2_debug ("syncing 0x%x[%ul]", pl->offset, pl->length); + pager_sync_some (pokel->pager, pl->offset, pl->length, wait); + } + + if (last) + { + spin_lock (&pokel->lock); + last->next = pokel->free_pokes; + pokel->free_pokes = pokes; + spin_unlock (&pokel->lock); + } +} + +/* Sync all the modified pieces of disk */ +void +pokel_sync (struct pokel *pokel, int wait) +{ + _pokel_exec (pokel, 1, wait); +} + +/* Flush (that is, drop on the ground) all pending pokes in POKEL. */ +void +pokel_flush (struct pokel *pokel) +{ + _pokel_exec (pokel, 0, 0); +} + +/* Transfer all regions from FROM to POKEL, which must have the same pager. */ +void +pokel_inherit (struct pokel *pokel, struct pokel *from) +{ + struct poke *pokes, *last; + + assert (pokel->pager == from->pager); + assert (pokel->image == from->image); + + /* Take all pokes from FROM... */ + spin_lock (&from->lock); + pokes = from->pokes; + from->pokes = NULL; + spin_unlock (&from->lock); + + /* And put them in POKEL. */ + spin_lock (&pokel->lock); + last = pokel->pokes; + if (last) + { + while (last->next) + last = last->next; + last->next = pokes; + } + else + pokel->pokes = pokes; + spin_unlock (&pokel->lock); +} |