diff options
Diffstat (limited to 'storeio/dev.h')
| -rw-r--r-- | storeio/dev.h | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/storeio/dev.h b/storeio/dev.h index d6e50102..b223fe7e 100644 --- a/storeio/dev.h +++ b/storeio/dev.h @@ -1,8 +1,7 @@ /* store `device' I/O - Copyright (C) 1995, 1996, 1997, 1999 Free Software Foundation, Inc. - - Written by Miles Bader <miles@gnu.ai.mit.edu> + Copyright (C) 1995,96,97,99,2000 Free Software Foundation, Inc. + Written by Miles Bader <miles@gnu.org> This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as @@ -26,12 +25,20 @@ #include <rwlock.h> #include <hurd/store.h> -/* Information about a kernel device. */ +/* Information about backend store, which we presumptively call a "device". */ struct dev { - /* The device to which we're doing io. */ + /* The argument specification that we use to open the store. */ + struct store_parsed *store_name; + + /* The device to which we're doing io. This is null when the + device is closed, in which case we will open from `store_name'. */ struct store *store; + int readonly; /* Nonzero if user gave --readonly flag. */ + int enforced; /* Nonzero if user gave --enforced flag. */ + dev_t rdev; /* A unixy device number for st_rdev. */ + /* The current owner of the open device. For terminals, this affects controlling terminal behavior (see term_become_ctty). For all objects this affects old-style async IO. Negative values represent pgrps. This @@ -40,7 +47,9 @@ struct dev indicates that there is no owner. */ pid_t owner; - int enforced; /* Nonzero iff --enforced flag was given. */ + /* This lock protects `store' and `owner'. The other members never + change after creation, except for those locked by io_lock (below). */ + struct mutex lock; /* Nonzero iff the --no-cache flag was given. If this is set, the remaining members are not used at all @@ -68,14 +77,18 @@ struct dev struct mutex pager_lock; }; -/* Returns a pointer to a new device structure in DEV for the device - NAME, with the given FLAGS. If BLOCK_SIZE is non-zero, it should be the - desired block size, and must be a multiple of the device block size. - If an error occurs, the error code is returned, otherwise 0. */ -error_t dev_open (struct store_parsed *name, int flags, int inhibit_cache, - struct dev **dev); +static inline int +dev_is_readonly (const struct dev *dev) +{ + return dev->readonly || (dev->store && (dev->store->flags & STORE_READONLY)); +} + +/* Called with DEV->lock held. Try to open the store underlying DEV. */ +error_t dev_open (struct dev *dev); -/* Free DEV and any resources it consumes. */ +/* Shut down the store underlying DEV and free any resources it consumes. + DEV itself remains intact so that dev_open can be called again. + This should be called with DEV->lock held. */ void dev_close (struct dev *dev); /* Returns in MEMOBJ the port for a memory object backed by the storage on |