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Diffstat (limited to 'storeio/dev.h')
| -rw-r--r-- | storeio/dev.h | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/storeio/dev.h b/storeio/dev.h new file mode 100644 index 00000000..23924ca5 --- /dev/null +++ b/storeio/dev.h @@ -0,0 +1,127 @@ +/* store `device' I/O + + Copyright (C) 1995,96,97,99,2000,2001 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 + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + This program 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. */ + +#ifndef __DEV_H__ +#define __DEV_H__ + +#include <mach.h> +#include <device/device.h> +#include <rwlock.h> +#include <hurd/store.h> +#include <hurd/trivfs.h> + +extern struct trivfs_control *storeio_fsys; + +/* Information about backend store, which we presumptively call a "device". */ +struct dev +{ + /* 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. */ + int no_fileio; /* Nonzero if user gave --no-fileio 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 + has nothing to do with the owner of a file (as returned by io_stat, and + as used for various permission checks by filesystems). An owner of 0 + indicates that there is no owner. */ + pid_t owner; + + /* The number of active opens. */ + int nperopens; + + /* This lock protects `store', `owner' and `nperopens'. 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 + and don't need to be initialized or cleaned up. */ + int inhibit_cache; + + /* A bitmask corresponding to the part of an offset that lies within a + device block. */ + unsigned block_mask; + + /* Lock to arbitrate I/O through this device. Block I/O can occur in + parallel, and requires only a reader-lock. + Non-block I/O is always serialized, and requires a writer-lock. */ + struct rwlock io_lock; + + /* Non-block I/O is buffered through BUF. BUF_OFFS is the device offset + corresponding to the start of BUF (which holds one block); if it is -1, + then BUF is inactive. */ + void *buf; + off_t buf_offs; + int buf_dirty; + + struct pager *pager; + struct mutex pager_lock; +}; + +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); + +/* 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 + DEV. Returns 0 or the error code if an error occurred. */ +error_t dev_get_memory_object(struct dev *dev, vm_prot_t prot, + memory_object_t *memobj); + +/* Try to stop all paging activity on DEV, returning true if we were + successful. If NOSYNC is true, then we won't write back any (kernel) + cached pages to the device. */ +int dev_stop_paging (struct dev *dev, int nosync); + +/* Try and write out any pending writes to DEV. If WAIT is true, will wait + for any paging activity to cease. */ +error_t dev_sync (struct dev *dev, int wait); + +/* Write LEN bytes from BUF to DEV, returning the amount actually written in + AMOUNT. If successful, 0 is returned, otherwise an error code is + returned. */ +error_t dev_write (struct dev *dev, off_t offs, void *buf, size_t len, + size_t *amount); + +/* Read up to AMOUNT bytes from DEV, returned in BUF and LEN in the with the + usual mach memory result semantics. If successful, 0 is returned, + otherwise an error code is returned. */ +error_t dev_read (struct dev *dev, off_t offs, size_t amount, + void **buf, size_t *len); + +#endif /* !__DEV_H__ */ |