rockbox/firmware/common/fileobj_mgr.c
Michael Sevakis a931c76b3a Do some debug and preparatory work for ramcache and playlist
The file system rework introduced incompatibility between dircache
and the tagcache ramcache and playlist dircache path caching. This
update makes changes to filesystem code to reintegrate all that.

It also fixes a couple bugs that were found when vetting all the
code. The filestream cache was being reset without regard to
the stream even if it was shared in write mode (made work of
.playlist_control). Better handling of unmounting gives files a
better go at force-closing them without risk to disk integrity.

Did some miscellaneous pedantic changes. Improved efficiency of
testing a file's existence (a little) since the path parser will
be shared between file code and parsing for the sake of finding
dircache references, not duplicated as before.

This commit doesn't reenable said items just for the sake of
keeping changes separate and related.

Plan for the next is to enable dircache again for the playlists
(easy peasy) and reenable tagcache ramcache but *without* the
dircache path caching because it's rather substantial to change
in itself. The ramcache will still function without dircache.

Change-Id: I7e2a9910b866251fa8333e1275f72fcfc8425d2d
2017-01-17 14:35:36 -05:00

403 lines
13 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2014 by Michael Sevakis
*
* 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
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "system.h"
#include "debug.h"
#include "file.h"
#include "dir.h"
#include "disk_cache.h"
#include "fileobj_mgr.h"
#include "dircache_redirect.h"
/**
* Manages file and directory streams on all volumes
*
* Intended for internal use by disk, file and directory code
*/
/* there will always be enough of these for all user handles, thus these
functions don't return failure codes */
#define MAX_FILEOBJS (MAX_OPEN_HANDLES + AUX_FILEOBJS)
/* describes the file as an image on the storage medium */
static struct fileobj_binding
{
struct file_base_binding bind; /* base info list item (first!) */
uint16_t flags; /* F(D)(O)_* bits of this file/dir */
uint16_t writers; /* number of writer streams */
struct filestr_cache cache; /* write mode shared cache */
file_size_t size; /* size of this file */
struct ll_head list; /* open streams for this file/dir */
} fobindings[MAX_FILEOBJS];
static struct mutex stream_mutexes[MAX_FILEOBJS] SHAREDBSS_ATTR;
static struct ll_head free_bindings;
static struct ll_head busy_bindings[NUM_VOLUMES];
#define BUSY_BINDINGS(volume) \
(&busy_bindings[IF_MV_VOL(volume)])
#define BASEBINDING_LIST(bindp) \
(BUSY_BINDINGS(BASEBINDING_VOL(bindp)))
#define FREE_BINDINGS() \
(&free_bindings)
#define BINDING_FIRST(type, volume...) \
((struct fileobj_binding *)type##_BINDINGS(volume)->head)
#define BINDING_NEXT(fobp) \
((struct fileobj_binding *)(fobp)->bind.node.next)
#define FOR_EACH_BINDING(volume, fobp) \
for (struct fileobj_binding *fobp = BINDING_FIRST(BUSY, volume); \
fobp; fobp = BINDING_NEXT(fobp))
#define STREAM_FIRST(fobp) \
((struct filestr_base *)(fobp)->list.head)
#define STREAM_NEXT(s) \
((struct filestr_base *)(s)->node.next)
#define STREAM_THIS(s) \
(s)
#define FOR_EACH_STREAM(what, start, s) \
for (struct filestr_base *s = STREAM_##what(start); \
s; s = STREAM_NEXT(s))
/* syncs information for the stream's old and new parent directory if any are
currently opened */
static void fileobj_sync_parent(const struct file_base_info *infop[],
int count)
{
FOR_EACH_BINDING(infop[0]->volume, fobp)
{
if ((fobp->flags & (FO_DIRECTORY|FO_REMOVED)) != FO_DIRECTORY)
continue; /* not directory or removed can't be parent of anything */
struct filestr_base *parentstrp = STREAM_FIRST(fobp);
struct fat_file *parentfilep = &parentstrp->infop->fatfile;
for (int i = 0; i < count; i++)
{
if (!fat_dir_is_parent(parentfilep, &infop[i]->fatfile))
continue;
/* discard scan/read caches' parent dir info */
FOR_EACH_STREAM(THIS, parentstrp, s)
filestr_discard_cache(s);
}
}
}
/* see if this file has open streams and return that fileobj_binding if so,
else grab a new one from the free list; returns true if this stream is
the only open one */
static bool binding_assign(const struct file_base_info *srcinfop,
struct fileobj_binding **fobpp)
{
FOR_EACH_BINDING(srcinfop->fatfile.volume, fobp)
{
if (fobp->flags & FO_REMOVED)
continue;
if (fat_file_is_same(&srcinfop->fatfile, &fobp->bind.info.fatfile))
{
/* already has open streams */
*fobpp = fobp;
return false;
}
}
/* not found - allocate anew */
*fobpp = BINDING_FIRST(FREE);
ll_remove_first(FREE_BINDINGS());
ll_init(&(*fobpp)->list);
return true;
}
/* mark descriptor as unused and return to the free list */
static void binding_add_to_free_list(struct fileobj_binding *fobp)
{
fobp->flags = 0;
ll_insert_last(FREE_BINDINGS(), &fobp->bind.node);
}
/** File and directory internal interface **/
void file_binding_insert_last(struct file_base_binding *bindp)
{
ll_insert_last(BASEBINDING_LIST(bindp), &bindp->node);
}
void file_binding_remove(struct file_base_binding *bindp)
{
ll_remove(BASEBINDING_LIST(bindp), &bindp->node);
}
#ifdef HAVE_DIRCACHE
void file_binding_insert_first(struct file_base_binding *bindp)
{
ll_insert_first(BASEBINDING_LIST(bindp), &bindp->node);
}
void file_binding_remove_next(struct file_base_binding *prevp,
struct file_base_binding *bindp)
{
ll_remove_next(BASEBINDING_LIST(bindp), &prevp->node);
(void)bindp;
}
#endif /* HAVE_DIRCACHE */
/* opens the file object for a new stream and sets up the caches;
* the stream must already be opened at the FS driver level and *stream
* initialized.
*
* NOTE: switches stream->infop to the one kept in common for all streams of
* the same file, making a copy for only the first stream
*/
void fileobj_fileop_open(struct filestr_base *stream,
const struct file_base_info *srcinfop,
unsigned int callflags)
{
struct fileobj_binding *fobp;
bool first = binding_assign(srcinfop, &fobp);
/* add stream to this file's list */
ll_insert_last(&fobp->list, &stream->node);
/* initiate the new stream into the enclave */
stream->flags = FDO_BUSY |
(callflags & (FF_MASK|FD_WRITE|FD_WRONLY|FD_APPEND));
stream->infop = &fobp->bind.info;
stream->fatstr.fatfilep = &fobp->bind.info.fatfile;
stream->bindp = &fobp->bind;
stream->mtx = &stream_mutexes[fobp - fobindings];
if (first)
{
/* first stream for file */
fobp->bind.info = *srcinfop;
fobp->flags = FDO_BUSY | FO_SINGLE |
(callflags & (FO_DIRECTORY|FO_TRUNC));
fobp->writers = 0;
fobp->size = 0;
fileobj_bind_file(&fobp->bind);
}
else
{
/* additional stream for file */
fobp->flags &= ~FO_SINGLE;
fobp->flags |= callflags & FO_TRUNC;
/* once a file/directory, always a file/directory; such a change
is a bug */
if ((callflags ^ fobp->flags) & FO_DIRECTORY)
{
DEBUGF("%s - FO_DIRECTORY flag does not match: %p %u\n",
__func__, stream, callflags);
}
}
if ((callflags & FD_WRITE) && ++fobp->writers == 1)
{
/* first writer */
file_cache_init(&fobp->cache);
FOR_EACH_STREAM(FIRST, fobp, s)
filestr_assign_cache(s, &fobp->cache);
}
else if (fobp->writers)
{
/* already writers present */
filestr_assign_cache(stream, &fobp->cache);
}
else
{
/* another reader and no writers present */
file_cache_reset(stream->cachep);
}
}
/* close the stream and free associated resources */
void fileobj_fileop_close(struct filestr_base *stream)
{
if (!(stream->flags & FDO_BUSY))
{
/* not added to manager or forced-closed by unmounting */
filestr_base_destroy(stream);
return;
}
struct fileobj_binding *fobp = (struct fileobj_binding *)stream->bindp;
unsigned int foflags = fobp->flags;
ll_remove(&fobp->list, &stream->node);
if (foflags & FO_SINGLE)
{
/* last stream for file; close everything */
fileobj_unbind_file(&fobp->bind);
if (fobp->writers)
file_cache_free(&fobp->cache);
binding_add_to_free_list(fobp);
}
else
{
if ((stream->flags & FD_WRITE) && --fobp->writers == 0)
{
/* only readers remain; switch back to stream-local caching */
FOR_EACH_STREAM(FIRST, fobp, s)
filestr_copy_cache(s, &fobp->cache);
file_cache_free(&fobp->cache);
}
if (fobp->list.head == fobp->list.tail)
fobp->flags |= FO_SINGLE; /* only one open stream remaining */
}
filestr_base_destroy(stream);
}
/* informs manager that file has been created */
void fileobj_fileop_create(struct filestr_base *stream,
const struct file_base_info *srcinfop,
unsigned int callflags)
{
fileobj_fileop_open(stream, srcinfop, callflags);
fileobj_sync_parent((const struct file_base_info *[]){ stream->infop }, 1);
}
/* informs manager that file has been removed */
void fileobj_fileop_remove(struct filestr_base *stream,
const struct file_base_info *oldinfop)
{
((struct fileobj_binding *)stream->bindp)->flags |= FO_REMOVED;
fileobj_sync_parent((const struct file_base_info *[]){ oldinfop }, 1);
}
/* informs manager that file has been renamed */
void fileobj_fileop_rename(struct filestr_base *stream,
const struct file_base_info *oldinfop)
{
/* if there is old info then this was a move and the old parent has to be
informed */
int count = oldinfop ? 2 : 1;
fileobj_sync_parent(&(const struct file_base_info *[])
{ oldinfop, stream->infop }[2 - count],
count);
}
/* informs manager than directory entries have been updated */
void fileobj_fileop_sync(struct filestr_base *stream)
{
if (((struct fileobj_binding *)stream->bindp)->flags & FO_REMOVED)
return; /* no dir to sync */
fileobj_sync_parent((const struct file_base_info *[]){ stream->infop }, 1);
}
/* query for the pointer to the size storage for the file object */
file_size_t * fileobj_get_sizep(const struct filestr_base *stream)
{
if (!stream->bindp)
return NULL;
return &((struct fileobj_binding *)stream->bindp)->size;
}
/* iterate the list of streams for this stream's file */
struct filestr_base * fileobj_get_next_stream(const struct filestr_base *stream,
const struct filestr_base *s)
{
if (!stream->bindp)
return NULL;
return s ? STREAM_NEXT(s) : STREAM_FIRST((struct fileobj_binding *)stream->bindp);
}
/* query manager bitflags for the file object */
unsigned int fileobj_get_flags(const struct filestr_base *stream)
{
if (!stream->bindp)
return 0;
return ((struct fileobj_binding *)stream->bindp)->flags;
}
/* change manager bitflags for the file object (permitted only) */
void fileobj_change_flags(struct filestr_base *stream,
unsigned int flags, unsigned int mask)
{
struct fileobj_binding *fobp = (struct fileobj_binding *)stream->bindp;
if (!fobp)
return;
mask &= FDO_CHG_MASK;
fobp->flags = (fobp->flags & ~mask) | (flags & mask);
}
/* mark all open streams on a device as "nonexistant" */
void fileobj_mgr_unmount(IF_MV_NONVOID(int volume))
{
FOR_EACH_VOLUME(volume, v)
{
struct fileobj_binding *fobp;
while ((fobp = BINDING_FIRST(BUSY, v)))
{
struct filestr_base *s;
while ((s = STREAM_FIRST(fobp)))
{
/* last ditch effort to preserve FS integrity; we could still
be alive (soft unmount, maybe); we get informed early */
fileop_onunmount_internal(s);
if (STREAM_FIRST(fobp) == s)
fileop_onclose_internal(s); /* above didn't close it */
/* keep it "busy" to avoid races; any valid file/directory
descriptor returned by an open call should always be
closed by whoever opened it (of course!) */
s->flags = (s->flags & ~FDO_BUSY) | FD_NONEXIST;
}
}
}
}
/* one-time init at startup */
void fileobj_mgr_init(void)
{
for (unsigned int i = 0; i < NUM_VOLUMES; i++)
ll_init(BUSY_BINDINGS(i));
ll_init(FREE_BINDINGS());
for (unsigned int i = 0; i < MAX_FILEOBJS; i++)
{
mutex_init(&stream_mutexes[i]);
binding_add_to_free_list(&fobindings[i]);
}
}