Rewrite filesystem code (WIP)

This patch redoes the filesystem code from the FAT driver up to the
clipboard code in onplay.c.

Not every aspect of this is finished therefore it is still "WIP". I
don't wish to do too much at once (haha!). What is left to do is get
dircache back in the sim and find an implementation for the dircache
indicies in the tagcache and playlist code or do something else that
has the same benefit. Leaving these out for now does not make anything
unusable. All the basics are done.

Phone app code should probably get vetted (and app path handling
just plain rewritten as environment expansions); the SDL app and
Android run well.

Main things addressed:
1) Thread safety: There is none right now in the trunk code. Most of
what currently works is luck when multiple threads are involved or
multiple descriptors to the same file are open.

2) POSIX compliance: Many of the functions behave nothing like their
counterparts on a host system. This leads to inconsistent code or very
different behavior from native to hosted. One huge offender was
rename(). Going point by point would fill a book.

3) Actual running RAM usage: Many targets will use less RAM and less
stack space (some more RAM because I upped the number of cache buffers
for large memory). There's very little memory lying fallow in rarely-used
areas (see 'Key core changes' below). Also, all targets may open the same
number of directory streams whereas before those with less than 8MB RAM
were limited to 8, not 12 implying those targets will save slightly
less.

4) Performance: The test_disk plugin shows markedly improved performance,
particularly in the area of (uncached) directory scanning, due partly to
more optimal directory reading and to a better sector cache algorithm.
Uncached times tend to be better while there is a bit of a slowdown in
dircache due to it being a bit heavier of an implementation. It's not
noticeable by a human as far as I can say.

Key core changes:
1) Files and directories share core code and data structures.

2) The filesystem code knows which descriptors refer to same file.
This ensures that changes from one stream are appropriately reflected
in every open descriptor for that file (fileobj_mgr.c).

3) File and directory cache buffers are borrowed from the main sector
cache. This means that when they are not in use by a file, they are not
wasted, but used for the cache. Most of the time, only a few of them
are needed. It also means that adding more file and directory handles
is less expensive. All one must do in ensure a large enough cache to
borrow from.

4) Relative path components are supported and the namespace is unified.
It does not support full relative paths to an implied current directory;
what is does support is use of "." and "..". Adding the former would
not be very difficult. The namespace is unified in the sense that
volumes may be specified several times along with relative parts, e.g.:
"/<0>/foo/../../<1>/bar" :<=> "/<1>/bar".

5) Stack usage is down due to sharing of data, static allocation and
less duplication of strings on the stack. This requires more
serialization than I would like but since the number of threads is
limited to a low number, the tradoff in favor of the stack seems
reasonable.

6) Separates and heirarchicalizes (sic) the SIM and APP filesystem
code. SIM path and volume handling is just like the target. Some
aspects of the APP file code get more straightforward (e.g. no path
hashing is needed).

Dircache:
Deserves its own section. Dircache is new but pays homage to the old.
The old one was not compatible and so it, since it got redone, does
all the stuff it always should have done such as:

1) It may be update and used at any time during the build process.
No longer has one to wait for it to finish building to do basic file
management (create, remove, rename, etc.).

2) It does not need to be either fully scanned or completely disabled;
it can be incomplete (i.e. overfilled, missing paths), still be
of benefit and be correct.

3) Handles mounting and dismounting of individual volumes which means
a full rebuild is not needed just because you pop a new SD card in the
slot. Now, because it reuses its freed entry data, may rebuild only
that volume.

4) Much more fundamental to the file code. When it is built, it is
the keeper of the master file list whether enabled or not ("disabled"
is just a state of the cache). Its must always to ready to be started
and bind all streams opened prior to being enabled.

5) Maintains any short filenames in OEM format which means that it does
not need to be rebuilt when changing the default codepage.

Miscellaneous Compatibility:
1) Update any other code that would otherwise not work such as the
hotswap mounting code in various card drivers.

2) File management: Clipboard needed updating because of the behavioral
changes. Still needs a little more work on some finer points.

3) Remove now-obsolete functionality such as the mutex's "no preempt"
flag (which was only for the prior FAT driver).

4) struct dirinfo uses time_t rather than raw FAT directory entry
time fields. I plan to follow up on genericizing everything there
(i.e. no FAT attributes).

5) unicode.c needed some redoing so that the file code does not try
try to load codepages during a scan, which is actually a problem with
the current code. The default codepage, if any is required, is now
kept in RAM separarately (bufalloced) from codepages specified to
iso_decode() (which must not be bufalloced because the conversion
may be done by playback threads).

Brings with it some additional reusable core code:
1) Revised file functions: Reusable code that does things such as
safe path concatenation and parsing without buffer limitations or
data duplication. Variants that copy or alter the input path may be
based off these.

To do:
1) Put dircache functionality back in the sim. Treating it internally
as a different kind of file system seems the best approach at this
time.

2) Restore use of dircache indexes in the playlist and database or
something effectively the same. Since the cache doesn't have to be
complete in order to be used, not getting a hit on the cache doesn't
unambiguously say if the path exists or not.

Change-Id: Ia30f3082a136253e3a0eae0784e3091d138915c8
Reviewed-on: http://gerrit.rockbox.org/566
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested: Michael Sevakis <jethead71@rockbox.org>

1 files changed, 297 insertions, 154 deletions

diff --git a/firmware/common/disk.c b/firmware/common/disk.c
index 5a55a3b6ac..3a2d27e0d7 100644
--- a/firmware/common/disk.c
+++ b/firmware/common/disk.c
@@ -19,14 +19,25 @@
  *
  ****************************************************************************/
 #include <stdio.h>
+#include <string.h>
+#include "config.h"
 #include "kernel.h"
 #include "storage.h"
 #include "debug.h"
-#include "fat.h"
-#include "dir.h" /* for release_dirs() */
-#include "file.h" /* for release_files() */
+#include "disk_cache.h"
+#include "fileobj_mgr.h"
+#include "dir.h"
+#include "dircache_redirect.h"
 #include "disk.h"
-#include <string.h>
+
+#ifndef CONFIG_DEFAULT_PARTNUM
+#define CONFIG_DEFAULT_PARTNUM 0
+#endif
+
+#define disk_reader_lock()      file_internal_lock_READER()
+#define disk_reader_unlock()    file_internal_unlock_READER()
+#define disk_writer_lock()      file_internal_lock_WRITER()
+#define disk_writer_unlock()    file_internal_unlock_WRITER()
 
 /* Partition table entry layout:
    -----------------------
@@ -42,11 +53,18 @@
    12-15: nr of sectors in partition
 */
 
-#define BYTES2INT32(array,pos)                  \
-    ((long)array[pos] | ((long)array[pos+1] << 8 ) |        \
-     ((long)array[pos+2] << 16 ) | ((long)array[pos+3] << 24 ))
+#define BYTES2INT32(array, pos) \
+    (((uint32_t)array[pos+0] <<  0) | \
+     ((uint32_t)array[pos+1] <<  8) | \
+     ((uint32_t)array[pos+2] << 16) | \
+     ((uint32_t)array[pos+3] << 24))
+
+#define BYTES2INT16(array, pos) \
+    (((uint32_t)array[pos+0] << 0) | \
+     ((uint32_t)array[pos+1] << 8))
 
-static const unsigned char fat_partition_types[] = {
+static const unsigned char fat_partition_types[] =
+{
     0x0b, 0x1b, /* FAT32 + hidden variant */
     0x0c, 0x1c, /* FAT32 (LBA) + hidden variant */
 #ifdef HAVE_FAT16SUPPORT
@@ -56,159 +74,135 @@ static const unsigned char fat_partition_types[] = {
 #endif
 };
 
-static struct partinfo part[NUM_DRIVES*4]; /* space for 4 partitions on 2 drives */
-static int vol_drive[NUM_VOLUMES]; /* mounted to which drive (-1 if none) */
-static struct mutex disk_mutex;
+/* space for 4 partitions on 2 drives */
+static struct partinfo part[NUM_DRIVES*4];
+/* mounted to which drive (-1 if none) */
+static int vol_drive[NUM_VOLUMES];
+
+static int get_free_volume(void)
+{
+    for (int i = 0; i < NUM_VOLUMES; i++)
+    {
+        if (vol_drive[i] == -1) /* unassigned? */
+            return i;
+    }
+
+    return -1; /* none found */
+}
 
 #ifdef MAX_LOG_SECTOR_SIZE
-static int disk_sector_multiplier[NUM_DRIVES] = {[0 ... NUM_DRIVES-1] = 1};
+static int disk_sector_multiplier[NUM_DRIVES] =
+    { [0 ... NUM_DRIVES-1] = 1 };
 
 int disk_get_sector_multiplier(IF_MD_NONVOID(int drive))
 {
-    #ifdef HAVE_MULTIDRIVE
-    return disk_sector_multiplier[drive];
-    #else
-    return disk_sector_multiplier[0];
-    #endif
+    if (!CHECK_DRV(drive))
+        return 0;
+
+    disk_reader_lock();
+    int multiplier = disk_sector_multiplier[IF_MD_DRV(drive)];
+    disk_reader_unlock();
+    return multiplier;
 }
-#endif
+#endif /* MAX_LOG_SECTOR_SIZE */
 
-struct partinfo* disk_init(IF_MD_NONVOID(int drive))
+bool disk_init(IF_MD_NONVOID(int drive))
 {
-    int i;
-#ifdef HAVE_MULTIDRIVE
-    /* For each drive, start at a different position, in order not to destroy 
-       the first entry of drive 0. 
-       That one is needed to calculate config sector position. */
-    struct partinfo* pinfo = &part[drive*4];
-    if ((size_t)drive >= sizeof(part)/sizeof(*part)/4)
-        return NULL; /* out of space in table */
-#else
-    struct partinfo* pinfo = part;
-    const int drive = 0;
-    (void)drive;
-#endif
+    if (!CHECK_DRV(drive))
+        return false; /* out of space in table */
 
-    unsigned char* sector = fat_get_sector_buffer();
-    storage_read_sectors(IF_MD(drive,) 0,1, sector);
-    /* check that the boot sector is initialized */
-    if ( (sector[510] != 0x55) ||
-         (sector[511] != 0xaa)) {
-        fat_release_sector_buffer();
-        DEBUGF("Bad boot sector signature\n");
-        return NULL;
-    }
+    unsigned char *sector = dc_get_buffer();
+    if (!sector)
+        return false;
 
-    /* parse partitions */
-    for ( i=0; i<4; i++ ) {
-        unsigned char* ptr = sector + 0x1be + 16*i;
-        pinfo[i].type  = ptr[4];
-        pinfo[i].start = BYTES2INT32(ptr, 8);
-        pinfo[i].size  = BYTES2INT32(ptr, 12);
+    memset(sector, 0, SECTOR_SIZE);
+    storage_read_sectors(IF_MD(drive,) 0, 1, sector);
 
-        DEBUGF("Part%d: Type %02x, start: %08lx size: %08lx\n",
-               i,pinfo[i].type,pinfo[i].start,pinfo[i].size);
+    bool init = false;
 
-        /* extended? */
-        if ( pinfo[i].type == 5 ) {
-            /* not handled yet */
-        }
-    }
-    fat_release_sector_buffer();
-    return pinfo;
-}
+    /* check that the boot sector is initialized */
+    if (BYTES2INT16(sector, 510) == 0xaa55)
+    {
+        /* For each drive, start at a different position, in order not to
+           destroy the first entry of drive 0. That one is needed to calculate
+           config sector position. */
+        struct partinfo *pinfo = &part[IF_MD_DRV(drive)*4];
 
-struct partinfo* disk_partinfo(int partition)
-{
-    return &part[partition];
-}
+        disk_writer_lock();
 
-void disk_init_subsystem(void)
-{
-   mutex_init(&disk_mutex);
-}
+        /* parse partitions */
+        for (int i = 0; i < 4; i++)
+        {
+            unsigned char* ptr = sector + 0x1be + 16*i;
+            pinfo[i].type  = ptr[4];
+            pinfo[i].start = BYTES2INT32(ptr, 8);
+            pinfo[i].size  = BYTES2INT32(ptr, 12);
 
-int disk_mount_all(void)
-{
-    int mounted=0;
-    int i;
-    
-#ifdef HAVE_HOTSWAP
-    mutex_lock(&disk_mutex);
-#endif
+            DEBUGF("Part%d: Type %02x, start: %08lx size: %08lx\n",
+                   i,pinfo[i].type,pinfo[i].start,pinfo[i].size);
 
-    fat_init(); /* reset all mounted partitions */
-    for (i=0; i<NUM_VOLUMES; i++)
-        vol_drive[i] = -1; /* mark all as unassigned */
+            /* extended? */
+            if ( pinfo[i].type == 5 )
+            {
+                /* not handled yet */
+            }
+        }
 
-#ifndef HAVE_MULTIDRIVE
-    mounted = disk_mount(0);
-#else
-    for(i=0;i<NUM_DRIVES;i++)
+        disk_writer_unlock();
+
+        init = true;
+    }
+    else
     {
-#ifdef HAVE_HOTSWAP
-        if (storage_present(i))
-#endif
-            mounted += disk_mount(i); 
+        DEBUGF("Bad boot sector signature\n");
     }
-#endif
 
-#ifdef HAVE_HOTSWAP
-    mutex_unlock(&disk_mutex);
-#endif
-    return mounted;
+    dc_release_buffer(sector);
+    return init;
 }
 
-static int get_free_volume(void)
+bool disk_partinfo(int partition, struct partinfo *info)
 {
-    int i;
-    for (i=0; i<NUM_VOLUMES; i++)
-    {
-        if (vol_drive[i] == -1) /* unassigned? */
-            return i;
-    }
+    if (partition < 0 || partition >= (int)ARRAYLEN(part) || !info)
+        return false;
 
-    return -1; /* none found */
+    disk_reader_lock();
+    *info = part[partition];
+    disk_reader_unlock();
+    return true;
 }
 
 int disk_mount(int drive)
 {
     int mounted = 0; /* reset partition-on-drive flag */
-    int volume;
-    struct partinfo* pinfo;
 
-#ifdef HAVE_HOTSWAP
-    mutex_lock(&disk_mutex);
-#endif
+    disk_writer_lock();
 
-    volume = get_free_volume();
-    pinfo = disk_init(IF_MD(drive));
-#ifdef MAX_LOG_SECTOR_SIZE
-    disk_sector_multiplier[drive] = 1;
-#endif
+    int volume = get_free_volume();
 
-    if (pinfo == NULL)
+    if (!disk_init(IF_MD(drive)))
     {
-#ifdef HAVE_HOTSWAP
-        mutex_unlock(&disk_mutex);
-#endif
+        disk_writer_unlock();
         return 0;
     }
-#if defined(TOSHIBA_GIGABEAT_S)
-    int i = 1;  /* For the Gigabeat S, we mount the second partition */
-#else
-    int i = 0;
+
+    struct partinfo *pinfo = &part[IF_MD_DRV(drive)*4];
+#ifdef MAX_LOG_SECTOR_SIZE
+    disk_sector_multiplier[IF_MD_DRV(drive)] = 1;
 #endif
-    for (; volume != -1 && i<4 && mounted<NUM_VOLUMES_PER_DRIVE; i++)
+
+    for (int i = CONFIG_DEFAULT_PARTNUM;
+         volume != -1 && i < 4 && mounted < NUM_VOLUMES_PER_DRIVE;
+         i++)
     {
         if (memchr(fat_partition_types, pinfo[i].type,
                    sizeof(fat_partition_types)) == NULL)
             continue;  /* not an accepted partition type */
 
-#ifdef MAX_LOG_SECTOR_SIZE
-        int j;
-        
-        for (j = 1; j <= (MAX_LOG_SECTOR_SIZE/SECTOR_SIZE); j <<= 1)
+        bool success = false;
+
+    #ifdef MAX_LOG_SECTOR_SIZE
+        for (int j = 1; j <= (MAX_LOG_SECTOR_SIZE/SECTOR_SIZE); j <<= 1)
         {
             if (!fat_mount(IF_MV(volume,) IF_MD(drive,) pinfo[i].start * j))
             {
@@ -218,93 +212,242 @@ int disk_mount(int drive)
                 vol_drive[volume] = drive; /* remember the drive for this volume */
                 volume = get_free_volume(); /* prepare next entry */
                 disk_sector_multiplier[drive] = j;
+                success = true;
                 break;
             }
         }
-#else
+    #else /* ndef MAX_LOG_SECTOR_SIZE */
         if (!fat_mount(IF_MV(volume,) IF_MD(drive,) pinfo[i].start))
         {
             mounted++;
             vol_drive[volume] = drive; /* remember the drive for this volume */
             volume = get_free_volume(); /* prepare next entry */
+            success = true;
         }
-#endif
+    #endif /* MAX_LOG_SECTOR_SIZE */
+
+        if (success)
+            volume_onmount_internal(IF_MV(volume));
     }
 
     if (mounted == 0 && volume != -1) /* none of the 4 entries worked? */
     {   /* try "superfloppy" mode */
         DEBUGF("No partition found, trying to mount sector 0.\n");
+
         if (!fat_mount(IF_MV(volume,) IF_MD(drive,) 0))
         {
-#ifdef MAX_LOG_SECTOR_SIZE
-            disk_sector_multiplier[drive] = fat_get_bytes_per_sector(IF_MV(volume))/SECTOR_SIZE;
-#endif
+        #ifdef MAX_LOG_SECTOR_SIZE
+            disk_sector_multiplier[drive] =
+                fat_get_bytes_per_sector(IF_MV(volume)) / SECTOR_SIZE;
+        #endif
             mounted = 1;
             vol_drive[volume] = drive; /* remember the drive for this volume */
+            volume_onmount_internal(IF_MV(volume));
         }
     }
-#ifdef HAVE_HOTSWAP
-    mutex_unlock(&disk_mutex);
-#endif
+
+    disk_writer_unlock();
+    return mounted;
+}
+
+int disk_mount_all(void)
+{
+    int mounted = 0;
+
+    disk_writer_lock();
+
+    /* reset all mounted partitions */
+    volume_onunmount_internal(IF_MV(-1));
+    fat_init();
+
+    for (int i = 0; i < NUM_VOLUMES; i++)
+        vol_drive[i] = -1; /* mark all as unassigned */
+
+    for (int i = 0; i < NUM_DRIVES; i++)
+    {
+    #ifdef HAVE_HOTSWAP
+        if (storage_present(i))
+    #endif
+            mounted += disk_mount(i);
+    }
+
+    disk_writer_unlock();
     return mounted;
 }
 
 int disk_unmount(int drive)
 {
+    if (!CHECK_DRV(drive))
+        return 0;
+
     int unmounted = 0;
-    int i;
-#ifdef HAVE_HOTSWAP
-    mutex_lock(&disk_mutex);
-#endif
-    for (i=0; i<NUM_VOLUMES; i++)
+
+    disk_writer_lock();
+
+    for (int i = 0; i < NUM_VOLUMES; i++)
     {
         if (vol_drive[i] == drive)
         {   /* force releasing resources */
             vol_drive[i] = -1; /* mark unused */
+
+            volume_onunmount_internal(IF_MV(i));
+            fat_unmount(IF_MV(i));
+
             unmounted++;
-            release_files(i);
-            release_dirs(i);
-            fat_unmount(i, false);
         }
     }
-#ifdef HAVE_HOTSWAP
-    mutex_unlock(&disk_mutex);
-#endif
 
+    disk_writer_unlock();
     return unmounted;
 }
 
 int disk_unmount_all(void)
 {
-#ifndef HAVE_MULTIDRIVE
-    return disk_unmount(0);
-#else  /* HAVE_MULTIDRIVE */
     int unmounted = 0;
-    int i;
-    for (i = 0; i < NUM_DRIVES; i++)
+
+    disk_writer_lock();
+
+    volume_onunmount_internal(IF_MV(-1));
+
+    for (int i = 0; i < NUM_DRIVES; i++)
     {
-#ifdef HAVE_HOTSWAP
+    #ifdef HAVE_HOTSWAP
         if (storage_present(i))
-#endif
+    #endif
             unmounted += disk_unmount(i);
     }
 
+    disk_writer_unlock();
     return unmounted;
-#endif  /* HAVE_MULTIDRIVE */
+}
+
+bool disk_present(IF_MD_NONVOID(int drive))
+{
+    int rc = -1;
+
+    if (CHECK_DRV(drive))
+    {
+        void *sector = dc_get_buffer();
+        if (sector)
+        {
+            rc = storage_read_sectors(IF_MD(drive,) 0, 1, sector);
+            dc_release_buffer(sector);
+        }
+    }
+
+    return rc == 0;
+}
+
+
+/** Volume-centric functions **/
+
+void volume_recalc_free(IF_MV_NONVOID(int volume))
+{
+    if (!CHECK_VOL(volume))
+        return;
+
+    /* FIXME: this is crummy but the only way to ensure a correct freecount
+       if other threads are writing and changing the fsinfo; it is possible
+       to get multiple threads calling here and also writing and get correct
+       freespace counts, however a bit complicated to do; if thou desireth I
+       shall implement the concurrent version -- jethead71 */
+    disk_writer_lock();
+    fat_recalc_free(IF_MV(volume));
+    disk_writer_unlock();
+}
+
+unsigned int volume_get_cluster_size(IF_MV_NONVOID(int volume))
+{
+    if (!CHECK_VOL(volume))
+        return 0;
+
+    disk_reader_lock();
+    unsigned int clustersize = fat_get_cluster_size(IF_MV(volume));
+    disk_reader_unlock();
+    return clustersize;
+}
+
+void volume_size(IF_MV(int volume,) unsigned long *sizep, unsigned long *freep)
+{
+    disk_reader_lock();
+
+    if (!CHECK_VOL(volume) || !fat_size(IF_MV(volume,) sizep, freep))
+    {
+        if (freep) *sizep = 0;
+        if (freep) *freep = 0;
+    }
+
+    disk_reader_unlock();
+}
+
+#if defined (HAVE_HOTSWAP) || defined (HAVE_MULTIDRIVE) \
+    || defined (HAVE_DIRCACHE)
+enum volume_info_type
+{
+#ifdef HAVE_HOTSWAP
+    VP_REMOVABLE,
+    VP_PRESENT,
+#endif
+#if defined (HAVE_MULTIDRIVE) || defined (HAVE_DIRCACHE)
+    VP_DRIVE,
+#endif
+};
+
+static int volume_properties(int volume, enum volume_info_type infotype)
+{
+    int res = -1;
+
+    disk_reader_lock();
+
+    if (CHECK_VOL(volume))
+    {
+        int vd = vol_drive[volume];
+        switch (infotype)
+        {
+    #ifdef HAVE_HOTSWAP
+        case VP_REMOVABLE:
+            res = storage_removable(vd) ? 1 : 0;
+            break;
+        case VP_PRESENT:
+            res = storage_present(vd) ? 1 : 0;
+            break;
+    #endif
+    #if defined(HAVE_MULTIDRIVE) || defined(HAVE_DIRCACHE)
+        case VP_DRIVE:
+            res = vd;
+            break;
+    #endif
+        }
+    }
+
+    disk_reader_unlock();
+    return res;
 }
 
 #ifdef HAVE_HOTSWAP
 bool volume_removable(int volume)
 {
-    if(vol_drive[volume] == -1)
-        return false;
-    return storage_removable(vol_drive[volume]);
+    return volume_properties(volume, VP_REMOVABLE) > 0;
 }
 
 bool volume_present(int volume)
 {
-    if(vol_drive[volume] == -1)
-        return false;
-    return storage_present(vol_drive[volume]);
+    return volume_properties(volume, VP_PRESENT) > 0;
 }
-#endif
+#endif /* HAVE_HOTSWAP */
+
+#ifdef HAVE_MULTIDRIVE
+int volume_drive(int volume)
+{
+    return volume_properties(volume, VP_DRIVE);
+}
+#endif /* HAVE_MULTIDRIVE */
+
+#ifdef HAVE_DIRCACHE
+bool volume_ismounted(IF_MV_NONVOID(int volume))
+{
+    return volume_properties(IF_MV_VOL(volume), VP_DRIVE) >= 0;
+}
+#endif /* HAVE_DIRCACHE */
+
+#endif /* HAVE_HOTSWAP || HAVE_MULTIDRIVE || HAVE_DIRCACHE */