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fs/fat: merge readwrite get_fatent_value() with readonly get_fatent()

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get_fatent_value(...) flushes changed FAT entries to disk when fetching
the next FAT blocks, in every other aspect it is identical to
get_fatent(...).

Provide a stub implementation for flush_dirty_fat_buffer if
CONFIG_FAT_WRITE is not set. Calling flush_dirty_fat_buffer during read
only operation is fine as it checks if any buffers needs flushing.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
master
Stefan Brüns 8 years ago committed by Tom Rini
parent 6c1a808052
commit b8948d2aef
2 changed files with 27 additions and 116 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 25
      fs/fat/fat.c
  2. 118
      fs/fat/fat_write.c

25
fs/fat/fat.c
Unescape View File

@ -162,6 +162,16 @@ static void get_name(dir_entry *dirent, char *s_name)
downcase(s_name);
}
static int flush_dirty_fat_buffer(fsdata *mydata);
#if !defined(CONFIG_FAT_WRITE)
/* Stub for read only operation */
int flush_dirty_fat_buffer(fsdata *mydata)
{
(void)(mydata);
return 0;
}
#endif
/*
* Get the entry at index 'entry' in a FAT (12/16/32) table.
* On failure 0x00 is returned.
@ -173,6 +183,11 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
__u32 ret = 0x00;
__u16 val1, val2;
if (CHECK_CLUST(entry, mydata->fatsize)) {
printf("Error: Invalid FAT entry: 0x%08x\n", entry);
return ret;
}
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
@ -192,7 +207,7 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
return ret;
}
debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
debug("FAT%d: entry: 0x%08x = %d, offset: 0x%04x = %d\n",
mydata->fatsize, entry, entry, offset, offset);
/* Read a new block of FAT entries into the cache. */
@ -208,6 +223,10 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
startblock += mydata->fat_sect; /* Offset from start of disk */
/* Write back the fatbuf to the disk */
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return ret;
@ -254,8 +273,8 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
}
break;
}
debug("FAT%d: ret: %08x, offset: %04x\n",
mydata->fatsize, ret, offset);
debug("FAT%d: ret: 0x%08x, entry: 0x%08x, offset: 0x%04x\n",
mydata->fatsize, ret, entry, offset);
return ret;
}

118
fs/fat/fat_write.c
Unescape View File

@ -143,114 +143,6 @@ static int flush_dirty_fat_buffer(fsdata *mydata)
}
/*
* Get the entry at index 'entry' in a FAT (12/16/32) table.
* On failure 0x00 is returned.
* When bufnum is changed, write back the previous fatbuf to the disk.
*/
static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
{
__u32 bufnum;
__u32 off16, offset;
__u32 ret = 0x00;
__u16 val1, val2;
if (CHECK_CLUST(entry, mydata->fatsize)) {
printf("Error: Invalid FAT entry: 0x%08x\n", entry);
return ret;
}
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
offset = entry - bufnum * FAT32BUFSIZE;
break;
case 16:
bufnum = entry / FAT16BUFSIZE;
offset = entry - bufnum * FAT16BUFSIZE;
break;
case 12:
bufnum = entry / FAT12BUFSIZE;
offset = entry - bufnum * FAT12BUFSIZE;
break;
default:
/* Unsupported FAT size */
return ret;
}
debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
mydata->fatsize, entry, entry, offset, offset);
/* Read a new block of FAT entries into the cache. */
if (bufnum != mydata->fatbufnum) {
int getsize = FATBUFBLOCKS;
__u8 *bufptr = mydata->fatbuf;
__u32 fatlength = mydata->fatlength;
__u32 startblock = bufnum * FATBUFBLOCKS;
/* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
startblock += mydata->fat_sect; /* Offset from start of disk */
/* Write back the fatbuf to the disk */
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return ret;
}
mydata->fatbufnum = bufnum;
}
/* Get the actual entry from the table */
switch (mydata->fatsize) {
case 32:
ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
break;
case 16:
ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
break;
case 12:
off16 = (offset * 3) / 4;
switch (offset & 0x3) {
case 0:
ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
ret &= 0xfff;
break;
case 1:
val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
val1 &= 0xf000;
val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
val2 &= 0x00ff;
ret = (val2 << 4) | (val1 >> 12);
break;
case 2:
val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
val1 &= 0xff00;
val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
val2 &= 0x000f;
ret = (val2 << 8) | (val1 >> 8);
break;
case 3:
ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
ret = (ret & 0xfff0) >> 4;
break;
default:
break;
}
break;
}
debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
mydata->fatsize, ret, entry, offset);
return ret;
}
/*
* Set the file name information from 'name' into 'slotptr',
*/
static int str2slot(dir_slot *slotptr, const char *name, int *idx)
@ -407,7 +299,7 @@ get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
if ((__u8 *)slotptr >= buflimit) {
if (curclust == 0)
return -1;
curclust = get_fatent_value(mydata, dir_curclust);
curclust = get_fatent(mydata, dir_curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
@ -583,7 +475,7 @@ static __u32 determine_fatent(fsdata *mydata, __u32 entry)
__u32 next_fat, next_entry = entry + 1;
while (1) {
next_fat = get_fatent_value(mydata, next_entry);
next_fat = get_fatent(mydata, next_entry);
if (next_fat == 0) {
/* found free entry, link to entry */
set_fatent_value(mydata, entry, next_entry);
@ -669,7 +561,7 @@ static int find_empty_cluster(fsdata *mydata)
__u32 fat_val, entry = 3;
while (1) {
fat_val = get_fatent_value(mydata, entry);
fat_val = get_fatent(mydata, entry);
if (fat_val == 0)
break;
entry++;
@ -719,7 +611,7 @@ static int clear_fatent(fsdata *mydata, __u32 entry)
__u32 fat_val;
while (!CHECK_CLUST(entry, mydata->fatsize)) {
fat_val = get_fatent_value(mydata, entry);
fat_val = get_fatent(mydata, entry);
if (fat_val != 0)
set_fatent_value(mydata, entry, 0);
else
@ -996,7 +888,7 @@ static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
return NULL;
}
curclust = get_fatent_value(mydata, dir_curclust);
curclust = get_fatent(mydata, dir_curclust);
if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
empty_dentptr = dentptr;
return NULL;

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