fs/fat: merge readwrite get_fatent_value() with readonly get_fatent()
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>
This commit is contained in:
Stefan Brüns
Tom Rini
parent
6c1a808052
commit
b8948d2aef
25
fs/fat/fat.c
25
fs/fat/fat.c
@ -162,6 +162,16 @@ static void get_name(dir_entry *dirent, char *s_name)
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downcase(s_name);
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}
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static int flush_dirty_fat_buffer(fsdata *mydata);
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#if !defined(CONFIG_FAT_WRITE)
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/* Stub for read only operation */
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int flush_dirty_fat_buffer(fsdata *mydata)
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{
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(void)(mydata);
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return 0;
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}
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#endif
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/*
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* Get the entry at index 'entry' in a FAT (12/16/32) table.
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* On failure 0x00 is returned.
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@ -173,6 +183,11 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
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__u32 ret = 0x00;
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__u16 val1, val2;
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if (CHECK_CLUST(entry, mydata->fatsize)) {
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printf("Error: Invalid FAT entry: 0x%08x\n", entry);
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return ret;
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}
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switch (mydata->fatsize) {
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case 32:
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bufnum = entry / FAT32BUFSIZE;
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@ -192,7 +207,7 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
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return ret;
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}
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debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
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debug("FAT%d: entry: 0x%08x = %d, offset: 0x%04x = %d\n",
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mydata->fatsize, entry, entry, offset, offset);
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/* Read a new block of FAT entries into the cache. */
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@ -208,6 +223,10 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
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startblock += mydata->fat_sect; /* Offset from start of disk */
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/* Write back the fatbuf to the disk */
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if (flush_dirty_fat_buffer(mydata) < 0)
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return -1;
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if (disk_read(startblock, getsize, bufptr) < 0) {
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debug("Error reading FAT blocks\n");
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return ret;
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@ -254,8 +273,8 @@ static __u32 get_fatent(fsdata *mydata, __u32 entry)
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}
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break;
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}
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debug("FAT%d: ret: %08x, offset: %04x\n",
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mydata->fatsize, ret, offset);
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debug("FAT%d: ret: 0x%08x, entry: 0x%08x, offset: 0x%04x\n",
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mydata->fatsize, ret, entry, offset);
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return ret;
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}
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@ -142,114 +142,6 @@ static int flush_dirty_fat_buffer(fsdata *mydata)
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return 0;
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}
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/*
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* Get the entry at index 'entry' in a FAT (12/16/32) table.
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* On failure 0x00 is returned.
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* When bufnum is changed, write back the previous fatbuf to the disk.
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*/
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static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
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{
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__u32 bufnum;
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__u32 off16, offset;
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__u32 ret = 0x00;
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__u16 val1, val2;
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if (CHECK_CLUST(entry, mydata->fatsize)) {
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printf("Error: Invalid FAT entry: 0x%08x\n", entry);
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return ret;
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}
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switch (mydata->fatsize) {
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case 32:
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bufnum = entry / FAT32BUFSIZE;
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offset = entry - bufnum * FAT32BUFSIZE;
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break;
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case 16:
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bufnum = entry / FAT16BUFSIZE;
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offset = entry - bufnum * FAT16BUFSIZE;
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break;
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case 12:
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bufnum = entry / FAT12BUFSIZE;
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offset = entry - bufnum * FAT12BUFSIZE;
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break;
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default:
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/* Unsupported FAT size */
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return ret;
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}
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debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
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mydata->fatsize, entry, entry, offset, offset);
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/* Read a new block of FAT entries into the cache. */
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if (bufnum != mydata->fatbufnum) {
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int getsize = FATBUFBLOCKS;
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__u8 *bufptr = mydata->fatbuf;
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__u32 fatlength = mydata->fatlength;
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__u32 startblock = bufnum * FATBUFBLOCKS;
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/* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
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if (startblock + getsize > fatlength)
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getsize = fatlength - startblock;
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startblock += mydata->fat_sect; /* Offset from start of disk */
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/* Write back the fatbuf to the disk */
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if (flush_dirty_fat_buffer(mydata) < 0)
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return -1;
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if (disk_read(startblock, getsize, bufptr) < 0) {
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debug("Error reading FAT blocks\n");
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return ret;
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}
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mydata->fatbufnum = bufnum;
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}
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/* Get the actual entry from the table */
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switch (mydata->fatsize) {
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case 32:
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ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
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break;
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case 16:
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ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
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break;
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case 12:
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off16 = (offset * 3) / 4;
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switch (offset & 0x3) {
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case 0:
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ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
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ret &= 0xfff;
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break;
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case 1:
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val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
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val1 &= 0xf000;
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val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
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val2 &= 0x00ff;
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ret = (val2 << 4) | (val1 >> 12);
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break;
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case 2:
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val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
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val1 &= 0xff00;
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val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
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val2 &= 0x000f;
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ret = (val2 << 8) | (val1 >> 8);
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break;
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case 3:
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ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
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ret = (ret & 0xfff0) >> 4;
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break;
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default:
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break;
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}
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break;
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}
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debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
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mydata->fatsize, ret, entry, offset);
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return ret;
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}
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/*
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* Set the file name information from 'name' into 'slotptr',
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*/
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@ -407,7 +299,7 @@ get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
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if ((__u8 *)slotptr >= buflimit) {
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if (curclust == 0)
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return -1;
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curclust = get_fatent_value(mydata, dir_curclust);
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curclust = get_fatent(mydata, dir_curclust);
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if (CHECK_CLUST(curclust, mydata->fatsize)) {
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debug("curclust: 0x%x\n", curclust);
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printf("Invalid FAT entry\n");
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@ -583,7 +475,7 @@ static __u32 determine_fatent(fsdata *mydata, __u32 entry)
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__u32 next_fat, next_entry = entry + 1;
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while (1) {
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next_fat = get_fatent_value(mydata, next_entry);
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next_fat = get_fatent(mydata, next_entry);
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if (next_fat == 0) {
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/* found free entry, link to entry */
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set_fatent_value(mydata, entry, next_entry);
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@ -669,7 +561,7 @@ static int find_empty_cluster(fsdata *mydata)
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__u32 fat_val, entry = 3;
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while (1) {
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fat_val = get_fatent_value(mydata, entry);
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fat_val = get_fatent(mydata, entry);
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if (fat_val == 0)
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break;
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entry++;
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@ -719,7 +611,7 @@ static int clear_fatent(fsdata *mydata, __u32 entry)
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__u32 fat_val;
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while (!CHECK_CLUST(entry, mydata->fatsize)) {
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fat_val = get_fatent_value(mydata, entry);
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fat_val = get_fatent(mydata, entry);
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if (fat_val != 0)
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set_fatent_value(mydata, entry, 0);
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else
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@ -996,7 +888,7 @@ static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
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return NULL;
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}
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curclust = get_fatent_value(mydata, dir_curclust);
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curclust = get_fatent(mydata, dir_curclust);
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if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
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empty_dentptr = dentptr;
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return NULL;
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