fs: fat: support write with sub-directory path
authorAKASHI Takahiro <takahiro.akashi@linaro.org>
Tue, 11 Sep 2018 06:59:04 +0000 (15:59 +0900)
committerAlexander Graf <agraf@suse.de>
Sun, 23 Sep 2018 19:55:29 +0000 (21:55 +0200)
In this patch, write implementation is overhauled and rewritten by
making full use of directory iterator. The obvious bonus is that we are
now able to write to a file with a directory path, like /A/B/C/FILE.

Please note that, as there is no notion of "current directory" on u-boot,
a file name specified must contain an absolute directory path. Otherwise,
"/" (root directory) is assumed.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
fs/fat/fat.c
fs/fat/fat_write.c

index 8122fef..6d7012c 100644 (file)
@@ -465,15 +465,6 @@ static __u8 mkcksum(const char name[8], const char ext[3])
 }
 
 /*
- * TODO these should go away once fat_write is reworked to use the
- * directory iterator
- */
-__u8 get_dentfromdir_block[MAX_CLUSTSIZE]
-       __aligned(ARCH_DMA_MINALIGN);
-__u8 do_fat_read_at_block[MAX_CLUSTSIZE]
-       __aligned(ARCH_DMA_MINALIGN);
-
-/*
  * Read boot sector and volume info from a FAT filesystem
  */
 static int
index 1e4f5af..37ef056 100644 (file)
@@ -99,7 +99,6 @@ static void set_name(dir_entry *dirent, const char *filename)
        debug("ext : %s\n", dirent->ext);
 }
 
-static __u8 num_of_fats;
 /*
  * Write fat buffer into block device
  */
@@ -128,7 +127,7 @@ static int flush_dirty_fat_buffer(fsdata *mydata)
                return -1;
        }
 
-       if (num_of_fats == 2) {
+       if (mydata->fats == 2) {
                /* Update corresponding second FAT blocks */
                startblock += mydata->fatlength;
                if (disk_write(startblock, getsize, bufptr) < 0) {
@@ -210,15 +209,14 @@ name11_12:
        return 1;
 }
 
-static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
-static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
+static int flush_dir_table(fat_itr *itr);
 
 /*
  * Fill dir_slot entries with appropriate name, id, and attr
- * The real directory entry is returned by 'dentptr'
+ * 'itr' will point to a next entry
  */
-static void
-fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
+static int
+fill_dir_slot(fat_itr *itr, const char *l_name)
 {
        __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
        dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
@@ -226,7 +224,7 @@ fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
        int idx = 0, ret;
 
        /* Get short file name checksum value */
-       checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
+       checksum = mkcksum(itr->dent->name, itr->dent->ext);
 
        do {
                memset(slotptr, 0x00, sizeof(dir_slot));
@@ -241,120 +239,21 @@ fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
        slotptr->id |= LAST_LONG_ENTRY_MASK;
 
        while (counter >= 1) {
-               if (is_next_clust(mydata, *dentptr)) {
-                       /* A new cluster is allocated for directory table */
-                       flush_dir_table(mydata, dentptr);
-               }
-               memcpy(*dentptr, slotptr, sizeof(dir_slot));
-               (*dentptr)++;
+               memcpy(itr->dent, slotptr, sizeof(dir_slot));
                slotptr--;
                counter--;
-       }
-
-       if (is_next_clust(mydata, *dentptr)) {
-               /* A new cluster is allocated for directory table */
-               flush_dir_table(mydata, dentptr);
-       }
-}
-
-static __u32 dir_curclust;
-
-/*
- * Extract the full long filename starting at 'retdent' (which is really
- * a slot) into 'l_name'. If successful also copy the real directory entry
- * into 'retdent'
- * If additional adjacent cluster for directory entries is read into memory,
- * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
- * the location of the real directory entry is returned by 'retdent'
- * Return 0 on success, -1 otherwise.
- */
-static int
-get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
-             dir_entry **retdent, char *l_name)
-{
-       dir_entry *realdent;
-       dir_slot *slotptr = (dir_slot *)(*retdent);
-       dir_slot *slotptr2 = NULL;
-       __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
-                                                       PREFETCH_BLOCKS :
-                                                       mydata->clust_size);
-       __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
-       int idx = 0, cur_position = 0;
-
-       if (counter > VFAT_MAXSEQ) {
-               debug("Error: VFAT name is too long\n");
-               return -1;
-       }
-
-       while ((__u8 *)slotptr < buflimit) {
-               if (counter == 0)
-                       break;
-               if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
-                       return -1;
-               slotptr++;
-               counter--;
-       }
-
-       if ((__u8 *)slotptr >= buflimit) {
-               if (curclust == 0)
-                       return -1;
-               curclust = get_fatent(mydata, dir_curclust);
-               if (CHECK_CLUST(curclust, mydata->fatsize)) {
-                       debug("curclust: 0x%x\n", curclust);
-                       printf("Invalid FAT entry\n");
-                       return -1;
-               }
-
-               dir_curclust = curclust;
-
-               if (get_cluster(mydata, curclust, get_contents_vfatname_block,
-                               mydata->clust_size * mydata->sect_size) != 0) {
-                       debug("Error: reading directory block\n");
-                       return -1;
-               }
-
-               slotptr2 = (dir_slot *)get_contents_vfatname_block;
-               while (counter > 0) {
-                       if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
-                           & 0xff) != counter)
+               if (!fat_itr_next(itr))
+                       if (!itr->dent && !itr->is_root && flush_dir_table(itr))
                                return -1;
-                       slotptr2++;
-                       counter--;
-               }
-
-               /* Save the real directory entry */
-               realdent = (dir_entry *)slotptr2;
-               while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
-                       slotptr2--;
-                       slot2str(slotptr2, l_name, &idx);
-               }
-       } else {
-               /* Save the real directory entry */
-               realdent = (dir_entry *)slotptr;
        }
 
-       do {
-               slotptr--;
-               if (slot2str(slotptr, l_name, &idx))
-                       break;
-       } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
-
-       l_name[idx] = '\0';
-       if (*l_name == DELETED_FLAG)
-               *l_name = '\0';
-       else if (*l_name == aRING)
-               *l_name = DELETED_FLAG;
-       downcase(l_name, INT_MAX);
-
-       /* Return the real directory entry */
-       *retdent = realdent;
-
-       if (slotptr2) {
-               memcpy(get_dentfromdir_block, get_contents_vfatname_block,
-                       mydata->clust_size * mydata->sect_size);
-               cur_position = (__u8 *)realdent - get_contents_vfatname_block;
-               *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
-       }
+       if (!itr->dent && !itr->is_root)
+               /*
+                * don't care return value here because we have already
+                * finished completing an entry with name, only ending up
+                * no more entry left
+                */
+               flush_dir_table(itr);
 
        return 0;
 }
@@ -569,20 +468,20 @@ static int find_empty_cluster(fsdata *mydata)
 }
 
 /*
- * Write directory entries in 'get_dentfromdir_block' to block device
+ * Write directory entries in itr's buffer to block device
  */
-static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
+static int flush_dir_table(fat_itr *itr)
 {
+       fsdata *mydata = itr->fsdata;
        int dir_newclust = 0;
+       unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 
-       if (set_cluster(mydata, dir_curclust,
-                   get_dentfromdir_block,
-                   mydata->clust_size * mydata->sect_size) != 0) {
-               printf("error: wrinting directory entry\n");
-               return;
+       if (set_cluster(mydata, itr->clust, itr->block, bytesperclust) != 0) {
+               printf("error: writing directory entry\n");
+               return -1;
        }
        dir_newclust = find_empty_cluster(mydata);
-       set_fatent_value(mydata, dir_curclust, dir_newclust);
+       set_fatent_value(mydata, itr->clust, dir_newclust);
        if (mydata->fatsize == 32)
                set_fatent_value(mydata, dir_newclust, 0xffffff8);
        else if (mydata->fatsize == 16)
@@ -590,15 +489,19 @@ static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
        else if (mydata->fatsize == 12)
                set_fatent_value(mydata, dir_newclust, 0xff8);
 
-       dir_curclust = dir_newclust;
+       itr->clust = dir_newclust;
+       itr->next_clust = dir_newclust;
 
        if (flush_dirty_fat_buffer(mydata) < 0)
-               return;
+               return -1;
+
+       memset(itr->block, 0x00, bytesperclust);
 
-       memset(get_dentfromdir_block, 0x00,
-               mydata->clust_size * mydata->sect_size);
+       itr->dent = (dir_entry *)itr->block;
+       itr->last_cluster = 1;
+       itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
 
-       *dentptr = (dir_entry *) get_dentfromdir_block;
+       return 0;
 }
 
 /*
@@ -765,138 +668,82 @@ static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 }
 
 /*
- * Check if adding several entries exceed one cluster boundary
- */
-static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
-{
-       int cur_position;
-
-       cur_position = (__u8 *)dentptr - get_dentfromdir_block;
-
-       if (cur_position >= mydata->clust_size * mydata->sect_size)
-               return 1;
-       else
-               return 0;
-}
-
-static dir_entry *empty_dentptr;
-/*
  * Find a directory entry based on filename or start cluster number
  * If the directory entry is not found,
  * the new position for writing a directory entry will be returned
  */
-static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
-       char *filename, dir_entry *retdent, __u32 start)
+static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 {
-       __u32 curclust = sect_to_clust(mydata, startsect);
-
-       debug("get_dentfromdir: %s\n", filename);
+       int match = 0;
 
-       while (1) {
-               dir_entry *dentptr;
+       while (fat_itr_next(itr)) {
+               /* check both long and short name: */
+               if (!strcasecmp(filename, itr->name))
+                       match = 1;
+               else if (itr->name != itr->s_name &&
+                        !strcasecmp(filename, itr->s_name))
+                       match = 1;
 
-               int i;
+               if (!match)
+                       continue;
 
-               if (get_cluster(mydata, curclust, get_dentfromdir_block,
-                           mydata->clust_size * mydata->sect_size) != 0) {
-                       printf("Error: reading directory block\n");
+               if (itr->dent->name[0] == '\0')
                        return NULL;
-               }
-
-               dentptr = (dir_entry *)get_dentfromdir_block;
-
-               dir_curclust = curclust;
-
-               for (i = 0; i < DIRENTSPERCLUST; i++) {
-                       char s_name[14], l_name[VFAT_MAXLEN_BYTES];
-
-                       l_name[0] = '\0';
-                       if (dentptr->name[0] == DELETED_FLAG) {
-                               dentptr++;
-                               if (is_next_clust(mydata, dentptr))
-                                       break;
-                               continue;
-                       }
-                       if ((dentptr->attr & ATTR_VOLUME)) {
-                               if ((dentptr->attr & ATTR_VFAT) &&
-                                   (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
-                                       get_long_file_name(mydata, curclust,
-                                                    get_dentfromdir_block,
-                                                    &dentptr, l_name);
-                                       debug("vfatname: |%s|\n", l_name);
-                               } else {
-                                       /* Volume label or VFAT entry */
-                                       dentptr++;
-                                       if (is_next_clust(mydata, dentptr))
-                                               break;
-                                       continue;
-                               }
-                       }
-                       if (dentptr->name[0] == 0) {
-                               debug("Dentname == NULL - %d\n", i);
-                               empty_dentptr = dentptr;
-                               return NULL;
-                       }
-
-                       get_name(dentptr, s_name);
-
-                       if (strncasecmp(filename, s_name, sizeof(s_name)) &&
-                           strncasecmp(filename, l_name, sizeof(l_name))) {
-                               debug("Mismatch: |%s|%s|\n",
-                                       s_name, l_name);
-                               dentptr++;
-                               if (is_next_clust(mydata, dentptr))
-                                       break;
-                               continue;
-                       }
+               else
+                       return itr->dent;
+       }
 
-                       memcpy(retdent, dentptr, sizeof(dir_entry));
+       if (!itr->dent && !itr->is_root && flush_dir_table(itr))
+               /* indicate that allocating dent failed */
+               itr->dent = NULL;
 
-                       debug("DentName: %s", s_name);
-                       debug(", start: 0x%x", START(dentptr));
-                       debug(", size:  0x%x %s\n",
-                             FAT2CPU32(dentptr->size),
-                             (dentptr->attr & ATTR_DIR) ?
-                             "(DIR)" : "");
+       return NULL;
+}
 
-                       return dentptr;
+static int split_filename(char *filename, char **dirname, char **basename)
+{
+       char *p, *last_slash, *last_slash_cont;
+
+again:
+       p = filename;
+       last_slash = NULL;
+       last_slash_cont = NULL;
+       while (*p) {
+               if (ISDIRDELIM(*p)) {
+                       last_slash = p;
+                       last_slash_cont = p;
+                       /* continuous slashes */
+                       while (ISDIRDELIM(*p))
+                               last_slash_cont = p++;
+                       if (!*p)
+                               break;
                }
+               p++;
+       }
 
-               /*
-                * In FAT16/12, the root dir is locate before data area, shows
-                * in following:
-                * -------------------------------------------------------------
-                * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
-                * -------------------------------------------------------------
-                *
-                * As a result if curclust is in Root dir, it is a negative
-                * number or 0, 1.
-                *
-                */
-               if (mydata->fatsize != 32 && (int)curclust <= 1) {
-                       /* Current clust is in root dir, set to next clust */
-                       curclust++;
-                       if ((int)curclust <= 1)
-                               continue;       /* continue to find */
-
-                       /* Reach the end of root dir */
-                       empty_dentptr = dentptr;
-                       return NULL;
+       if (last_slash) {
+               if (last_slash_cont == (filename + strlen(filename) - 1)) {
+                       /* remove trailing slashes */
+                       *last_slash = '\0';
+                       goto again;
                }
 
-               curclust = get_fatent(mydata, dir_curclust);
-               if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
-                       empty_dentptr = dentptr;
-                       return NULL;
-               }
-               if (CHECK_CLUST(curclust, mydata->fatsize)) {
-                       debug("curclust: 0x%x\n", curclust);
-                       debug("Invalid FAT entry\n");
-                       return NULL;
+               if (last_slash == filename) {
+                       /* avoid ""(null) directory */
+                       *dirname = "/";
+               } else {
+                       *last_slash = '\0';
+                       *dirname = filename;
                }
+
+               *last_slash_cont = '\0';
+               *basename = last_slash_cont + 1;
+       } else {
+               *dirname = "/"; /* root by default */
+               *basename = filename;
        }
 
-       return NULL;
+       return 0;
 }
 
 static int normalize_longname(char *l_filename, const char *filename)
@@ -940,86 +787,58 @@ static int normalize_longname(char *l_filename, const char *filename)
 static int do_fat_write(const char *filename, void *buffer, loff_t size,
                        loff_t *actwrite)
 {
-       dir_entry *dentptr, *retdent;
-       __u32 startsect;
+       dir_entry *retdent;
        __u32 start_cluster;
-       boot_sector bs;
-       volume_info volinfo;
-       fsdata datablock;
+       fsdata datablock = { .fatbuf = NULL, };
        fsdata *mydata = &datablock;
-       int cursect;
+       fat_itr *itr = NULL;
        int ret = -1;
+       char *filename_copy, *parent, *basename;
        char l_filename[VFAT_MAXLEN_BYTES];
 
-       *actwrite = size;
-       dir_curclust = 0;
+       filename_copy = strdup(filename);
+       if (!filename_copy)
+               return -ENOMEM;
 
-       if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
-               debug("error: reading boot sector\n");
-               return -EIO;
+       split_filename(filename_copy, &parent, &basename);
+       if (!strlen(basename)) {
+               ret = -EINVAL;
+               goto exit;
        }
 
-       total_sector = bs.total_sect;
-       if (total_sector == 0)
-               total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
-
-       if (mydata->fatsize == 32)
-               mydata->fatlength = bs.fat32_length;
-       else
-               mydata->fatlength = bs.fat_length;
-
-       mydata->fat_sect = bs.reserved;
-
-       cursect = mydata->rootdir_sect
-               = mydata->fat_sect + mydata->fatlength * bs.fats;
-       num_of_fats = bs.fats;
-
-       mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
-       mydata->clust_size = bs.cluster_size;
-
-       if (mydata->fatsize == 32) {
-               mydata->data_begin = mydata->rootdir_sect -
-                                       (mydata->clust_size * 2);
-       } else {
-               int rootdir_size;
-
-               rootdir_size = ((bs.dir_entries[1]  * (int)256 +
-                                bs.dir_entries[0]) *
-                                sizeof(dir_entry)) /
-                                mydata->sect_size;
-               mydata->data_begin = mydata->rootdir_sect +
-                                       rootdir_size -
-                                       (mydata->clust_size * 2);
+       filename = basename;
+       if (normalize_longname(l_filename, filename)) {
+               printf("FAT: illegal filename (%s)\n", filename);
+               ret = -EINVAL;
+               goto exit;
        }
 
-       mydata->fatbufnum = -1;
-       mydata->fat_dirty = 0;
-       mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
-       if (mydata->fatbuf == NULL) {
-               debug("Error: allocating memory\n");
-               return -ENOMEM;
+       itr = malloc_cache_aligned(sizeof(fat_itr));
+       if (!itr) {
+               ret = -ENOMEM;
+               goto exit;
        }
 
-       if (disk_read(cursect,
-               (mydata->fatsize == 32) ?
-               (mydata->clust_size) :
-               PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
-               debug("Error: reading rootdir block\n");
-               ret = -EIO;
+       ret = fat_itr_root(itr, &datablock);
+       if (ret)
                goto exit;
-       }
-       dentptr = (dir_entry *) do_fat_read_at_block;
 
-       if (normalize_longname(l_filename, filename)) {
-               printf("FAT: illegal filename (%s)\n", filename);
-               ret = -EINVAL;
+       total_sector = datablock.total_sect;
+
+       ret = fat_itr_resolve(itr, parent, TYPE_DIR);
+       if (ret) {
+               printf("%s: doesn't exist (%d)\n", parent, ret);
                goto exit;
        }
 
-       startsect = mydata->rootdir_sect;
-       retdent = find_directory_entry(mydata, startsect,
-                               l_filename, dentptr, 0);
+       retdent = find_directory_entry(itr, l_filename);
+
        if (retdent) {
+               if (fat_itr_isdir(itr)) {
+                       ret = -EISDIR;
+                       goto exit;
+               }
+
                /* Update file size and start_cluster in a directory entry */
                retdent->size = cpu_to_le32(size);
                start_cluster = START(retdent);
@@ -1062,9 +881,31 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
                        set_start_cluster(mydata, retdent, start_cluster);
                }
        } else {
+               /* Create a new file */
+
+               if (itr->is_root) {
+                       /* root dir cannot have "." or ".." */
+                       if (!strcmp(l_filename, ".") ||
+                           !strcmp(l_filename, "..")) {
+                               ret = -EINVAL;
+                               goto exit;
+                       }
+               }
+
+               if (!itr->dent) {
+                       printf("Error: allocating new dir entry\n");
+                       ret = -EIO;
+                       goto exit;
+               }
+
+               memset(itr->dent, 0, sizeof(*itr->dent));
+
                /* Set short name to set alias checksum field in dir_slot */
-               set_name(empty_dentptr, filename);
-               fill_dir_slot(mydata, &empty_dentptr, filename);
+               set_name(itr->dent, filename);
+               if (fill_dir_slot(itr, filename)) {
+                       ret = -EIO;
+                       goto exit;
+               }
 
                if (size) {
                        ret = start_cluster = find_empty_cluster(mydata);
@@ -1084,11 +925,11 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
                        start_cluster = 0;
                }
 
-               /* Set attribute as archieve for regular file */
-               fill_dentry(mydata, empty_dentptr, filename,
-                       start_cluster, size, 0x20);
+               /* Set attribute as archive for regular file */
+               fill_dentry(itr->fsdata, itr->dent, filename,
+                           start_cluster, size, 0x20);
 
-               retdent = empty_dentptr;
+               retdent = itr->dent;
        }
 
        ret = set_contents(mydata, retdent, buffer, size, actwrite);
@@ -1108,15 +949,17 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
        }
 
        /* Write directory table to device */
-       ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
-                       mydata->clust_size * mydata->sect_size);
+       ret = set_cluster(mydata, itr->clust, itr->block,
+                         mydata->clust_size * mydata->sect_size);
        if (ret) {
                printf("Error: writing directory entry\n");
                ret = -EIO;
        }
 
 exit:
+       free(filename_copy);
        free(mydata->fatbuf);
+       free(itr);
        return ret;
 }