udf: Cleanup volume descriptor sequence processing

Cleanup processing of volume descriptor sequence so that it is more readable,
make code handle errors (e.g. media problems) better.

Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 137153c..500d1e4 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -85,16 +85,12 @@ static int udf_remount_fs(struct super_block *, int *, char *);
 static int udf_check_valid(struct super_block *, int, int);
 static int udf_vrs(struct super_block *sb, int silent);
 static int udf_load_partition(struct super_block *, kernel_lb_addr *);
-static int udf_load_logicalvol(struct super_block *, struct buffer_head *,
-                              kernel_lb_addr *);
 static void udf_load_logicalvolint(struct super_block *, kernel_extent_ad);
 static void udf_find_anchor(struct super_block *);
 static int udf_find_fileset(struct super_block *, kernel_lb_addr *,
                            kernel_lb_addr *);
-static void udf_load_pvoldesc(struct super_block *, struct buffer_head *);
 static void udf_load_fileset(struct super_block *, struct buffer_head *,
                             kernel_lb_addr *);
-static int udf_load_partdesc(struct super_block *, struct buffer_head *);
 static void udf_open_lvid(struct super_block *);
 static void udf_close_lvid(struct super_block *);
 static unsigned int udf_count_free(struct super_block *);
@@ -935,11 +931,18 @@ static int udf_find_fileset(struct super_block *sb,
        return 1;
 }
 
-static void udf_load_pvoldesc(struct super_block *sb, struct buffer_head *bh)
+static int udf_load_pvoldesc(struct super_block *sb, sector_t block)
 {
        struct primaryVolDesc *pvoldesc;
        struct ustr instr;
        struct ustr outstr;
+       struct buffer_head *bh;
+       uint16_t ident;
+
+       bh = udf_read_tagged(sb, block, block, &ident);
+       if (!bh)
+               return 1;
+       BUG_ON(ident != TAG_IDENT_PVD);
 
        pvoldesc = (struct primaryVolDesc *)bh->b_data;
 
@@ -965,6 +968,9 @@ static void udf_load_pvoldesc(struct super_block *sb, struct buffer_head *bh)
        if (!udf_build_ustr(&instr, pvoldesc->volSetIdent, 128))
                if (udf_CS0toUTF8(&outstr, &instr))
                        udf_debug("volSetIdent[] = '%s'\n", outstr.u_name);
+
+       brelse(bh);
+       return 0;
 }
 
 static void udf_load_fileset(struct super_block *sb, struct buffer_head *bh,
@@ -1018,16 +1024,27 @@ static struct udf_bitmap *udf_sb_alloc_bitmap(struct super_block *sb, u32 index)
        return bitmap;
 }
 
-static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
+static int udf_load_partdesc(struct super_block *sb, sector_t block)
 {
+       struct buffer_head *bh;
        struct partitionHeaderDesc *phd;
-       struct partitionDesc *p = (struct partitionDesc *)bh->b_data;
+       struct partitionDesc *p;
        struct udf_part_map *map;
        struct udf_sb_info *sbi = UDF_SB(sb);
        bool found = false;
        int i;
-       u16 partitionNumber = le16_to_cpu(p->partitionNumber);
+       uint16_t partitionNumber;
+       uint16_t ident;
+       int ret = 0;
+
+       bh = udf_read_tagged(sb, block, block, &ident);
+       if (!bh)
+               return 1;
+       if (ident != TAG_IDENT_PD)
+               goto out_bh;
 
+       p = (struct partitionDesc *)bh->b_data;
+       partitionNumber = le16_to_cpu(p->partitionNumber);
        for (i = 0; i < sbi->s_partitions; i++) {
                map = &sbi->s_partmaps[i];
                udf_debug("Searching map: (%d == %d)\n",
@@ -1040,7 +1057,7 @@ static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
        if (!found) {
                udf_debug("Partition (%d) not found in partition map\n",
                          partitionNumber);
-               return 0;
+               goto out_bh;
        }
 
        map->s_partition_len = le32_to_cpu(p->partitionLength); /* blocks */
@@ -1062,7 +1079,7 @@ static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
 
        if (strcmp(p->partitionContents.ident, PD_PARTITION_CONTENTS_NSR02) &&
            strcmp(p->partitionContents.ident, PD_PARTITION_CONTENTS_NSR03))
-               return 0;
+               goto out_bh;
 
        phd = (struct partitionHeaderDesc *)p->partitionContentsUse;
        if (phd->unallocSpaceTable.extLength) {
@@ -1076,7 +1093,8 @@ static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
                if (!map->s_uspace.s_table) {
                        udf_debug("cannot load unallocSpaceTable (part %d)\n",
                                        i);
-                       return 1;
+                       ret = 1;
+                       goto out_bh;
                }
                map->s_partition_flags |= UDF_PART_FLAG_UNALLOC_TABLE;
                udf_debug("unallocSpaceTable (part %d) @ %ld\n",
@@ -1110,7 +1128,8 @@ static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
                map->s_fspace.s_table = udf_iget(sb, loc);
                if (!map->s_fspace.s_table) {
                        udf_debug("cannot load freedSpaceTable (part %d)\n", i);
-                       return 1;
+                       ret = 1;
+                       goto out_bh;
                }
 
                map->s_partition_flags |= UDF_PART_FLAG_FREED_TABLE;
@@ -1132,10 +1151,12 @@ static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
                }
        }
 
-       return 0;
+out_bh:
+       brelse(bh);
+       return ret;
 }
 
-static int udf_load_logicalvol(struct super_block *sb, struct buffer_head *bh,
+static int udf_load_logicalvol(struct super_block *sb, sector_t block,
                               kernel_lb_addr *fileset)
 {
        struct logicalVolDesc *lvd;
@@ -1143,12 +1164,21 @@ static int udf_load_logicalvol(struct super_block *sb, struct buffer_head *bh,
        uint8_t type;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct genericPartitionMap *gpm;
+       uint16_t ident;
+       struct buffer_head *bh;
+       int ret = 0;
 
+       bh = udf_read_tagged(sb, block, block, &ident);
+       if (!bh)
+               return 1;
+       BUG_ON(ident != TAG_IDENT_LVD);
        lvd = (struct logicalVolDesc *)bh->b_data;
 
        i = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
-       if (i != 0)
-               return i;
+       if (i != 0) {
+               ret = i;
+               goto out_bh;
+       }
 
        for (i = 0, offset = 0;
             i < sbi->s_partitions && offset < le32_to_cpu(lvd->mapTableLength);
@@ -1187,7 +1217,6 @@ static int udf_load_logicalvol(struct super_block *sb, struct buffer_head *bh,
                                                UDF_ID_SPARABLE,
                                                strlen(UDF_ID_SPARABLE))) {
                                uint32_t loc;
-                               uint16_t ident;
                                struct sparingTable *st;
                                struct sparablePartitionMap *spm =
                                        (struct sparablePartitionMap *)gpm;
@@ -1243,7 +1272,9 @@ static int udf_load_logicalvol(struct super_block *sb, struct buffer_head *bh,
        if (lvd->integritySeqExt.extLength)
                udf_load_logicalvolint(sb, leea_to_cpu(lvd->integritySeqExt));
 
-       return 0;
+out_bh:
+       brelse(bh);
+       return ret;
 }
 
 /*
@@ -1301,19 +1332,25 @@ static noinline int udf_process_sequence(struct super_block *sb, long block,
        struct generic_desc *gd;
        struct volDescPtr *vdp;
        int done = 0;
-       int i, j;
        uint32_t vdsn;
        uint16_t ident;
        long next_s = 0, next_e = 0;
 
        memset(vds, 0, sizeof(struct udf_vds_record) * VDS_POS_LENGTH);
 
-       /* Read the main descriptor sequence */
+       /*
+        * Read the main descriptor sequence and find which descriptors
+        * are in it.
+        */
        for (; (!done && block <= lastblock); block++) {
 
                bh = udf_read_tagged(sb, block, block, &ident);
-               if (!bh)
-                       break;
+               if (!bh) {
+                       printk(KERN_ERR "udf: Block %Lu of volume descriptor "
+                              "sequence is corrupted or we could not read "
+                              "it.\n", (unsigned long long)block);
+                       return 1;
+               }
 
                /* Process each descriptor (ISO 13346 3/8.3-8.4) */
                gd = (struct generic_desc *)bh->b_data;
@@ -1379,41 +1416,31 @@ static noinline int udf_process_sequence(struct super_block *sb, long block,
                }
                brelse(bh);
        }
-       for (i = 0; i < VDS_POS_LENGTH; i++) {
-               if (!vds[i].block)
-                       continue;
+       /*
+        * Now read interesting descriptors again and process them
+        * in a suitable order
+        */
+       if (!vds[VDS_POS_PRIMARY_VOL_DESC].block) {
+               printk(KERN_ERR "udf: Primary Volume Descriptor not found!\n");
+               return 1;
+       }
+       if (udf_load_pvoldesc(sb, vds[VDS_POS_PRIMARY_VOL_DESC].block))
+               return 1;
 
-               bh = udf_read_tagged(sb, vds[i].block, vds[i].block,
-                                       &ident);
+       if (vds[VDS_POS_LOGICAL_VOL_DESC].block && udf_load_logicalvol(sb,
+           vds[VDS_POS_LOGICAL_VOL_DESC].block, fileset))
+               return 1;
 
-               if (i == VDS_POS_PRIMARY_VOL_DESC)
-                       udf_load_pvoldesc(sb, bh);
-               else if (i == VDS_POS_LOGICAL_VOL_DESC) {
-                       if (udf_load_logicalvol(sb, bh, fileset)) {
-                               brelse(bh);
+       if (vds[VDS_POS_PARTITION_DESC].block) {
+               /*
+                * We rescan the whole descriptor sequence to find
+                * partition descriptor blocks and process them.
+                */
+               for (block = vds[VDS_POS_PARTITION_DESC].block;
+                    block < vds[VDS_POS_TERMINATING_DESC].block;
+                    block++)
+                       if (udf_load_partdesc(sb, block))
                                return 1;
-                       }
-               } else if (i == VDS_POS_PARTITION_DESC) {
-                       struct buffer_head *bh2 = NULL;
-                       if (udf_load_partdesc(sb, bh)) {
-                               brelse(bh);
-                               return 1;
-                       }
-                       for (j = vds[i].block + 1;
-                               j <  vds[VDS_POS_TERMINATING_DESC].block;
-                               j++) {
-                               bh2 = udf_read_tagged(sb, j, j, &ident);
-                               gd = (struct generic_desc *)bh2->b_data;
-                               if (ident == TAG_IDENT_PD)
-                                       if (udf_load_partdesc(sb, bh2)) {
-                                               brelse(bh);
-                                               brelse(bh2);
-                                               return 1;
-                                       }
-                               brelse(bh2);
-                       }
-               }
-               brelse(bh);
        }
 
        return 0;