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libext2fs: Byte-swap 64-bit block group descriptors
[tools/e2fsprogs.git] / lib / ext2fs / openfs.c
index b0b433f..7b325a1 100644 (file)
@@ -1,8 +1,8 @@
 /*
  * openfs.c --- open an ext2 filesystem
- * 
+ *
  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
- * 
+ *
  * %Begin-Header%
  * This file may be redistributed under the terms of the GNU Public
  * License.
 #include <sys/types.h>
 #endif
 
-#if EXT2_FLAT_INCLUDES
 #include "ext2_fs.h"
-#else
-#include <linux/ext2_fs.h>
-#endif
+
 
 #include "ext2fs.h"
+#include "e2image.h"
+
+blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block,
+                                    dgrp_t i)
+{
+       int     bg;
+       int     has_super = 0;
+       blk64_t ret_blk;
+
+       if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
+           (i < fs->super->s_first_meta_bg))
+               return (group_block + i + 1);
+
+       bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
+       if (ext2fs_bg_has_super(fs, bg))
+               has_super = 1;
+       ret_blk = ext2fs_group_first_block2(fs, bg) + has_super;
+       /*
+        * If group_block is not the normal value, we're trying to use
+        * the backup group descriptors and superblock --- so use the
+        * alternate location of the second block group in the
+        * metablock group.  Ideally we should be testing each bg
+        * descriptor block individually for correctness, but we don't
+        * have the infrastructure in place to do that.
+        */
+       if (group_block != fs->super->s_first_data_block &&
+           ((ret_blk + fs->super->s_blocks_per_group) <
+            ext2fs_blocks_count(fs->super)))
+               ret_blk += fs->super->s_blocks_per_group;
+       return ret_blk;
+}
+
+blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
+{
+       return ext2fs_descriptor_block_loc2(fs, group_block, i);
+}
+
+errcode_t ext2fs_open(const char *name, int flags, int superblock,
+                     unsigned int block_size, io_manager manager,
+                     ext2_filsys *ret_fs)
+{
+       return ext2fs_open2(name, 0, flags, superblock, block_size,
+                           manager, ret_fs);
+}
 
 /*
  *  Note: if superblock is non-zero, block-size must also be non-zero.
  *     Superblock and block_size can be zero to use the default size.
  *
  * Valid flags for ext2fs_open()
- * 
+ *
  *     EXT2_FLAG_RW    - Open the filesystem for read/write.
  *     EXT2_FLAG_FORCE - Open the filesystem even if some of the
- *                             features aren't supported.
+ *                             features aren't supported.
+ *     EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
  */
-errcode_t ext2fs_open(const char *name, int flags, int superblock,
-                     int block_size, io_manager manager, ext2_filsys *ret_fs)
+errcode_t ext2fs_open2(const char *name, const char *io_options,
+                      int flags, int superblock,
+                      unsigned int block_size, io_manager manager,
+                      ext2_filsys *ret_fs)
 {
        ext2_filsys     fs;
        errcode_t       retval;
-       int             i, j, groups_per_block;
-       blk_t           group_block;
-       char            *dest;
+       unsigned long   i, first_meta_bg;
+       __u32           features;
+       int             groups_per_block, blocks_per_group, io_flags;
+       blk_t           group_block, blk;
+       char            *dest, *cp;
+#ifdef WORDS_BIGENDIAN
        struct ext2_group_desc *gdp;
-       struct ext2fs_sb        *s;
-       
+       int             j;
+#endif
+
        EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
 
-       retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
-                               (void **) &fs);
+       retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
        if (retval)
                return retval;
-       
+
        memset(fs, 0, sizeof(struct struct_ext2_filsys));
        fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
        fs->flags = flags;
-       retval = manager->open(name, (flags & EXT2_FLAG_RW) ? IO_FLAG_RW : 0,
-                              &fs->io);
+       /* don't overwrite sb backups unless flag is explicitly cleared */
+       fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
+       fs->umask = 022;
+       retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
        if (retval)
                goto cleanup;
-       fs->io->app_data = fs;
-       retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
+       strcpy(fs->device_name, name);
+       cp = strchr(fs->device_name, '?');
+       if (!io_options && cp) {
+               *cp++ = 0;
+               io_options = cp;
+       }
+
+       io_flags = 0;
+       if (flags & EXT2_FLAG_RW)
+               io_flags |= IO_FLAG_RW;
+       if (flags & EXT2_FLAG_EXCLUSIVE)
+               io_flags |= IO_FLAG_EXCLUSIVE;
+       retval = manager->open(fs->device_name, io_flags, &fs->io);
        if (retval)
                goto cleanup;
-       strcpy(fs->device_name, name);
-       retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &fs->super);
+       if (io_options &&
+           (retval = io_channel_set_options(fs->io, io_options)))
+               goto cleanup;
+       fs->image_io = fs->io;
+       fs->io->app_data = fs;
+       retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);
        if (retval)
                goto cleanup;
+       if (flags & EXT2_FLAG_IMAGE_FILE) {
+               retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
+                                       &fs->image_header);
+               if (retval)
+                       goto cleanup;
+               retval = io_channel_read_blk(fs->io, 0,
+                                            -(int)sizeof(struct ext2_image_hdr),
+                                            fs->image_header);
+               if (retval)
+                       goto cleanup;
+               if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
+                       return EXT2_ET_MAGIC_E2IMAGE;
+               superblock = 1;
+               block_size = fs->image_header->fs_blocksize;
+       }
 
        /*
         * If the user specifies a specific block # for the
         * superblock, then he/she must also specify the block size!
         * Otherwise, read the master superblock located at offset
         * SUPERBLOCK_OFFSET from the start of the partition.
+        *
+        * Note: we only save a backup copy of the superblock if we
+        * are reading the superblock from the primary superblock location.
         */
        if (superblock) {
                if (!block_size) {
@@ -87,65 +169,87 @@ errcode_t ext2fs_open(const char *name, int flags, int superblock,
                        goto cleanup;
                }
                io_channel_set_blksize(fs->io, block_size);
-               group_block = superblock + 1;
+               group_block = superblock;
+               fs->orig_super = 0;
        } else {
                io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
                superblock = 1;
                group_block = 0;
+               retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
+               if (retval)
+                       goto cleanup;
        }
        retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
                                     fs->super);
        if (retval)
                goto cleanup;
+       if (fs->orig_super)
+               memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
 
-       if ((fs->super->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) ||
-           (fs->flags & EXT2_FLAG_SWAP_BYTES)) {
-               fs->flags |= EXT2_FLAG_SWAP_BYTES;
-
-               ext2fs_swap_super(fs->super);
+#ifdef WORDS_BIGENDIAN
+       fs->flags |= EXT2_FLAG_SWAP_BYTES;
+       ext2fs_swap_super(fs->super);
+#else
+       if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
+               retval = EXT2_ET_UNIMPLEMENTED;
+               goto cleanup;
        }
-       
+#endif
+
        if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
                retval = EXT2_ET_BAD_MAGIC;
                goto cleanup;
        }
-#ifdef EXT2_DYNAMIC_REV
-       if (fs->super->s_rev_level > EXT2_DYNAMIC_REV) {
-               retval = EXT2_ET_REV_TOO_HIGH;
-               goto cleanup;
-       }
-#else
-#ifdef EXT2_CURRENT_REV
        if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
                retval = EXT2_ET_REV_TOO_HIGH;
                goto cleanup;
        }
-#endif
-#endif
+
        /*
         * Check for feature set incompatibility
         */
        if (!(flags & EXT2_FLAG_FORCE)) {
-               s = (struct ext2fs_sb *) fs->super;
-               if (s->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
+               features = fs->super->s_feature_incompat;
+#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
+               if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
+                       features &= !EXT2_LIB_SOFTSUPP_INCOMPAT;
+#endif
+               if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
                        retval = EXT2_ET_UNSUPP_FEATURE;
                        goto cleanup;
                }
+
+               features = fs->super->s_feature_ro_compat;
+#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
+               if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
+                       features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT;
+#endif
                if ((flags & EXT2_FLAG_RW) &&
-                   (s->s_feature_ro_compat &
-                    ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
+                   (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
                        retval = EXT2_ET_RO_UNSUPP_FEATURE;
                        goto cleanup;
                }
+
+               if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
+                   (fs->super->s_feature_incompat &
+                    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
+                       retval = EXT2_ET_UNSUPP_FEATURE;
+                       goto cleanup;
+               }
+       }
+
+       if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
+           EXT2_MAX_BLOCK_LOG_SIZE) {
+               retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+               goto cleanup;
        }
-       
        fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
-       if (fs->blocksize == 0) {
+       if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
                retval = EXT2_ET_CORRUPT_SUPERBLOCK;
                goto cleanup;
        }
        fs->fragsize = EXT2_FRAG_SIZE(fs->super);
-       fs->inode_blocks_per_group = ((fs->super->s_inodes_per_group *
+       fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
                                       EXT2_INODE_SIZE(fs->super) +
                                       EXT2_BLOCK_SIZE(fs->super) - 1) /
                                      EXT2_BLOCK_SIZE(fs->super));
@@ -159,47 +263,144 @@ errcode_t ext2fs_open(const char *name, int flags, int superblock,
         * Set the blocksize to the filesystem's blocksize.
         */
        io_channel_set_blksize(fs->io, fs->blocksize);
-       
+
+       /*
+        * If this is an external journal device, don't try to read
+        * the group descriptors, because they're not there.
+        */
+       if (fs->super->s_feature_incompat &
+           EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
+               fs->group_desc_count = 0;
+               *ret_fs = fs;
+               return 0;
+       }
+
+       if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
+               retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+               goto cleanup;
+       }
+
        /*
         * Read group descriptors
         */
-       if ((EXT2_BLOCKS_PER_GROUP(fs->super)) == 0) {
+       blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
+       if (blocks_per_group == 0 ||
+           blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
+           fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
+           EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
+           fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
+               retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+               goto cleanup;
+       }
+       fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
+                                                fs->super->s_first_data_block,
+                                                blocks_per_group);
+       if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
+           fs->super->s_inodes_count) {
                retval = EXT2_ET_CORRUPT_SUPERBLOCK;
                goto cleanup;
        }
-       fs->group_desc_count = (fs->super->s_blocks_count -
-                               fs->super->s_first_data_block +
-                               EXT2_BLOCKS_PER_GROUP(fs->super) - 1)
-               / EXT2_BLOCKS_PER_GROUP(fs->super);
-       fs->desc_blocks = (fs->group_desc_count +
-                          EXT2_DESC_PER_BLOCK(fs->super) - 1)
-               / EXT2_DESC_PER_BLOCK(fs->super);
-       retval = ext2fs_get_mem(fs->desc_blocks * fs->blocksize,
-                               (void **) &fs->group_desc);
+       fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
+                                         EXT2_DESC_PER_BLOCK(fs->super));
+       retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
+                               &fs->group_desc);
        if (retval)
                goto cleanup;
        if (!group_block)
-               group_block = fs->super->s_first_data_block + 1;
+               group_block = fs->super->s_first_data_block;
        dest = (char *) fs->group_desc;
-       for (i=0 ; i < fs->desc_blocks; i++) {
-               retval = io_channel_read_blk(fs->io, group_block, 1, dest);
+       groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
+       if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
+               first_meta_bg = fs->super->s_first_meta_bg;
+       else
+               first_meta_bg = fs->desc_blocks;
+       if (first_meta_bg) {
+               retval = io_channel_read_blk(fs->io, group_block+1,
+                                            first_meta_bg, dest);
+               if (retval)
+                       goto cleanup;
+#ifdef WORDS_BIGENDIAN
+               gdp = (struct ext2_group_desc *) dest;
+               for (j=0; j < groups_per_block*first_meta_bg; j++)
+                       ext2fs_swap_group_desc2(fs, gdp++);
+#endif
+               dest += fs->blocksize*first_meta_bg;
+       }
+       for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
+               blk = ext2fs_descriptor_block_loc(fs, group_block, i);
+               retval = io_channel_read_blk64(fs->io, blk, 1, dest);
                if (retval)
                        goto cleanup;
-               group_block++;
-               if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
-                       gdp = (struct ext2_group_desc *) dest;
-                       groups_per_block = fs->blocksize /
-                               sizeof(struct ext2_group_desc);
-                       for (j=0; j < groups_per_block; j++)
-                               ext2fs_swap_group_desc(gdp++);
+#ifdef WORDS_BIGENDIAN
+               for (j=0; j < groups_per_block; j++) {
+                       /* The below happens to work... be careful. */
+                       gdp = ext2fs_group_desc(fs, blk, j);
+                       ext2fs_swap_group_desc2(fs, gdp);
                }
+#endif
                dest += fs->blocksize;
        }
 
+       fs->stride = fs->super->s_raid_stride;
+
+       /*
+        * If recovery is from backup superblock, Clear _UNININT flags &
+        * reset bg_itable_unused to zero
+        */
+       if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+                                       EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+               struct ext2_group_desc *gd;
+               dgrp_t group;
+
+               for (group = 0; group < fs->group_desc_count; group++) {
+                       ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
+                       ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
+                       ext2fs_bg_itable_unused_set(fs, group, 0);
+               }
+               ext2fs_mark_super_dirty(fs);
+       }
+
+       fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
        *ret_fs = fs;
        return 0;
 cleanup:
-       ext2fs_free(fs);
+       if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
+               *ret_fs = fs;
+       else
+               ext2fs_free(fs);
        return retval;
 }
 
+/*
+ * Set/get the filesystem data I/O channel.
+ *
+ * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
+ */
+errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
+{
+       if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
+               return EXT2_ET_NOT_IMAGE_FILE;
+       if (old_io) {
+               *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
+       }
+       return 0;
+}
+
+errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
+{
+       if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
+               return EXT2_ET_NOT_IMAGE_FILE;
+       fs->io = new_io ? new_io : fs->image_io;
+       return 0;
+}
+
+errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
+{
+       if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
+               return EXT2_ET_NOT_IMAGE_FILE;
+       fs->io = fs->image_io = new_io;
+       fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
+               EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
+       fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
+       return 0;
+}