Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: remove write-only variables from ext4_ordered_write_end
  ext4: unexport jbd2_journal_update_superblock
  ext4: Cleanup whitespace and other miscellaneous style issues
  ext4: improve ext4_fill_flex_info() a bit
  ext4: Cleanup the block reservation code path
  ext4: don't assume extents can't cross block groups when truncating
  ext4: Fix lack of credits BUG() when deleting a badly fragmented inode
  ext4: Fix ext4_ext_journal_restart()
  ext4: fix ext4_da_write_begin error path
  jbd2: don't abort if flushing file data failed
  ext4: don't read inode block if the buffer has a write error
  ext4: Don't allow lg prealloc list to be grow large.
  ext4: Convert the usage of NR_CPUS to nr_cpu_ids.
  ext4: Improve error handling in mballoc
  ext4: lock block groups when initializing
  ext4: sync up block and inode bitmap reading functions
  ext4: Allow read/only mounts with corrupted block group checksums
  ext4: Fix data corruption when writing to prealloc area

1 files changed, 167 insertions, 149 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1e69f29a8c55..d5d77958b861 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -49,20 +49,19 @@ static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
                              unsigned long journal_devnum);
 static int ext4_create_journal(struct super_block *, struct ext4_super_block *,
                                unsigned int);
-static void ext4_commit_super (struct super_block * sb,
-                               struct ext4_super_block * es,
-                               int sync);
-static void ext4_mark_recovery_complete(struct super_block * sb,
-                                        struct ext4_super_block * es);
-static void ext4_clear_journal_err(struct super_block * sb,
-                                   struct ext4_super_block * es);
+static void ext4_commit_super(struct super_block *sb,
+                              struct ext4_super_block *es, int sync);
+static void ext4_mark_recovery_complete(struct super_block *sb,
+                                        struct ext4_super_block *es);
+static void ext4_clear_journal_err(struct super_block *sb,
+                                   struct ext4_super_block *es);
 static int ext4_sync_fs(struct super_block *sb, int wait);
-static const char *ext4_decode_error(struct super_block * sb, int errno,
+static const char *ext4_decode_error(struct super_block *sb, int errno,
                                      char nbuf[16]);
-static int ext4_remount (struct super_block * sb, int * flags, char * data);
-static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf);
+static int ext4_remount(struct super_block *sb, int *flags, char *data);
+static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
 static void ext4_unlockfs(struct super_block *sb);
-static void ext4_write_super (struct super_block * sb);
+static void ext4_write_super(struct super_block *sb);
 static void ext4_write_super_lockfs(struct super_block *sb);
 
 
@@ -211,15 +210,15 @@ static void ext4_handle_error(struct super_block *sb)
         if (sb->s_flags & MS_RDONLY)
                 return;
 
-        if (!test_opt (sb, ERRORS_CONT)) {
+        if (!test_opt(sb, ERRORS_CONT)) {
                 journal_t *journal = EXT4_SB(sb)->s_journal;
 
                 EXT4_SB(sb)->s_mount_opt |= EXT4_MOUNT_ABORT;
                 if (journal)
                         jbd2_journal_abort(journal, -EIO);
         }
-        if (test_opt (sb, ERRORS_RO)) {
-                printk (KERN_CRIT "Remounting filesystem read-only\n");
+        if (test_opt(sb, ERRORS_RO)) {
+                printk(KERN_CRIT "Remounting filesystem read-only\n");
                 sb->s_flags |= MS_RDONLY;
         }
         ext4_commit_super(sb, es, 1);
@@ -228,13 +227,13 @@ static void ext4_handle_error(struct super_block *sb)
                         sb->s_id);
 }
 
-void ext4_error (struct super_block * sb, const char * function,
-                 const char * fmt, ...)
+void ext4_error(struct super_block *sb, const char *function,
+                const char *fmt, ...)
 {
         va_list args;
 
         va_start(args, fmt);
-        printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
+        printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
         vprintk(fmt, args);
         printk("\n");
         va_end(args);
@@ -242,7 +241,7 @@ void ext4_error (struct super_block * sb, const char * function,
         ext4_handle_error(sb);
 }
 
-static const char *ext4_decode_error(struct super_block * sb, int errno,
+static const char *ext4_decode_error(struct super_block *sb, int errno,
                                      char nbuf[16])
 {
         char *errstr = NULL;
@@ -278,8 +277,7 @@ static const char *ext4_decode_error(struct super_block * sb, int errno,
 /* __ext4_std_error decodes expected errors from journaling functions
  * automatically and invokes the appropriate error response.  */
 
-void __ext4_std_error (struct super_block * sb, const char * function,
-                       int errno)
+void __ext4_std_error(struct super_block *sb, const char *function, int errno)
 {
         char nbuf[16];
         const char *errstr;
@@ -292,8 +290,8 @@ void __ext4_std_error (struct super_block * sb, const char * function,
                 return;
 
         errstr = ext4_decode_error(sb, errno, nbuf);
-        printk (KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
-                sb->s_id, function, errstr);
+        printk(KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
+               sb->s_id, function, errstr);
 
         ext4_handle_error(sb);
 }
@@ -308,15 +306,15 @@ void __ext4_std_error (struct super_block * sb, const char * function,
  * case we take the easy way out and panic immediately.
  */
 
-void ext4_abort (struct super_block * sb, const char * function,
-                 const char * fmt, ...)
+void ext4_abort(struct super_block *sb, const char *function,
+                const char *fmt, ...)
 {
         va_list args;
 
-        printk (KERN_CRIT "ext4_abort called.\n");
+        printk(KERN_CRIT "ext4_abort called.\n");
 
         va_start(args, fmt);
-        printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
+        printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
         vprintk(fmt, args);
         printk("\n");
         va_end(args);
@@ -334,8 +332,8 @@ void ext4_abort (struct super_block * sb, const char * function,
         jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
 }
 
-void ext4_warning (struct super_block * sb, const char * function,
-                   const char * fmt, ...)
+void ext4_warning(struct super_block *sb, const char *function,
+                  const char *fmt, ...)
 {
         va_list args;
 
@@ -496,7 +494,7 @@ static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
         }
 }
 
-static void ext4_put_super (struct super_block * sb)
+static void ext4_put_super(struct super_block *sb)
 {
         struct ext4_sb_info *sbi = EXT4_SB(sb);
         struct ext4_super_block *es = sbi->s_es;
@@ -647,7 +645,8 @@ static void ext4_clear_inode(struct inode *inode)
                                        &EXT4_I(inode)->jinode);
 }
 
-static inline void ext4_show_quota_options(struct seq_file *seq, struct super_block *sb)
+static inline void ext4_show_quota_options(struct seq_file *seq,
+                                           struct super_block *sb)
 {
 #if defined(CONFIG_QUOTA)
         struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -822,8 +821,8 @@ static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
 }
 
 #ifdef CONFIG_QUOTA
-#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
-#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
+#define QTYPE2NAME(t) ((t) == USRQUOTA?"user":"group")
+#define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
 
 static int ext4_dquot_initialize(struct inode *inode, int type);
 static int ext4_dquot_drop(struct inode *inode);
@@ -991,12 +990,12 @@ static ext4_fsblk_t get_sb_block(void **data)
         return sb_block;
 }
 
-static int parse_options (char *options, struct super_block *sb,
-                          unsigned int *inum, unsigned long *journal_devnum,
-                          ext4_fsblk_t *n_blocks_count, int is_remount)
+static int parse_options(char *options, struct super_block *sb,
+                         unsigned int *inum, unsigned long *journal_devnum,
+                         ext4_fsblk_t *n_blocks_count, int is_remount)
 {
         struct ext4_sb_info *sbi = EXT4_SB(sb);
-        char * p;
+        char *p;
         substring_t args[MAX_OPT_ARGS];
         int data_opt = 0;
         int option;
@@ -1009,7 +1008,7 @@ static int parse_options (char *options, struct super_block *sb,
         if (!options)
                 return 1;
 
-        while ((p = strsep (&options, ",")) != NULL) {
+        while ((p = strsep(&options, ",")) != NULL) {
                 int token;
                 if (!*p)
                         continue;
@@ -1017,16 +1016,16 @@ static int parse_options (char *options, struct super_block *sb,
                 token = match_token(p, tokens, args);
                 switch (token) {
                 case Opt_bsd_df:
-                        clear_opt (sbi->s_mount_opt, MINIX_DF);
+                        clear_opt(sbi->s_mount_opt, MINIX_DF);
                         break;
                 case Opt_minix_df:
-                        set_opt (sbi->s_mount_opt, MINIX_DF);
+                        set_opt(sbi->s_mount_opt, MINIX_DF);
                         break;
                 case Opt_grpid:
-                        set_opt (sbi->s_mount_opt, GRPID);
+                        set_opt(sbi->s_mount_opt, GRPID);
                         break;
                 case Opt_nogrpid:
-                        clear_opt (sbi->s_mount_opt, GRPID);
+                        clear_opt(sbi->s_mount_opt, GRPID);
                         break;
                 case Opt_resuid:
                         if (match_int(&args[0], &option))
@@ -1043,41 +1042,41 @@ static int parse_options (char *options, struct super_block *sb,
                         /* *sb_block = match_int(&args[0]); */
                         break;
                 case Opt_err_panic:
-                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
-                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
-                        set_opt (sbi->s_mount_opt, ERRORS_PANIC);
+                        clear_opt(sbi->s_mount_opt, ERRORS_CONT);
+                        clear_opt(sbi->s_mount_opt, ERRORS_RO);
+                        set_opt(sbi->s_mount_opt, ERRORS_PANIC);
                         break;
                 case Opt_err_ro:
-                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
-                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
-                        set_opt (sbi->s_mount_opt, ERRORS_RO);
+                        clear_opt(sbi->s_mount_opt, ERRORS_CONT);
+                        clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
+                        set_opt(sbi->s_mount_opt, ERRORS_RO);
                         break;
                 case Opt_err_cont:
-                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
-                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
-                        set_opt (sbi->s_mount_opt, ERRORS_CONT);
+                        clear_opt(sbi->s_mount_opt, ERRORS_RO);
+                        clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
+                        set_opt(sbi->s_mount_opt, ERRORS_CONT);
                         break;
                 case Opt_nouid32:
-                        set_opt (sbi->s_mount_opt, NO_UID32);
+                        set_opt(sbi->s_mount_opt, NO_UID32);
                         break;
                 case Opt_nocheck:
-                        clear_opt (sbi->s_mount_opt, CHECK);
+                        clear_opt(sbi->s_mount_opt, CHECK);
                         break;
                 case Opt_debug:
-                        set_opt (sbi->s_mount_opt, DEBUG);
+                        set_opt(sbi->s_mount_opt, DEBUG);
                         break;
                 case Opt_oldalloc:
-                        set_opt (sbi->s_mount_opt, OLDALLOC);
+                        set_opt(sbi->s_mount_opt, OLDALLOC);
                         break;
                 case Opt_orlov:
-                        clear_opt (sbi->s_mount_opt, OLDALLOC);
+                        clear_opt(sbi->s_mount_opt, OLDALLOC);
                         break;
 #ifdef CONFIG_EXT4DEV_FS_XATTR
                 case Opt_user_xattr:
-                        set_opt (sbi->s_mount_opt, XATTR_USER);
+                        set_opt(sbi->s_mount_opt, XATTR_USER);
                         break;
                 case Opt_nouser_xattr:
-                        clear_opt (sbi->s_mount_opt, XATTR_USER);
+                        clear_opt(sbi->s_mount_opt, XATTR_USER);
                         break;
 #else
                 case Opt_user_xattr:
@@ -1115,7 +1114,7 @@ static int parse_options (char *options, struct super_block *sb,
                                        "journal on remount\n");
                                 return 0;
                         }
-                        set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
+                        set_opt(sbi->s_mount_opt, UPDATE_JOURNAL);
                         break;
                 case Opt_journal_inum:
                         if (is_remount) {
@@ -1145,7 +1144,7 @@ static int parse_options (char *options, struct super_block *sb,
                         set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
                         break;
                 case Opt_noload:
-                        set_opt (sbi->s_mount_opt, NOLOAD);
+                        set_opt(sbi->s_mount_opt, NOLOAD);
                         break;
                 case Opt_commit:
                         if (match_int(&args[0], &option))
@@ -1331,7 +1330,7 @@ set_qf_format:
                                         "on this filesystem, use tune2fs\n");
                                 return 0;
                         }
-                        set_opt (sbi->s_mount_opt, EXTENTS);
+                        set_opt(sbi->s_mount_opt, EXTENTS);
                         break;
                 case Opt_noextents:
                         /*
@@ -1348,7 +1347,7 @@ set_qf_format:
                                                 "-o noextents options\n");
                                 return 0;
                         }
-                        clear_opt (sbi->s_mount_opt, EXTENTS);
+                        clear_opt(sbi->s_mount_opt, EXTENTS);
                         break;
                 case Opt_i_version:
                         set_opt(sbi->s_mount_opt, I_VERSION);
@@ -1374,9 +1373,9 @@ set_qf_format:
                         set_opt(sbi->s_mount_opt, DELALLOC);
                         break;
                 default:
-                        printk (KERN_ERR
-                                "EXT4-fs: Unrecognized mount option \"%s\" "
-                                "or missing value\n", p);
+                        printk(KERN_ERR
+                               "EXT4-fs: Unrecognized mount option \"%s\" "
+                               "or missing value\n", p);
                         return 0;
                 }
         }
@@ -1423,31 +1422,31 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
         int res = 0;
 
         if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
-                printk (KERN_ERR "EXT4-fs warning: revision level too high, "
-                        "forcing read-only mode\n");
+                printk(KERN_ERR "EXT4-fs warning: revision level too high, "
+                       "forcing read-only mode\n");
                 res = MS_RDONLY;
         }
         if (read_only)
                 return res;
         if (!(sbi->s_mount_state & EXT4_VALID_FS))
-                printk (KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
-                        "running e2fsck is recommended\n");
+                printk(KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
+                       "running e2fsck is recommended\n");
         else if ((sbi->s_mount_state & EXT4_ERROR_FS))
-                printk (KERN_WARNING
-                        "EXT4-fs warning: mounting fs with errors, "
-                        "running e2fsck is recommended\n");
+                printk(KERN_WARNING
+                       "EXT4-fs warning: mounting fs with errors, "
+                       "running e2fsck is recommended\n");
         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
                  le16_to_cpu(es->s_mnt_count) >=
                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
-                printk (KERN_WARNING
-                        "EXT4-fs warning: maximal mount count reached, "
-                        "running e2fsck is recommended\n");
+                printk(KERN_WARNING
+                       "EXT4-fs warning: maximal mount count reached, "
+                       "running e2fsck is recommended\n");
         else if (le32_to_cpu(es->s_checkinterval) &&
                 (le32_to_cpu(es->s_lastcheck) +
                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
-                printk (KERN_WARNING
-                        "EXT4-fs warning: checktime reached, "
-                        "running e2fsck is recommended\n");
+                printk(KERN_WARNING
+                       "EXT4-fs warning: checktime reached, "
+                       "running e2fsck is recommended\n");
 #if 0
                 /* @@@ We _will_ want to clear the valid bit if we find
                  * inconsistencies, to force a fsck at reboot.  But for
@@ -1506,14 +1505,13 @@ static int ext4_fill_flex_info(struct super_block *sb)
 
         flex_group_count = (sbi->s_groups_count + groups_per_flex - 1) /
                 groups_per_flex;
-        sbi->s_flex_groups = kmalloc(flex_group_count *
+        sbi->s_flex_groups = kzalloc(flex_group_count *
                                      sizeof(struct flex_groups), GFP_KERNEL);
         if (sbi->s_flex_groups == NULL) {
-                printk(KERN_ERR "EXT4-fs: not enough memory\n");
+                printk(KERN_ERR "EXT4-fs: not enough memory for "
+                                "%lu flex groups\n", flex_group_count);
                 goto failed;
         }
-        memset(sbi->s_flex_groups, 0, flex_group_count *
-               sizeof(struct flex_groups));
 
         gdp = ext4_get_group_desc(sb, 1, &bh);
         block_bitmap = ext4_block_bitmap(sb, gdp) - 1;
@@ -1597,16 +1595,14 @@ static int ext4_check_descriptors(struct super_block *sb)
                                 (EXT4_BLOCKS_PER_GROUP(sb) - 1);
 
                 block_bitmap = ext4_block_bitmap(sb, gdp);
-                if (block_bitmap < first_block || block_bitmap > last_block)
-                {
+                if (block_bitmap < first_block || block_bitmap > last_block) {
                         printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
                                "Block bitmap for group %lu not in group "
                                "(block %llu)!", i, block_bitmap);
                         return 0;
                 }
                 inode_bitmap = ext4_inode_bitmap(sb, gdp);
-                if (inode_bitmap < first_block || inode_bitmap > last_block)
-                {
+                if (inode_bitmap < first_block || inode_bitmap > last_block) {
                         printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
                                "Inode bitmap for group %lu not in group "
                                "(block %llu)!", i, inode_bitmap);
@@ -1614,26 +1610,28 @@ static int ext4_check_descriptors(struct super_block *sb)
                 }
                 inode_table = ext4_inode_table(sb, gdp);
                 if (inode_table < first_block ||
-                    inode_table + sbi->s_itb_per_group - 1 > last_block)
-                {
+                    inode_table + sbi->s_itb_per_group - 1 > last_block) {
                         printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
                                "Inode table for group %lu not in group "
                                "(block %llu)!", i, inode_table);
                         return 0;
                 }
+                spin_lock(sb_bgl_lock(sbi, i));
                 if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
                         printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
                                "Checksum for group %lu failed (%u!=%u)\n",
                                i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
                                gdp)), le16_to_cpu(gdp->bg_checksum));
-                        return 0;
+                        if (!(sb->s_flags & MS_RDONLY))
+                                return 0;
                 }
+                spin_unlock(sb_bgl_lock(sbi, i));
                 if (!flexbg_flag)
                         first_block += EXT4_BLOCKS_PER_GROUP(sb);
         }
 
         ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
-        sbi->s_es->s_free_inodes_count=cpu_to_le32(ext4_count_free_inodes(sb));
+        sbi->s_es->s_free_inodes_count = cpu_to_le32(ext4_count_free_inodes(sb));
         return 1;
 }
 
@@ -1654,8 +1652,8 @@ static int ext4_check_descriptors(struct super_block *sb)
  * e2fsck was run on this filesystem, and it must have already done the orphan
  * inode cleanup for us, so we can safely abort without any further action.
  */
-static void ext4_orphan_cleanup (struct super_block * sb,
-                                 struct ext4_super_block * es)
+static void ext4_orphan_cleanup(struct super_block *sb,
+                                struct ext4_super_block *es)
 {
         unsigned int s_flags = sb->s_flags;
         int nr_orphans = 0, nr_truncates = 0;
@@ -1732,7 +1730,7 @@ static void ext4_orphan_cleanup (struct super_block * sb,
                 iput(inode);  /* The delete magic happens here! */
         }
 
-#define PLURAL(x) (x), ((x)==1) ? "" : "s"
+#define PLURAL(x) (x), ((x) == 1) ? "" : "s"
 
         if (nr_orphans)
                 printk(KERN_INFO "EXT4-fs: %s: %d orphan inode%s deleted\n",
@@ -1899,12 +1897,12 @@ static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
         return 0;
 }
 
-static int ext4_fill_super (struct super_block *sb, void *data, int silent)
+static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                                 __releases(kernel_lock)
                                 __acquires(kernel_lock)
 
 {
-        struct buffer_head * bh;
+        struct buffer_head *bh;
         struct ext4_super_block *es = NULL;
         struct ext4_sb_info *sbi;
         ext4_fsblk_t block;
@@ -1953,7 +1951,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
         }
 
         if (!(bh = sb_bread(sb, logical_sb_block))) {
-                printk (KERN_ERR "EXT4-fs: unable to read superblock\n");
+                printk(KERN_ERR "EXT4-fs: unable to read superblock\n");
                 goto out_fail;
         }
         /*
@@ -2026,8 +2024,8 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
         set_opt(sbi->s_mount_opt, DELALLOC);
 
 
-        if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
-                            NULL, 0))
+        if (!parse_options((char *) data, sb, &journal_inum, &journal_devnum,
+                           NULL, 0))
                 goto failed_mount;
 
         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
@@ -2102,7 +2100,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                         goto failed_mount;
                 }
 
-                brelse (bh);
+                brelse(bh);
                 logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
                 offset = do_div(logical_sb_block, blocksize);
                 bh = sb_bread(sb, logical_sb_block);
@@ -2114,8 +2112,8 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                 es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
                 sbi->s_es = es;
                 if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
-                        printk (KERN_ERR
-                                "EXT4-fs: Magic mismatch, very weird !\n");
+                        printk(KERN_ERR
+                               "EXT4-fs: Magic mismatch, very weird !\n");
                         goto failed_mount;
                 }
         }
@@ -2132,9 +2130,9 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                 if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
                     (!is_power_of_2(sbi->s_inode_size)) ||
                     (sbi->s_inode_size > blocksize)) {
-                        printk (KERN_ERR
-                                "EXT4-fs: unsupported inode size: %d\n",
-                                sbi->s_inode_size);
+                        printk(KERN_ERR
+                               "EXT4-fs: unsupported inode size: %d\n",
+                               sbi->s_inode_size);
                         goto failed_mount;
                 }
                 if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
@@ -2166,20 +2164,20 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
         sbi->s_mount_state = le16_to_cpu(es->s_state);
         sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
         sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
-        for (i=0; i < 4; i++)
+        for (i = 0; i < 4; i++)
                 sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
         sbi->s_def_hash_version = es->s_def_hash_version;
 
         if (sbi->s_blocks_per_group > blocksize * 8) {
-                printk (KERN_ERR
-                        "EXT4-fs: #blocks per group too big: %lu\n",
-                        sbi->s_blocks_per_group);
+                printk(KERN_ERR
+                       "EXT4-fs: #blocks per group too big: %lu\n",
+                       sbi->s_blocks_per_group);
                 goto failed_mount;
         }
         if (sbi->s_inodes_per_group > blocksize * 8) {
-                printk (KERN_ERR
-                        "EXT4-fs: #inodes per group too big: %lu\n",
-                        sbi->s_inodes_per_group);
+                printk(KERN_ERR
+                       "EXT4-fs: #inodes per group too big: %lu\n",
+                       sbi->s_inodes_per_group);
                 goto failed_mount;
         }
 
@@ -2213,10 +2211,10 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
         sbi->s_groups_count = blocks_count;
         db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
                    EXT4_DESC_PER_BLOCK(sb);
-        sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
+        sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
                                     GFP_KERNEL);
         if (sbi->s_group_desc == NULL) {
-                printk (KERN_ERR "EXT4-fs: not enough memory\n");
+                printk(KERN_ERR "EXT4-fs: not enough memory\n");
                 goto failed_mount;
         }
 
@@ -2226,13 +2224,13 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                 block = descriptor_loc(sb, logical_sb_block, i);
                 sbi->s_group_desc[i] = sb_bread(sb, block);
                 if (!sbi->s_group_desc[i]) {
-                        printk (KERN_ERR "EXT4-fs: "
-                                "can't read group descriptor %d\n", i);
+                        printk(KERN_ERR "EXT4-fs: "
+                               "can't read group descriptor %d\n", i);
                         db_count = i;
                         goto failed_mount2;
                 }
         }
-        if (!ext4_check_descriptors (sb)) {
+        if (!ext4_check_descriptors(sb)) {
                 printk(KERN_ERR "EXT4-fs: group descriptors corrupted!\n");
                 goto failed_mount2;
         }
@@ -2308,11 +2306,11 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                     EXT4_SB(sb)->s_journal->j_failed_commit) {
                         printk(KERN_CRIT "EXT4-fs error (device %s): "
                                "ext4_fill_super: Journal transaction "
-                               "%u is corrupt\n", sb->s_id, 
+                               "%u is corrupt\n", sb->s_id,
                                EXT4_SB(sb)->s_journal->j_failed_commit);
-                        if (test_opt (sb, ERRORS_RO)) {
-                                printk (KERN_CRIT
-                                        "Mounting filesystem read-only\n");
+                        if (test_opt(sb, ERRORS_RO)) {
+                                printk(KERN_CRIT
+                                       "Mounting filesystem read-only\n");
                                 sb->s_flags |= MS_RDONLY;
                                 EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
                                 es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
@@ -2332,9 +2330,9 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                         goto failed_mount3;
         } else {
                 if (!silent)
-                        printk (KERN_ERR
-                                "ext4: No journal on filesystem on %s\n",
-                                sb->s_id);
+                        printk(KERN_ERR
+                               "ext4: No journal on filesystem on %s\n",
+                               sb->s_id);
                 goto failed_mount3;
         }
 
@@ -2418,7 +2416,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
                 goto failed_mount4;
         }
 
-        ext4_setup_super (sb, es, sb->s_flags & MS_RDONLY);
+        ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY);
 
         /* determine the minimum size of new large inodes, if present */
         if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
@@ -2457,12 +2455,12 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
         ext4_orphan_cleanup(sb, es);
         EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
         if (needs_recovery)
-                printk (KERN_INFO "EXT4-fs: recovery complete.\n");
+                printk(KERN_INFO "EXT4-fs: recovery complete.\n");
         ext4_mark_recovery_complete(sb, es);
-        printk (KERN_INFO "EXT4-fs: mounted filesystem with %s data mode.\n",
-                test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ? "journal":
-                test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
-                "writeback");
+        printk(KERN_INFO "EXT4-fs: mounted filesystem with %s data mode.\n",
+               test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ? "journal":
+               test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
+               "writeback");
 
         if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
                 printk(KERN_WARNING "EXT4-fs: Ignoring delalloc option - "
@@ -2575,14 +2573,14 @@ static journal_t *ext4_get_journal(struct super_block *sb,
 static journal_t *ext4_get_dev_journal(struct super_block *sb,
                                        dev_t j_dev)
 {
-        struct buffer_head * bh;
+        struct buffer_head *bh;
         journal_t *journal;
         ext4_fsblk_t start;
         ext4_fsblk_t len;
         int hblock, blocksize;
         ext4_fsblk_t sb_block;
         unsigned long offset;
-        struct ext4_super_block * es;
+        struct ext4_super_block *es;
         struct block_device *bdev;
 
         bdev = ext4_blkdev_get(j_dev);
@@ -2697,8 +2695,8 @@ static int ext4_load_journal(struct super_block *sb,
                                         "unavailable, cannot proceed.\n");
                                 return -EROFS;
                         }
-                        printk (KERN_INFO "EXT4-fs: write access will "
-                                        "be enabled during recovery.\n");
+                        printk(KERN_INFO "EXT4-fs: write access will "
+                               "be enabled during recovery.\n");
                 }
         }
 
@@ -2751,8 +2749,8 @@ static int ext4_load_journal(struct super_block *sb,
         return 0;
 }
 
-static int ext4_create_journal(struct super_block * sb,
-                               struct ext4_super_block * es,
+static int ext4_create_journal(struct super_block *sb,
+                               struct ext4_super_block *es,
                                unsigned int journal_inum)
 {
         journal_t *journal;
@@ -2793,9 +2791,8 @@ static int ext4_create_journal(struct super_block * sb,
         return 0;
 }
 
-static void ext4_commit_super (struct super_block * sb,
-                               struct ext4_super_block * es,
-                               int sync)
+static void ext4_commit_super(struct super_block *sb,
+                              struct ext4_super_block *es, int sync)
 {
         struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
 
@@ -2816,8 +2813,8 @@ static void ext4_commit_super (struct super_block * sb,
  * remounting) the filesystem readonly, then we will end up with a
  * consistent fs on disk.  Record that fact.
  */
-static void ext4_mark_recovery_complete(struct super_block * sb,
-                                        struct ext4_super_block * es)
+static void ext4_mark_recovery_complete(struct super_block *sb,
+                                        struct ext4_super_block *es)
 {
         journal_t *journal = EXT4_SB(sb)->s_journal;
 
@@ -2839,8 +2836,8 @@ static void ext4_mark_recovery_complete(struct super_block * sb,
  * has recorded an error from a previous lifetime, move that error to the
  * main filesystem now.
  */
-static void ext4_clear_journal_err(struct super_block * sb,
-                                   struct ext4_super_block * es)
+static void ext4_clear_journal_err(struct super_block *sb,
+                                   struct ext4_super_block *es)
 {
         journal_t *journal;
         int j_errno;
@@ -2865,7 +2862,7 @@ static void ext4_clear_journal_err(struct super_block * sb,
 
                 EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
                 es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
-                ext4_commit_super (sb, es, 1);
+                ext4_commit_super(sb, es, 1);
 
                 jbd2_journal_clear_err(journal);
         }
@@ -2898,7 +2895,7 @@ int ext4_force_commit(struct super_block *sb)
  * This implicitly triggers the writebehind on sync().
  */
 
-static void ext4_write_super (struct super_block * sb)
+static void ext4_write_super(struct super_block *sb)
 {
         if (mutex_trylock(&sb->s_lock) != 0)
                 BUG();
@@ -2954,13 +2951,14 @@ static void ext4_unlockfs(struct super_block *sb)
         }
 }
 
-static int ext4_remount (struct super_block * sb, int * flags, char * data)
+static int ext4_remount(struct super_block *sb, int *flags, char *data)
 {
-        struct ext4_super_block * es;
+        struct ext4_super_block *es;
         struct ext4_sb_info *sbi = EXT4_SB(sb);
         ext4_fsblk_t n_blocks_count = 0;
         unsigned long old_sb_flags;
         struct ext4_mount_options old_opts;
+        ext4_group_t g;
         int err;
 #ifdef CONFIG_QUOTA
         int i;
@@ -3039,6 +3037,26 @@ static int ext4_remount (struct super_block * sb, int * flags, char * data)
                         }
 
                         /*
+                         * Make sure the group descriptor checksums
+                         * are sane.  If they aren't, refuse to
+                         * remount r/w.
+                         */
+                        for (g = 0; g < sbi->s_groups_count; g++) {
+                                struct ext4_group_desc *gdp =
+                                        ext4_get_group_desc(sb, g, NULL);
+
+                                if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
+                                        printk(KERN_ERR
+               "EXT4-fs: ext4_remount: "
+                "Checksum for group %lu failed (%u!=%u)\n",
+                g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
+                                               le16_to_cpu(gdp->bg_checksum));
+                                        err = -EINVAL;
+                                        goto restore_opts;
+                                }
+                        }
+
+                        /*
                          * If we have an unprocessed orphan list hanging
                          * around from a previously readonly bdev mount,
                          * require a full umount/remount for now.
@@ -3063,7 +3081,7 @@ static int ext4_remount (struct super_block * sb, int * flags, char * data)
                         sbi->s_mount_state = le16_to_cpu(es->s_state);
                         if ((err = ext4_group_extend(sb, es, n_blocks_count)))
                                 goto restore_opts;
-                        if (!ext4_setup_super (sb, es, 0))
+                        if (!ext4_setup_super(sb, es, 0))
                                 sb->s_flags &= ~MS_RDONLY;
                 }
         }
@@ -3093,7 +3111,7 @@ restore_opts:
         return err;
 }
 
-static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
+static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         struct super_block *sb = dentry->d_sb;
         struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -3331,12 +3349,12 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
         }
         /* Journaling quota? */
         if (EXT4_SB(sb)->s_qf_names[type]) {
-                /* Quotafile not of fs root? */
+                /* Quotafile not in fs root? */
                 if (nd.path.dentry->d_parent->d_inode != sb->s_root->d_inode)
                         printk(KERN_WARNING
                                 "EXT4-fs: Quota file not on filesystem root. "
                                 "Journaled quota will not work.\n");
-        }
+        }
 
         /*
          * When we journal data on quota file, we have to flush journal to see