nilfs2: add barrier mount option
[pandora-kernel.git] / fs / nilfs2 / super.c
index 414ef68..13b0e95 100644 (file)
@@ -74,6 +74,25 @@ struct kmem_cache *nilfs_btree_path_cache;
 
 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
 
+static void nilfs_set_error(struct nilfs_sb_info *sbi)
+{
+       struct the_nilfs *nilfs = sbi->s_nilfs;
+       struct nilfs_super_block **sbp;
+
+       down_write(&nilfs->ns_sem);
+       if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
+               nilfs->ns_mount_state |= NILFS_ERROR_FS;
+               sbp = nilfs_prepare_super(sbi, 0);
+               if (likely(sbp)) {
+                       sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
+                       if (sbp[1])
+                               sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
+                       nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
+               }
+       }
+       up_write(&nilfs->ns_sem);
+}
+
 /**
  * nilfs_error() - report failure condition on a filesystem
  *
@@ -99,16 +118,7 @@ void nilfs_error(struct super_block *sb, const char *function,
        va_end(args);
 
        if (!(sb->s_flags & MS_RDONLY)) {
-               struct the_nilfs *nilfs = sbi->s_nilfs;
-
-               down_write(&nilfs->ns_sem);
-               if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
-                       nilfs->ns_mount_state |= NILFS_ERROR_FS;
-                       nilfs->ns_sbp[0]->s_state |=
-                               cpu_to_le16(NILFS_ERROR_FS);
-                       nilfs_commit_super(sbi, 1);
-               }
-               up_write(&nilfs->ns_sem);
+               nilfs_set_error(sbi);
 
                if (nilfs_test_opt(sbi, ERRORS_RO)) {
                        printk(KERN_CRIT "Remounting filesystem read-only\n");
@@ -176,7 +186,7 @@ static void nilfs_clear_inode(struct inode *inode)
        nilfs_btnode_cache_clear(&ii->i_btnode_cache);
 }
 
-static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
+static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 {
        struct the_nilfs *nilfs = sbi->s_nilfs;
        int err;
@@ -202,12 +212,20 @@ static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
                printk(KERN_ERR
                       "NILFS: unable to write superblock (err=%d)\n", err);
                if (err == -EIO && nilfs->ns_sbh[1]) {
+                       /*
+                        * sbp[0] points to newer log than sbp[1],
+                        * so copy sbp[0] to sbp[1] to take over sbp[0].
+                        */
+                       memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
+                              nilfs->ns_sbsize);
                        nilfs_fall_back_super_block(nilfs);
                        goto retry;
                }
        } else {
                struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 
+               nilfs->ns_sbwcount++;
+
                /*
                 * The latest segment becomes trailable from the position
                 * written in superblock.
@@ -216,66 +234,122 @@ static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
 
                /* update GC protection for recent segments */
                if (nilfs->ns_sbh[1]) {
-                       sbp = NULL;
-                       if (dupsb) {
+                       if (flag == NILFS_SB_COMMIT_ALL) {
                                set_buffer_dirty(nilfs->ns_sbh[1]);
-                               if (!sync_dirty_buffer(nilfs->ns_sbh[1]))
-                                       sbp = nilfs->ns_sbp[1];
+                               if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
+                                       goto out;
                        }
+                       if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
+                           le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
+                               sbp = nilfs->ns_sbp[1];
                }
-               if (sbp) {
-                       spin_lock(&nilfs->ns_last_segment_lock);
-                       nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
-                       spin_unlock(&nilfs->ns_last_segment_lock);
-               }
-       }
 
+               spin_lock(&nilfs->ns_last_segment_lock);
+               nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
+               spin_unlock(&nilfs->ns_last_segment_lock);
+       }
+ out:
        return err;
 }
 
-int nilfs_commit_super(struct nilfs_sb_info *sbi, int dupsb)
+void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
+                         struct the_nilfs *nilfs)
+{
+       sector_t nfreeblocks;
+
+       /* nilfs->ns_sem must be locked by the caller. */
+       nilfs_count_free_blocks(nilfs, &nfreeblocks);
+       sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
+
+       spin_lock(&nilfs->ns_last_segment_lock);
+       sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
+       sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
+       sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
+       spin_unlock(&nilfs->ns_last_segment_lock);
+}
+
+struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
+                                              int flip)
 {
        struct the_nilfs *nilfs = sbi->s_nilfs;
        struct nilfs_super_block **sbp = nilfs->ns_sbp;
-       sector_t nfreeblocks;
-       time_t t;
-       int err;
 
-       /* nilfs->sem must be locked by the caller. */
+       /* nilfs->ns_sem must be locked by the caller. */
        if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
-               if (sbp[1] && sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC))
-                       nilfs_swap_super_block(nilfs);
-               else {
+               if (sbp[1] &&
+                   sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
+                       memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
+               } else {
                        printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
                               sbi->s_super->s_id);
-                       return -EIO;
+                       return NULL;
                }
+       } else if (sbp[1] &&
+                  sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
+                       memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
        }
-       err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
-       if (unlikely(err)) {
-               printk(KERN_ERR "NILFS: failed to count free blocks\n");
-               return err;
-       }
-       spin_lock(&nilfs->ns_last_segment_lock);
-       sbp[0]->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
-       sbp[0]->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
-       sbp[0]->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
-       spin_unlock(&nilfs->ns_last_segment_lock);
 
+       if (flip && sbp[1])
+               nilfs_swap_super_block(nilfs);
+
+       return sbp;
+}
+
+int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
+{
+       struct the_nilfs *nilfs = sbi->s_nilfs;
+       struct nilfs_super_block **sbp = nilfs->ns_sbp;
+       time_t t;
+
+       /* nilfs->ns_sem must be locked by the caller. */
        t = get_seconds();
-       nilfs->ns_sbwtime[0] = t;
-       sbp[0]->s_free_blocks_count = cpu_to_le64(nfreeblocks);
+       nilfs->ns_sbwtime = t;
        sbp[0]->s_wtime = cpu_to_le64(t);
        sbp[0]->s_sum = 0;
        sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
                                             (unsigned char *)sbp[0],
                                             nilfs->ns_sbsize));
-       if (dupsb && sbp[1]) {
-               memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
-               nilfs->ns_sbwtime[1] = t;
+       if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
+               sbp[1]->s_wtime = sbp[0]->s_wtime;
+               sbp[1]->s_sum = 0;
+               sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
+                                           (unsigned char *)sbp[1],
+                                           nilfs->ns_sbsize));
        }
        clear_nilfs_sb_dirty(nilfs);
-       return nilfs_sync_super(sbi, dupsb);
+       return nilfs_sync_super(sbi, flag);
+}
+
+/**
+ * nilfs_cleanup_super() - write filesystem state for cleanup
+ * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
+ *
+ * This function restores state flags in the on-disk super block.
+ * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
+ * filesystem was not clean previously.
+ */
+int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
+{
+       struct nilfs_super_block **sbp;
+       int flag = NILFS_SB_COMMIT;
+       int ret = -EIO;
+
+       sbp = nilfs_prepare_super(sbi, 0);
+       if (sbp) {
+               sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
+               nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
+               if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
+                       /*
+                        * make the "clean" flag also to the opposite
+                        * super block if both super blocks point to
+                        * the same checkpoint.
+                        */
+                       sbp[1]->s_state = sbp[0]->s_state;
+                       flag = NILFS_SB_COMMIT_ALL;
+               }
+               ret = nilfs_commit_super(sbi, flag);
+       }
+       return ret;
 }
 
 static void nilfs_put_super(struct super_block *sb)
@@ -289,8 +363,7 @@ static void nilfs_put_super(struct super_block *sb)
 
        if (!(sb->s_flags & MS_RDONLY)) {
                down_write(&nilfs->ns_sem);
-               nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
-               nilfs_commit_super(sbi, 1);
+               nilfs_cleanup_super(sbi);
                up_write(&nilfs->ns_sem);
        }
        down_write(&nilfs->ns_super_sem);
@@ -311,6 +384,7 @@ static int nilfs_sync_fs(struct super_block *sb, int wait)
 {
        struct nilfs_sb_info *sbi = NILFS_SB(sb);
        struct the_nilfs *nilfs = sbi->s_nilfs;
+       struct nilfs_super_block **sbp;
        int err = 0;
 
        /* This function is called when super block should be written back */
@@ -318,8 +392,13 @@ static int nilfs_sync_fs(struct super_block *sb, int wait)
                err = nilfs_construct_segment(sb);
 
        down_write(&nilfs->ns_sem);
-       if (nilfs_sb_dirty(nilfs))
-               nilfs_commit_super(sbi, 1);
+       if (nilfs_sb_dirty(nilfs)) {
+               sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
+               if (likely(sbp)) {
+                       nilfs_set_log_cursor(sbp[0], nilfs);
+                       nilfs_commit_super(sbi, NILFS_SB_COMMIT);
+               }
+       }
        up_write(&nilfs->ns_sem);
 
        return err;
@@ -524,7 +603,7 @@ static const struct export_operations nilfs_export_ops = {
 
 enum {
        Opt_err_cont, Opt_err_panic, Opt_err_ro,
-       Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
+       Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
        Opt_discard, Opt_err,
 };
 
@@ -532,6 +611,7 @@ static match_table_t tokens = {
        {Opt_err_cont, "errors=continue"},
        {Opt_err_panic, "errors=panic"},
        {Opt_err_ro, "errors=remount-ro"},
+       {Opt_barrier, "barrier"},
        {Opt_nobarrier, "nobarrier"},
        {Opt_snapshot, "cp=%u"},
        {Opt_order, "order=%s"},
@@ -557,6 +637,9 @@ static int parse_options(char *options, struct super_block *sb)
 
                token = match_token(p, tokens, args);
                switch (token) {
+               case Opt_barrier:
+                       nilfs_set_opt(sbi, BARRIER);
+                       break;
                case Opt_nobarrier:
                        nilfs_clear_opt(sbi, BARRIER);
                        break;
@@ -613,11 +696,18 @@ nilfs_set_default_options(struct nilfs_sb_info *sbi,
 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 {
        struct the_nilfs *nilfs = sbi->s_nilfs;
-       struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
-       int max_mnt_count = le16_to_cpu(sbp->s_max_mnt_count);
-       int mnt_count = le16_to_cpu(sbp->s_mnt_count);
+       struct nilfs_super_block **sbp;
+       int max_mnt_count;
+       int mnt_count;
+
+       /* nilfs->ns_sem must be locked by the caller. */
+       sbp = nilfs_prepare_super(sbi, 0);
+       if (!sbp)
+               return -EIO;
+
+       max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
+       mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 
-       /* nilfs->sem must be locked by the caller. */
        if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
                printk(KERN_WARNING
                       "NILFS warning: mounting fs with errors\n");
@@ -628,12 +718,15 @@ static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 #endif
        }
        if (!max_mnt_count)
-               sbp->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
-
-       sbp->s_mnt_count = cpu_to_le16(mnt_count + 1);
-       sbp->s_state = cpu_to_le16(le16_to_cpu(sbp->s_state) & ~NILFS_VALID_FS);
-       sbp->s_mtime = cpu_to_le64(get_seconds());
-       return nilfs_commit_super(sbi, 1);
+               sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
+
+       sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
+       sbp[0]->s_state =
+               cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
+       sbp[0]->s_mtime = cpu_to_le64(get_seconds());
+       /* synchronize sbp[1] with sbp[0] */
+       memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
+       return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 }
 
 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
@@ -819,7 +912,6 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 {
        struct nilfs_sb_info *sbi = NILFS_SB(sb);
-       struct nilfs_super_block *sbp;
        struct the_nilfs *nilfs = sbi->s_nilfs;
        unsigned long old_sb_flags;
        struct nilfs_mount_options old_opts;
@@ -880,12 +972,7 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data)
                 * the RDONLY flag and then mark the partition as valid again.
                 */
                down_write(&nilfs->ns_sem);
-               sbp = nilfs->ns_sbp[0];
-               if (!(sbp->s_state & le16_to_cpu(NILFS_VALID_FS)) &&
-                   (nilfs->ns_mount_state & NILFS_VALID_FS))
-                       sbp->s_state = cpu_to_le16(nilfs->ns_mount_state);
-               sbp->s_mtime = cpu_to_le64(get_seconds());
-               nilfs_commit_super(sbi, 1);
+               nilfs_cleanup_super(sbi);
                up_write(&nilfs->ns_sem);
        } else {
                /*