1 files changed, 128 insertions, 7 deletions

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 45853e0d1f21..1ce240a23ebb 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -50,7 +50,7 @@
  * need to use it within a single byte (to ensure we get endianness right).
  * We can use memset for the rest of the bitmap as there are no other users.
  */
-void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
+void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
 {
         int i;
 
@@ -65,9 +65,10 @@ void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
 }
 
 /* Initializes an uninitialized inode bitmap */
-unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
-                                ext4_group_t block_group,
-                                struct ext4_group_desc *gdp)
+static unsigned ext4_init_inode_bitmap(struct super_block *sb,
+                                       struct buffer_head *bh,
+                                       ext4_group_t block_group,
+                                       struct ext4_group_desc *gdp)
 {
         struct ext4_sb_info *sbi = EXT4_SB(sb);
 
@@ -85,7 +86,7 @@ unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
         }
 
         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
-        mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
+        ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
                         bh->b_data);
 
         return EXT4_INODES_PER_GROUP(sb);
@@ -107,6 +108,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
         desc = ext4_get_group_desc(sb, block_group, NULL);
         if (!desc)
                 return NULL;
+
         bitmap_blk = ext4_inode_bitmap(sb, desc);
         bh = sb_getblk(sb, bitmap_blk);
         if (unlikely(!bh)) {
@@ -123,6 +125,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
                 unlock_buffer(bh);
                 return bh;
         }
+
         ext4_lock_group(sb, block_group);
         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
@@ -133,6 +136,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
                 return bh;
         }
         ext4_unlock_group(sb, block_group);
+
         if (buffer_uptodate(bh)) {
                 /*
                  * if not uninit if bh is uptodate,
@@ -411,8 +415,8 @@ struct orlov_stats {
  * for a particular block group or flex_bg.  If flex_size is 1, then g
  * is a block group number; otherwise it is flex_bg number.
  */
-void get_orlov_stats(struct super_block *sb, ext4_group_t g,
-                       int flex_size, struct orlov_stats *stats)
+static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
+                            int flex_size, struct orlov_stats *stats)
 {
         struct ext4_group_desc *desc;
         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
@@ -712,8 +716,17 @@ static int ext4_claim_inode(struct super_block *sb,
 {
         int free = 0, retval = 0, count;
         struct ext4_sb_info *sbi = EXT4_SB(sb);
+        struct ext4_group_info *grp = ext4_get_group_info(sb, group);
         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 
+        /*
+         * We have to be sure that new inode allocation does not race with
+         * inode table initialization, because otherwise we may end up
+         * allocating and writing new inode right before sb_issue_zeroout
+         * takes place and overwriting our new inode with zeroes. So we
+         * take alloc_sem to prevent it.
+         */
+        down_read(&grp->alloc_sem);
         ext4_lock_group(sb, group);
         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
                 /* not a free inode */
@@ -724,6 +737,7 @@ static int ext4_claim_inode(struct super_block *sb,
         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
                         ino > EXT4_INODES_PER_GROUP(sb)) {
                 ext4_unlock_group(sb, group);
+                up_read(&grp->alloc_sem);
                 ext4_error(sb, "reserved inode or inode > inodes count - "
                            "block_group = %u, inode=%lu", group,
                            ino + group * EXT4_INODES_PER_GROUP(sb));
@@ -772,6 +786,7 @@ static int ext4_claim_inode(struct super_block *sb,
         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 err_ret:
         ext4_unlock_group(sb, group);
+        up_read(&grp->alloc_sem);
         return retval;
 }
 
@@ -1205,3 +1220,109 @@ unsigned long ext4_count_dirs(struct super_block * sb)
         }
         return count;
 }
+
+/*
+ * Zeroes not yet zeroed inode table - just write zeroes through the whole
+ * inode table. Must be called without any spinlock held. The only place
+ * where it is called from on active part of filesystem is ext4lazyinit
+ * thread, so we do not need any special locks, however we have to prevent
+ * inode allocation from the current group, so we take alloc_sem lock, to
+ * block ext4_claim_inode until we are finished.
+ */
+extern int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
+                                 int barrier)
+{
+        struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+        struct ext4_sb_info *sbi = EXT4_SB(sb);
+        struct ext4_group_desc *gdp = NULL;
+        struct buffer_head *group_desc_bh;
+        handle_t *handle;
+        ext4_fsblk_t blk;
+        int num, ret = 0, used_blks = 0;
+
+        /* This should not happen, but just to be sure check this */
+        if (sb->s_flags & MS_RDONLY) {
+                ret = 1;
+                goto out;
+        }
+
+        gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
+        if (!gdp)
+                goto out;
+
+        /*
+         * We do not need to lock this, because we are the only one
+         * handling this flag.
+         */
+        if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
+                goto out;
+
+        handle = ext4_journal_start_sb(sb, 1);
+        if (IS_ERR(handle)) {
+                ret = PTR_ERR(handle);
+                goto out;
+        }
+
+        down_write(&grp->alloc_sem);
+        /*
+         * If inode bitmap was already initialized there may be some
+         * used inodes so we need to skip blocks with used inodes in
+         * inode table.
+         */
+        if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
+                used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
+                            ext4_itable_unused_count(sb, gdp)),
+                            sbi->s_inodes_per_block);
+
+        if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
+                ext4_error(sb, "Something is wrong with group %u\n"
+                           "Used itable blocks: %d"
+                           "itable unused count: %u\n",
+                           group, used_blks,
+                           ext4_itable_unused_count(sb, gdp));
+                ret = 1;
+                goto out;
+        }
+
+        blk = ext4_inode_table(sb, gdp) + used_blks;
+        num = sbi->s_itb_per_group - used_blks;
+
+        BUFFER_TRACE(group_desc_bh, "get_write_access");
+        ret = ext4_journal_get_write_access(handle,
+                                            group_desc_bh);
+        if (ret)
+                goto err_out;
+
+        /*
+         * Skip zeroout if the inode table is full. But we set the ZEROED
+         * flag anyway, because obviously, when it is full it does not need
+         * further zeroing.
+         */
+        if (unlikely(num == 0))
+                goto skip_zeroout;
+
+        ext4_debug("going to zero out inode table in group %d\n",
+                   group);
+        ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
+        if (ret < 0)
+                goto err_out;
+        if (barrier)
+                blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
+
+skip_zeroout:
+        ext4_lock_group(sb, group);
+        gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
+        gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+        ext4_unlock_group(sb, group);
+
+        BUFFER_TRACE(group_desc_bh,
+                     "call ext4_handle_dirty_metadata");
+        ret = ext4_handle_dirty_metadata(handle, NULL,
+                                         group_desc_bh);
+
+err_out:
+        up_write(&grp->alloc_sem);
+        ext4_journal_stop(handle);
+out:
+        return ret;
+}