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: enable barriers by default
  jbd2: Fix barrier fallback code to re-lock the buffer head
  ext4: Display the journal_async_commit mount option in /proc/mounts
  jbd2: If a journal checksum error is detected, propagate the error to ext4
  jbd2: Fix memory leak when verifying checksums in the journal
  ext4: fix online resize bug
  ext4: Fix uninit block group initialization with FLEX_BG
  ext4: Fix use of uninitialized data with debug enabled.

8 files changed, 121 insertions, 25 deletions

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 560f88dc7090..0c5086db8352 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -139,8 +139,16 @@ commit=nrsec	(*)	Ext4 can be told to sync all its data and metadata
                         Setting it to very large values will improve
                         performance.
 
-barrier=1               This enables/disables barriers.  barrier=0 disables
-                        it, barrier=1 enables it.
+barrier=<0|1(*)>        This enables/disables the use of write barriers in
+                        the jbd code.  barrier=0 disables, barrier=1 enables.
+                        This also requires an IO stack which can support
+                        barriers, and if jbd gets an error on a barrier
+                        write, it will disable again with a warning.
+                        Write barriers enforce proper on-disk ordering
+                        of journal commits, making volatile disk write caches
+                        safe to use, at some performance penalty.  If
+                        your disks are battery-backed in one way or another,
+                        disabling barriers may safely improve performance.
 
 orlov           (*)     This enables the new Orlov block allocator. It is
                         enabled by default.
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 30494c5da843..9cc80b9cc8d8 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -43,6 +43,46 @@ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
 
 }
 
+static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
+                        ext4_group_t block_group)
+{
+        ext4_group_t actual_group;
+        ext4_get_group_no_and_offset(sb, block, &actual_group, 0);
+        if (actual_group == block_group)
+                return 1;
+        return 0;
+}
+
+static int ext4_group_used_meta_blocks(struct super_block *sb,
+                                ext4_group_t block_group)
+{
+        ext4_fsblk_t tmp;
+        struct ext4_sb_info *sbi = EXT4_SB(sb);
+        /* block bitmap, inode bitmap, and inode table blocks */
+        int used_blocks = sbi->s_itb_per_group + 2;
+
+        if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
+                struct ext4_group_desc *gdp;
+                struct buffer_head *bh;
+
+                gdp = ext4_get_group_desc(sb, block_group, &bh);
+                if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
+                                        block_group))
+                        used_blocks--;
+
+                if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),
+                                        block_group))
+                        used_blocks--;
+
+                tmp = ext4_inode_table(sb, gdp);
+                for (; tmp < ext4_inode_table(sb, gdp) +
+                                sbi->s_itb_per_group; tmp++) {
+                        if (!ext4_block_in_group(sb, tmp, block_group))
+                                used_blocks -= 1;
+                }
+        }
+        return used_blocks;
+}
 /* Initializes an uninitialized block bitmap if given, and returns the
  * number of blocks free in the group. */
 unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
@@ -105,20 +145,34 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
         free_blocks = group_blocks - bit_max;
 
         if (bh) {
-                ext4_fsblk_t start;
+                ext4_fsblk_t start, tmp;
+                int flex_bg = 0;
 
                 for (bit = 0; bit < bit_max; bit++)
                         ext4_set_bit(bit, bh->b_data);
 
                 start = ext4_group_first_block_no(sb, block_group);
 
-                /* Set bits for block and inode bitmaps, and inode table */
-                ext4_set_bit(ext4_block_bitmap(sb, gdp) - start, bh->b_data);
-                ext4_set_bit(ext4_inode_bitmap(sb, gdp) - start, bh->b_data);
-                for (bit = (ext4_inode_table(sb, gdp) - start),
-                     bit_max = bit + sbi->s_itb_per_group; bit < bit_max; bit++)
-                        ext4_set_bit(bit, bh->b_data);
+                if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+                                              EXT4_FEATURE_INCOMPAT_FLEX_BG))
+                        flex_bg = 1;
 
+                /* Set bits for block and inode bitmaps, and inode table */
+                tmp = ext4_block_bitmap(sb, gdp);
+                if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+                        ext4_set_bit(tmp - start, bh->b_data);
+
+                tmp = ext4_inode_bitmap(sb, gdp);
+                if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
+                        ext4_set_bit(tmp - start, bh->b_data);
+
+                tmp = ext4_inode_table(sb, gdp);
+                for (; tmp < ext4_inode_table(sb, gdp) +
+                                sbi->s_itb_per_group; tmp++) {
+                        if (!flex_bg ||
+                                ext4_block_in_group(sb, tmp, block_group))
+                                ext4_set_bit(tmp - start, bh->b_data);
+                }
                 /*
                  * Also if the number of blocks within the group is
                  * less than the blocksize * 8 ( which is the size
@@ -126,8 +180,7 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
                  */
                 mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data);
         }
-
-        return free_blocks - sbi->s_itb_per_group - 2;
+        return free_blocks - ext4_group_used_meta_blocks(sb, block_group);
 }
 
 
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 873ad9b3418c..c9900aade150 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2745,8 +2745,6 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
         sbi = EXT4_SB(sb);
         es = sbi->s_es;
 
-        ext4_debug("using block group %lu(%d)\n", ac->ac_b_ex.fe_group,
-                        gdp->bg_free_blocks_count);
 
         err = -EIO;
         bitmap_bh = read_block_bitmap(sb, ac->ac_b_ex.fe_group);
@@ -2762,6 +2760,9 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
         if (!gdp)
                 goto out_err;
 
+        ext4_debug("using block group %lu(%d)\n", ac->ac_b_ex.fe_group,
+                        gdp->bg_free_blocks_count);
+
         err = ext4_journal_get_write_access(handle, gdp_bh);
         if (err)
                 goto out_err;
@@ -3094,8 +3095,7 @@ static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
 static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
                                 struct ext4_prealloc_space *pa)
 {
-        unsigned len = ac->ac_o_ex.fe_len;
-
+        unsigned int len = ac->ac_o_ex.fe_len;
         ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
                                         &ac->ac_b_ex.fe_group,
                                         &ac->ac_b_ex.fe_start);
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 9f086a6a472b..9ecb92f68543 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -563,7 +563,8 @@ static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
         }
 
         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;