1 files changed, 84 insertions, 73 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3e3b45458ef8..84eeb8f515a3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1043,43 +1043,47 @@ static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
         return ext4_indirect_calc_metadata_amount(inode, blocks);
 }
 
+/*
+ * Called with i_data_sem down, which is important since we can call
+ * ext4_discard_preallocations() from here.
+ */
 static void ext4_da_update_reserve_space(struct inode *inode, int used)
 {
         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-        int total, mdb, mdb_free, mdb_claim = 0;
-
-        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
-        /* recalculate the number of metablocks still need to be reserved */
-        total = EXT4_I(inode)->i_reserved_data_blocks - used;
-        mdb = ext4_calc_metadata_amount(inode, total);
-
-        /* figure out how many metablocks to release */
-        BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
-        mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
-
-        if (mdb_free) {
-                /* Account for allocated meta_blocks */
-                mdb_claim = EXT4_I(inode)->i_allocated_meta_blocks;
-                BUG_ON(mdb_free < mdb_claim);
-                mdb_free -= mdb_claim;
-
-                /* update fs dirty blocks counter */
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        int mdb_free = 0;
+
+        spin_lock(&ei->i_block_reservation_lock);
+        if (unlikely(used > ei->i_reserved_data_blocks)) {
+                ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
+                         "with only %d reserved data blocks\n",
+                         __func__, inode->i_ino, used,
+                         ei->i_reserved_data_blocks);
+                WARN_ON(1);
+                used = ei->i_reserved_data_blocks;
+        }
+
+        /* Update per-inode reservations */
+        ei->i_reserved_data_blocks -= used;
+        used += ei->i_allocated_meta_blocks;
+        ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
+        ei->i_allocated_meta_blocks = 0;
+        percpu_counter_sub(&sbi->s_dirtyblocks_counter, used);
+
+        if (ei->i_reserved_data_blocks == 0) {
+                /*
+                 * We can release all of the reserved metadata blocks
+                 * only when we have written all of the delayed
+                 * allocation blocks.
+                 */
+                mdb_free = ei->i_allocated_meta_blocks;
                 percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
-                EXT4_I(inode)->i_allocated_meta_blocks = 0;
-                EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+                ei->i_allocated_meta_blocks = 0;
         }
-
-        /* update per-inode reservations */
-        BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
-        EXT4_I(inode)->i_reserved_data_blocks -= used;
-        percpu_counter_sub(&sbi->s_dirtyblocks_counter, used + mdb_claim);
         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
-        vfs_dq_claim_block(inode, used + mdb_claim);
-
-        /*
-         * free those over-booking quota for metadata blocks
-         */
+        /* Update quota subsystem */
+        vfs_dq_claim_block(inode, used);
         if (mdb_free)
                 vfs_dq_release_reservation_block(inode, mdb_free);
 
@@ -1088,7 +1092,8 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
          * there aren't any writers on the inode, we can discard the
          * inode's preallocations.
          */
-        if (!total && (atomic_read(&inode->i_writecount) == 0))
+        if ((ei->i_reserved_data_blocks == 0) &&
+            (atomic_read(&inode->i_writecount) == 0))
                 ext4_discard_preallocations(inode);
 }
 
@@ -1801,7 +1806,8 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
 {
         int retries = 0;
         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-        unsigned long md_needed, mdblocks, total = 0;
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        unsigned long md_needed, md_reserved, total = 0;
 
         /*
          * recalculate the amount of metadata blocks to reserve
@@ -1809,35 +1815,44 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
          * worse case is one extent per block
          */
 repeat:
-        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
-        total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
-        mdblocks = ext4_calc_metadata_amount(inode, total);
-        BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
-
-        md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
+        spin_lock(&ei->i_block_reservation_lock);
+        md_reserved = ei->i_reserved_meta_blocks;
+        md_needed = ext4_calc_metadata_amount(inode, nrblocks);
         total = md_needed + nrblocks;
-        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+        spin_unlock(&ei->i_block_reservation_lock);
 
         /*
          * Make quota reservation here to prevent quota overflow
          * later. Real quota accounting is done at pages writeout
          * time.
          */
-        if (vfs_dq_reserve_block(inode, total))
+        if (vfs_dq_reserve_block(inode, total)) {
+                /* 
+                 * We tend to badly over-estimate the amount of
+                 * metadata blocks which are needed, so if we have
+                 * reserved any metadata blocks, try to force out the
+                 * inode and see if we have any better luck.
+                 */
+                if (md_reserved && retries++ <= 3)
+                        goto retry;
                 return -EDQUOT;
+        }
 
         if (ext4_claim_free_blocks(sbi, total)) {
                 vfs_dq_release_reservation_block(inode, total);
                 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
+                retry:
+                        if (md_reserved)
+                                write_inode_now(inode, (retries == 3));
                         yield();
                         goto repeat;
                 }
                 return -ENOSPC;
         }
-        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
-        EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
-        EXT4_I(inode)->i_reserved_meta_blocks += md_needed;
-        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+        spin_lock(&ei->i_block_reservation_lock);
+        ei->i_reserved_data_blocks += nrblocks;
+        ei->i_reserved_meta_blocks += md_needed;
+        spin_unlock(&ei->i_block_reservation_lock);
 
         return 0;       /* success */
 }
@@ -1845,49 +1860,45 @@ repeat:
 static void ext4_da_release_space(struct inode *inode, int to_free)
 {
         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-        int total, mdb, mdb_free, release;
+        struct ext4_inode_info *ei = EXT4_I(inode);
 
         if (!to_free)
                 return;         /* Nothing to release, exit */
 
         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
 
-        if (!EXT4_I(inode)->i_reserved_data_blocks) {
+        if (unlikely(to_free > ei->i_reserved_data_blocks)) {
                 /*
-                 * if there is no reserved blocks, but we try to free some
-                 * then the counter is messed up somewhere.
-                 * but since this function is called from invalidate
-                 * page, it's harmless to return without any action
+                 * if there aren't enough reserved blocks, then the
+                 * counter is messed up somewhere.  Since this
+                 * function is called from invalidate page, it's
+                 * harmless to return without any action.
                  */
-                printk(KERN_INFO "ext4 delalloc try to release %d reserved "
-                            "blocks for inode %lu, but there is no reserved "
-                            "data blocks\n", to_free, inode->i_ino);
-                spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
-                return;
+                ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
+                         "ino %lu, to_free %d with only %d reserved "
+                         "data blocks\n", inode->i_ino, to_free,
+                         ei->i_reserved_data_blocks);
+                WARN_ON(1);
+                to_free = ei->i_reserved_data_blocks;
         }
+        ei->i_reserved_data_blocks -= to_free;
 
-        /* recalculate the number of metablocks still need to be reserved */
-        total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
-        mdb = ext4_calc_metadata_amount(inode, total);
-
-        /* figure out how many metablocks to release */
-        BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
-        mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
-
-        release = to_free + mdb_free;
-
-        /* update fs dirty blocks counter for truncate case */
-        percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
+        if (ei->i_reserved_data_blocks == 0) {
+                /*
+                 * We can release all of the reserved metadata blocks
+                 * only when we have written all of the delayed
+                 * allocation blocks.
+                 */
+                to_free += ei->i_allocated_meta_blocks;
+                ei->i_allocated_meta_blocks = 0;
+        }
 
-        /* update per-inode reservations */
-        BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
-        EXT4_I(inode)->i_reserved_data_blocks -= to_free;
+        /* update fs dirty blocks counter */
+        percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free);
 
-        BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
-        EXT4_I(inode)->i_reserved_meta_blocks = mdb;
         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
-        vfs_dq_release_reservation_block(inode, release);
+        vfs_dq_release_reservation_block(inode, to_free);
 }
 
 static void ext4_da_page_release_reservation(struct page *page,