1 files changed, 126 insertions, 99 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ab807963a614..c818972c8302 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1009,77 +1009,88 @@ qsize_t *ext4_get_reserved_space(struct inode *inode)
         return &EXT4_I(inode)->i_reserved_quota;
 }
 #endif
+
 /*
  * Calculate the number of metadata blocks need to reserve
- * to allocate @blocks for non extent file based file
+ * to allocate a new block at @lblocks for non extent file based file
  */
-static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
+static int ext4_indirect_calc_metadata_amount(struct inode *inode,
+                                              sector_t lblock)
 {
-        int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
-        int ind_blks, dind_blks, tind_blks;
-
-        /* number of new indirect blocks needed */
-        ind_blks = (blocks + icap - 1) / icap;
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        int dind_mask = EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1;
+        int blk_bits;
 
-        dind_blks = (ind_blks + icap - 1) / icap;
+        if (lblock < EXT4_NDIR_BLOCKS)
+                return 0;
 
-        tind_blks = 1;
+        lblock -= EXT4_NDIR_BLOCKS;
 
-        return ind_blks + dind_blks + tind_blks;
+        if (ei->i_da_metadata_calc_len &&
+            (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
+                ei->i_da_metadata_calc_len++;
+                return 0;
+        }
+        ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
+        ei->i_da_metadata_calc_len = 1;
+        blk_bits = roundup_pow_of_two(lblock + 1);
+        return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
 }
 
 /*
  * Calculate the number of metadata blocks need to reserve
- * to allocate given number of blocks
+ * to allocate a block located at @lblock
  */
-static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
+static int ext4_calc_metadata_amount(struct inode *inode, sector_t lblock)
 {
-        if (!blocks)
-                return 0;
-
         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
-                return ext4_ext_calc_metadata_amount(inode, blocks);
+                return ext4_ext_calc_metadata_amount(inode, lblock);
 
-        return ext4_indirect_calc_metadata_amount(inode, blocks);
+        return ext4_indirect_calc_metadata_amount(inode, lblock);
 }
 
+/*
+ * 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_reserved_meta_blocks;
+                ei->i_reserved_meta_blocks = 0;
+                ei->i_da_metadata_calc_len = 0;
                 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;
         }
-
-        /* 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 +1099,8 @@ 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);
 }
 
@@ -1797,11 +1809,15 @@ static int ext4_journalled_write_end(struct file *file,
         return ret ? ret : copied;
 }
 
-static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
+/*
+ * Reserve a single block located at lblock
+ */
+static int ext4_da_reserve_space(struct inode *inode, sector_t lblock)
 {
         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;
 
         /*
          * recalculate the amount of metadata blocks to reserve
@@ -1809,35 +1825,43 @@ 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;
-        total = md_needed + nrblocks;
-        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+        spin_lock(&ei->i_block_reservation_lock);
+        md_reserved = ei->i_reserved_meta_blocks;
+        md_needed = ext4_calc_metadata_amount(inode, lblock);
+        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, md_needed + 1)) {
+                /* 
+                 * 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_claim_free_blocks(sbi, md_needed + 1)) {
+                vfs_dq_release_reservation_block(inode, md_needed + 1);
                 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++;
+        ei->i_reserved_meta_blocks += md_needed;
+        spin_unlock(&ei->i_block_reservation_lock);
 
         return 0;       /* success */
 }
@@ -1845,49 +1869,46 @@ 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_reserved_meta_blocks;
+                ei->i_reserved_meta_blocks = 0;
+                ei->i_da_metadata_calc_len = 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,
@@ -2493,7 +2514,7 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                  * XXX: __block_prepare_write() unmaps passed block,
                  * is it OK?
                  */
-                ret = ext4_da_reserve_space(inode, 1);
+                ret = ext4_da_reserve_space(inode, iblock);
                 if (ret)
                         /* not enough space to reserve */
                         return ret;
@@ -2967,8 +2988,7 @@ retry:
 out_writepages:
         if (!no_nrwrite_index_update)
                 wbc->no_nrwrite_index_update = 0;
-        if (wbc->nr_to_write > nr_to_writebump)
-                wbc->nr_to_write -= nr_to_writebump;
+        wbc->nr_to_write -= nr_to_writebump;
         wbc->range_start = range_start;
         trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
         return ret;
@@ -2993,11 +3013,18 @@ static int ext4_nonda_switch(struct super_block *sb)
         if (2 * free_blocks < 3 * dirty_blocks ||
                 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
                 /*
-                 * free block count is less that 150% of dirty blocks
-                 * or free blocks is less that watermark
+                 * free block count is less than 150% of dirty blocks
+                 * or free blocks is less than watermark
                  */
                 return 1;
         }
+        /*
+         * Even if we don't switch but are nearing capacity,
+         * start pushing delalloc when 1/2 of free blocks are dirty.
+         */
+        if (free_blocks < 2 * dirty_blocks)
+                writeback_inodes_sb_if_idle(sb);
+
         return 0;
 }