1 files changed, 156 insertions, 28 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2bef4f879e4b..a6b800c58474 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -39,6 +39,7 @@
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
+#include "ext4_extents.h"
 
 static inline int ext4_begin_ordered_truncate(struct inode *inode,
                                               loff_t new_size)
@@ -982,7 +983,7 @@ out:
  */
 int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
                         unsigned long max_blocks, struct buffer_head *bh,
-                        int create, int extend_disksize)
+                        int create, int extend_disksize, int flag)
 {
         int retval;
 
@@ -1023,6 +1024,15 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
          * with create == 1 flag.
          */
         down_write((&EXT4_I(inode)->i_data_sem));
+
+        /*
+         * if the caller is from delayed allocation writeout path
+         * we have already reserved fs blocks for allocation
+         * let the underlying get_block() function know to
+         * avoid double accounting
+         */
+        if (flag)
+                EXT4_I(inode)->i_delalloc_reserved_flag = 1;
         /*
          * We need to check for EXT4 here because migrate
          * could have changed the inode type in between
@@ -1044,6 +1054,18 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
                                                         ~EXT4_EXT_MIGRATE;
                 }
         }
+
+        if (flag) {
+                EXT4_I(inode)->i_delalloc_reserved_flag = 0;
+                /*
+                 * Update reserved blocks/metadata blocks
+                 * after successful block allocation
+                 * which were deferred till now
+                 */
+                if ((retval > 0) && buffer_delay(bh))
+                        ext4_da_release_space(inode, retval, 0);
+        }
+
         up_write((&EXT4_I(inode)->i_data_sem));
         return retval;
 }
@@ -1069,7 +1091,7 @@ static int ext4_get_block(struct inode *inode, sector_t iblock,
         }
 
         ret = ext4_get_blocks_wrap(handle, inode, iblock,
-                                        max_blocks, bh_result, create, 0);
+                                        max_blocks, bh_result, create, 0, 0);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
                 ret = 0;
@@ -1095,7 +1117,7 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
         dummy.b_blocknr = -1000;
         buffer_trace_init(&dummy.b_history);
         err = ext4_get_blocks_wrap(handle, inode, block, 1,
-                                        &dummy, create, 1);
+                                        &dummy, create, 1, 0);
         /*
          * ext4_get_blocks_handle() returns number of blocks
          * mapped. 0 in case of a HOLE.
@@ -1409,6 +1431,122 @@ static int ext4_journalled_write_end(struct file *file,
 
         return ret ? ret : copied;
 }
+/*
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate @blocks for non extent file based file
+ */
+static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
+{
+        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;
+
+        dind_blks = (ind_blks + icap - 1) / icap;
+
+        tind_blks = 1;
+
+        return ind_blks + dind_blks + tind_blks;
+}
+
+/*
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate given number of blocks
+ */
+static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
+{
+        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
+                return ext4_ext_calc_metadata_amount(inode, blocks);
+
+        return ext4_indirect_calc_metadata_amount(inode, blocks);
+}
+
+static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
+{
+       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+       unsigned long md_needed, mdblocks, total = 0;
+
+        /*
+         * recalculate the amount of metadata blocks to reserve
+         * in order to allocate nrblocks
+         * worse case is one extent per block
+         */
+        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;
+
+        if (ext4_has_free_blocks(sbi, total) < total) {
+                spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+                return -ENOSPC;
+        }
+
+        /* reduce fs free blocks counter */
+        percpu_counter_sub(&sbi->s_freeblocks_counter, total);
+
+        EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
+        EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
+
+        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+        return 0;       /* success */
+}
+
+void ext4_da_release_space(struct inode *inode, int used, int to_free)
+{
+        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+        int total, mdb, mdb_free, release;
+
+        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 - 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;
+
+        /* Account for allocated meta_blocks */
+        mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
+
+        release = to_free + mdb_free;
+
+        /* update fs free blocks counter for truncate case */
+        percpu_counter_add(&sbi->s_freeblocks_counter, release);
+
+        /* update per-inode reservations */
+        BUG_ON(used + to_free > EXT4_I(inode)->i_reserved_data_blocks);
+        EXT4_I(inode)->i_reserved_data_blocks -= (used + to_free);
+
+        BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
+        EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+        EXT4_I(inode)->i_allocated_meta_blocks = 0;
+        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+}
+
+static void ext4_da_page_release_reservation(struct page *page,
+                                                unsigned long offset)
+{
+        int to_release = 0;
+        struct buffer_head *head, *bh;
+        unsigned int curr_off = 0;
+
+        head = page_buffers(page);
+        bh = head;
+        do {
+                unsigned int next_off = curr_off + bh->b_size;
+
+                if ((offset <= curr_off) && (buffer_delay(bh))) {
+                        to_release++;
+                        clear_buffer_delay(bh);
+                }
+                curr_off = next_off;
+        } while ((bh = bh->b_this_page) != head);
+        ext4_da_release_space(page->mapping->host, 0, to_release);
+}
 
 /*
  * Delayed allocation stuff
@@ -1829,14 +1967,18 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
          * preallocated blocks are unmapped but should treated
          * the same as allocated blocks.
          */
-        ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1,  bh_result, 0, 0);
-        if (ret == 0) {
-                /* the block isn't allocated yet, let's reserve space */
-                /* XXX: call reservation here */
+        ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1,  bh_result, 0, 0, 0);
+        if ((ret == 0) && !buffer_delay(bh_result)) {
+                /* the block isn't (pre)allocated yet, let's reserve space */
                 /*
                  * XXX: __block_prepare_write() unmaps passed block,
                  * is it OK?
                  */
+                ret = ext4_da_reserve_space(inode, 1);
+                if (ret)
+                        /* not enough space to reserve */
+                        return ret;
+
                 map_bh(bh_result, inode->i_sb, 0);
                 set_buffer_new(bh_result);
                 set_buffer_delay(bh_result);
@@ -1847,7 +1989,7 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
 
         return ret;
 }
-
+#define         EXT4_DELALLOC_RSVED     1
 static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
                                    struct buffer_head *bh_result, int create)
 {
@@ -1865,7 +2007,7 @@ static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
         }
 
         ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
-                                   bh_result, create, 0);
+                                   bh_result, create, 0, EXT4_DELALLOC_RSVED);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
 
@@ -1952,7 +2094,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
                                 loff_t pos, unsigned len, unsigned flags,
                                 struct page **pagep, void **fsdata)
 {
-        int ret;
+        int ret, retries = 0;
         struct page *page;
         pgoff_t index;
         unsigned from, to;
@@ -1963,6 +2105,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
         from = pos & (PAGE_CACHE_SIZE - 1);
         to = from + len;
 
+retry:
         /*
          * With delayed allocation, we don't log the i_disksize update
          * if there is delayed block allocation. But we still need
@@ -1988,6 +2131,8 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
                 page_cache_release(page);
         }
 
+        if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+                goto retry;
 out:
         return ret;
 }
@@ -2040,9 +2185,6 @@ static int ext4_da_write_end(struct file *file,
 
 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
 {
-        struct buffer_head *head, *bh;
-        unsigned int curr_off = 0;
-
         /*
          * Drop reserved blocks
          */
@@ -2050,21 +2192,7 @@ static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
         if (!page_has_buffers(page))
                 goto out;
 
-        head = page_buffers(page);
-        bh = head;
-        do {
-                unsigned int next_off = curr_off + bh->b_size;
-
-                /*
-                 * is this block fully invalidated?
-                 */
-                if (offset <= curr_off && buffer_delay(bh)) {
-                        clear_buffer_delay(bh);
-                        /* XXX: add real stuff here */
-                }
-                curr_off = next_off;
-                bh = bh->b_this_page;
-        } while (bh != head);
+        ext4_da_page_release_reservation(page, offset);
 
 out:
         ext4_invalidatepage(page, offset);