Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
authorLinus Torvalds <torvalds@linux-foundation.org>
Fri, 15 May 2009 15:07:25 +0000 (08:07 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 15 May 2009 15:07:25 +0000 (08:07 -0700)
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: Fix race in ext4_inode_info.i_cached_extent
  ext4: Clear the unwritten buffer_head flag after the extent is initialized
  ext4: Use a fake block number for delayed new buffer_head
  ext4: Fix sub-block zeroing for writes into preallocated extents

fs/ext4/extents.c
fs/ext4/inode.c

index e4033215834074fe724987098aac17d36ab3ac85..e3a55eb8b26a5df9cc41fb5efd79e23fc275da22 100644 (file)
@@ -1841,11 +1841,13 @@ ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
 {
        struct ext4_ext_cache *cex;
        BUG_ON(len == 0);
+       spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
        cex = &EXT4_I(inode)->i_cached_extent;
        cex->ec_type = type;
        cex->ec_block = block;
        cex->ec_len = len;
        cex->ec_start = start;
+       spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 }
 
 /*
@@ -1902,12 +1904,17 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
                        struct ext4_extent *ex)
 {
        struct ext4_ext_cache *cex;
+       int ret = EXT4_EXT_CACHE_NO;
 
+       /* 
+        * We borrow i_block_reservation_lock to protect i_cached_extent
+        */
+       spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
        cex = &EXT4_I(inode)->i_cached_extent;
 
        /* has cache valid data? */
        if (cex->ec_type == EXT4_EXT_CACHE_NO)
-               return EXT4_EXT_CACHE_NO;
+               goto errout;
 
        BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
                        cex->ec_type != EXT4_EXT_CACHE_EXTENT);
@@ -1918,11 +1925,11 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
                ext_debug("%u cached by %u:%u:%llu\n",
                                block,
                                cex->ec_block, cex->ec_len, cex->ec_start);
-               return cex->ec_type;
+               ret = cex->ec_type;
        }
-
-       /* not in cache */
-       return EXT4_EXT_CACHE_NO;
+errout:
+       spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+       return ret;
 }
 
 /*
@@ -2875,6 +2882,8 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                                if (allocated > max_blocks)
                                        allocated = max_blocks;
                                set_buffer_unwritten(bh_result);
+                               bh_result->b_bdev = inode->i_sb->s_bdev;
+                               bh_result->b_blocknr = newblock;
                                goto out2;
                        }
 
index e91f978c7f12848616855876628189a44a6885f8..2a9ffd528dd1271e179a35322ce2e0a522f4d5b2 100644 (file)
@@ -1149,6 +1149,7 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
        int retval;
 
        clear_buffer_mapped(bh);
+       clear_buffer_unwritten(bh);
 
        /*
         * Try to see if we can get  the block without requesting
@@ -1178,6 +1179,18 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
        if (retval > 0 && buffer_mapped(bh))
                return retval;
 
+       /*
+        * When we call get_blocks without the create flag, the
+        * BH_Unwritten flag could have gotten set if the blocks
+        * requested were part of a uninitialized extent.  We need to
+        * clear this flag now that we are committed to convert all or
+        * part of the uninitialized extent to be an initialized
+        * extent.  This is because we need to avoid the combination
+        * of BH_Unwritten and BH_Mapped flags being simultaneously
+        * set on the buffer_head.
+        */
+       clear_buffer_unwritten(bh);
+
        /*
         * New blocks allocate and/or writing to uninitialized extent
         * will possibly result in updating i_data, so we take
@@ -2297,6 +2310,10 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                                  struct buffer_head *bh_result, int create)
 {
        int ret = 0;
+       sector_t invalid_block = ~((sector_t) 0xffff);
+
+       if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
+               invalid_block = ~0;
 
        BUG_ON(create == 0);
        BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
@@ -2318,11 +2335,18 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                        /* not enough space to reserve */
                        return ret;
 
-               map_bh(bh_result, inode->i_sb, 0);
+               map_bh(bh_result, inode->i_sb, invalid_block);
                set_buffer_new(bh_result);
                set_buffer_delay(bh_result);
        } else if (ret > 0) {
                bh_result->b_size = (ret << inode->i_blkbits);
+               /*
+                * With sub-block writes into unwritten extents
+                * we also need to mark the buffer as new so that
+                * the unwritten parts of the buffer gets correctly zeroed.
+                */
+               if (buffer_unwritten(bh_result))
+                       set_buffer_new(bh_result);
                ret = 0;
        }