8 files changed, 53 insertions, 43 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index d460223b8e1d..7ae223ed152f 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -526,7 +526,7 @@ static inline int rsv_is_empty(struct ext4_reserve_window *rsv)
  * when setting the reservation window size through ioctl before the file
  * is open for write (needs block allocation).
  *
- * Needs truncate_mutex protection prior to call this function.
+ * Needs down_write(i_data_sem) protection prior to call this function.
  */
 void ext4_init_block_alloc_info(struct inode *inode)
 {
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ec5019fa552f..03d1bbb78a2f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1565,7 +1565,7 @@ static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
  * This routine returns max. credits that the extent tree can consume.
  * It should be OK for low-performance paths like ->writepage()
  * To allow many writing processes to fit into a single transaction,
- * the caller should calculate credits under truncate_mutex and
+ * the caller should calculate credits under i_data_sem and
  * pass the actual path.
  */
 int ext4_ext_calc_credits_for_insert(struct inode *inode,
@@ -2131,7 +2131,8 @@ out:
 
 /*
  * Need to be called with
- * mutex_lock(&EXT4_I(inode)->truncate_mutex);
+ * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
+ * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
  */
 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                         ext4_lblk_t iblock,
@@ -2350,7 +2351,7 @@ void ext4_ext_truncate(struct inode * inode, struct page *page)
         if (page)
                 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
 
-        mutex_lock(&EXT4_I(inode)->truncate_mutex);
+        down_write(&EXT4_I(inode)->i_data_sem);
         ext4_ext_invalidate_cache(inode);
 
         /*
@@ -2386,7 +2387,7 @@ out_stop:
         if (inode->i_nlink)
                 ext4_orphan_del(handle, inode);
 
-        mutex_unlock(&EXT4_I(inode)->truncate_mutex);
+        up_write(&EXT4_I(inode)->i_data_sem);
         ext4_journal_stop(handle);
 }
 
@@ -2450,7 +2451,7 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
          * modify 1 super block, 1 block bitmap and 1 group descriptor.
          */
         credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
-        mutex_lock(&EXT4_I(inode)->truncate_mutex)
+        down_write((&EXT4_I(inode)->i_data_sem));
 retry:
         while (ret >= 0 && ret < max_blocks) {
                 block = block + ret;
@@ -2507,7 +2508,7 @@ retry:
         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
                 goto retry;
 
-        mutex_unlock(&EXT4_I(inode)->truncate_mutex)
+        up_write((&EXT4_I(inode)->i_data_sem));
         /*
          * Time to update the file size.
          * Update only when preallocation was requested beyond the file size.
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index a6b2aa14626e..ac35ec58db55 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -37,9 +37,9 @@ static int ext4_release_file (struct inode * inode, struct file * filp)
         if ((filp->f_mode & FMODE_WRITE) &&
                         (atomic_read(&inode->i_writecount) == 1))
         {
-                mutex_lock(&EXT4_I(inode)->truncate_mutex);
+                down_write(&EXT4_I(inode)->i_data_sem);
                 ext4_discard_reservation(inode);
-                mutex_unlock(&EXT4_I(inode)->truncate_mutex);
+                up_write(&EXT4_I(inode)->i_data_sem);
         }
         if (is_dx(inode) && filp->private_data)
                 ext4_htree_free_dir_info(filp->private_data);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 71c7ad0c6723..a7eb8bb4bdd4 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -308,7 +308,7 @@ static int ext4_block_to_path(struct inode *inode,
                 final = ptrs;
         } else {
                 ext4_warning(inode->i_sb, "ext4_block_to_path",
-                                "block %u > max",
+                                "block %lu > max",
                                 i_block + direct_blocks +
                                 indirect_blocks + double_blocks);
         }
@@ -345,7 +345,7 @@ static int ext4_block_to_path(struct inode *inode,
  *      the whole chain, all way to the data (returns %NULL, *err == 0).
  *
  *      Need to be called with
- *      mutex_lock(&EXT4_I(inode)->truncate_mutex)
+ *      down_read(&EXT4_I(inode)->i_data_sem)
  */
 static Indirect *ext4_get_branch(struct inode *inode, int depth,
                                  ext4_lblk_t  *offsets,
@@ -777,7 +777,8 @@ err_out:
  *
  *
  * Need to be called with
- * mutex_lock(&EXT4_I(inode)->truncate_mutex)
+ * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
+ * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
  */
 int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
                 ext4_lblk_t iblock, unsigned long maxblocks,
@@ -865,7 +866,7 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
                 err = ext4_splice_branch(handle, inode, iblock,
                                         partial, indirect_blks, count);
         /*
-         * i_disksize growing is protected by truncate_mutex.  Don't forget to
+         * i_disksize growing is protected by i_data_sem.  Don't forget to
          * protect it if you're about to implement concurrent
          * ext4_get_block() -bzzz
         */
@@ -895,6 +896,31 @@ out:
 
 #define DIO_CREDITS (EXT4_RESERVE_TRANS_BLOCKS + 32)
 
+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 retval;
+        if (create) {
+                down_write((&EXT4_I(inode)->i_data_sem));
+        } else {
+                down_read((&EXT4_I(inode)->i_data_sem));
+        }
+        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
+                retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
+                                bh, create, extend_disksize);
+        } else {
+                retval = ext4_get_blocks_handle(handle, inode, block,
+                                max_blocks, bh, create, extend_disksize);
+        }
+        if (create) {
+                up_write((&EXT4_I(inode)->i_data_sem));
+        } else {
+                up_read((&EXT4_I(inode)->i_data_sem));
+        }
+        return retval;
+}
+
 static int ext4_get_block(struct inode *inode, sector_t iblock,
                         struct buffer_head *bh_result, int create)
 {
@@ -1399,7 +1425,7 @@ static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
  *      ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
  *
  * Same applies to ext4_get_block().  We will deadlock on various things like
- * lock_journal and i_truncate_mutex.
+ * lock_journal and i_data_sem
  *
  * Setting PF_MEMALLOC here doesn't work - too many internal memory
  * allocations fail.
@@ -2325,7 +2351,7 @@ void ext4_truncate(struct inode *inode)
          * From here we block out all ext4_get_block() callers who want to
          * modify the block allocation tree.
          */
-        mutex_lock(&ei->truncate_mutex);
+        down_write(&ei->i_data_sem);
 
         if (n == 1) {           /* direct blocks */
                 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
@@ -2389,7 +2415,7 @@ do_indirects:
 
         ext4_discard_reservation(inode);
 
-        mutex_unlock(&ei->truncate_mutex);
+        up_write(&ei->i_data_sem);
         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
         ext4_mark_inode_dirty(handle, inode);
 
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index e7f894bdb420..c0e5b8cf635c 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -199,7 +199,7 @@ flags_err:
                  * need to allocate reservation structure for this inode
                  * before set the window size
                  */
-                mutex_lock(&ei->truncate_mutex);
+                down_write(&ei->i_data_sem);
                 if (!ei->i_block_alloc_info)
                         ext4_init_block_alloc_info(inode);
 
@@ -207,7 +207,7 @@ flags_err:
                         struct ext4_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
                         rsv->rsv_goal_size = rsv_window_size;
                 }
-                mutex_unlock(&ei->truncate_mutex);
+                up_write(&ei->i_data_sem);
                 return 0;
         }
         case EXT4_IOC_GROUP_EXTEND: {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index effd375ece80..c7305443e100 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -593,7 +593,7 @@ static void init_once(struct kmem_cache *cachep, void *foo)
 #ifdef CONFIG_EXT4DEV_FS_XATTR
         init_rwsem(&ei->xattr_sem);
 #endif
-        mutex_init(&ei->truncate_mutex);
+        init_rwsem(&ei->i_data_sem);
         inode_init_once(&ei->vfs_inode);
 }
 
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index 583049c1d366..300cc5a5adb9 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -1107,27 +1107,10 @@ extern void ext4_ext_init(struct super_block *);
 extern void ext4_ext_release(struct super_block *);
 extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
                           loff_t len);
-static inline 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 retval;
-        mutex_lock(&EXT4_I(inode)->truncate_mutex);
-        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
-                retval = ext4_ext_get_blocks(handle, inode,
-                                                (ext4_lblk_t)block, max_blocks,
-                                                bh, create, extend_disksize);
-        } else {
-                retval = ext4_get_blocks_handle(handle, inode,
-                                                (ext4_lblk_t)block, max_blocks,
-                                                bh, create, extend_disksize);
-        }
-        mutex_unlock(&EXT4_I(inode)->truncate_mutex);
-        return retval;
-}
-
-
+extern 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);
 #endif  /* __KERNEL__ */
 
 #endif  /* _LINUX_EXT4_FS_H */
diff --git a/include/linux/ext4_fs_i.h b/include/linux/ext4_fs_i.h
index f1cd4934e46f..4377d249d378 100644
--- a/include/linux/ext4_fs_i.h
+++ b/include/linux/ext4_fs_i.h
@@ -139,16 +139,16 @@ struct ext4_inode_info {
         __u16 i_extra_isize;
 
         /*
-         * truncate_mutex is for serialising ext4_truncate() against
+         * i_data_sem is for serialising ext4_truncate() against
          * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
          * data tree are chopped off during truncate. We can't do that in
          * ext4 because whenever we perform intermediate commits during
          * truncate, the inode and all the metadata blocks *must* be in a
          * consistent state which allows truncation of the orphans to restart
          * during recovery.  Hence we must fix the get_block-vs-truncate race
-         * by other means, so we have truncate_mutex.
+         * by other means, so we have i_data_sem.
          */
-        struct mutex truncate_mutex;
+        struct rw_semaphore i_data_sem;
         struct inode vfs_inode;
 
         unsigned long i_ext_generation;