Merge remote branch 'ocfs2/linux-next'

20 files changed, 645 insertions, 78 deletions

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 5dbf4dba03c4..a367dd044280 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1849,8 +1849,8 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 	}
 
-	if (le32_to_cpu(es->s_blocks_count) >
-		    (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
+	if (generic_check_addressable(sb->s_blocksize_bits,
+				      le32_to_cpu(es->s_blocks_count))) {
 		ext3_msg(sb, KERN_ERR,
 			"error: filesystem is too large to mount safely");
 		if (sizeof(sector_t) < 8)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 26147746c272..7f47c366bf15 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2831,15 +2831,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	 * Test whether we have more sectors than will fit in sector_t,
 	 * and whether the max offset is addressable by the page cache.
 	 */
-	if ((ext4_blocks_count(es) >
-	     (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) ||
-	    (ext4_blocks_count(es) >
-	     (pgoff_t)(~0ULL) >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits))) {
+	ret = generic_check_addressable(sb->s_blocksize_bits,
+					ext4_blocks_count(es));
+	if (ret) {
 		ext4_msg(sb, KERN_ERR, "filesystem"
 			 " too large to mount safely on this system");
 		if (sizeof(sector_t) < 8)
 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
-		ret = -EFBIG;
 		goto failed_mount;
 	}
 
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0e8014ea6b94..262419f83d80 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1371,6 +1371,10 @@ int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
 
 	if (!compat && !ro && !incompat)
 		return 1;
+	/* Load journal superblock if it is not loaded yet. */
+	if (journal->j_format_version == 0 &&
+	    journal_get_superblock(journal) != 0)
+		return 0;
 	if (journal->j_format_version == 1)
 		return 0;
 
diff --git a/fs/libfs.c b/fs/libfs.c
index 0a9da95317f7..62baa0387d6e 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -913,6 +913,35 @@ int generic_file_fsync(struct file *file, int datasync)
 }
 EXPORT_SYMBOL(generic_file_fsync);
 
+/**
+ * generic_check_addressable - Check addressability of file system
+ * @blocksize_bits:	log of file system block size
+ * @num_blocks:		number of blocks in file system
+ *
+ * Determine whether a file system with @num_blocks blocks (and a
+ * block size of 2**@blocksize_bits) is addressable by the sector_t
+ * and page cache of the system.  Return 0 if so and -EFBIG otherwise.
+ */
+int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
+{
+	u64 last_fs_block = num_blocks - 1;
+	u64 last_fs_page =
+		last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
+
+	if (unlikely(num_blocks == 0))
+		return 0;
+
+	if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
+		return -EINVAL;
+
+	if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
+	    (last_fs_page > (pgoff_t)(~0ULL))) {
+		return -EFBIG;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(generic_check_addressable);
+
 /*
  * No-op implementation of ->fsync for in-memory filesystems.
  */
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 0de69c9a08be..5cfeee118158 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -883,8 +883,8 @@ struct ocfs2_write_ctxt {
 	 * out in so that future reads from that region will get
 	 * zero's.
 	 */
-	struct page			*w_pages[OCFS2_MAX_CTXT_PAGES];
 	unsigned int			w_num_pages;
+	struct page			*w_pages[OCFS2_MAX_CTXT_PAGES];
 	struct page			*w_target_page;
 
 	/*
@@ -1642,7 +1642,8 @@ static int ocfs2_zero_tail(struct inode *inode, struct buffer_head *di_bh,
 	return ret;
 }
 
-int ocfs2_write_begin_nolock(struct address_space *mapping,
+int ocfs2_write_begin_nolock(struct file *filp,
+			     struct address_space *mapping,
 			     loff_t pos, unsigned len, unsigned flags,
 			     struct page **pagep, void **fsdata,
 			     struct buffer_head *di_bh, struct page *mmap_page)
@@ -1692,7 +1693,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
 		mlog_errno(ret);
 		goto out;
 	} else if (ret == 1) {
-		ret = ocfs2_refcount_cow(inode, di_bh,
+		ret = ocfs2_refcount_cow(inode, filp, di_bh,
 					 wc->w_cpos, wc->w_clen, UINT_MAX);
 		if (ret) {
 			mlog_errno(ret);
@@ -1854,7 +1855,7 @@ static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
 	 */
 	down_write(&OCFS2_I(inode)->ip_alloc_sem);
 
-	ret = ocfs2_write_begin_nolock(mapping, pos, len, flags, pagep,
+	ret = ocfs2_write_begin_nolock(file, mapping, pos, len, flags, pagep,
 				       fsdata, di_bh, NULL);
 	if (ret) {
 		mlog_errno(ret);
diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h
index c48e93ffc513..7606f663da6d 100644
--- a/fs/ocfs2/aops.h
+++ b/fs/ocfs2/aops.h
@@ -48,7 +48,8 @@ int ocfs2_write_end_nolock(struct address_space *mapping,
 			   loff_t pos, unsigned len, unsigned copied,
 			   struct page *page, void *fsdata);
 
-int ocfs2_write_begin_nolock(struct address_space *mapping,
+int ocfs2_write_begin_nolock(struct file *filp,
+			     struct address_space *mapping,
 			     loff_t pos, unsigned len, unsigned flags,
 			     struct page **pagep, void **fsdata,
 			     struct buffer_head *di_bh, struct page *mmap_page);
diff --git a/fs/ocfs2/blockcheck.c b/fs/ocfs2/blockcheck.c
index ec6d12339593..c7ee03c22226 100644
--- a/fs/ocfs2/blockcheck.c
+++ b/fs/ocfs2/blockcheck.c
@@ -439,7 +439,7 @@ int ocfs2_block_check_validate(void *data, size_t blocksize,
 
 	ocfs2_blockcheck_inc_failure(stats);
 	mlog(ML_ERROR,
-	     "CRC32 failed: stored: %u, computed %u.  Applying ECC.\n",
+	     "CRC32 failed: stored: 0x%x, computed 0x%x. Applying ECC.\n",
 	     (unsigned int)check.bc_crc32e, (unsigned int)crc);
 
 	/* Ok, try ECC fixups */
@@ -453,7 +453,7 @@ int ocfs2_block_check_validate(void *data, size_t blocksize,
 		goto out;
 	}
 
-	mlog(ML_ERROR, "Fixed CRC32 failed: stored: %u, computed %u\n",
+	mlog(ML_ERROR, "Fixed CRC32 failed: stored: 0x%x, computed 0x%x\n",
 	     (unsigned int)check.bc_crc32e, (unsigned int)crc);
 
 	rc = -EIO;
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 81296b4e3646..b714f76b82db 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -36,6 +36,7 @@
 #include <linux/writeback.h>
 #include <linux/falloc.h>
 #include <linux/quotaops.h>
+#include <linux/blkdev.h>
 
 #define MLOG_MASK_PREFIX ML_INODE
 #include <cluster/masklog.h>
@@ -63,12 +64,6 @@
 
 #include "buffer_head_io.h"
 
-static int ocfs2_sync_inode(struct inode *inode)
-{
-	filemap_fdatawrite(inode->i_mapping);
-	return sync_mapping_buffers(inode->i_mapping);
-}
-
 static int ocfs2_init_file_private(struct inode *inode, struct file *file)
 {
 	struct ocfs2_file_private *fp;
@@ -186,12 +181,16 @@ static int ocfs2_sync_file(struct file *file, int datasync)
 	mlog_entry("(0x%p, 0x%p, %d, '%.*s')\n", file, dentry, datasync,
 		   dentry->d_name.len, dentry->d_name.name);
 
-	err = ocfs2_sync_inode(dentry->d_inode);
-	if (err)
-		goto bail;
-
-	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) {
+		/*
+		 * We still have to flush drive's caches to get data to the
+		 * platter
+		 */
+		if (osb->s_mount_opt & OCFS2_MOUNT_BARRIER)
+			blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL,
+					   NULL, BLKDEV_IFL_WAIT);
 		goto bail;
+	}
 
 	journal = osb->journal->j_journal;
 	err = jbd2_journal_force_commit(journal);
@@ -361,7 +360,7 @@ static int ocfs2_cow_file_pos(struct inode *inode,
 	if (!(ext_flags & OCFS2_EXT_REFCOUNTED))
 		goto out;
 
-	return ocfs2_refcount_cow(inode, fe_bh, cpos, 1, cpos+1);
+	return ocfs2_refcount_cow(inode, NULL, fe_bh, cpos, 1, cpos+1);
 
 out:
 	return status;
@@ -904,8 +903,8 @@ static int ocfs2_zero_extend_get_range(struct inode *inode,
 		zero_clusters = last_cpos - zero_cpos;
 
 	if (needs_cow) {
-		rc = ocfs2_refcount_cow(inode, di_bh, zero_cpos, zero_clusters,
-					UINT_MAX);
+		rc = ocfs2_refcount_cow(inode, NULL, di_bh, zero_cpos,
+					zero_clusters, UINT_MAX);
 		if (rc) {
 			mlog_errno(rc);
 			goto out;
@@ -2053,6 +2052,7 @@ out:
 }
 
 static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
+					    struct file *file,
 					    loff_t pos, size_t count,
 					    int *meta_level)
 {
@@ -2070,7 +2070,7 @@ static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
 
 	*meta_level = 1;
 
-	ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX);
+	ret = ocfs2_refcount_cow(inode, file, di_bh, cpos, clusters, UINT_MAX);
 	if (ret)
 		mlog_errno(ret);
 out:
@@ -2078,7 +2078,7 @@ out:
 	return ret;
 }
 
-static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
+static int ocfs2_prepare_inode_for_write(struct file *file,
 					 loff_t *ppos,
 					 size_t count,
 					 int appending,
@@ -2086,6 +2086,7 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
 					 int *has_refcount)
 {
 	int ret = 0, meta_level = 0;
+	struct dentry *dentry = file->f_path.dentry;
 	struct inode *inode = dentry->d_inode;
 	loff_t saved_pos, end;
 
@@ -2141,6 +2142,7 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
 			meta_level = -1;
 
 			ret = ocfs2_prepare_inode_for_refcount(inode,
+							       file,
 							       saved_pos,
 							       count,
 							       &meta_level);
@@ -2255,7 +2257,7 @@ relock:
 	}
 
 	can_do_direct = direct_io;
-	ret = ocfs2_prepare_inode_for_write(file->f_path.dentry, ppos,
+	ret = ocfs2_prepare_inode_for_write(file, ppos,
 					    iocb->ki_left, appending,
 					    &can_do_direct, &has_refcount);
 	if (ret < 0) {
@@ -2303,17 +2305,6 @@ relock:
 		written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
 						    ppos, count, ocount);
 		if (written < 0) {
-			/*
-			 * direct write may have instantiated a few
-			 * blocks outside i_size. Trim these off again.
-			 * Don't need i_size_read because we hold i_mutex.
-			 *
-			 * XXX(truncate): this looks buggy because ocfs2 did not
-			 * actually implement ->truncate.  Take a look at
-			 * the new truncate sequence and update this accordingly
-			 */
-			if (*ppos + count > inode->i_size)
-				truncate_setsize(inode, inode->i_size);
 			ret = written;
 			goto out_dio;
 		}
@@ -2385,7 +2376,7 @@ static int ocfs2_splice_to_file(struct pipe_inode_info *pipe,
 {
 	int ret;
 
-	ret = ocfs2_prepare_inode_for_write(out->f_path.dentry,	&sd->pos,
+	ret = ocfs2_prepare_inode_for_write(out, &sd->pos,
 					    sd->total_len, 0, NULL, NULL);
 	if (ret < 0) {
 		mlog_errno(ret);
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 0492464916b1..eece3e05d9d0 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -488,7 +488,11 @@ static int ocfs2_read_locked_inode(struct inode *inode,
 						     OCFS2_BH_IGNORE_CACHE);
 	} else {
 		status = ocfs2_read_blocks_sync(osb, args->fi_blkno, 1, &bh);
-		if (!status)
+		/*
+		 * If buffer is in jbd, then its checksum may not have been
+		 * computed as yet.
+		 */
+		if (!status && !buffer_jbd(bh))
 			status = ocfs2_validate_inode_block(osb->sb, bh);
 	}
 	if (status < 0) {
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 6de5a869db30..0bc477a3aeb8 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -46,27 +46,24 @@ struct ocfs2_inode_info
 	/* These fields are protected by ip_lock */
 	spinlock_t			ip_lock;
 	u32				ip_open_count;
-	u32				ip_clusters;
 	struct list_head		ip_io_markers;
+	u32				ip_clusters;
 
+	u16				ip_dyn_features;
 	struct mutex			ip_io_mutex;
-
 	u32				ip_flags; /* see below */
 	u32				ip_attr; /* inode attributes */
-	u16				ip_dyn_features;
 
 	/* protected by recovery_lock. */
 	struct inode			*ip_next_orphan;
 
-	u32				ip_dir_start_lookup;
-
 	struct ocfs2_caching_info	ip_metadata_cache;
-
 	struct ocfs2_extent_map		ip_extent_map;
-
 	struct inode			vfs_inode;
 	struct jbd2_inode		ip_jinode;
 
+	u32				ip_dir_start_lookup;
+
 	/* Only valid if the inode is the dir. */
 	u32				ip_last_used_slot;
 	u64				ip_last_used_group;
diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 7d9d9c132cef..7a4868196152 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -26,6 +26,26 @@
 
 #include <linux/ext2_fs.h>
 
+#define o2info_from_user(a, b)	\
+		copy_from_user(&(a), (b), sizeof(a))
+#define o2info_to_user(a, b)	\
+		copy_to_user((typeof(a) __user *)b, &(a), sizeof(a))
+
+/*
+ * This call is void because we are already reporting an error that may
+ * be -EFAULT.  The error will be returned from the ioctl(2) call.  It's
+ * just a best-effort to tell userspace that this request caused the error.
+ */
+static inline void __o2info_set_request_error(struct ocfs2_info_request *kreq,
+					struct ocfs2_info_request __user *req)
+{
+	kreq->ir_flags |= OCFS2_INFO_FL_ERROR;
+	(void)put_user(kreq->ir_flags, (__u32 __user *)&(req->ir_flags));
+}
+
+#define o2info_set_request_error(a, b) \
+		__o2info_set_request_error((struct ocfs2_info_request *)&(a), b)
+
 static int ocfs2_get_inode_attr(struct inode *inode, unsigned *flags)
 {
 	int status;
@@ -109,6 +129,328 @@ bail:
 	return status;
 }
 
+int ocfs2_info_handle_blocksize(struct inode *inode,
+				struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_blocksize oib;
+
+	if (o2info_from_user(oib, req))
+		goto bail;
+
+	oib.ib_blocksize = inode->i_sb->s_blocksize;
+	oib.ib_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oib, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oib, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_clustersize(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_clustersize oic;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oic, req))
+		goto bail;
+
+	oic.ic_clustersize = osb->s_clustersize;
+	oic.ic_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oic, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oic, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_maxslots(struct inode *inode,
+			       struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_maxslots oim;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oim, req))
+		goto bail;
+
+	oim.im_max_slots = osb->max_slots;
+	oim.im_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oim, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oim, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_label(struct inode *inode,
+			    struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_label oil;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oil, req))
+		goto bail;
+
+	memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);
+	oil.il_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oil, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oil, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_uuid(struct inode *inode,
+			   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_uuid oiu;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oiu, req))
+		goto bail;
+
+	memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_TEXT_UUID_LEN + 1);
+	oiu.iu_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oiu, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oiu, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_fs_features(struct inode *inode,
+				  struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_fs_features oif;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oif, req))
+		goto bail;
+
+	oif.if_compat_features = osb->s_feature_compat;
+	oif.if_incompat_features = osb->s_feature_incompat;
+	oif.if_ro_compat_features = osb->s_feature_ro_compat;
+	oif.if_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oif, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oif, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_journal_size(struct inode *inode,
+				   struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_journal_size oij;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	if (o2info_from_user(oij, req))
+		goto bail;
+
+	oij.ij_journal_size = osb->journal->j_inode->i_size;
+
+	oij.ij_req.ir_flags |= OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oij, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oij, req);
+
+	return status;
+}
+
+int ocfs2_info_handle_unknown(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	oir.ir_flags &= ~OCFS2_INFO_FL_FILLED;
+
+	if (o2info_to_user(oir, req))
+		goto bail;
+
+	status = 0;
+bail:
+	if (status)
+		o2info_set_request_error(oir, req);
+
+	return status;
+}
+
+/*
+ * Validate and distinguish OCFS2_IOC_INFO requests.
+ *
+ * - validate the magic number.
+ * - distinguish different requests.
+ * - validate size of different requests.
+ */
+int ocfs2_info_handle_request(struct inode *inode,
+			      struct ocfs2_info_request __user *req)
+{
+	int status = -EFAULT;
+	struct ocfs2_info_request oir;
+
+	if (o2info_from_user(oir, req))
+		goto bail;
+
+	status = -EINVAL;
+	if (oir.ir_magic != OCFS2_INFO_MAGIC)
+		goto bail;
+
+	switch (oir.ir_code) {
+	case OCFS2_INFO_BLOCKSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_blocksize))
+			status = ocfs2_info_handle_blocksize(inode, req);
+		break;
+	case OCFS2_INFO_CLUSTERSIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_clustersize))
+			status = ocfs2_info_handle_clustersize(inode, req);
+		break;
+	case OCFS2_INFO_MAXSLOTS:
+		if (oir.ir_size == sizeof(struct ocfs2_info_maxslots))
+			status = ocfs2_info_handle_maxslots(inode, req);
+		break;
+	case OCFS2_INFO_LABEL:
+		if (oir.ir_size == sizeof(struct ocfs2_info_label))
+			status = ocfs2_info_handle_label(inode, req);
+		break;
+	case OCFS2_INFO_UUID:
+		if (oir.ir_size == sizeof(struct ocfs2_info_uuid))
+			status = ocfs2_info_handle_uuid(inode, req);
+		break;
+	case OCFS2_INFO_FS_FEATURES:
+		if (oir.ir_size == sizeof(struct ocfs2_info_fs_features))
+			status = ocfs2_info_handle_fs_features(inode, req);
+		break;
+	case OCFS2_INFO_JOURNAL_SIZE:
+		if (oir.ir_size == sizeof(struct ocfs2_info_journal_size))
+			status = ocfs2_info_handle_journal_size(inode, req);
+		break;
+	default:
+		status = ocfs2_info_handle_unknown(inode, req);
+		break;
+	}
+
+bail:
+	return status;
+}
+
+int ocfs2_get_request_ptr(struct ocfs2_info *info, int idx,
+			  u64 *req_addr, int compat_flag)
+{
+	int status = -EFAULT;
+	u64 __user *bp = NULL;
+
+	if (compat_flag) {
+#ifdef CONFIG_COMPAT
+		/*
+		 * pointer bp stores the base address of a pointers array,
+		 * which collects all addresses of separate request.
+		 */
+		bp = (u64 __user *)(unsigned long)compat_ptr(info->oi_requests);
+#else
+		BUG();
+#endif
+	} else
+		bp = (u64 __user *)(unsigned long)(info->oi_requests);
+
+	if (o2info_from_user(*req_addr, bp + idx))
+		goto bail;
+
+	status = 0;
+bail:
+	return status;
+}
+
+/*
+ * OCFS2_IOC_INFO handles an array of requests passed from userspace.
+ *
+ * ocfs2_info_handle() recevies a large info aggregation, grab and
+ * validate the request count from header, then break it into small
+ * pieces, later specific handlers can handle them one by one.
+ *
+ * Idea here is to make each separate request small enough to ensure
+ * a better backward&forward compatibility, since a small piece of
+ * request will be less likely to be broken if disk layout get changed.
+ */
+int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
+		      int compat_flag)
+{
+	int i, status = 0;
+	u64 req_addr;
+	struct ocfs2_info_request __user *reqp;
+
+	if ((info->oi_count > OCFS2_INFO_MAX_REQUEST) ||
+	    (!info->oi_requests)) {
+		status = -EINVAL;
+		goto bail;
+	}
+
+	for (i = 0; i < info->oi_count; i++) {
+
+		status = ocfs2_get_request_ptr(info, i, &req_addr, compat_flag);
+		if (status)
+			break;
+
+		reqp = (struct ocfs2_info_request *)(unsigned long)req_addr;
+		if (!reqp) {
+			status = -EINVAL;
+			goto bail;
+		}
+
+		status = ocfs2_info_handle_request(inode, reqp);
+		if (status)
+			break;
+	}
+
+bail:
+	return status;
+}
+
 long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
@@ -120,6 +462,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	struct reflink_arguments args;
 	const char *old_path, *new_path;
 	bool preserve;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC_GETFLAGS:
@@ -174,6 +517,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		preserve = (args.preserve != 0);
 
 		return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 0);
 	default:
 		return -ENOTTY;
 	}
@@ -185,6 +534,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	bool preserve;
 	struct reflink_arguments args;
 	struct inode *inode = file->f_path.dentry->d_inode;
+	struct ocfs2_info info;
 
 	switch (cmd) {
 	case OCFS2_IOC32_GETFLAGS:
@@ -209,6 +559,12 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 
 		return ocfs2_reflink_ioctl(inode, compat_ptr(args.old_path),
 					   compat_ptr(args.new_path), preserve);
+	case OCFS2_IOC_INFO:
+		if (copy_from_user(&info, (struct ocfs2_info __user *)arg,
+				   sizeof(struct ocfs2_info)))
+			return -EFAULT;
+
+		return ocfs2_info_handle(inode, &info, 1);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 9b57c0350ff9..faa2303dbf0a 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -301,7 +301,6 @@ static int ocfs2_commit_cache(struct ocfs2_super *osb)
 {
 	int status = 0;
 	unsigned int flushed;
-	unsigned long old_id;
 	struct ocfs2_journal *journal = NULL;
 
 	mlog_entry_void();
@@ -326,7 +325,7 @@ static int ocfs2_commit_cache(struct ocfs2_super *osb)
 		goto finally;
 	}
 
-	old_id = ocfs2_inc_trans_id(journal);
+	ocfs2_inc_trans_id(journal);
 
 	flushed = atomic_read(&journal->j_num_trans);
 	atomic_set(&journal->j_num_trans, 0);
@@ -342,9 +341,6 @@ finally:
 	return status;
 }
 
-/* pass it NULL and it will allocate a new handle object for you.  If
- * you pass it a handle however, it may still return error, in which
- * case it has free'd the passed handle for you. */
 handle_t *ocfs2_start_trans(struct ocfs2_super *osb, int max_buffs)
 {
 	journal_t *journal = osb->journal->j_journal;
@@ -1888,6 +1884,8 @@ void ocfs2_queue_orphan_scan(struct ocfs2_super *osb)
 
 	os = &osb->osb_orphan_scan;
 
+	mlog(0, "Begin orphan scan\n");
+
 	if (atomic_read(&os->os_state) == ORPHAN_SCAN_INACTIVE)
 		goto out;
 
@@ -1920,6 +1918,7 @@ void ocfs2_queue_orphan_scan(struct ocfs2_super *osb)
 unlock:
 	ocfs2_orphan_scan_unlock(osb, seqno);
 out:
+	mlog(0, "Orphan scan completed\n");
 	return;
 }
 
diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index b5baaa8e710f..43e56b97f9c0 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -67,11 +67,12 @@ struct ocfs2_journal {
 	struct buffer_head        *j_bh;      /* Journal disk inode block */
 	atomic_t                  j_num_trans; /* Number of transactions
 					        * currently in the system. */
+	spinlock_t                j_lock;
 	unsigned long             j_trans_id;
 	struct rw_semaphore       j_trans_barrier;
 	wait_queue_head_t         j_checkpointed;
 
-	spinlock_t                j_lock;
+	/* both fields protected by j_lock*/
 	struct list_head          j_la_cleanups;
 	struct work_struct        j_recovery_work;
 };
diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index af2b8fe1f139..b04d6961c0d4 100644
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -59,10 +59,11 @@ static int ocfs2_fault(struct vm_area_struct *area, struct vm_fault *vmf)
 	return ret;
 }
 
-static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
+static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
 				struct page *page)
 {
 	int ret;
+	struct inode *inode = file->f_path.dentry->d_inode;
 	struct address_space *mapping = inode->i_mapping;
 	loff_t pos = page_offset(page);
 	unsigned int len = PAGE_CACHE_SIZE;
@@ -109,7 +110,7 @@ static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
 	if (page->index == last_index)
 		len = size & ~PAGE_CACHE_MASK;
 
-	ret = ocfs2_write_begin_nolock(mapping, pos, len, 0, &locked_page,
+	ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &locked_page,
 				       &fsdata, di_bh, page);
 	if (ret) {
 		if (ret != -ENOSPC)
@@ -157,7 +158,7 @@ static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	 */
 	down_write(&OCFS2_I(inode)->ip_alloc_sem);
 
-	ret = __ocfs2_page_mkwrite(inode, di_bh, page);
+	ret = __ocfs2_page_mkwrite(vma->vm_file, di_bh, page);
 
 	up_write(&OCFS2_I(inode)->ip_alloc_sem);
 
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index c67003b6b5a2..65739b3b3276 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -150,26 +150,33 @@ typedef void (*ocfs2_lock_callback)(int status, unsigned long data);
 struct ocfs2_lock_res {
 	void                    *l_priv;
 	struct ocfs2_lock_res_ops *l_ops;
-	spinlock_t               l_lock;
+
 
 	struct list_head         l_blocked_list;
 	struct list_head         l_mask_waiters;
 
-	enum ocfs2_lock_type     l_type;
 	unsigned long		 l_flags;
 	char                     l_name[OCFS2_LOCK_ID_MAX_LEN];
-	int                      l_level;
 	unsigned int             l_ro_holders;
 	unsigned int             l_ex_holders;
-	struct ocfs2_dlm_lksb    l_lksb;
+	unsigned char            l_level;
+
+	/* Data packed - type enum ocfs2_lock_type */
+	unsigned char            l_type;
 
 	/* used from AST/BAST funcs. */
-	enum ocfs2_ast_action    l_action;
-	enum ocfs2_unlock_action l_unlock_action;
-	int                      l_requested;
-	int                      l_blocking;
+	/* Data packed - enum type ocfs2_ast_action */
+	unsigned char            l_action;
+	/* Data packed - enum type ocfs2_unlock_action */
+	unsigned char            l_unlock_action;
+	unsigned char            l_requested;
+	unsigned char            l_blocking;
 	unsigned int             l_pending_gen;
 
+	spinlock_t               l_lock;
+
+	struct ocfs2_dlm_lksb    l_lksb;
+
 	wait_queue_head_t        l_event;
 
 	struct list_head         l_debug_list;
diff --git a/fs/ocfs2/ocfs2_ioctl.h b/fs/ocfs2/ocfs2_ioctl.h
index 2d3420af1a83..9bc535499868 100644
--- a/fs/ocfs2/ocfs2_ioctl.h
+++ b/fs/ocfs2/ocfs2_ioctl.h
@@ -76,4 +76,99 @@ struct reflink_arguments {
 };
 #define OCFS2_IOC_REFLINK	_IOW('o', 4, struct reflink_arguments)
 
+/* Following definitions dedicated for ocfs2_info_request ioctls. */
+#define OCFS2_INFO_MAX_REQUEST		(50)
+#define OCFS2_TEXT_UUID_LEN		(OCFS2_VOL_UUID_LEN * 2)
+
+/* Magic number of all requests */
+#define OCFS2_INFO_MAGIC		(0x4F32494E)
+
+/*
+ * Always try to separate info request into small pieces to
+ * guarantee the backward&forward compatibility.
+ */
+struct ocfs2_info {
+	__u64 oi_requests;	/* Array of __u64 pointers to requests */
+	__u32 oi_count;		/* Number of requests in info_requests */
+	__u32 oi_pad;
+};
+
+struct ocfs2_info_request {
+/*00*/	__u32 ir_magic;	/* Magic number */
+	__u32 ir_code;	/* Info request code */
+	__u32 ir_size;	/* Size of request */
+	__u32 ir_flags;	/* Request flags */
+/*10*/			/* Request specific fields */
+};
+
+struct ocfs2_info_clustersize {
+	struct ocfs2_info_request ic_req;
+	__u32 ic_clustersize;
+	__u32 ic_pad;
+};
+
+struct ocfs2_info_blocksize {
+	struct ocfs2_info_request ib_req;
+	__u32 ib_blocksize;
+	__u32 ib_pad;
+};
+
+struct ocfs2_info_maxslots {
+	struct ocfs2_info_request im_req;
+	__u32 im_max_slots;
+	__u32 im_pad;
+};
+
+struct ocfs2_info_label {
+	struct ocfs2_info_request il_req;
+	__u8	il_label[OCFS2_MAX_VOL_LABEL_LEN];
+} __attribute__ ((packed));
+
+struct ocfs2_info_uuid {
+	struct ocfs2_info_request iu_req;
+	__u8	iu_uuid_str[OCFS2_TEXT_UUID_LEN + 1];
+} __attribute__ ((packed));
+
+struct ocfs2_info_fs_features {
+	struct ocfs2_info_request if_req;
+	__u32 if_compat_features;
+	__u32 if_incompat_features;
+	__u32 if_ro_compat_features;
+	__u32 if_pad;
+};
+
+struct ocfs2_info_journal_size {
+	struct ocfs2_info_request ij_req;
+	__u64 ij_journal_size;
+};
+
+/* Codes for ocfs2_info_request */
+enum ocfs2_info_type {
+	OCFS2_INFO_CLUSTERSIZE = 1,
+	OCFS2_INFO_BLOCKSIZE,
+	OCFS2_INFO_MAXSLOTS,
+	OCFS2_INFO_LABEL,
+	OCFS2_INFO_UUID,
+	OCFS2_INFO_FS_FEATURES,
+	OCFS2_INFO_JOURNAL_SIZE,
+	OCFS2_INFO_NUM_TYPES
+};
+
+/* Flags for struct ocfs2_info_request */
+/* Filled by the caller */
+#define OCFS2_INFO_FL_NON_COHERENT	(0x00000001)	/* Cluster coherency not
+							   required. This is a hint.
+							   It is up to ocfs2 whether
+							   the request can be fulfilled
+							   without locking. */
+/* Filled by ocfs2 */
+#define OCFS2_INFO_FL_FILLED		(0x40000000)	/* Filesystem understood
+							   this request and
+							   filled in the answer */
+
+#define OCFS2_INFO_FL_ERROR		(0x80000000)	/* Error happened during
+							   request handling. */
+
+#define OCFS2_IOC_INFO		_IOR('o', 5, struct ocfs2_info)
+
 #endif /* OCFS2_IOCTL_H */
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 73a11ccfd4c2..7f13d2059b44 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -49,6 +49,7 @@
 
 struct ocfs2_cow_context {
 	struct inode *inode;
+	struct file *file;
 	u32 cow_start;
 	u32 cow_len;
 	struct ocfs2_extent_tree data_et;
@@ -2932,13 +2933,16 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
 	u64 new_block = ocfs2_clusters_to_blocks(sb, new_cluster);
 	struct page *page;
 	pgoff_t page_index;
-	unsigned int from, to;
+	unsigned int from, to, readahead_pages;
 	loff_t offset, end, map_end;
 	struct address_space *mapping = context->inode->i_mapping;
 
 	mlog(0, "old_cluster %u, new %u, len %u at offset %u\n", old_cluster,
 	     new_cluster, new_len, cpos);
 
+	readahead_pages =
+		(ocfs2_cow_contig_clusters(sb) <<
+		 OCFS2_SB(sb)->s_clustersize_bits) >> PAGE_CACHE_SHIFT;
 	offset = ((loff_t)cpos) << OCFS2_SB(sb)->s_clustersize_bits;
 	end = offset + (new_len << OCFS2_SB(sb)->s_clustersize_bits);
 	/*
@@ -2969,6 +2973,14 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
 		if (PAGE_CACHE_SIZE <= OCFS2_SB(sb)->s_clustersize)
 			BUG_ON(PageDirty(page));
 
+		if (PageReadahead(page) && context->file) {
+			page_cache_async_readahead(mapping,
+						   &context->file->f_ra,
+						   context->file,
+						   page, page_index,
+						   readahead_pages);
+		}
+
 		if (!PageUptodate(page)) {
 			ret = block_read_full_page(page, ocfs2_get_block);
 			if (ret) {
@@ -3408,12 +3420,35 @@ static int ocfs2_replace_cow(struct ocfs2_cow_context *context)
 	return ret;
 }
 
+static void ocfs2_readahead_for_cow(struct inode *inode,
+				    struct file *file,
+				    u32 start, u32 len)
+{
+	struct address_space *mapping;
+	pgoff_t index;
+	unsigned long num_pages;
+	int cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+
+	if (!file)
+		return;
+
+	mapping = file->f_mapping;
+	num_pages = (len << cs_bits) >> PAGE_CACHE_SHIFT;
+	if (!num_pages)
+		num_pages = 1;
+
+	index = ((loff_t)start << cs_bits) >> PAGE_CACHE_SHIFT;
+	page_cache_sync_readahead(mapping, &file->f_ra, file,
+				  index, num_pages);
+}
+
 /*
  * Starting at cpos, try to CoW write_len clusters.  Don't CoW
  * past max_cpos.  This will stop when it runs into a hole or an
  * unrefcounted extent.
  */
 static int ocfs2_refcount_cow_hunk(struct inode *inode,
+				   struct file *file,
 				   struct buffer_head *di_bh,
 				   u32 cpos, u32 write_len, u32 max_cpos)
 {
@@ -3442,6 +3477,8 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
 
 	BUG_ON(cow_len == 0);
 
+	ocfs2_readahead_for_cow(inode, file, cow_start, cow_len);
+
 	context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
 	if (!context) {
 		ret = -ENOMEM;
@@ -3463,6 +3500,7 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
 	context->ref_root_bh = ref_root_bh;
 	context->cow_duplicate_clusters = ocfs2_duplicate_clusters_by_page;
 	context->get_clusters = ocfs2_di_get_clusters;
+	context->file = file;
 
 	ocfs2_init_dinode_extent_tree(&context->data_et,
 				      INODE_CACHE(inode), di_bh);
@@ -3491,6 +3529,7 @@ out:
  * clusters between cpos and cpos+write_len are safe to modify.
  */
 int ocfs2_refcount_cow(struct inode *inode,
+		       struct file *file,
 		       struct buffer_head *di_bh,
 		       u32 cpos, u32 write_len, u32 max_cpos)
 {
@@ -3510,7 +3549,7 @@ int ocfs2_refcount_cow(struct inode *inode,
 			num_clusters = write_len;
 
 		if (ext_flags & OCFS2_EXT_REFCOUNTED) {
-			ret = ocfs2_refcount_cow_hunk(inode, di_bh, cpos,
+			ret = ocfs2_refcount_cow_hunk(inode, file, di_bh, cpos,
 						      num_clusters, max_cpos);
 			if (ret) {
 				mlog_errno(ret);
diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
index 9983ba1570e2..c8ce46f7d8e3 100644
--- a/fs/ocfs2/refcounttree.h
+++ b/fs/ocfs2/refcounttree.h
@@ -21,14 +21,14 @@ struct ocfs2_refcount_tree {
 	struct rb_node rf_node;
 	u64 rf_blkno;
 	u32 rf_generation;
+	struct kref rf_getcnt;
 	struct rw_semaphore rf_sem;
 	struct ocfs2_lock_res rf_lockres;
-	struct kref rf_getcnt;
 	int rf_removed;
 
 	/* the following 4 fields are used by caching_info. */
-	struct ocfs2_caching_info rf_ci;
 	spinlock_t rf_lock;
+	struct ocfs2_caching_info rf_ci;
 	struct mutex rf_io_mutex;
 	struct super_block *rf_sb;
 };
@@ -52,7 +52,8 @@ int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
 					  u32 clusters,
 					  int *credits,
 					  int *ref_blocks);
-int ocfs2_refcount_cow(struct inode *inode, struct buffer_head *di_bh,
+int ocfs2_refcount_cow(struct inode *inode,
+		       struct file *filep, struct buffer_head *di_bh,
 		       u32 cpos, u32 write_len, u32 max_cpos);
 
 typedef int (ocfs2_post_refcount_func)(struct inode *inode,
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index fa1be1b304d1..47415398d56a 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1990,6 +1990,36 @@ static int ocfs2_setup_osb_uuid(struct ocfs2_super *osb, const unsigned char *uu
 	return 0;
 }
 
+/* Make sure entire volume is addressable by our journal.  Requires
+   osb_clusters_at_boot to be valid and for the journal to have been
+   initialized by ocfs2_journal_init(). */
+static int ocfs2_journal_addressable(struct ocfs2_super *osb)
+{
+	int status = 0;
+	u64 max_block =
+		ocfs2_clusters_to_blocks(osb->sb,
+					 osb->osb_clusters_at_boot) - 1;
+
+	/* 32-bit block number is always OK. */
+	if (max_block <= (u32)~0ULL)
+		goto out;
+
+	/* Volume is "huge", so see if our journal is new enough to
+	   support it. */
+	if (!(OCFS2_HAS_COMPAT_FEATURE(osb->sb,
+				       OCFS2_FEATURE_COMPAT_JBD2_SB) &&
+	      jbd2_journal_check_used_features(osb->journal->j_journal, 0, 0,
+					       JBD2_FEATURE_INCOMPAT_64BIT))) {
+		mlog(ML_ERROR, "The journal cannot address the entire volume. "
+		     "Enable the 'block64' journal option with tunefs.ocfs2");
+		status = -EFBIG;
+		goto out;
+	}
+
+ out:
+	return status;
+}
+
 static int ocfs2_initialize_super(struct super_block *sb,
 				  struct buffer_head *bh,
 				  int sector_size,
@@ -2002,6 +2032,7 @@ static int ocfs2_initialize_super(struct super_block *sb,
 	struct ocfs2_journal *journal;
 	__le32 uuid_net_key;
 	struct ocfs2_super *osb;
+	u64 total_blocks;
 
 	mlog_entry_void();
 
@@ -2214,11 +2245,15 @@ static int ocfs2_initialize_super(struct super_block *sb,
 		goto bail;
 	}
 
-	if (ocfs2_clusters_to_blocks(osb->sb, le32_to_cpu(di->i_clusters) - 1)
-	    > (u32)~0UL) {
-		mlog(ML_ERROR, "Volume might try to write to blocks beyond "
-		     "what jbd can address in 32 bits.\n");
-		status = -EINVAL;
+	total_blocks = ocfs2_clusters_to_blocks(osb->sb,
+						le32_to_cpu(di->i_clusters));
+
+	status = generic_check_addressable(osb->sb->s_blocksize_bits,
+					   total_blocks);
+	if (status) {
+		mlog(ML_ERROR, "Volume too large "
+		     "to mount safely on this system");
+		status = -EFBIG;
 		goto bail;
 	}
 
@@ -2380,6 +2415,12 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
 		goto finally;
 	}
 
+	/* Now that journal has been initialized, check to make sure
+	   entire volume is addressable. */
+	status = ocfs2_journal_addressable(osb);
+	if (status)
+		goto finally;
+
 	/* If the journal was unmounted cleanly then we don't want to
 	 * recover anything. Otherwise, journal_load will do that
 	 * dirty work for us :) */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 76041b614758..1a759f40ab9e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2374,6 +2374,8 @@ extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
 
 extern int generic_file_fsync(struct file *, int);
 
+extern int generic_check_addressable(unsigned, u64);
+
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
 				struct page *, struct page *);