Remove Btrfs compat code for older kernels

Btrfs had compatibility code for kernels back to 2.6.18.  These have
been removed, and will be maintained in a separate backport
git tree from now on.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

12 files changed, 10 insertions, 368 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 2ee3017..4e780b2 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -20,13 +20,7 @@
 #include <linux/kthread.h>
 #include <linux/list.h>
 #include <linux/spinlock.h>
-
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
 # include <linux/freezer.h>
-#else
-# include <linux/sched.h>
-#endif
-
 #include "async-thread.h"
 
 /*
diff --git a/fs/btrfs/compat.h b/fs/btrfs/compat.h
index b0ed188..cd6598b 100644
--- a/fs/btrfs/compat.h
+++ b/fs/btrfs/compat.h
@@ -1,9 +1,8 @@
 #ifndef _COMPAT_H_
 #define _COMPAT_H_
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,26)
-#define trylock_page(page) (!TestSetPageLocked(page))
-#endif
+#define btrfs_drop_nlink(inode) drop_nlink(inode)
+#define btrfs_inc_nlink(inode)	inc_nlink(inode)
 
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,27)
 static inline struct dentry *d_obtain_alias(struct inode *inode)
@@ -22,39 +21,4 @@ static inline struct dentry *d_obtain_alias(struct inode *inode)
 }
 #endif
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
-static inline void btrfs_drop_nlink(struct inode *inode)
-{
-	inode->i_nlink--;
-}
-
-static inline void btrfs_inc_nlink(struct inode *inode)
-{
-	inode->i_nlink++;
-}
-#else
-# define btrfs_drop_nlink(inode) drop_nlink(inode)
-# define btrfs_inc_nlink(inode)	inc_nlink(inode)
-#endif
-
-/*
- * Even if AppArmor isn't enabled, it still has different prototypes.
- * Add more distro/version pairs here to declare which has AppArmor applied.
- */
-#if defined(CONFIG_SUSE_KERNEL)
-# if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
-# define REMOVE_SUID_PATH 1
-# endif
-#endif
-
-/*
- * catch any other distros that have patched in apparmor.  This isn't
- * 100% reliable because it won't catch people that hand compile their
- * own distro kernels without apparmor compiled in.  But, it is better
- * than nothing.
- */
-#ifdef CONFIG_SECURITY_APPARMOR
-# define REMOVE_SUID_PATH 1
-#endif
-
 #endif /* _COMPAT_H_ */
diff --git a/fs/btrfs/crc32c.h b/fs/btrfs/crc32c.h
index bf6c12e..4f0fefe 100644
--- a/fs/btrfs/crc32c.h
+++ b/fs/btrfs/crc32c.h
@@ -96,13 +96,7 @@ static inline u32 __btrfs_crc32c(u32 crc, unsigned char const *address,
  * We must workaround older implementations of crc32c_le()
  * found on older kernel versions.
  */
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
-#define btrfs_crc32c(seed, data, length) \
-	__cpu_to_le32( __btrfs_crc32c( __le32_to_cpu(seed), \
-		                      (unsigned char const *)data, length) )
-#else
 #define btrfs_crc32c(seed, data, length) \
 	__btrfs_crc32c(seed, (unsigned char const *)data, length)
 #endif
-#endif
 
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 138c157..3b3c1ca 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1472,12 +1472,9 @@ static inline u32 btrfs_level_size(struct btrfs_root *root, int level) {
 	((unsigned long)(btrfs_leaf_data(leaf) + \
 	btrfs_item_offset_nr(leaf, slot)))
 
-static inline struct dentry *fdentry(struct file *file) {
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
-	return file->f_dentry;
-#else
+static inline struct dentry *fdentry(struct file *file)
+{
 	return file->f_path.dentry;
-#endif
 }
 
 /* extent-tree.c */
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d35ca6a..dffb8da 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -26,11 +26,7 @@
 #include <linux/buffer_head.h> // for block_sync_page
 #include <linux/workqueue.h>
 #include <linux/kthread.h>
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
 # include <linux/freezer.h>
-#else
-# include <linux/sched.h>
-#endif
 #include "crc32c.h"
 #include "ctree.h"
 #include "disk-io.h"
@@ -373,21 +369,11 @@ out:
 	return ret;
 }
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 static void end_workqueue_bio(struct bio *bio, int err)
-#else
-static int end_workqueue_bio(struct bio *bio,
-				   unsigned int bytes_done, int err)
-#endif
 {
 	struct end_io_wq *end_io_wq = bio->bi_private;
 	struct btrfs_fs_info *fs_info;
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	if (bio->bi_size)
-		return 1;
-#endif
-
 	fs_info = end_io_wq->info;
 	end_io_wq->error = err;
 	end_io_wq->work.func = end_workqueue_fn;
@@ -397,10 +383,6 @@ static int end_workqueue_bio(struct bio *bio,
 				   &end_io_wq->work);
 	else
 		btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
-
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	return 0;
-#endif
 }
 
 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
@@ -1161,9 +1143,7 @@ void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 
 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
 {
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 	bdi_init(bdi);
-#endif
 	bdi->ra_pages	= default_backing_dev_info.ra_pages;
 	bdi->state		= 0;
 	bdi->capabilities	= default_backing_dev_info.capabilities;
@@ -1242,11 +1222,7 @@ static void end_workqueue_fn(struct btrfs_work *work)
 	bio->bi_private = end_io_wq->private;
 	bio->bi_end_io = end_io_wq->end_io;
 	kfree(end_io_wq);
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	bio_endio(bio, bio->bi_size, error);
-#else
 	bio_endio(bio, error);
-#endif
 }
 
 static int cleaner_kthread(void *arg)
@@ -1673,9 +1649,7 @@ fail:
 
 	kfree(extent_root);
 	kfree(tree_root);
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 	bdi_destroy(&fs_info->bdi);
-#endif
 	kfree(fs_info);
 	return ERR_PTR(err);
 }
@@ -1936,9 +1910,7 @@ int close_ctree(struct btrfs_root *root)
 	btrfs_close_devices(fs_info->fs_devices);
 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 	bdi_destroy(&fs_info->bdi);
-#endif
 
 	kfree(fs_info->extent_root);
 	kfree(fs_info->tree_root);
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 2b357a6..48b82cd 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -7,12 +7,6 @@
 #include "export.h"
 #include "compat.h"
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
-#define FILEID_BTRFS_WITHOUT_PARENT		0x4d
-#define FILEID_BTRFS_WITH_PARENT 		0x4e
-#define FILEID_BTRFS_WITH_PARENT_ROOT 		0x4f
-#endif
-
 #define BTRFS_FID_SIZE_NON_CONNECTABLE		(offsetof(struct btrfs_fid, parent_objectid)/4)
 #define BTRFS_FID_SIZE_CONNECTABLE		(offsetof(struct btrfs_fid, parent_root_objectid)/4)
 #define BTRFS_FID_SIZE_CONNECTABLE_ROOT		(sizeof(struct btrfs_fid)/4)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 58ad258..e3a25be 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1397,12 +1397,7 @@ static int check_page_writeback(struct extent_io_tree *tree,
  * Scheduling is not allowed, so the extent state tree is expected
  * to have one and only one object corresponding to this IO.
  */
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 static void end_bio_extent_writepage(struct bio *bio, int err)
-#else
-static int end_bio_extent_writepage(struct bio *bio,
-				   unsigned int bytes_done, int err)
-#endif
 {
 	int uptodate = err == 0;
 	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
@@ -1412,10 +1407,6 @@ static int end_bio_extent_writepage(struct bio *bio,
 	int whole_page;
 	int ret;
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	if (bio->bi_size)
-		return 1;
-#endif
 	do {
 		struct page *page = bvec->bv_page;
 		tree = &BTRFS_I(page->mapping->host)->io_tree;
@@ -1461,10 +1452,8 @@ static int end_bio_extent_writepage(struct bio *bio,
 		else
 			check_page_writeback(tree, page);
 	} while (bvec >= bio->bi_io_vec);
+
 	bio_put(bio);
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	return 0;
-#endif
 }
 
 /*
@@ -1478,12 +1467,7 @@ static int end_bio_extent_writepage(struct bio *bio,
  * Scheduling is not allowed, so the extent state tree is expected
  * to have one and only one object corresponding to this IO.
  */
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 static void end_bio_extent_readpage(struct bio *bio, int err)
-#else
-static int end_bio_extent_readpage(struct bio *bio,
-				   unsigned int bytes_done, int err)
-#endif
 {
 	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
@@ -1493,11 +1477,6 @@ static int end_bio_extent_readpage(struct bio *bio,
 	int whole_page;
 	int ret;
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	if (bio->bi_size)
-		return 1;
-#endif
-
 	do {
 		struct page *page = bvec->bv_page;
 		tree = &BTRFS_I(page->mapping->host)->io_tree;
@@ -1556,9 +1535,6 @@ static int end_bio_extent_readpage(struct bio *bio,
 	} while (bvec >= bio->bi_io_vec);
 
 	bio_put(bio);
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	return 0;
-#endif
 }
 
 /*
@@ -1566,12 +1542,7 @@ static int end_bio_extent_readpage(struct bio *bio,
  * the structs in the extent tree when done, and set the uptodate bits
  * as appropriate.
  */
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 static void end_bio_extent_preparewrite(struct bio *bio, int err)
-#else
-static int end_bio_extent_preparewrite(struct bio *bio,
-				       unsigned int bytes_done, int err)
-#endif
 {
 	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
@@ -1579,11 +1550,6 @@ static int end_bio_extent_preparewrite(struct bio *bio,
 	u64 start;
 	u64 end;
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	if (bio->bi_size)
-		return 1;
-#endif
-
 	do {
 		struct page *page = bvec->bv_page;
 		tree = &BTRFS_I(page->mapping->host)->io_tree;
@@ -1607,9 +1573,6 @@ static int end_bio_extent_preparewrite(struct bio *bio,
 	} while (bvec >= bio->bi_io_vec);
 
 	bio_put(bio);
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	return 0;
-#endif
 }
 
 static struct bio *
@@ -2079,12 +2042,6 @@ done:
 	return 0;
 }
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
-/* Taken directly from 2.6.23 with a mod for a lockpage hook */
-typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
-                                void *data);
-#endif
-
 /**
  * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
  * @mapping: address space structure to write
@@ -2201,10 +2158,9 @@ retry:
 	}
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		mapping->writeback_index = index;
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+
 	if (wbc->range_cont)
 		wbc->range_start = index << PAGE_CACHE_SHIFT;
-#endif
 	return ret;
 }
 EXPORT_SYMBOL(extent_write_cache_pages);
@@ -2560,18 +2516,10 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
 	 * by increasing the reference count.  So we know the page must
 	 * be in the radix tree.
 	 */
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
 	rcu_read_lock();
-#else
-	read_lock_irq(&mapping->tree_lock);
-#endif
 	p = radix_tree_lookup(&mapping->page_tree, i);
-
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
 	rcu_read_unlock();
-#else
-	read_unlock_irq(&mapping->tree_lock);
-#endif
+
 	return p;
 }
 
@@ -2773,21 +2721,13 @@ int clear_extent_buffer_dirty(struct extent_io_tree *tree,
 			}
 		}
 		clear_page_dirty_for_io(page);
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
 		spin_lock_irq(&page->mapping->tree_lock);
-#else
-		read_lock_irq(&page->mapping->tree_lock);
-#endif
 		if (!PageDirty(page)) {
 			radix_tree_tag_clear(&page->mapping->page_tree,
 						page_index(page),
 						PAGECACHE_TAG_DIRTY);
 		}
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
 		spin_unlock_irq(&page->mapping->tree_lock);
-#else
-		read_unlock_irq(&page->mapping->tree_lock);
-#endif
 		unlock_page(page);
 	}
 	return 0;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 48a702d..8856570 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -871,15 +871,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 		goto out_nolock;
 	if (count == 0)
 		goto out_nolock;
-#ifdef REMOVE_SUID_PATH
-	err = remove_suid(&file->f_path);
-#else
-# if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+
 	err = file_remove_suid(file);
-# else
-	err = remove_suid(fdentry(file));
-# endif
-#endif
 	if (err)
 		goto out_nolock;
 	file_update_time(file);
@@ -1003,17 +996,10 @@ out_nolock:
 			btrfs_commit_transaction(trans, root);
 		}
 	} else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
-		do_sync_file_range(file, start_pos,
-				      start_pos + num_written - 1,
-				      SYNC_FILE_RANGE_WRITE |
-				      SYNC_FILE_RANGE_WAIT_AFTER);
-#else
 		do_sync_mapping_range(inode->i_mapping, start_pos,
 				      start_pos + num_written - 1,
 				      SYNC_FILE_RANGE_WRITE |
 				      SYNC_FILE_RANGE_WAIT_AFTER);
-#endif
 		invalidate_mapping_pages(inode->i_mapping,
 		      start_pos >> PAGE_CACHE_SHIFT,
 		     (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
@@ -1097,12 +1083,7 @@ out:
 }
 
 static struct vm_operations_struct btrfs_file_vm_ops = {
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
-	.nopage         = filemap_nopage,
-	.populate       = filemap_populate,
-#else
 	.fault		= filemap_fault,
-#endif
 	.page_mkwrite	= btrfs_page_mkwrite,
 };
 
@@ -1118,9 +1099,6 @@ struct file_operations btrfs_file_operations = {
 	.read		= do_sync_read,
 	.aio_read       = generic_file_aio_read,
 	.splice_read	= generic_file_splice_read,
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
-	.sendfile	= generic_file_sendfile,
-#endif
 	.write		= btrfs_file_write,
 	.mmap		= btrfs_file_mmap,
 	.open		= generic_file_open,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index adb169d..48a3dc0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2073,104 +2073,6 @@ err:
 	return ret;
 }
 
-/* Kernels earlier than 2.6.28 still have the NFS deadlock where nfsd
-   will call the file system's ->lookup() method from within its
-   filldir callback, which in turn was called from the file system's
-   ->readdir() method. And will deadlock for many file systems. */
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
-
-struct nfshack_dirent {
-	u64		ino;
-	loff_t		offset;
-	int		namlen;
-	unsigned int	d_type;
-	char		name[];
-};
-
-struct nfshack_readdir {
-	char		*dirent;
-	size_t		used;
-	int		full;
-};
-
-
-
-static int btrfs_nfshack_filldir(void *__buf, const char *name, int namlen,
-			      loff_t offset, u64 ino, unsigned int d_type)
-{
-	struct nfshack_readdir *buf = __buf;
-	struct nfshack_dirent *de = (void *)(buf->dirent + buf->used);
-	unsigned int reclen;
-
-	reclen = ALIGN(sizeof(struct nfshack_dirent) + namlen, sizeof(u64));
-	if (buf->used + reclen > PAGE_SIZE) {
-		buf->full = 1;
-		return -EINVAL;
-	}
-
-	de->namlen = namlen;
-	de->offset = offset;
-	de->ino = ino;
-	de->d_type = d_type;
-	memcpy(de->name, name, namlen);
-	buf->used += reclen;
-
-	return 0;
-}
-
-static int btrfs_nfshack_readdir(struct file *file, void *dirent,
-				 filldir_t filldir)
-{
-	struct nfshack_readdir buf;
-	struct nfshack_dirent *de;
-	int err;
-	int size;
-	loff_t offset;
-
-	buf.dirent = (void *)__get_free_page(GFP_KERNEL);
-	if (!buf.dirent)
-		return -ENOMEM;
-
-	offset = file->f_pos;
-
-	do {
-		unsigned int reclen;
-
-		buf.used = 0;
-		buf.full = 0;
-		err = btrfs_real_readdir(file, &buf, btrfs_nfshack_filldir);
-		if (err)
-			break;
-
-		size = buf.used;
-
-		if (!size)
-			break;
-
-		de = (struct nfshack_dirent *)buf.dirent;
-		while (size > 0) {
-			offset = de->offset;
-
-			if (filldir(dirent, de->name, de->namlen, de->offset,
-				    de->ino, de->d_type))
-				goto done;
-			offset = file->f_pos;
-
-			reclen = ALIGN(sizeof(*de) + de->namlen,
-				       sizeof(u64));
-			size -= reclen;
-			de = (struct nfshack_dirent *)((char *)de + reclen);
-		}
-	} while (buf.full);
-
- done:
-	free_page((unsigned long)buf.dirent);
-	file->f_pos = offset;
-
-	return err;
-}
-#endif
-
 int btrfs_write_inode(struct inode *inode, int wait)
 {
 	struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -3311,13 +3213,8 @@ unsigned long btrfs_force_ra(struct address_space *mapping,
 {
 	pgoff_t req_size = last_index - offset + 1;
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
-	offset = page_cache_readahead(mapping, ra, file, offset, req_size);
-	return offset;
-#else
 	page_cache_sync_readahead(mapping, ra, file, offset, req_size);
 	return offset + req_size;
-#endif
 }
 
 struct inode *btrfs_alloc_inode(struct super_block *sb)
@@ -3373,14 +3270,7 @@ void btrfs_destroy_inode(struct inode *inode)
 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
 static void init_once(void *foo)
-#elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
-static void init_once(struct kmem_cache * cachep, void *foo)
-#else
-static void init_once(void * foo, struct kmem_cache * cachep,
-		      unsigned long flags)
-#endif
 {
 	struct btrfs_inode *ei = (struct btrfs_inode *) foo;
 
@@ -3403,22 +3293,10 @@ void btrfs_destroy_cachep(void)
 
 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
 				       unsigned long extra_flags,
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
-				       void (*ctor)(void *)
-#elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
-				       void (*ctor)(struct kmem_cache *, void *)
-#else
-				       void (*ctor)(void *, struct kmem_cache *,
-						    unsigned long)
-#endif
-				     )
+				       void (*ctor)(void *))
 {
 	return kmem_cache_create(name, size, 0, (SLAB_RECLAIM_ACCOUNT |
-				 SLAB_MEM_SPREAD | extra_flags), ctor
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
-				 ,NULL
-#endif
-				);
+				 SLAB_MEM_SPREAD | extra_flags), ctor);
 }
 
 int btrfs_init_cachep(void)
@@ -3666,12 +3544,7 @@ static int btrfs_set_page_dirty(struct page *page)
 	return __set_page_dirty_nobuffers(page);
 }
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
 static int btrfs_permission(struct inode *inode, int mask)
-#else
-static int btrfs_permission(struct inode *inode, int mask,
-			    struct nameidata *nd)
-#endif
 {
 	if (btrfs_test_flag(inode, READONLY) && (mask & MAY_WRITE))
 		return -EACCES;
@@ -3702,11 +3575,7 @@ static struct inode_operations btrfs_dir_ro_inode_operations = {
 static struct file_operations btrfs_dir_file_operations = {
 	.llseek		= generic_file_llseek,
 	.read		= generic_read_dir,
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
-	.readdir	= btrfs_nfshack_readdir,
-#else /* NFSd readdir/lookup deadlock is fixed */
 	.readdir	= btrfs_real_readdir,
-#endif
 	.unlocked_ioctl	= btrfs_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= btrfs_ioctl,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index f7b3eac..8399d6d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -349,10 +349,7 @@ static int btrfs_fill_super(struct super_block * sb,
 
 	sb->s_root = root_dentry;
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
 	save_mount_options(sb, data);
-#endif
-
 	return 0;
 
 fail_close:
@@ -566,11 +563,7 @@ static struct super_operations btrfs_super_ops = {
 	.put_super	= btrfs_put_super,
 	.write_super	= btrfs_write_super,
 	.sync_fs	= btrfs_sync_fs,
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
-	.read_inode     = btrfs_read_locked_inode,
-#else
 	.show_options	= generic_show_options,
-#endif
 	.write_inode	= btrfs_write_inode,
 	.dirty_inode	= btrfs_dirty_inode,
 	.alloc_inode	= btrfs_alloc_inode,
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 61af5d8..300076e 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -28,7 +28,6 @@
 #include "disk-io.h"
 #include "transaction.h"
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
 static ssize_t root_blocks_used_show(struct btrfs_root *root, char *buf)
 {
 	return snprintf(buf, PAGE_SIZE, "%llu\n",
@@ -267,35 +266,3 @@ void btrfs_exit_sysfs(void)
 	kset_unregister(btrfs_kset);
 }
 
-#else
-
-int btrfs_sysfs_add_super(struct btrfs_fs_info *fs)
-{
-	return 0;
-}
-
-int btrfs_sysfs_add_root(struct btrfs_root *root)
-{
-	return 0;
-}
-
-void btrfs_sysfs_del_root(struct btrfs_root *root)
-{
-	return;
-}
-
-void btrfs_sysfs_del_super(struct btrfs_fs_info *fs)
-{
-	return;
-}
-
-int btrfs_init_sysfs(void)
-{
-	return 0;
-}
-
-void btrfs_exit_sysfs(void)
-{
-	return;
-}
-#endif
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b9e5c2d..ddf8962 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2080,20 +2080,11 @@ int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
 }
 
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 static void end_bio_multi_stripe(struct bio *bio, int err)
-#else
-static int end_bio_multi_stripe(struct bio *bio,
-				   unsigned int bytes_done, int err)
-#endif
 {
 	struct btrfs_multi_bio *multi = bio->bi_private;
 	int is_orig_bio = 0;
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	if (bio->bi_size)
-		return 1;
-#endif
 	if (err)
 		atomic_inc(&multi->error);
 
@@ -2122,17 +2113,10 @@ static int end_bio_multi_stripe(struct bio *bio,
 		}
 		kfree(multi);
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-		bio_endio(bio, bio->bi_size, err);
-#else
 		bio_endio(bio, err);
-#endif
 	} else if (!is_orig_bio) {
 		bio_put(bio);
 	}
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-	return 0;
-#endif
 }
 
 struct async_sched {
@@ -2248,11 +2232,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 		} else {
 			bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
 			bio->bi_sector = logical >> 9;
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
-			bio_endio(bio, bio->bi_size, -EIO);
-#else
 			bio_endio(bio, -EIO);
-#endif
 		}
 		dev_nr++;
 	}