Pull request from git://github.com/prasad-joshi/logfs_upstream.git

There are few important bug fixes for LogFS
 
 9f0bbd8 logfs: query block device for number of pages to send with bio
 	This BUG was found when LogFS was used on KVM. The patch fixes
 	the problem by asking for underlaying block device the number
 	of pages to send with each BIO.
 
 41b93bc logfs: maintain the ordering of meta-inode destruction
 	LogFS maintains file system meta-data in special inodes. These
 	inodes are releated to each other, therefore they must be
 	destroyed in a proper order.
 
 ddb24bb logfs: create a pagecache page if it is not present
 
 cd8bfa9 logfs: initialize the number of iovecs in bio
 	LogFS used to panic when it was created on an encrypted LVM
 	volume. The patch fixes the problem by properly initializing
 	the BIO.
 
 d2dcd90 logfs: destroy the reserved inodes while unmounting
 
 Diffstat:
  fs/logfs/dev_bdev.c  |   15 ++++++++-------
  fs/logfs/inode.c     |   18 +-----------------
  fs/logfs/journal.c   |    2 +-
  fs/logfs/readwrite.c |    1 +
  fs/logfs/segment.c   |    2 +-
  5 files changed, 12 insertions(+), 26 deletions(-)
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Merge tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream

Pull LogFS bugfixes from Prasad Joshi:

 - "logfs: query block device for number of pages to send with bio"

	This BUG was found when LogFS was used on KVM. The patch fixes
	the problem by asking for underlaying block device the number
	of pages to send with each BIO.

 - "logfs: maintain the ordering of meta-inode destruction"

	LogFS maintains file system meta-data in special inodes. These
	inodes are releated to each other, therefore they must be
	destroyed in a proper order.

 - "logfs: initialize the number of iovecs in bio"

	LogFS used to panic when it was created on an encrypted LVM
	volume. The patch fixes the problem by properly initializing
	the BIO.

Plus a couple more:
 - logfs: create a pagecache page if it is not present
 - logfs: destroy the reserved inodes while unmounting

* tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream:
  logfs: query block device for number of pages to send with bio
  logfs: maintain the ordering of meta-inode destruction
  logfs: create a pagecache page if it is not present
  logfs: initialize the number of iovecs in bio
  logfs: destroy the reserved inodes while unmounting

fs/logfs/dev_bdev.c

@@ -26,6 +26,7 @@ static int sync_request(struct page *page, struct block_device *bdev, int rw)
 	struct completion complete;
 
 	bio_init(&bio);
+	bio.bi_max_vecs = 1;
 	bio.bi_io_vec = &bio_vec;
 	bio_vec.bv_page = page;
 	bio_vec.bv_len = PAGE_SIZE;
@@ -95,12 +96,11 @@ static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
 	struct address_space *mapping = super->s_mapping_inode->i_mapping;
 	struct bio *bio;
 	struct page *page;
-	struct request_queue *q = bdev_get_queue(sb->s_bdev);
-	unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
+	unsigned int max_pages;
 	int i;
 
-	if (max_pages > BIO_MAX_PAGES)
-		max_pages = BIO_MAX_PAGES;
+	max_pages = min(nr_pages, (size_t) bio_get_nr_vecs(super->s_bdev));
+
 	bio = bio_alloc(GFP_NOFS, max_pages);
 	BUG_ON(!bio);
 
@@ -190,12 +190,11 @@ static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
 {
 	struct logfs_super *super = logfs_super(sb);
 	struct bio *bio;
-	struct request_queue *q = bdev_get_queue(sb->s_bdev);
-	unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
+	unsigned int max_pages;
 	int i;
 
-	if (max_pages > BIO_MAX_PAGES)
-		max_pages = BIO_MAX_PAGES;
+	max_pages = min(nr_pages, (size_t) bio_get_nr_vecs(super->s_bdev));
+
 	bio = bio_alloc(GFP_NOFS, max_pages);
 	BUG_ON(!bio);
 

fs/logfs/inode.c

@@ -156,10 +156,26 @@ static void __logfs_destroy_inode(struct inode *inode)
 	call_rcu(&inode->i_rcu, logfs_i_callback);
 }
 
+static void __logfs_destroy_meta_inode(struct inode *inode)
+{
+	struct logfs_inode *li = logfs_inode(inode);
+	BUG_ON(li->li_block);
+	call_rcu(&inode->i_rcu, logfs_i_callback);
+}
+
 static void logfs_destroy_inode(struct inode *inode)
 {
 	struct logfs_inode *li = logfs_inode(inode);
 
+	if (inode->i_ino < LOGFS_RESERVED_INOS) {
+		/*
+		 * The reserved inodes are never destroyed unless we are in
+		 * unmont path.
+		 */
+		__logfs_destroy_meta_inode(inode);
+		return;
+	}
+
 	BUG_ON(list_empty(&li->li_freeing_list));
 	spin_lock(&logfs_inode_lock);
 	li->li_refcount--;
@@ -373,8 +389,8 @@ static void logfs_put_super(struct super_block *sb)
 {
 	struct logfs_super *super = logfs_super(sb);
 	/* kill the meta-inodes */
-	iput(super->s_master_inode);
 	iput(super->s_segfile_inode);
+	iput(super->s_master_inode);
 	iput(super->s_mapping_inode);
 }
 

fs/logfs/journal.c

@@ -565,7 +565,7 @@ static void write_wbuf(struct super_block *sb, struct logfs_area *area,
 	index = ofs >> PAGE_SHIFT;
 	page_ofs = ofs & (PAGE_SIZE - 1);
 
-	page = find_lock_page(mapping, index);
+	page = find_or_create_page(mapping, index, GFP_NOFS);
 	BUG_ON(!page);
 	memcpy(wbuf, page_address(page) + page_ofs, super->s_writesize);
 	unlock_page(page);

fs/logfs/readwrite.c

@@ -2189,7 +2189,6 @@ void logfs_evict_inode(struct inode *inode)
 		return;
 	}
 
-	BUG_ON(inode->i_ino < LOGFS_RESERVED_INOS);
 	page = inode_to_page(inode);
 	BUG_ON(!page); /* FIXME: Use emergency page */
 	logfs_put_write_page(page);

fs/logfs/segment.c

@@ -886,7 +886,7 @@ static struct logfs_area *alloc_area(struct super_block *sb)
 
 static void map_invalidatepage(struct page *page, unsigned long l)
 {
-	BUG();
+	return;
 }
 
 static int map_releasepage(struct page *page, gfp_t g)