From af62baea252c06282ba926012bbb5dce0005429c Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Fri, 24 Jun 2011 14:29:40 -0400
Subject: [PATCH] --- yaml --- r: 257375 b: refs/heads/master c:
 582686915803e34adc8fdcd90bff7ca7f6a42221 h: refs/heads/master i:   257373:
 f54087661a742a83251009b31ccd0b460e43d6a1   257371:
 5ec70b73d772fa9a70936e6208cf60bf636b3fba   257367:
 0a62310511165d4c25594badc4c9757a43bd93dd   257359:
 06d1ae9a9676213ac060d439b0ce4d3ceba9b4a9   257343:
 8efaec26038fdf48cc459dd323c1b555c99a1c46 v: v3

---
 [refs]               | 2 +-
 trunk/fs/fat/fat.h   | 1 +
 trunk/fs/fat/file.c  | 2 ++
 trunk/fs/fat/inode.c | 6 ++++--
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 3e012ffc7a6e..8f5cfb21ed9d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8c5dc70aae29d2571c0f461d69b37e4e6e01ff4c
+refs/heads/master: 582686915803e34adc8fdcd90bff7ca7f6a42221
diff --git a/trunk/fs/fat/fat.h b/trunk/fs/fat/fat.h
index 8276cc282dec..a975b4147e91 100644
--- a/trunk/fs/fat/fat.h
+++ b/trunk/fs/fat/fat.h
@@ -109,6 +109,7 @@ struct msdos_inode_info {
 	int i_attrs;		/* unused attribute bits */
 	loff_t i_pos;		/* on-disk position of directory entry or 0 */
 	struct hlist_node i_fat_hash;	/* hash by i_location */
+	struct rw_semaphore truncate_lock; /* protect bmap against truncate */
 	struct inode vfs_inode;
 };
 
diff --git a/trunk/fs/fat/file.c b/trunk/fs/fat/file.c
index 7018e1d8902d..a4a3a3c06436 100644
--- a/trunk/fs/fat/file.c
+++ b/trunk/fs/fat/file.c
@@ -429,8 +429,10 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
 	}
 
 	if (attr->ia_valid & ATTR_SIZE) {
+		down_write(&MSDOS_I(inode)->truncate_lock);
 		truncate_setsize(inode, attr->ia_size);
 		fat_truncate_blocks(inode, attr->ia_size);
+		up_write(&MSDOS_I(inode)->truncate_lock);
 	}
 
 	setattr_copy(inode, attr);
diff --git a/trunk/fs/fat/inode.c b/trunk/fs/fat/inode.c
index cb8d8391ac0b..3decce46c38f 100644
--- a/trunk/fs/fat/inode.c
+++ b/trunk/fs/fat/inode.c
@@ -224,9 +224,9 @@ static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
 	sector_t blocknr;
 
 	/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
-	down_read(&mapping->host->i_alloc_sem);
+	down_read(&MSDOS_I(mapping->host)->truncate_lock);
 	blocknr = generic_block_bmap(mapping, block, fat_get_block);
-	up_read(&mapping->host->i_alloc_sem);
+	up_read(&MSDOS_I(mapping->host)->truncate_lock);
 
 	return blocknr;
 }
@@ -510,6 +510,8 @@ static struct inode *fat_alloc_inode(struct super_block *sb)
 	ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
 	if (!ei)
 		return NULL;
+
+	init_rwsem(&ei->truncate_lock);
 	return &ei->vfs_inode;
 }