From 582686915803e34adc8fdcd90bff7ca7f6a42221 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 24 Jun 2011 14:29:40 -0400 Subject: [PATCH] fat: remove i_alloc_sem abuse Add a new rw_semaphore to protect bmap against truncate. Previous i_alloc_sem was abused for this, but it's going away in this series. Note that we can't simply use i_mutex, given that the swapon code calls ->bmap under it. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/fat/fat.h | 1 + fs/fat/file.c | 2 ++ fs/fat/inode.c | 6 ++++-- 3 files changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 8276cc282dec..a975b4147e91 100644 --- a/fs/fat/fat.h +++ b/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/fs/fat/file.c b/fs/fat/file.c index 7018e1d8902d..a4a3a3c06436 100644 --- a/fs/fat/file.c +++ b/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/fs/fat/inode.c b/fs/fat/inode.c index cb8d8391ac0b..3decce46c38f 100644 --- a/fs/fat/inode.c +++ b/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; } -- 2.34.1