udf: Replace bkl with the UDF_I(inode)->i_data_sem for protect udf_inode_info struct

Replace bkl with the UDF_I(inode)->i_data_sem rw semaphore in
udf_release_file(), udf_symlink(), udf_symlink_filler(), udf_get_block(),
udf_block_map(), and udf_setattr(). The rule now is that any operation
on regular file's or symlink's extents (or generally allocation information
including goal block) needs to hold i_data_sem.

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 701fcda18415..d5eb000ddddd 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -893,18 +893,18 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
         struct udf_inode_info *iinfo;
         struct super_block *sb = dir->i_sb;
 
-        lock_kernel();
         inode = udf_new_inode(dir, S_IFLNK | S_IRWXUGO, &err);
         if (!inode)
                 goto out;
 
+        iinfo = UDF_I(inode);
+        down_write(&iinfo->i_data_sem);
         name = kmalloc(UDF_NAME_LEN, GFP_NOFS);
         if (!name) {
                 err = -ENOMEM;
                 goto out_no_entry;
         }
 
-        iinfo = UDF_I(inode);
         inode->i_data.a_ops = &udf_symlink_aops;
         inode->i_op = &udf_symlink_inode_operations;
 
@@ -1024,6 +1024,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
         udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
         if (UDF_I(dir)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
                 mark_inode_dirty(dir);
+        up_write(&iinfo->i_data_sem);
         if (fibh.sbh != fibh.ebh)
                 brelse(fibh.ebh);
         brelse(fibh.sbh);
@@ -1032,10 +1033,10 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
 
 out:
         kfree(name);
-        unlock_kernel();
         return err;
 
 out_no_entry:
+        up_write(&iinfo->i_data_sem);
         inode_dec_link_count(inode);
         iput(inode);
         goto out;