udf: Push i_data_sem locking into udf_expand_file_adinicb()

The checks we do in udf_setsize() and udf_file_write_iter() are safe to
do only with i_rwsem locked as it stabilizes both file type and file
size. Hence we don't need to lock i_data_sem before we enter
udf_expand_file_adinicb() which simplifies the locking somewhat.

Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/file.c b/fs/udf/file.c
index 8be5116..6052481 100644 (file)
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -148,7 +148,6 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
        if (retval <= 0)
                goto out;
 
-       down_write(&iinfo->i_data_sem);
        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
            inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
                                 iocb->ki_pos + iov_iter_count(from))) {
@@ -158,15 +157,15 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                        udf_debug("udf_expand_adinicb: err=%d\n", err);
                        return err;
                }
-       } else
-               up_write(&iinfo->i_data_sem);
+       }
 
        retval = __generic_file_write_iter(iocb, from);
 out:
-       down_write(&iinfo->i_data_sem);
-       if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0)
+       if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0) {
+               down_write(&iinfo->i_data_sem);
                iinfo->i_lenAlloc = inode->i_size;
-       up_write(&iinfo->i_data_sem);
+               up_write(&iinfo->i_data_sem);
+       }
        inode_unlock(inode);
 
        if (retval > 0) {

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index adef328..627cdcb 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -247,7 +247,6 @@ const struct address_space_operations udf_aops = {
 /*
  * Expand file stored in ICB to a normal one-block-file
  *
- * This function requires i_data_sem for writing and releases it.
  * This function requires i_mutex held
  */
 int udf_expand_file_adinicb(struct inode *inode)
@@ -259,6 +258,7 @@ int udf_expand_file_adinicb(struct inode *inode)
 
        WARN_ON_ONCE(!inode_is_locked(inode));
        if (!iinfo->i_lenAlloc) {
+               down_write(&iinfo->i_data_sem);
                if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
                        iinfo->i_alloc_type = ICBTAG_FLAG_AD_SHORT;
                else
@@ -269,11 +269,6 @@ int udf_expand_file_adinicb(struct inode *inode)
                mark_inode_dirty(inode);
                return 0;
        }
-       /*
-        * Release i_data_sem so that we can lock a page - page lock ranks
-        * above i_data_sem. i_mutex still protects us against file changes.
-        */
-       up_write(&iinfo->i_data_sem);
 
        page = find_or_create_page(inode->i_mapping, 0, GFP_NOFS);
        if (!page)
@@ -1160,19 +1155,18 @@ int udf_setsize(struct inode *inode, loff_t newsize)
 
        iinfo = UDF_I(inode);
        if (newsize > inode->i_size) {
-               down_write(&iinfo->i_data_sem);
                if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
-                       if (bsize <
+                       if (bsize >=
                            (udf_file_entry_alloc_offset(inode) + newsize)) {
-                               err = udf_expand_file_adinicb(inode);
-                               if (err)
-                                       return err;
                                down_write(&iinfo->i_data_sem);
-                       } else {
                                iinfo->i_lenAlloc = newsize;
                                goto set_size;
                        }
+                       err = udf_expand_file_adinicb(inode);
+                       if (err)
+                               return err;
                }
+               down_write(&iinfo->i_data_sem);
                err = udf_extend_file(inode, newsize);
                if (err) {
                        up_write(&iinfo->i_data_sem);