ext4: replace opencoded i_writecount usage with inode_is_open_for_write()

There is a function which clearly conveys the objective of checking
i_writecount. Additionally the usage in ext4_mb_initialize_context was
wrong, since a node would have wrongfully been reported as writable if
i_writecount had a negative value (MMAP_DENY_WRITE).

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

2 files changed, 4 insertions, 5 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 34d7e0703cc6..213d1857a7cf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -391,7 +391,7 @@ void ext4_da_update_reserve_space(struct inode *inode,
          * inode's preallocations.
          */
         if ((ei->i_reserved_data_blocks == 0) &&
-            (atomic_read(&inode->i_writecount) == 0))
+            !inode_is_open_for_write(inode))
                 ext4_discard_preallocations(inode);
 }
 
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index e2248083cdca..6fb76d408093 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4176,9 +4176,8 @@ static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
         isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
                 >> bsbits;
 
-        if ((size == isize) &&
-            !ext4_fs_is_busy(sbi) &&
-            (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
+        if ((size == isize) && !ext4_fs_is_busy(sbi) &&
+            !inode_is_open_for_write(ac->ac_inode)) {
                 ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
                 return;
         }
@@ -4258,7 +4257,7 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac,
                         (unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
                         (unsigned) ar->lleft, (unsigned) ar->pleft,
                         (unsigned) ar->lright, (unsigned) ar->pright,
-                        atomic_read(&ar->inode->i_writecount) ? "" : "non-");
+                        inode_is_open_for_write(ar->inode) ? "" : "non-");
         return 0;
 
 }