bcachefs: Fix for not dropping privs in fallocate

When modifying a file, we may be required to drop the suid/sgid bits -
we were missing a file_modified() call to do this.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index cca764cdb4f4ee21989bf1fbff884bde6f56372f..9a0751a140e479892a57d80dc78581875584e54b 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -3113,6 +3113,10 @@ long bch2_fallocate_dispatch(struct file *file, int mode,
        inode_dio_wait(&inode->v);
        bch2_pagecache_block_get(&inode->ei_pagecache_lock);
 
+       ret = file_modified(file);
+       if (ret)
+               goto err;
+
        if (!(mode & ~(FALLOC_FL_KEEP_SIZE|FALLOC_FL_ZERO_RANGE)))
                ret = bchfs_fallocate(inode, mode, offset, len);
        else if (mode == (FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE))
@@ -3123,8 +3127,7 @@ long bch2_fallocate_dispatch(struct file *file, int mode,
                ret = bchfs_fcollapse_finsert(inode, offset, len, false);
        else
                ret = -EOPNOTSUPP;
-
-
+err:
        bch2_pagecache_block_put(&inode->ei_pagecache_lock);
        inode_unlock(&inode->v);
        percpu_ref_put(&c->writes);