fs: Preserve error code in get_empty_filp(), part 2

Allocating a file structure in function get_empty_filp() might fail because
of several reasons:
 - not enough memory for file structures
 - operation is not allowed
 - user is over its limit

Currently the function returns NULL in all cases and we loose the exact
reason of the error. All callers of get_empty_filp() assume that the function
can fail with ENFILE only.

Return error through pointer. Change all callers to preserve this error code.

[AV: cleaned up a bit, carved the get_empty_filp() part out into a separate commit
(things remaining here deal with alloc_file()), removed pipe(2) behaviour change]

Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Reviewed-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 5 insertions, 7 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index edb42ea60c76..99fe7ef2f09b 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -923,8 +923,7 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
                                 struct user_struct **user,
                                 int creat_flags, int page_size_log)
 {
-        int error = -ENOMEM;
-        struct file *file;
+        struct file *file = ERR_PTR(-ENOMEM);
         struct inode *inode;
         struct path path;
         struct dentry *root;
@@ -964,7 +963,7 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
                 goto out_shm_unlock;
 
         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
-        error = -ENOSPC;
+        file = ERR_PTR(-ENOSPC);
         inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
         if (!inode)
                 goto out_dentry;
@@ -973,7 +972,7 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
         size += addr & ~huge_page_mask(hstate);
         num_pages = ALIGN(size, huge_page_size(hstate)) >>
                         huge_page_shift(hstate);
-        error = -ENOMEM;
+        file = ERR_PTR(-ENOMEM);
         if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
                 goto out_inode;
 
@@ -981,10 +980,9 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr,
         inode->i_size = size;
         clear_nlink(inode);
 
-        error = -ENFILE;
         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
                         &hugetlbfs_file_operations);
-        if (!file)
+        if (IS_ERR(file))
                 goto out_dentry; /* inode is already attached */
 
         return file;
@@ -998,7 +996,7 @@ out_shm_unlock:
                 user_shm_unlock(size, *user);
                 *user = NULL;
         }
-        return ERR_PTR(error);
+        return file;
 }
 
 static int __init init_hugetlbfs_fs(void)