shmem: make shmem_get_inode() return ERR_PTR instead of NULL

Make shmem_get_inode() return ERR_PTR instead of NULL on error. This will be
useful later when we introduce quota support.

There should be no functional change.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230725144510.253763-3-cem@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/mm/shmem.c b/mm/shmem.c
index be71cdcaeb1462701a1de8a427522e2a3bc27533..e89c35c6558679dca2a37f319188978c696abddf 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2365,67 +2365,74 @@ static struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block
        struct shmem_inode_info *info;
        struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
        ino_t ino;
+       int err;
+
+       err = shmem_reserve_inode(sb, &ino);
+       if (err)
+               return ERR_PTR(err);
 
-       if (shmem_reserve_inode(sb, &ino))
-               return NULL;
 
        inode = new_inode(sb);
-       if (inode) {
-               inode->i_ino = ino;
-               inode_init_owner(idmap, inode, dir, mode);
-               inode->i_blocks = 0;
-               inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
-               inode->i_generation = get_random_u32();
-               info = SHMEM_I(inode);
-               memset(info, 0, (char *)inode - (char *)info);
-               spin_lock_init(&info->lock);
-               atomic_set(&info->stop_eviction, 0);
-               info->seals = F_SEAL_SEAL;
-               info->flags = flags & VM_NORESERVE;
-               info->i_crtime = inode->i_mtime;
-               info->fsflags = (dir == NULL) ? 0 :
-                       SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
-               if (info->fsflags)
-                       shmem_set_inode_flags(inode, info->fsflags);
-               INIT_LIST_HEAD(&info->shrinklist);
-               INIT_LIST_HEAD(&info->swaplist);
-               if (sbinfo->noswap)
-                       mapping_set_unevictable(inode->i_mapping);
-               simple_xattrs_init(&info->xattrs);
-               cache_no_acl(inode);
-               mapping_set_large_folios(inode->i_mapping);
-
-               switch (mode & S_IFMT) {
-               default:
-                       inode->i_op = &shmem_special_inode_operations;
-                       init_special_inode(inode, mode, dev);
-                       break;
-               case S_IFREG:
-                       inode->i_mapping->a_ops = &shmem_aops;
-                       inode->i_op = &shmem_inode_operations;
-                       inode->i_fop = &shmem_file_operations;
-                       mpol_shared_policy_init(&info->policy,
-                                                shmem_get_sbmpol(sbinfo));
-                       break;
-               case S_IFDIR:
-                       inc_nlink(inode);
-                       /* Some things misbehave if size == 0 on a directory */
-                       inode->i_size = 2 * BOGO_DIRENT_SIZE;
-                       inode->i_op = &shmem_dir_inode_operations;
-                       inode->i_fop = &simple_dir_operations;
-                       break;
-               case S_IFLNK:
-                       /*
-                        * Must not load anything in the rbtree,
-                        * mpol_free_shared_policy will not be called.
-                        */
-                       mpol_shared_policy_init(&info->policy, NULL);
-                       break;
-               }
 
-               lockdep_annotate_inode_mutex_key(inode);
-       } else
+       if (!inode) {
                shmem_free_inode(sb);
+               return ERR_PTR(-ENOSPC);
+       }
+
+       inode->i_ino = ino;
+       inode_init_owner(idmap, inode, dir, mode);
+       inode->i_blocks = 0;
+       inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+       inode->i_generation = get_random_u32();
+       info = SHMEM_I(inode);
+       memset(info, 0, (char *)inode - (char *)info);
+       spin_lock_init(&info->lock);
+       atomic_set(&info->stop_eviction, 0);
+       info->seals = F_SEAL_SEAL;
+       info->flags = flags & VM_NORESERVE;
+       info->i_crtime = inode->i_mtime;
+       info->fsflags = (dir == NULL) ? 0 :
+               SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
+       if (info->fsflags)
+               shmem_set_inode_flags(inode, info->fsflags);
+       INIT_LIST_HEAD(&info->shrinklist);
+       INIT_LIST_HEAD(&info->swaplist);
+       INIT_LIST_HEAD(&info->swaplist);
+       if (sbinfo->noswap)
+               mapping_set_unevictable(inode->i_mapping);
+       simple_xattrs_init(&info->xattrs);
+       cache_no_acl(inode);
+       mapping_set_large_folios(inode->i_mapping);
+
+       switch (mode & S_IFMT) {
+       default:
+               inode->i_op = &shmem_special_inode_operations;
+               init_special_inode(inode, mode, dev);
+               break;
+       case S_IFREG:
+               inode->i_mapping->a_ops = &shmem_aops;
+               inode->i_op = &shmem_inode_operations;
+               inode->i_fop = &shmem_file_operations;
+               mpol_shared_policy_init(&info->policy,
+                                        shmem_get_sbmpol(sbinfo));
+               break;
+       case S_IFDIR:
+               inc_nlink(inode);
+               /* Some things misbehave if size == 0 on a directory */
+               inode->i_size = 2 * BOGO_DIRENT_SIZE;
+               inode->i_op = &shmem_dir_inode_operations;
+               inode->i_fop = &simple_dir_operations;
+               break;
+       case S_IFLNK:
+               /*
+                * Must not load anything in the rbtree,
+                * mpol_free_shared_policy will not be called.
+                */
+               mpol_shared_policy_init(&info->policy, NULL);
+               break;
+       }
+
+       lockdep_annotate_inode_mutex_key(inode);
        return inode;
 }
 
@@ -3074,27 +3081,30 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir,
            struct dentry *dentry, umode_t mode, dev_t dev)
 {
        struct inode *inode;
-       int error = -ENOSPC;
+       int error;
 
        inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, dev, VM_NORESERVE);
-       if (inode) {
-               error = simple_acl_create(dir, inode);
-               if (error)
-                       goto out_iput;
-               error = security_inode_init_security(inode, dir,
-                                                    &dentry->d_name,
-                                                    shmem_initxattrs, NULL);
-               if (error && error != -EOPNOTSUPP)
-                       goto out_iput;
 
-               error = 0;
-               dir->i_size += BOGO_DIRENT_SIZE;
-               dir->i_ctime = dir->i_mtime = current_time(dir);
-               inode_inc_iversion(dir);
-               d_instantiate(dentry, inode);
-               dget(dentry); /* Extra count - pin the dentry in core */
-       }
+       if (IS_ERR(inode))
+               return PTR_ERR(inode);
+
+       error = simple_acl_create(dir, inode);
+       if (error)
+               goto out_iput;
+       error = security_inode_init_security(inode, dir,
+                                            &dentry->d_name,
+                                            shmem_initxattrs, NULL);
+       if (error && error != -EOPNOTSUPP)
+               goto out_iput;
+
+       error = 0;
+       dir->i_size += BOGO_DIRENT_SIZE;
+       dir->i_ctime = dir->i_mtime = current_time(dir);
+       inode_inc_iversion(dir);
+       d_instantiate(dentry, inode);
+       dget(dentry); /* Extra count - pin the dentry in core */
        return error;
+
 out_iput:
        iput(inode);
        return error;
@@ -3105,20 +3115,26 @@ shmem_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
              struct file *file, umode_t mode)
 {
        struct inode *inode;
-       int error = -ENOSPC;
+       int error;
 
        inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, 0, VM_NORESERVE);
-       if (inode) {
-               error = security_inode_init_security(inode, dir,
-                                                    NULL,
-                                                    shmem_initxattrs, NULL);
-               if (error && error != -EOPNOTSUPP)
-                       goto out_iput;
-               error = simple_acl_create(dir, inode);
-               if (error)
-                       goto out_iput;
-               d_tmpfile(file, inode);
+
+       if (IS_ERR(inode)) {
+               error = PTR_ERR(inode);
+               goto err_out;
        }
+
+       error = security_inode_init_security(inode, dir,
+                                            NULL,
+                                            shmem_initxattrs, NULL);
+       if (error && error != -EOPNOTSUPP)
+               goto out_iput;
+       error = simple_acl_create(dir, inode);
+       if (error)
+               goto out_iput;
+       d_tmpfile(file, inode);
+
+err_out:
        return finish_open_simple(file, error);
 out_iput:
        iput(inode);
@@ -3293,8 +3309,9 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir,
 
        inode = shmem_get_inode(idmap, dir->i_sb, dir, S_IFLNK | 0777, 0,
                                VM_NORESERVE);
-       if (!inode)
-               return -ENOSPC;
+
+       if (IS_ERR(inode))
+               return PTR_ERR(inode);
 
        error = security_inode_init_security(inode, dir, &dentry->d_name,
                                             shmem_initxattrs, NULL);
@@ -3932,12 +3949,13 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
        struct shmem_options *ctx = fc->fs_private;
        struct inode *inode;
        struct shmem_sb_info *sbinfo;
+       int error = -ENOMEM;
 
        /* Round up to L1_CACHE_BYTES to resist false sharing */
        sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info),
                                L1_CACHE_BYTES), GFP_KERNEL);
        if (!sbinfo)
-               return -ENOMEM;
+               return error;
 
        sb->s_fs_info = sbinfo;
 
@@ -4000,8 +4018,10 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 
        inode = shmem_get_inode(&nop_mnt_idmap, sb, NULL, S_IFDIR | sbinfo->mode, 0,
                                VM_NORESERVE);
-       if (!inode)
+       if (IS_ERR(inode)) {
+               error = PTR_ERR(inode);
                goto failed;
+       }
        inode->i_uid = sbinfo->uid;
        inode->i_gid = sbinfo->gid;
        sb->s_root = d_make_root(inode);
@@ -4011,7 +4031,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 
 failed:
        shmem_put_super(sb);
-       return -ENOMEM;
+       return error;
 }
 
 static int shmem_get_tree(struct fs_context *fc)
@@ -4380,10 +4400,16 @@ EXPORT_SYMBOL_GPL(shmem_truncate_range);
 #define shmem_vm_ops                           generic_file_vm_ops
 #define shmem_anon_vm_ops                      generic_file_vm_ops
 #define shmem_file_operations                  ramfs_file_operations
-#define shmem_get_inode(idmap, sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
 #define shmem_acct_size(flags, size)           0
 #define shmem_unacct_size(flags, size)         do {} while (0)
 
+static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb, struct inode *dir,
+                                           umode_t mode, dev_t dev, unsigned long flags)
+{
+       struct inode *inode = ramfs_get_inode(sb, dir, mode, dev);
+       return inode ? inode : ERR_PTR(-ENOSPC);
+}
+
 #endif /* CONFIG_SHMEM */
 
 /* common code */
@@ -4408,9 +4434,10 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
 
        inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL,
                                S_IFREG | S_IRWXUGO, 0, flags);
-       if (unlikely(!inode)) {
+
+       if (IS_ERR(inode)) {
                shmem_unacct_size(flags, size);
-               return ERR_PTR(-ENOSPC);
+               return ERR_CAST(inode);
        }
        inode->i_flags |= i_flags;
        inode->i_size = size;