ext4: enforce bigalloc restrictions (e.g., no online resizing, etc.)

At least initially if the bigalloc feature is enabled, we will not
support non-extent mapped inodes, online resizing, online defrag, or
the FITRIM ioctl.  This simplifies the initial implementation.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

4 files changed, 48 insertions, 4 deletions

diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index ea704dff8669..3cfc73fbca8e 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -699,6 +699,13 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
         /*
          * Okay, we need to do block allocation.
         */
+        if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+                                       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+                EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
+                                 "non-extent mapped inodes with bigalloc");
+                return -ENOSPC;
+        }
+
         goal = ext4_find_goal(inode, map->m_lblk, partial);
 
         /* the number of blocks need to allocate for [d,t]indirect blocks */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6ecc93979e48..904a9a623dab 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3358,6 +3358,11 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
                 return -ENOTSUPP;
         }
 
+        if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) {
+                /* TODO: Add support for bigalloc file systems */
+                return -ENOTSUPP;
+        }
+
         return ext4_ext_punch_hole(file, offset, length);
 }
 
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index f18bfe37aff8..2046d699b4a7 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -21,6 +21,7 @@
 long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
         struct inode *inode = filp->f_dentry->d_inode;
+        struct super_block *sb = inode->i_sb;
         struct ext4_inode_info *ei = EXT4_I(inode);
         unsigned int flags;
 
@@ -183,7 +184,6 @@ setversion_out:
                  * Returns 1 if it slept, else zero.
                  */
                 {
-                        struct super_block *sb = inode->i_sb;
                         DECLARE_WAITQUEUE(wait, current);
                         int ret = 0;
 
@@ -199,7 +199,6 @@ setversion_out:
 #endif
         case EXT4_IOC_GROUP_EXTEND: {
                 ext4_fsblk_t n_blocks_count;
-                struct super_block *sb = inode->i_sb;
                 int err, err2=0;
 
                 err = ext4_resize_begin(sb);
@@ -209,6 +208,13 @@ setversion_out:
                 if (get_user(n_blocks_count, (__u32 __user *)arg))
                         return -EFAULT;
 
+                if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+                               EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+                        ext4_msg(sb, KERN_ERR,
+                                 "Online resizing not supported with bigalloc");
+                        return -EOPNOTSUPP;
+                }
+
                 err = mnt_want_write(filp->f_path.mnt);
                 if (err)
                         return err;
@@ -250,6 +256,13 @@ setversion_out:
                         goto mext_out;
                 }
 
+                if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+                               EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+                        ext4_msg(sb, KERN_ERR,
+                                 "Online defrag not supported with bigalloc");
+                        return -EOPNOTSUPP;
+                }
+
                 err = mnt_want_write(filp->f_path.mnt);
                 if (err)
                         goto mext_out;
@@ -270,7 +283,6 @@ mext_out:
 
         case EXT4_IOC_GROUP_ADD: {
                 struct ext4_new_group_data input;
-                struct super_block *sb = inode->i_sb;
                 int err, err2=0;
 
                 err = ext4_resize_begin(sb);
@@ -281,6 +293,13 @@ mext_out:
                                 sizeof(input)))
                         return -EFAULT;
 
+                if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+                               EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+                        ext4_msg(sb, KERN_ERR,
+                                 "Online resizing not supported with bigalloc");
+                        return -EOPNOTSUPP;
+                }
+
                 err = mnt_want_write(filp->f_path.mnt);
                 if (err)
                         return err;
@@ -337,7 +356,6 @@ mext_out:
 
         case FITRIM:
         {
-                struct super_block *sb = inode->i_sb;
                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
                 struct fstrim_range range;
                 int ret = 0;
@@ -348,6 +366,13 @@ mext_out:
                 if (!blk_queue_discard(q))
                         return -EOPNOTSUPP;
 
+                if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+                               EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+                        ext4_msg(sb, KERN_ERR,
+                                 "FITRIM not supported with bigalloc");
+                        return -EOPNOTSUPP;
+                }
+
                 if (copy_from_user(&range, (struct fstrim_range *)arg,
                     sizeof(range)))
                         return -EFAULT;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 823e7d9deee2..25a4bfe3f39f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2701,6 +2701,13 @@ static int ext4_feature_set_ok(struct super_block *sb, int readonly)
                         return 0;
                 }
         }
+        if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
+            !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
+                ext4_msg(sb, KERN_ERR,
+                         "Can't support bigalloc feature without "
+                         "extents feature\n");
+                return 0;
+        }
         return 1;
 }