iget: stop EXT4 from using iget() and read_inode()

Stop the EXT4 filesystem from using iget() and read_inode().  Replace
ext4_read_inode() with ext4_iget(), and call that instead of iget().
ext4_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

ext4_fill_super() returns any error incurred when getting the root inode
instead of EINVAL.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 87 insertions, 70 deletions

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 575b5215c808..da18a74b966a 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -782,14 +782,15 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
         ext4_group_t block_group;
         int bit;
-        struct buffer_head *bitmap_bh = NULL;
+        struct buffer_head *bitmap_bh;
         struct inode *inode = NULL;
+        long err = -EIO;
 
         /* Error cases - e2fsck has already cleaned up for us */
         if (ino > max_ino) {
                 ext4_warning(sb, __FUNCTION__,
                              "bad orphan ino %lu!  e2fsck was run?", ino);
-                goto out;
+                goto error;
         }
 
         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
@@ -798,38 +799,49 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
         if (!bitmap_bh) {
                 ext4_warning(sb, __FUNCTION__,
                              "inode bitmap error for orphan %lu", ino);
-                goto out;
+                goto error;
         }
 
         /* Having the inode bit set should be a 100% indicator that this
          * is a valid orphan (no e2fsck run on fs).  Orphans also include
          * inodes that were being truncated, so we can't check i_nlink==0.
          */
-        if (!ext4_test_bit(bit, bitmap_bh->b_data) ||
-                        !(inode = iget(sb, ino)) || is_bad_inode(inode) ||
-                        NEXT_ORPHAN(inode) > max_ino) {
-                ext4_warning(sb, __FUNCTION__,
-                             "bad orphan inode %lu!  e2fsck was run?", ino);
-                printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
-                       bit, (unsigned long long)bitmap_bh->b_blocknr,
-                       ext4_test_bit(bit, bitmap_bh->b_data));
-                printk(KERN_NOTICE "inode=%p\n", inode);
-                if (inode) {
-                        printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
-                               is_bad_inode(inode));
-                        printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
-                               NEXT_ORPHAN(inode));
-                        printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
-                }
+        if (!ext4_test_bit(bit, bitmap_bh->b_data))
+                goto bad_orphan;
+
+        inode = ext4_iget(sb, ino);
+        if (IS_ERR(inode))
+                goto iget_failed;
+
+        if (NEXT_ORPHAN(inode) > max_ino)
+                goto bad_orphan;
+        brelse(bitmap_bh);
+        return inode;
+
+iget_failed:
+        err = PTR_ERR(inode);
+        inode = NULL;
+bad_orphan:
+        ext4_warning(sb, __FUNCTION__,
+                     "bad orphan inode %lu!  e2fsck was run?", ino);
+        printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
+               bit, (unsigned long long)bitmap_bh->b_blocknr,
+               ext4_test_bit(bit, bitmap_bh->b_data));
+        printk(KERN_NOTICE "inode=%p\n", inode);
+        if (inode) {
+                printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
+                       is_bad_inode(inode));
+                printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
+                       NEXT_ORPHAN(inode));
+                printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
                 /* Avoid freeing blocks if we got a bad deleted inode */
-                if (inode && inode->i_nlink == 0)
+                if (inode->i_nlink == 0)
                         inode->i_blocks = 0;
                 iput(inode);
-                inode = NULL;
         }
-out:
         brelse(bitmap_bh);
-        return inode;
+error:
+        return ERR_PTR(err);
 }
 
 unsigned long ext4_count_free_inodes (struct super_block * sb)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0e9055cf700e..f4e387452246 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2680,21 +2680,31 @@ static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
         }
 }
 
-void ext4_read_inode(struct inode * inode)
+struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 {
         struct ext4_iloc iloc;
         struct ext4_inode *raw_inode;
-        struct ext4_inode_info *ei = EXT4_I(inode);
+        struct ext4_inode_info *ei;
         struct buffer_head *bh;
+        struct inode *inode;
+        long ret;
         int block;
 
+        inode = iget_locked(sb, ino);
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+        if (!(inode->i_state & I_NEW))
+                return inode;
+
+        ei = EXT4_I(inode);
 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
         ei->i_acl = EXT4_ACL_NOT_CACHED;
         ei->i_default_acl = EXT4_ACL_NOT_CACHED;
 #endif
         ei->i_block_alloc_info = NULL;
 
-        if (__ext4_get_inode_loc(inode, &iloc, 0))
+        ret = __ext4_get_inode_loc(inode, &iloc, 0);
+        if (ret < 0)
                 goto bad_inode;
         bh = iloc.bh;
         raw_inode = ext4_raw_inode(&iloc);
@@ -2720,6 +2730,7 @@ void ext4_read_inode(struct inode * inode)
                     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
                         /* this inode is deleted */
                         brelse (bh);
+                        ret = -ESTALE;
                         goto bad_inode;
                 }
                 /* The only unlinked inodes we let through here have
@@ -2758,6 +2769,7 @@ void ext4_read_inode(struct inode * inode)
                 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
                     EXT4_INODE_SIZE(inode->i_sb)) {
                         brelse (bh);
+                        ret = -EIO;
                         goto bad_inode;
                 }
                 if (ei->i_extra_isize == 0) {
@@ -2811,11 +2823,12 @@ void ext4_read_inode(struct inode * inode)
         }
         brelse (iloc.bh);
         ext4_set_inode_flags(inode);
-        return;
+        unlock_new_inode(inode);
+        return inode;
 
 bad_inode:
-        make_bad_inode(inode);
-        return;
+        iget_failed(inode);
+        return ERR_PTR(ret);
 }
 
 static int ext4_inode_blocks_set(handle_t *handle,
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 67b6d8a1ceff..d153bb5922fc 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1039,17 +1039,11 @@ static struct dentry *ext4_lookup(struct inode * dir, struct dentry *dentry, str
                 if (!ext4_valid_inum(dir->i_sb, ino)) {
                         ext4_error(dir->i_sb, "ext4_lookup",
                                    "bad inode number: %lu", ino);
-                        inode = NULL;
-                } else
-                        inode = iget(dir->i_sb, ino);
-
-                if (!inode)
-                        return ERR_PTR(-EACCES);
-
-                if (is_bad_inode(inode)) {
-                        iput(inode);
-                        return ERR_PTR(-ENOENT);
+                        return ERR_PTR(-EIO);
                 }
+                inode = ext4_iget(dir->i_sb, ino);
+                if (IS_ERR(inode))
+                        return ERR_CAST(inode);
         }
         return d_splice_alias(inode, dentry);
 }
@@ -1078,18 +1072,13 @@ struct dentry *ext4_get_parent(struct dentry *child)
         if (!ext4_valid_inum(child->d_inode->i_sb, ino)) {
                 ext4_error(child->d_inode->i_sb, "ext4_get_parent",
                            "bad inode number: %lu", ino);
-                inode = NULL;
-        } else
-                inode = iget(child->d_inode->i_sb, ino);
-
-        if (!inode)
-                return ERR_PTR(-EACCES);
-
-        if (is_bad_inode(inode)) {
-                iput(inode);
-                return ERR_PTR(-ENOENT);
+                return ERR_PTR(-EIO);
         }
 
+        inode = ext4_iget(child->d_inode->i_sb, ino);
+        if (IS_ERR(inode))
+                return ERR_CAST(inode);
+
         parent = d_alloc_anon(inode);
         if (!parent) {
                 iput(inode);
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 4fbba60816f4..9477a2bd6ff2 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -779,12 +779,11 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
                                      "No reserved GDT blocks, can't resize");
                         return -EPERM;
                 }
-                inode = iget(sb, EXT4_RESIZE_INO);
-                if (!inode || is_bad_inode(inode)) {
+                inode = ext4_iget(sb, EXT4_RESIZE_INO);
+                if (IS_ERR(inode)) {
                         ext4_warning(sb, __FUNCTION__,
                                      "Error opening resize inode");
-                        iput(inode);
-                        return -ENOENT;
+                        return PTR_ERR(inode);
                 }
         }
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c89bb8797765..93beb865c20d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -777,11 +777,10 @@ static struct inode *ext4_nfs_get_inode(struct super_block *sb,
          * Currently we don't know the generation for parent directory, so
          * a generation of 0 means "accept any"
          */
-        inode = iget(sb, ino);
-        if (inode == NULL)
-                return ERR_PTR(-ENOMEM);
-        if (is_bad_inode(inode) ||
-            (generation && inode->i_generation != generation)) {
+        inode = ext4_iget(sb, ino);
+        if (IS_ERR(inode))
+                return ERR_CAST(inode);
+        if (generation && inode->i_generation != generation) {
                 iput(inode);
                 return ERR_PTR(-ESTALE);
         }
@@ -850,7 +849,6 @@ static struct quotactl_ops ext4_qctl_operations = {
 static const struct super_operations ext4_sops = {
         .alloc_inode    = ext4_alloc_inode,
         .destroy_inode  = ext4_destroy_inode,
-        .read_inode     = ext4_read_inode,
         .write_inode    = ext4_write_inode,
         .dirty_inode    = ext4_dirty_inode,
         .delete_inode   = ext4_delete_inode,
@@ -1805,6 +1803,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
         unsigned long journal_devnum = 0;
         unsigned long def_mount_opts;
         struct inode *root;
+        int ret = -EINVAL;
         int blocksize;
         int db_count;
         int i;
@@ -2237,19 +2236,24 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
          * so we can safely mount the rest of the filesystem now.
          */
 
-        root = iget(sb, EXT4_ROOT_INO);
-        sb->s_root = d_alloc_root(root);
-        if (!sb->s_root) {
+        root = ext4_iget(sb, EXT4_ROOT_INO);
+        if (IS_ERR(root)) {
                 printk(KERN_ERR "EXT4-fs: get root inode failed\n");
-                iput(root);
+                ret = PTR_ERR(root);
                 goto failed_mount4;
         }
         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
-                dput(sb->s_root);
-                sb->s_root = NULL;
+                iput(root);
                 printk(KERN_ERR "EXT4-fs: corrupt root inode, run e2fsck\n");
                 goto failed_mount4;
         }
+        sb->s_root = d_alloc_root(root);
+        if (!sb->s_root) {
+                printk(KERN_ERR "EXT4-fs: get root dentry failed\n");
+                iput(root);
+                ret = -ENOMEM;
+                goto failed_mount4;
+        }
 
         ext4_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 
@@ -2330,7 +2334,7 @@ out_fail:
         sb->s_fs_info = NULL;
         kfree(sbi);
         lock_kernel();
-        return -EINVAL;
+        return ret;
 }
 
 /*
@@ -2366,8 +2370,8 @@ static journal_t *ext4_get_journal(struct super_block *sb,
          * things happen if we iget() an unused inode, as the subsequent
          * iput() will try to delete it. */
 
-        journal_inode = iget(sb, journal_inum);
-        if (!journal_inode) {
+        journal_inode = ext4_iget(sb, journal_inum);
+        if (IS_ERR(journal_inode)) {
                 printk(KERN_ERR "EXT4-fs: no journal found.\n");
                 return NULL;
         }
@@ -2380,7 +2384,7 @@ static journal_t *ext4_get_journal(struct super_block *sb,
 
         jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
                   journal_inode, journal_inode->i_size);
-        if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
+        if (!S_ISREG(journal_inode->i_mode)) {
                 printk(KERN_ERR "EXT4-fs: invalid journal inode.\n");
                 iput(journal_inode);
                 return NULL;
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index 1852313fc7c7..c4f635a4dd25 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -1024,7 +1024,7 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
                                 struct buffer_head *bh_result,
                                 int create, int extend_disksize);
 
-extern void ext4_read_inode (struct inode *);
+extern struct inode *ext4_iget(struct super_block *, unsigned long);
 extern int  ext4_write_inode (struct inode *, int);
 extern int  ext4_setattr (struct dentry *, struct iattr *);
 extern void ext4_delete_inode (struct inode *);