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>

1 files changed, 20 insertions, 16 deletions

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;