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;