ext4: start handle at the last possible moment when creating inodes

In ext4_{create,mknod,mkdir,symlink}(), don't start the journal handle
until the inode has been succesfully allocated.  In order to do this,
we need to start the handle in the ext4_new_inode().  So create a new
variant of this function, ext4_new_inode_start_handle(), so the handle
can be created at the last possible minute, before we need to modify
the inode allocation bitmap block.

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

3 files changed, 71 insertions, 55 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 61ecf059f70c..fc1c0375c9f2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2004,9 +2004,20 @@ extern int ext4fs_dirhash(const char *name, int len, struct
                           dx_hash_info *hinfo);
 
 /* ialloc.c */
-extern struct inode *ext4_new_inode(handle_t *, struct inode *, umode_t,
-                                    const struct qstr *qstr, __u32 goal,
-                                    uid_t *owner);
+extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
+                                      const struct qstr *qstr, __u32 goal,
+                                      uid_t *owner, int handle_type,
+                                      unsigned int line_no, int nblocks);
+
+#define ext4_new_inode(handle, dir, mode, qstr, goal, owner) \
+        __ext4_new_inode((handle), (dir), (mode), (qstr), (goal), (owner), \
+                         0, 0, 0)
+#define ext4_new_inode_start_handle(dir, mode, qstr, goal, owner, \
+                                    type, nblocks)                  \
+        __ext4_new_inode(NULL, (dir), (mode), (qstr), (goal), (owner), \
+                         (type), __LINE__, (nblocks))
+
+
 extern void ext4_free_inode(handle_t *, struct inode *);
 extern struct inode * ext4_orphan_get(struct super_block *, unsigned long);
 extern unsigned long ext4_count_free_inodes(struct super_block *);
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 10bd6fecc9ff..91d8fe3aced3 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -634,8 +634,10 @@ static int find_group_other(struct super_block *sb, struct inode *parent,
  * For other inodes, search forward from the parent directory's block
  * group to find a free inode.
  */
-struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode,
-                             const struct qstr *qstr, __u32 goal, uid_t *owner)
+struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
+                               umode_t mode, const struct qstr *qstr,
+                               __u32 goal, uid_t *owner, int handle_type,
+                               unsigned int line_no, int nblocks)
 {
         struct super_block *sb;
         struct buffer_head *inode_bitmap_bh = NULL;
@@ -725,6 +727,15 @@ repeat_in_this_group:
                                    "inode=%lu", ino + 1);
                         continue;
                 }
+                if (!handle) {
+                        BUG_ON(nblocks <= 0);
+                        handle = __ext4_journal_start_sb(dir->i_sb, line_no,
+                                                         handle_type, nblocks);
+                        if (IS_ERR(handle)) {
+                                err = PTR_ERR(handle);
+                                goto fail;
+                        }
+                }
                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
                 if (err)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 5f3d2b569c63..3e1529c39808 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2257,30 +2257,28 @@ static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 {
         handle_t *handle;
         struct inode *inode;
-        int err, retries = 0;
+        int err, credits, retries = 0;
 
         dquot_initialize(dir);
 
+        credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+                   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+                   EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb));
 retry:
-        handle = ext4_journal_start(dir, EXT4_HT_DIR,
-                (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
-                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
-                 EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb)));
-        if (IS_ERR(handle))
-                return PTR_ERR(handle);
-
-        if (IS_DIRSYNC(dir))
-                ext4_handle_sync(handle);
-
-        inode = ext4_new_inode(handle, dir, mode, &dentry->d_name, 0, NULL);
+        inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
+                                            NULL, EXT4_HT_DIR, credits);
+        handle = ext4_journal_current_handle();
         err = PTR_ERR(inode);
         if (!IS_ERR(inode)) {
                 inode->i_op = &ext4_file_inode_operations;
                 inode->i_fop = &ext4_file_operations;
                 ext4_set_aops(inode);
                 err = ext4_add_nondir(handle, dentry, inode);
+                if (!err && IS_DIRSYNC(dir))
+                        ext4_handle_sync(handle);
         }
-        ext4_journal_stop(handle);
+        if (handle)
+                ext4_journal_stop(handle);
         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
                 goto retry;
         return err;
@@ -2291,32 +2289,30 @@ static int ext4_mknod(struct inode *dir, struct dentry *dentry,
 {
         handle_t *handle;
         struct inode *inode;
-        int err, retries = 0;
+        int err, credits, retries = 0;
 
         if (!new_valid_dev(rdev))
                 return -EINVAL;
 
         dquot_initialize(dir);
 
+        credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+                   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+                   EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb));
 retry:
-        handle = ext4_journal_start(dir, EXT4_HT_DIR,
-                (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
-                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
-                 EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb)));
-        if (IS_ERR(handle))
-                return PTR_ERR(handle);
-
-        if (IS_DIRSYNC(dir))
-                ext4_handle_sync(handle);
-
-        inode = ext4_new_inode(handle, dir, mode, &dentry->d_name, 0, NULL);
+        inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
+                                            NULL, EXT4_HT_DIR, credits);
+        handle = ext4_journal_current_handle();
         err = PTR_ERR(inode);
         if (!IS_ERR(inode)) {
                 init_special_inode(inode, inode->i_mode, rdev);
                 inode->i_op = &ext4_special_inode_operations;
                 err = ext4_add_nondir(handle, dentry, inode);
+                if (!err && IS_DIRSYNC(dir))
+                        ext4_handle_sync(handle);
         }
-        ext4_journal_stop(handle);
+        if (handle)
+                ext4_journal_stop(handle);
         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
                 goto retry;
         return err;
@@ -2408,26 +2404,21 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
         handle_t *handle;
         struct inode *inode;
-        int err, retries = 0;
+        int err, credits, retries = 0;
 
         if (EXT4_DIR_LINK_MAX(dir))
                 return -EMLINK;
 
         dquot_initialize(dir);
 
+        credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+                   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+                   EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb));
 retry:
-        handle = ext4_journal_start(dir, EXT4_HT_DIR,
-                (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
-                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
-                 EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb)));
-        if (IS_ERR(handle))
-                return PTR_ERR(handle);
-
-        if (IS_DIRSYNC(dir))
-                ext4_handle_sync(handle);
-
-        inode = ext4_new_inode(handle, dir, S_IFDIR | mode,
-                               &dentry->d_name, 0, NULL);
+        inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
+                                            &dentry->d_name,
+                                            0, NULL, EXT4_HT_DIR, credits);
+        handle = ext4_journal_current_handle();
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
                 goto out_stop;
@@ -2455,8 +2446,12 @@ out_clear_inode:
                 goto out_clear_inode;
         unlock_new_inode(inode);
         d_instantiate(dentry, inode);
+        if (IS_DIRSYNC(dir))
+                ext4_handle_sync(handle);
+
 out_stop:
-        ext4_journal_stop(handle);
+        if (handle)
+                ext4_journal_stop(handle);
         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
                 goto retry;
         return err;
@@ -2883,15 +2878,10 @@ static int ext4_symlink(struct inode *dir,
                           EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb);
         }
 retry:
-        handle = ext4_journal_start(dir, EXT4_HT_DIR, credits);
-        if (IS_ERR(handle))
-                return PTR_ERR(handle);
-
-        if (IS_DIRSYNC(dir))
-                ext4_handle_sync(handle);
-
-        inode = ext4_new_inode(handle, dir, S_IFLNK|S_IRWXUGO,
-                               &dentry->d_name, 0, NULL);
+        inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
+                                            &dentry->d_name, 0, NULL,
+                                            EXT4_HT_DIR, credits);
+        handle = ext4_journal_current_handle();
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
                 goto out_stop;
@@ -2944,8 +2934,12 @@ retry:
         }
         EXT4_I(inode)->i_disksize = inode->i_size;
         err = ext4_add_nondir(handle, dentry, inode);
+        if (!err && IS_DIRSYNC(dir))
+                ext4_handle_sync(handle);
+
 out_stop:
-        ext4_journal_stop(handle);
+        if (handle)
+                ext4_journal_stop(handle);
         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
                 goto retry;
         return err;