ext4: cleanup transaction restarts during inode deletion

During inode deletion, the number of journal credits that will be
needed is hard to determine.  For that reason we have journal
extend/restart calls in several places.  Whenever a transaction is
restarted, filesystem must be in a consistent state because there is
no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of
journal extend/restart logic.  It also handles getting jbd2 write
access and dirty metadata calls.  This function is called at every
iteration of handling an ea_inode reference.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 17 insertions, 49 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3e9415e2e74d..46def73d3472 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode)
          */
         sb_start_intwrite(inode->i_sb);
 
-        handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
+        if (!IS_NOQUOTA(inode))
+                extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+        handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+                                 ext4_blocks_for_truncate(inode)+extra_credits);
         if (IS_ERR(handle)) {
                 ext4_std_error(inode->i_sb, PTR_ERR(handle));
                 /*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode)
                 sb_end_intwrite(inode->i_sb);
                 goto no_delete;
         }
+
         if (IS_SYNC(inode))
                 ext4_handle_sync(handle);
-
-        /*
-         * Delete xattr inode before deleting the main inode.
-         */
-        err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
-        if (err) {
-                ext4_warning(inode->i_sb,
-                             "couldn't delete inode's xattr (err %d)", err);
-                goto stop_handle;
-        }
-
-        if (!IS_NOQUOTA(inode))
-                extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-        if (!ext4_handle_has_enough_credits(handle,
-                        ext4_blocks_for_truncate(inode) + extra_credits)) {
-                err = ext4_journal_extend(handle,
-                        ext4_blocks_for_truncate(inode) + extra_credits);
-                if (err > 0)
-                        err = ext4_journal_restart(handle,
-                        ext4_blocks_for_truncate(inode) + extra_credits);
-                if (err != 0) {
-                        ext4_warning(inode->i_sb,
-                                     "couldn't extend journal (err %d)", err);
-                        goto stop_handle;
-                }
-        }
-
         inode->i_size = 0;
         err = ext4_mark_inode_dirty(handle, inode);
         if (err) {
@@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode)
                 }
         }
 
-        /*
-         * ext4_ext_truncate() doesn't reserve any slop when it
-         * restarts journal transactions; therefore there may not be
-         * enough credits left in the handle to remove the inode from
-         * the orphan list and set the dtime field.
-         */
-        if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
-                err = ext4_journal_extend(handle, extra_credits);
-                if (err > 0)
-                        err = ext4_journal_restart(handle, extra_credits);
-                if (err != 0) {
-                        ext4_warning(inode->i_sb,
-                                     "couldn't extend journal (err %d)", err);
-                stop_handle:
-                        ext4_journal_stop(handle);
-                        ext4_orphan_del(NULL, inode);
-                        sb_end_intwrite(inode->i_sb);
-                        goto no_delete;
-                }
+        /* Remove xattr references. */
+        err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+                                      extra_credits);
+        if (err) {
+                ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+stop_handle:
+                ext4_journal_stop(handle);
+                ext4_orphan_del(NULL, inode);
+                sb_end_intwrite(inode->i_sb);
+                ext4_xattr_inode_array_free(ea_inode_array);
+                goto no_delete;
         }
 
         /*
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode)
                 ext4_clear_inode(inode);
         else
                 ext4_free_inode(handle, inode);
-
         ext4_journal_stop(handle);
         sb_end_intwrite(inode->i_sb);
         ext4_xattr_inode_array_free(ea_inode_array);