ext4: Allow ext4 to run without a journal
A few weeks ago I posted a patch for discussion that allowed ext4 to run
without a journal. Since that time I've integrated the excellent
comments from Andreas and fixed several serious bugs. We're currently
running with this patch and generating some performance numbers against
both ext2 (with backported reservations code) and ext4 with and without
a journal. It just so happens that running without a journal is
slightly faster for most everything.
We did
iozone -T -t 4 s 2g -r 256k -T -I -i0 -i1 -i2
which creates 4 threads, each of which create and do reads and writes on
a 2G file, with a buffer size of 256K, using O_DIRECT for all file opens
to bypass the page cache. Results:
ext2 ext4, default ext4, no journal
initial writes 13.0 MB/s 15.4 MB/s 15.7 MB/s
rewrites 13.1 MB/s 15.6 MB/s 15.9 MB/s
reads 15.2 MB/s 16.9 MB/s 17.2 MB/s
re-reads 15.3 MB/s 16.9 MB/s 17.2 MB/s
random readers 5.6 MB/s 5.6 MB/s 5.7 MB/s
random writers 5.1 MB/s 5.3 MB/s 5.4 MB/s
So it seems that, so far, this was a useful exercise.
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 84a68ae..08873e9 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1233,10 +1233,10 @@
de = de2;
}
dx_insert_block(frame, hash2 + continued, newblock);
- err = ext4_journal_dirty_metadata(handle, bh2);
+ err = ext4_handle_dirty_metadata(handle, dir, bh2);
if (err)
goto journal_error;
- err = ext4_journal_dirty_metadata(handle, frame->bh);
+ err = ext4_handle_dirty_metadata(handle, dir, frame->bh);
if (err)
goto journal_error;
brelse(bh2);
@@ -1340,8 +1340,8 @@
ext4_update_dx_flag(dir);
dir->i_version++;
ext4_mark_inode_dirty(handle, dir);
- BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
- err = ext4_journal_dirty_metadata(handle, bh);
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, dir, bh);
if (err)
ext4_std_error(dir->i_sb, err);
brelse(bh);
@@ -1581,7 +1581,7 @@
dxtrace(dx_show_index("node", frames[1].entries));
dxtrace(dx_show_index("node",
((struct dx_node *) bh2->b_data)->entries));
- err = ext4_journal_dirty_metadata(handle, bh2);
+ err = ext4_handle_dirty_metadata(handle, inode, bh2);
if (err)
goto journal_error;
brelse (bh2);
@@ -1607,7 +1607,7 @@
if (err)
goto journal_error;
}
- ext4_journal_dirty_metadata(handle, frames[0].bh);
+ ext4_handle_dirty_metadata(handle, inode, frames[0].bh);
}
de = do_split(handle, dir, &bh, frame, &hinfo, &err);
if (!de)
@@ -1653,8 +1653,8 @@
else
de->inode = 0;
dir->i_version++;
- BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
- ext4_journal_dirty_metadata(handle, bh);
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ ext4_handle_dirty_metadata(handle, dir, bh);
return 0;
}
i += ext4_rec_len_from_disk(de->rec_len);
@@ -1732,7 +1732,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
inode = ext4_new_inode (handle, dir, mode);
err = PTR_ERR(inode);
@@ -1766,7 +1766,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
inode = ext4_new_inode(handle, dir, mode);
err = PTR_ERR(inode);
@@ -1802,7 +1802,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
inode = ext4_new_inode(handle, dir, S_IFDIR | mode);
err = PTR_ERR(inode);
@@ -1831,8 +1831,8 @@
strcpy(de->name, "..");
ext4_set_de_type(dir->i_sb, de, S_IFDIR);
inode->i_nlink = 2;
- BUFFER_TRACE(dir_block, "call ext4_journal_dirty_metadata");
- ext4_journal_dirty_metadata(handle, dir_block);
+ BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
+ ext4_handle_dirty_metadata(handle, dir, dir_block);
brelse(dir_block);
ext4_mark_inode_dirty(handle, inode);
err = ext4_add_entry(handle, dentry, inode);
@@ -1944,6 +1944,9 @@
struct ext4_iloc iloc;
int err = 0, rc;
+ if (!ext4_handle_valid(handle))
+ return 0;
+
lock_super(sb);
if (!list_empty(&EXT4_I(inode)->i_orphan))
goto out_unlock;
@@ -1972,7 +1975,7 @@
/* Insert this inode at the head of the on-disk orphan list... */
NEXT_ORPHAN(inode) = le32_to_cpu(EXT4_SB(sb)->s_es->s_last_orphan);
EXT4_SB(sb)->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
- err = ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
+ err = ext4_handle_dirty_metadata(handle, inode, EXT4_SB(sb)->s_sbh);
rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
if (!err)
err = rc;
@@ -2010,6 +2013,9 @@
struct ext4_iloc iloc;
int err = 0;
+ if (!ext4_handle_valid(handle))
+ return 0;
+
lock_super(inode->i_sb);
if (list_empty(&ei->i_orphan)) {
unlock_super(inode->i_sb);
@@ -2028,7 +2034,7 @@
* transaction handle with which to update the orphan list on
* disk, but we still need to remove the inode from the linked
* list in memory. */
- if (!handle)
+ if (sbi->s_journal && !handle)
goto out;
err = ext4_reserve_inode_write(handle, inode, &iloc);
@@ -2042,7 +2048,7 @@
if (err)
goto out_brelse;
sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
- err = ext4_journal_dirty_metadata(handle, sbi->s_sbh);
+ err = ext4_handle_dirty_metadata(handle, inode, sbi->s_sbh);
} else {
struct ext4_iloc iloc2;
struct inode *i_prev =
@@ -2093,7 +2099,7 @@
goto end_rmdir;
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
inode = dentry->d_inode;
@@ -2147,7 +2153,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
retval = -ENOENT;
bh = ext4_find_entry(dir, &dentry->d_name, &de);
@@ -2204,7 +2210,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
inode = ext4_new_inode(handle, dir, S_IFLNK|S_IRWXUGO);
err = PTR_ERR(inode);
@@ -2267,7 +2273,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
inode->i_ctime = ext4_current_time(inode);
ext4_inc_count(handle, inode);
@@ -2316,7 +2322,7 @@
return PTR_ERR(handle);
if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
- handle->h_sync = 1;
+ ext4_handle_sync(handle);
old_bh = ext4_find_entry(old_dir, &old_dentry->d_name, &old_de);
/*
@@ -2370,8 +2376,8 @@
new_dir->i_ctime = new_dir->i_mtime =
ext4_current_time(new_dir);
ext4_mark_inode_dirty(handle, new_dir);
- BUFFER_TRACE(new_bh, "call ext4_journal_dirty_metadata");
- ext4_journal_dirty_metadata(handle, new_bh);
+ BUFFER_TRACE(new_bh, "call ext4_handle_dirty_metadata");
+ ext4_handle_dirty_metadata(handle, new_dir, new_bh);
brelse(new_bh);
new_bh = NULL;
}
@@ -2421,8 +2427,8 @@
BUFFER_TRACE(dir_bh, "get_write_access");
ext4_journal_get_write_access(handle, dir_bh);
PARENT_INO(dir_bh->b_data) = cpu_to_le32(new_dir->i_ino);
- BUFFER_TRACE(dir_bh, "call ext4_journal_dirty_metadata");
- ext4_journal_dirty_metadata(handle, dir_bh);
+ BUFFER_TRACE(dir_bh, "call ext4_handle_dirty_metadata");
+ ext4_handle_dirty_metadata(handle, old_dir, dir_bh);
ext4_dec_count(handle, old_dir);
if (new_inode) {
/* checked empty_dir above, can't have another parent,