@@ -540,6 +540,7 @@ do { \
#define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT 0x1000000 /* Journal Async Commit */
#define EXT4_MOUNT_I_VERSION 0x2000000 /* i_version support */
#define EXT4_MOUNT_DELALLOC 0x8000000 /* Delalloc support */
+#define EXT4_MOUNT_AKPM_LOCK_HACK 0x10000000 /* akpm lock hack */
/* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
#ifndef _LINUX_EXT2_FS_H
#define clear_opt(o, opt) o &= ~EXT4_MOUNT_##opt
@@ -752,6 +752,8 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
seq_puts(seq, ",journal_async_commit");
if (test_opt(sb, NOBH))
seq_puts(seq, ",nobh");
+ if (test_opt(sb, AKPM_LOCK_HACK))
+ seq_puts(seq, ",akpm_lock_hack");
if (!test_opt(sb, EXTENTS))
seq_puts(seq, ",noextents");
if (test_opt(sb, I_VERSION))
@@ -911,7 +913,7 @@ enum {
Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
Opt_grpquota, Opt_extents, Opt_noextents, Opt_i_version,
Opt_mballoc, Opt_nomballoc, Opt_stripe, Opt_delalloc, Opt_nodelalloc,
- Opt_inode_readahead_blks
+ Opt_inode_readahead_blks, Opt_akpm_lock_hack,
};
static match_table_t tokens = {
@@ -973,6 +975,7 @@ static match_table_t tokens = {
{Opt_delalloc, "delalloc"},
{Opt_nodelalloc, "nodelalloc"},
{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
+ {Opt_akpm_lock_hack, "akpm_lock_hack"},
{Opt_err, NULL},
};
@@ -1382,6 +1385,9 @@ set_qf_format:
return 0;
sbi->s_inode_readahead_blks = option;
break;
+ case Opt_akpm_lock_hack:
+ set_opt(sbi->s_mount_opt, AKPM_LOCK_HACK);
+ break;
default:
printk(KERN_ERR
"EXT4-fs: Unrecognized mount option \"%s\" "
@@ -2534,6 +2540,10 @@ static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
journal->j_flags |= JBD2_BARRIER;
else
journal->j_flags &= ~JBD2_BARRIER;
+ if (test_opt(sb, AKPM_LOCK_HACK))
+ journal->j_flags |= JBD2_LOCK_HACK;
+ else
+ journal->j_flags &= ~JBD2_LOCK_HACK;
spin_unlock(&journal->j_state_lock);
}
@@ -546,6 +546,7 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
int error;
char *frozen_buffer = NULL;
int need_copy = 0;
+ int locked = 0;
if (is_handle_aborted(handle))
return -EROFS;
@@ -561,7 +562,13 @@ repeat:
/* @@@ Need to check for errors here at some point. */
- lock_buffer(bh);
+ if (journal->j_flags & JBD2_LOCK_HACK) {
+ if (trylock_buffer(bh))
+ locked = 1; /* lolz */
+ } else {
+ lock_buffer(bh);
+ locked = 1;
+ }
jbd_lock_bh_state(bh);
/* We now hold the buffer lock so it is safe to query the buffer
@@ -600,7 +607,8 @@ repeat:
jbd_unexpected_dirty_buffer(jh);
}
- unlock_buffer(bh);
+ if (locked)
+ unlock_buffer(bh);
error = -EROFS;
if (is_handle_aborted(handle)) {
@@ -967,6 +967,7 @@ struct journal_s
#define JBD2_FLUSHED 0x008 /* The journal superblock has been flushed */
#define JBD2_LOADED 0x010 /* The journal superblock has been loaded */
#define JBD2_BARRIER 0x020 /* Use IDE barriers */
+#define JBD2_LOCK_HACK 0x040 /* akpm's locking hack */
/*
* Function declarations for the journaling transaction and buffer