buffer_heads and journal_heads are joined at the hip. We need a lock to
protect the joint and its refcounts.
JBD is currently using a global spinlock for that. Change it to use one bit
in bh->b_state.
fs/jbd/checkpoint.c | 4 +-
fs/jbd/commit.c | 4 +-
fs/jbd/journal.c | 100 ++++++++++++++++++++++++++-------------------------
fs/jbd/transaction.c | 10 ++---
include/linux/jbd.h | 12 +++++-
5 files changed, 71 insertions(+), 59 deletions(-)
diff -puN fs/jbd/journal.c~jbd-040-journal_add_journal_head-locking fs/jbd/journal.c
--- 25/fs/jbd/journal.c~jbd-040-journal_add_journal_head-locking 2003-05-25 17:45:57.000000000 -0700
+++ 25-akpm/fs/jbd/journal.c 2003-05-25 17:45:57.000000000 -0700
@@ -297,7 +297,7 @@ restart:
BUFFER_TRACE(bh, "data writeout complete: unfile");
__journal_unfile_buffer(jh);
jh->b_transaction = NULL;
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
goto restart;
}
@@ -1710,59 +1710,49 @@ static void journal_free_journal_head(st
struct journal_head *journal_add_journal_head(struct buffer_head *bh)
{
struct journal_head *jh;
+ struct journal_head *new_jh = NULL;
- spin_lock(&journal_datalist_lock);
+repeat:
+ if (!buffer_jbd(bh)) {
+ new_jh = journal_alloc_journal_head();
+ memset(new_jh, 0, sizeof(*new_jh));
+ }
+
+ jbd_lock_bh_journal_head(bh);
if (buffer_jbd(bh)) {
jh = bh2jh(bh);
} else {
J_ASSERT_BH(bh,
(atomic_read(&bh->b_count) > 0) ||
(bh->b_page && bh->b_page->mapping));
- spin_unlock(&journal_datalist_lock);
- jh = journal_alloc_journal_head();
- memset(jh, 0, sizeof(*jh));
- spin_lock(&journal_datalist_lock);
- if (buffer_jbd(bh)) {
- /* Someone did it for us! */
- J_ASSERT_BH(bh, bh->b_private != NULL);
- journal_free_journal_head(jh);
- jh = bh->b_private;
- } else {
- set_bit(BH_JBD, &bh->b_state);
- bh->b_private = jh;
- jh->b_bh = bh;
- atomic_inc(&bh->b_count);
- BUFFER_TRACE(bh, "added journal_head");
+ if (!new_jh) {
+ jbd_unlock_bh_journal_head(bh);
+ goto repeat;
}
+
+ jh = new_jh;
+ new_jh = NULL; /* We consumed it */
+ set_buffer_jbd(bh);
+ bh->b_private = jh;
+ jh->b_bh = bh;
+ get_bh(bh);
+ BUFFER_TRACE(bh, "added journal_head");
}
jh->b_jcount++;
- spin_unlock(&journal_datalist_lock);
+ jbd_unlock_bh_journal_head(bh);
+ if (new_jh)
+ journal_free_journal_head(new_jh);
return bh->b_private;
}
-/*
- * journal_remove_journal_head(): if the buffer isn't attached to a transaction
- * and has a zero b_jcount then remove and release its journal_head. If we did
- * see that the buffer is not used by any transaction we also "logically"
- * decrement ->b_count.
- *
- * We in fact take an additional increment on ->b_count as a convenience,
- * because the caller usually wants to do additional things with the bh
- * after calling here.
- * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some
- * time. Once the caller has run __brelse(), the buffer is eligible for
- * reaping by try_to_free_buffers().
- *
- * Requires journal_datalist_lock.
- */
-void __journal_remove_journal_head(struct buffer_head *bh)
+static void __journal_remove_journal_head(struct buffer_head *bh)
{
struct journal_head *jh = bh2jh(bh);
- assert_spin_locked(&journal_datalist_lock);
J_ASSERT_JH(jh, jh->b_jcount >= 0);
- atomic_inc(&bh->b_count);
+
+ get_bh(bh);
if (jh->b_jcount == 0) {
if (jh->b_transaction == NULL &&
jh->b_next_transaction == NULL &&
@@ -1772,7 +1762,7 @@ void __journal_remove_journal_head(struc
BUFFER_TRACE(bh, "remove journal_head");
bh->b_private = NULL;
jh->b_bh = NULL; /* debug, really */
- clear_bit(BH_JBD, &bh->b_state);
+ clear_buffer_jbd(bh);
__brelse(bh);
journal_free_journal_head(jh);
} else {
@@ -1781,26 +1771,38 @@ void __journal_remove_journal_head(struc
}
}
+/*
+ * journal_remove_journal_head(): if the buffer isn't attached to a transaction
+ * and has a zero b_jcount then remove and release its journal_head. If we did
+ * see that the buffer is not used by any transaction we also "logically"
+ * decrement ->b_count.
+ *
+ * We in fact take an additional increment on ->b_count as a convenience,
+ * because the caller usually wants to do additional things with the bh
+ * after calling here.
+ * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some
+ * time. Once the caller has run __brelse(), the buffer is eligible for
+ * reaping by try_to_free_buffers().
+ */
+void journal_remove_journal_head(struct buffer_head *bh)
+{
+ jbd_lock_bh_journal_head(bh);
+ __journal_remove_journal_head(bh);
+ jbd_unlock_bh_journal_head(bh);
+}
+
void journal_unlock_journal_head(struct journal_head *jh)
{
- spin_lock(&journal_datalist_lock);
+ struct buffer_head *bh = jh2bh(jh);
+
+ jbd_lock_bh_journal_head(bh);
J_ASSERT_JH(jh, jh->b_jcount > 0);
--jh->b_jcount;
if (!jh->b_jcount && !jh->b_transaction) {
- struct buffer_head *bh;
- bh = jh2bh(jh);
__journal_remove_journal_head(bh);
__brelse(bh);
}
-
- spin_unlock(&journal_datalist_lock);
-}
-
-void journal_remove_journal_head(struct buffer_head *bh)
-{
- spin_lock(&journal_datalist_lock);
- __journal_remove_journal_head(bh);
- spin_unlock(&journal_datalist_lock);
+ jbd_unlock_bh_journal_head(bh);
}
/*
diff -puN include/linux/jbd.h~jbd-040-journal_add_journal_head-locking include/linux/jbd.h
--- 25/include/linux/jbd.h~jbd-040-journal_add_journal_head-locking 2003-05-25 17:45:57.000000000 -0700
+++ 25-akpm/include/linux/jbd.h 2003-05-25 17:45:57.000000000 -0700
@@ -293,6 +293,7 @@ enum jbd_state_bits {
BH_RevokeValid, /* Revoked flag is valid */
BH_JBDDirty, /* Is dirty but journaled */
BH_State, /* Pins most journal_head state */
+ BH_JournalHead, /* Pins bh->b_private and jh->b_bh */
};
BUFFER_FNS(JBD, jbd)
@@ -326,6 +327,16 @@ static inline void jbd_unlock_bh_state(s
bit_spin_unlock(BH_State, &bh->b_state);
}
+static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
+{
+ bit_spin_lock(BH_JournalHead, &bh->b_state);
+}
+
+static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
+{
+ bit_spin_unlock(BH_JournalHead, &bh->b_state);
+}
+
#define HAVE_JOURNAL_CALLBACK_STATUS
/**
* struct journal_callback - Base structure for callback information.
@@ -956,7 +967,6 @@ extern int journal_force_commit(journ
extern struct journal_head
*journal_add_journal_head(struct buffer_head *bh);
extern void journal_remove_journal_head(struct buffer_head *bh);
-extern void __journal_remove_journal_head(struct buffer_head *bh);
extern void journal_unlock_journal_head(struct journal_head *jh);
/*
diff -puN fs/jbd/checkpoint.c~jbd-040-journal_add_journal_head-locking fs/jbd/checkpoint.c
--- 25/fs/jbd/checkpoint.c~jbd-040-journal_add_journal_head-locking 2003-05-25 17:45:57.000000000 -0700
+++ 25-akpm/fs/jbd/checkpoint.c 2003-05-25 17:45:57.000000000 -0700
@@ -59,7 +59,7 @@ static int __try_to_free_cp_buf(struct j
if (jh->b_jlist == BJ_None && !buffer_locked(bh) && !buffer_dirty(bh)) {
JBUFFER_TRACE(jh, "remove from checkpoint list");
__journal_remove_checkpoint(jh);
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
BUFFER_TRACE(bh, "release");
__brelse(bh);
ret = 1;
@@ -156,7 +156,7 @@ static int __cleanup_transaction(journal
if (!buffer_dirty(bh) && !buffer_jbddirty(bh)) {
BUFFER_TRACE(bh, "remove from checkpoint");
__journal_remove_checkpoint(jh);
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
ret = 1;
}
diff -puN fs/jbd/commit.c~jbd-040-journal_add_journal_head-locking fs/jbd/commit.c
--- 25/fs/jbd/commit.c~jbd-040-journal_add_journal_head-locking 2003-05-25 17:45:57.000000000 -0700
+++ 25-akpm/fs/jbd/commit.c 2003-05-25 17:45:57.000000000 -0700
@@ -212,7 +212,7 @@ write_out_data_locked:
BUFFER_TRACE(bh, "writeout complete: unfile");
__journal_unfile_buffer(jh);
jh->b_transaction = NULL;
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
}
}
@@ -692,7 +692,7 @@ skip_commit: /* The journal should be un
J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
__journal_unfile_buffer(jh);
jh->b_transaction = 0;
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
}
spin_unlock(&journal_datalist_lock);
diff -puN fs/jbd/transaction.c~jbd-040-journal_add_journal_head-locking fs/jbd/transaction.c
--- 25/fs/jbd/transaction.c~jbd-040-journal_add_journal_head-locking 2003-05-25 17:45:57.000000000 -0700
+++ 25-akpm/fs/jbd/transaction.c 2003-05-25 17:45:57.000000000 -0700
@@ -1219,7 +1219,7 @@ void journal_forget (handle_t *handle, s
if (jh->b_cp_transaction) {
__journal_file_buffer(jh, transaction, BJ_Forget);
} else {
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
if (!buffer_jbd(bh)) {
spin_unlock(&journal_datalist_lock);
@@ -1623,7 +1623,7 @@ static inline int __journal_try_to_free_
JBUFFER_TRACE(jh, "release data");
__journal_unfile_buffer(jh);
jh->b_transaction = 0;
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
}
} else if (jh->b_cp_transaction != 0 && jh->b_transaction == 0) {
@@ -1631,7 +1631,7 @@ static inline int __journal_try_to_free_
if (jh->b_jlist == BJ_None) {
JBUFFER_TRACE(jh, "remove from checkpoint list");
__journal_remove_checkpoint(jh);
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
}
}
@@ -1725,7 +1725,7 @@ static int dispose_buffer(struct journal
may_free = 0;
} else {
JBUFFER_TRACE(jh, "on running transaction");
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
__brelse(bh);
}
spin_unlock(&journal_datalist_lock);
@@ -2066,7 +2066,7 @@ void journal_refile_buffer(struct journa
bh = jh2bh(jh);
__journal_refile_buffer(jh);
- __journal_remove_journal_head(bh);
+ journal_remove_journal_head(bh);
spin_unlock(&journal_datalist_lock);
__brelse(bh);
_