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jbd2: Remove __GFP_NOFAIL from jbd2 layer

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__GFP_NOFAIL is going away, so add our own retry loop.  Also add
jbd2__journal_start() and jbd2__journal_restart() which take a gfp
mask, so that file systems can optionally (re)start transaction
handles using GFP_KERNEL.  If they do this, then they need to be
prepared to handle receiving an PTR_ERR(-ENOMEM) error, and be ready
to reflect that error up to userspace.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2010-07-27 11:56:05 -04:00
parent 4038968738
commit 47def82672
3 changed files with 57 additions and 23 deletions
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15
fs/jbd2/journal.c
View File

@ -41,6 +41,7 @@
#include <linux/hash.h>
#include <linux/log2.h>
#include <linux/vmalloc.h>
#include <linux/backing-dev.h>
#define CREATE_TRACE_POINTS
#include <trace/events/jbd2.h>
@ -48,8 +49,6 @@
#include <asm/uaccess.h>
#include <asm/page.h>
EXPORT_SYMBOL(jbd2_journal_start);
EXPORT_SYMBOL(jbd2_journal_restart);
EXPORT_SYMBOL(jbd2_journal_extend);
EXPORT_SYMBOL(jbd2_journal_stop);
EXPORT_SYMBOL(jbd2_journal_lock_updates);
@ -311,7 +310,17 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
*/
J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
retry_alloc:
new_bh = alloc_buffer_head(GFP_NOFS);
if (!new_bh) {
/*
* Failure is not an option, but __GFP_NOFAIL is going
* away; so we retry ourselves here.
*/
congestion_wait(BLK_RW_ASYNC, HZ/50);
goto retry_alloc;
}
/* keep subsequent assertions sane */
new_bh->b_state = 0;
init_buffer(new_bh, NULL, NULL);

61
fs/jbd2/transaction.c
View File

@ -26,6 +26,8 @@
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/hrtimer.h>
#include <linux/backing-dev.h>
#include <linux/module.h>
static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
@ -83,30 +85,38 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
* transaction's buffer credits.
*/
static int start_this_handle(journal_t *journal, handle_t *handle)
static int start_this_handle(journal_t *journal, handle_t *handle,
int gfp_mask)
{
transaction_t *transaction;
int needed;
int nblocks = handle->h_buffer_credits;
transaction_t *new_transaction = NULL;
int ret = 0;
unsigned long ts = jiffies;
if (nblocks > journal->j_max_transaction_buffers) {
printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n",
current->comm, nblocks,
journal->j_max_transaction_buffers);
ret = -ENOSPC;
goto out;
return -ENOSPC;
}
alloc_transaction:
if (!journal->j_running_transaction) {
new_transaction = kzalloc(sizeof(*new_transaction),
GFP_NOFS|__GFP_NOFAIL);
new_transaction = kzalloc(sizeof(*new_transaction), gfp_mask);
if (!new_transaction) {
ret = -ENOMEM;
goto out;
/*
* If __GFP_FS is not present, then we may be
* being called from inside the fs writeback
* layer, so we MUST NOT fail. Since
* __GFP_NOFAIL is going away, we will arrange
* to retry the allocation ourselves.
*/
if ((gfp_mask & __GFP_FS) == 0) {
congestion_wait(BLK_RW_ASYNC, HZ/50);
goto alloc_transaction;
}
return -ENOMEM;
}
}
@ -123,8 +133,8 @@ repeat_locked:
if (is_journal_aborted(journal) ||
(journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
spin_unlock(&journal->j_state_lock);
ret = -EROFS;
goto out;
kfree(new_transaction);
return -EROFS;
}
/* Wait on the journal's transaction barrier if necessary */
@ -240,10 +250,8 @@ repeat_locked:
spin_unlock(&journal->j_state_lock);
lock_map_acquire(&handle->h_lockdep_map);
out:
if (unlikely(new_transaction)) /* It's usually NULL */
kfree(new_transaction);
return ret;
kfree(new_transaction);
return 0;
}
static struct lock_class_key jbd2_handle_key;
@ -278,7 +286,7 @@ static handle_t *new_handle(int nblocks)
*
* Return a pointer to a newly allocated handle, or NULL on failure
*/
handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int gfp_mask)
{
handle_t *handle = journal_current_handle();
int err;
@ -298,7 +306,7 @@ handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
current->journal_info = handle;
err = start_this_handle(journal, handle);
err = start_this_handle(journal, handle, gfp_mask);
if (err < 0) {
jbd2_free_handle(handle);
current->journal_info = NULL;
@ -308,6 +316,15 @@ handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
out:
return handle;
}
EXPORT_SYMBOL(jbd2__journal_start);
handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
{
return jbd2__journal_start(journal, nblocks, GFP_NOFS);
}
EXPORT_SYMBOL(jbd2_journal_start);
/**
* int jbd2_journal_extend() - extend buffer credits.
@ -394,8 +411,7 @@ out:
* transaction capabable of guaranteeing the requested number of
* credits.
*/
int jbd2_journal_restart(handle_t *handle, int nblocks)
int jbd2__journal_restart(handle_t *handle, int nblocks, int gfp_mask)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
@ -428,11 +444,18 @@ int jbd2_journal_restart(handle_t *handle, int nblocks)
lock_map_release(&handle->h_lockdep_map);
handle->h_buffer_credits = nblocks;
ret = start_this_handle(journal, handle);
ret = start_this_handle(journal, handle, gfp_mask);
return ret;
}
EXPORT_SYMBOL(jbd2__journal_restart);
int jbd2_journal_restart(handle_t *handle, int nblocks)
{
return jbd2__journal_restart(handle, nblocks, GFP_NOFS);
}
EXPORT_SYMBOL(jbd2_journal_restart);
/**
* void jbd2_journal_lock_updates () - establish a transaction barrier.
* @journal: Journal to establish a barrier on.

4
include/linux/jbd2.h
View File

@ -1081,7 +1081,9 @@ static inline handle_t *journal_current_handle(void)
*/
extern handle_t *jbd2_journal_start(journal_t *, int nblocks);
extern int jbd2_journal_restart (handle_t *, int nblocks);
extern handle_t *jbd2__journal_start(journal_t *, int nblocks, int gfp_mask);
extern int jbd2_journal_restart(handle_t *, int nblocks);
extern int jbd2__journal_restart(handle_t *, int nblocks, int gfp_mask);
extern int jbd2_journal_extend (handle_t *, int nblocks);
extern int jbd2_journal_get_write_access(handle_t *, struct buffer_head *);
extern int jbd2_journal_get_create_access (handle_t *, struct buffer_head *);