ocfs2: lighten up allocate transaction

The issue scenario is as following:

When fallocating a very large disk space for a small file,
__ocfs2_extend_allocation attempts to get a very large transaction.  For
some journal sizes, there may be not enough room for this transaction,
and the fallocate will fail.

The patch below extends & restarts the transaction as necessary while
allocating space, and should work with even the smallest journal.  This
patch refers ext4 resize.

Test:
# mkfs.ocfs2 -b 4K -C 32K -T datafiles /dev/sdc
...(jounral size is 32M)
# mount.ocfs2 /dev/sdc /mnt/ocfs2/
# touch /mnt/ocfs2/1.log
# fallocate -o 0 -l 400G /mnt/ocfs2/1.log
fallocate: /mnt/ocfs2/1.log: fallocate failed: Cannot allocate memory
# tail -f /var/log/messages
[ 7372.278591] JBD: fallocate wants too many credits (2051 > 2048)
[ 7372.278597] (fallocate,6438,0):__ocfs2_extend_allocation:709 ERROR: status = -12
[ 7372.278603] (fallocate,6438,0):ocfs2_allocate_unwritten_extents:1504 ERROR: status = -12
[ 7372.278607] (fallocate,6438,0):__ocfs2_change_file_space:1955 ERROR: status = -12
^C
With this patch, the test works well.

Signed-off-by: Younger Liu <younger.liu@huawei.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Younger Liu 2013-09-11 14:19:44 -07:00 committed by Linus Torvalds
parent 5e42781caf
commit 2b1e55c389
4 changed files with 49 additions and 5 deletions

View file

@ -671,11 +671,7 @@ restarted_transaction:
} else {
BUG_ON(why != RESTART_TRANS);
/* TODO: This can be more intelligent. */
credits = ocfs2_calc_extend_credits(osb->sb,
&fe->id2.i_list,
clusters_to_add);
status = ocfs2_extend_trans(handle, credits);
status = ocfs2_allocate_extend_trans(handle, 1);
if (status < 0) {
/* handle still has to be committed at
* this point. */

View file

@ -455,6 +455,41 @@ bail:
return status;
}
/*
* If we have fewer than thresh credits, extend by OCFS2_MAX_TRANS_DATA.
* If that fails, restart the transaction & regain write access for the
* buffer head which is used for metadata modifications.
* Taken from Ext4: extend_or_restart_transaction()
*/
int ocfs2_allocate_extend_trans(handle_t *handle, int thresh)
{
int status, old_nblks;
BUG_ON(!handle);
old_nblks = handle->h_buffer_credits;
trace_ocfs2_allocate_extend_trans(old_nblks, thresh);
if (old_nblks < thresh)
return 0;
status = jbd2_journal_extend(handle, OCFS2_MAX_TRANS_DATA);
if (status < 0) {
mlog_errno(status);
goto bail;
}
if (status > 0) {
status = jbd2_journal_restart(handle, OCFS2_MAX_TRANS_DATA);
if (status < 0)
mlog_errno(status);
}
bail:
return status;
}
struct ocfs2_triggers {
struct jbd2_buffer_trigger_type ot_triggers;
int ot_offset;

View file

@ -258,6 +258,17 @@ handle_t *ocfs2_start_trans(struct ocfs2_super *osb,
int ocfs2_commit_trans(struct ocfs2_super *osb,
handle_t *handle);
int ocfs2_extend_trans(handle_t *handle, int nblocks);
int ocfs2_allocate_extend_trans(handle_t *handle,
int thresh);
/*
* Define an arbitrary limit for the amount of data we will anticipate
* writing to any given transaction. For unbounded transactions such as
* fallocate(2) we can write more than this, but we always
* start off at the maximum transaction size and grow the transaction
* optimistically as we go.
*/
#define OCFS2_MAX_TRANS_DATA 64U
/*
* Create access is for when we get a newly created buffer and we're

View file

@ -2579,6 +2579,8 @@ DEFINE_OCFS2_INT_INT_EVENT(ocfs2_extend_trans);
DEFINE_OCFS2_INT_EVENT(ocfs2_extend_trans_restart);
DEFINE_OCFS2_INT_INT_EVENT(ocfs2_allocate_extend_trans);
DEFINE_OCFS2_ULL_ULL_UINT_UINT_EVENT(ocfs2_journal_access);
DEFINE_OCFS2_ULL_EVENT(ocfs2_journal_dirty);