Commit 2b1e55c3 authored by Younger Liu's avatar Younger Liu Committed by Linus Torvalds
Browse files

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: default avatarYounger 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5e42781c

fs/ocfs2/file.c

+1 −5
Original line number Diff line number Diff line
@@ -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. */

fs/ocfs2/journal.c

+35 −0
Original line number Diff line number Diff line
@@ -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;

fs/ocfs2/journal.h

+11 −0
Original line number Diff line number Diff line
@@ -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

fs/ocfs2/ocfs2_trace.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE