linux-stable/fs/xfs/xfs_icreate_item.c
Dave Chinner c230a4a85b xfs: fix potential log item leak
Ever since we added shadown format buffers to the log items, log
items need to handle the item being released with shadow buffers
attached. Due to the fact this requirement was added at the same
time we added new rmap/reflink intents, we missed the cleanup of
those items.

In theory, this means shadow buffers can be leaked in a very small
window when a shutdown is initiated. Testing with KASAN shows this
leak does not happen in practice - we haven't identified a single
leak in several years of shutdown testing since ~v4.8 kernels.

However, the intent whiteout cleanup mechanism results in every
cancelled intent in exactly the same state as this tiny race window
creates and so if intents down clean up shadow buffers on final
release we will leak the shadow buffer for just about every intent
we create.

Hence we start with this patch to close this condition off and
ensure that when whiteouts start to be used we don't leak lots of
memory.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-05-04 11:45:11 +10:00

262 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2008-2010, 2013 Dave Chinner
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_icreate_item.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_log_recover.h"
#include "xfs_ialloc.h"
#include "xfs_trace.h"
struct kmem_cache *xfs_icreate_cache; /* inode create item */
static inline struct xfs_icreate_item *ICR_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_icreate_item, ic_item);
}
/*
* This returns the number of iovecs needed to log the given inode item.
*
* We only need one iovec for the icreate log structure.
*/
STATIC void
xfs_icreate_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 1;
*nbytes += sizeof(struct xfs_icreate_log);
}
/*
* This is called to fill in the vector of log iovecs for the
* given inode create log item.
*/
STATIC void
xfs_icreate_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_icreate_item *icp = ICR_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ICREATE,
&icp->ic_format,
sizeof(struct xfs_icreate_log));
}
STATIC void
xfs_icreate_item_release(
struct xfs_log_item *lip)
{
kmem_free(ICR_ITEM(lip)->ic_item.li_lv_shadow);
kmem_cache_free(xfs_icreate_cache, ICR_ITEM(lip));
}
static const struct xfs_item_ops xfs_icreate_item_ops = {
.flags = XFS_ITEM_RELEASE_WHEN_COMMITTED,
.iop_size = xfs_icreate_item_size,
.iop_format = xfs_icreate_item_format,
.iop_release = xfs_icreate_item_release,
};
/*
* Initialize the inode log item for a newly allocated (in-core) inode.
*
* Inode extents can only reside within an AG. Hence specify the starting
* block for the inode chunk by offset within an AG as well as the
* length of the allocated extent.
*
* This joins the item to the transaction and marks it dirty so
* that we don't need a separate call to do this, nor does the
* caller need to know anything about the icreate item.
*/
void
xfs_icreate_log(
struct xfs_trans *tp,
xfs_agnumber_t agno,
xfs_agblock_t agbno,
unsigned int count,
unsigned int inode_size,
xfs_agblock_t length,
unsigned int generation)
{
struct xfs_icreate_item *icp;
icp = kmem_cache_zalloc(xfs_icreate_cache, GFP_KERNEL | __GFP_NOFAIL);
xfs_log_item_init(tp->t_mountp, &icp->ic_item, XFS_LI_ICREATE,
&xfs_icreate_item_ops);
icp->ic_format.icl_type = XFS_LI_ICREATE;
icp->ic_format.icl_size = 1; /* single vector */
icp->ic_format.icl_ag = cpu_to_be32(agno);
icp->ic_format.icl_agbno = cpu_to_be32(agbno);
icp->ic_format.icl_count = cpu_to_be32(count);
icp->ic_format.icl_isize = cpu_to_be32(inode_size);
icp->ic_format.icl_length = cpu_to_be32(length);
icp->ic_format.icl_gen = cpu_to_be32(generation);
xfs_trans_add_item(tp, &icp->ic_item);
tp->t_flags |= XFS_TRANS_DIRTY;
set_bit(XFS_LI_DIRTY, &icp->ic_item.li_flags);
}
static enum xlog_recover_reorder
xlog_recover_icreate_reorder(
struct xlog_recover_item *item)
{
/*
* Inode allocation buffers must be replayed before subsequent inode
* items try to modify those buffers. ICREATE items are the logical
* equivalent of logging a newly initialized inode buffer, so recover
* these at the same time that we recover logged buffers.
*/
return XLOG_REORDER_BUFFER_LIST;
}
/*
* This routine is called when an inode create format structure is found in a
* committed transaction in the log. It's purpose is to initialise the inodes
* being allocated on disk. This requires us to get inode cluster buffers that
* match the range to be initialised, stamped with inode templates and written
* by delayed write so that subsequent modifications will hit the cached buffer
* and only need writing out at the end of recovery.
*/
STATIC int
xlog_recover_icreate_commit_pass2(
struct xlog *log,
struct list_head *buffer_list,
struct xlog_recover_item *item,
xfs_lsn_t lsn)
{
struct xfs_mount *mp = log->l_mp;
struct xfs_icreate_log *icl;
struct xfs_ino_geometry *igeo = M_IGEO(mp);
xfs_agnumber_t agno;
xfs_agblock_t agbno;
unsigned int count;
unsigned int isize;
xfs_agblock_t length;
int bb_per_cluster;
int cancel_count;
int nbufs;
int i;
icl = (struct xfs_icreate_log *)item->ri_buf[0].i_addr;
if (icl->icl_type != XFS_LI_ICREATE) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad type");
return -EINVAL;
}
if (icl->icl_size != 1) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad icl size");
return -EINVAL;
}
agno = be32_to_cpu(icl->icl_ag);
if (agno >= mp->m_sb.sb_agcount) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad agno");
return -EINVAL;
}
agbno = be32_to_cpu(icl->icl_agbno);
if (!agbno || agbno == NULLAGBLOCK || agbno >= mp->m_sb.sb_agblocks) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad agbno");
return -EINVAL;
}
isize = be32_to_cpu(icl->icl_isize);
if (isize != mp->m_sb.sb_inodesize) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad isize");
return -EINVAL;
}
count = be32_to_cpu(icl->icl_count);
if (!count) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad count");
return -EINVAL;
}
length = be32_to_cpu(icl->icl_length);
if (!length || length >= mp->m_sb.sb_agblocks) {
xfs_warn(log->l_mp, "xlog_recover_do_icreate_trans: bad length");
return -EINVAL;
}
/*
* The inode chunk is either full or sparse and we only support
* m_ino_geo.ialloc_min_blks sized sparse allocations at this time.
*/
if (length != igeo->ialloc_blks &&
length != igeo->ialloc_min_blks) {
xfs_warn(log->l_mp,
"%s: unsupported chunk length", __func__);
return -EINVAL;
}
/* verify inode count is consistent with extent length */
if ((count >> mp->m_sb.sb_inopblog) != length) {
xfs_warn(log->l_mp,
"%s: inconsistent inode count and chunk length",
__func__);
return -EINVAL;
}
/*
* The icreate transaction can cover multiple cluster buffers and these
* buffers could have been freed and reused. Check the individual
* buffers for cancellation so we don't overwrite anything written after
* a cancellation.
*/
bb_per_cluster = XFS_FSB_TO_BB(mp, igeo->blocks_per_cluster);
nbufs = length / igeo->blocks_per_cluster;
for (i = 0, cancel_count = 0; i < nbufs; i++) {
xfs_daddr_t daddr;
daddr = XFS_AGB_TO_DADDR(mp, agno,
agbno + i * igeo->blocks_per_cluster);
if (xlog_is_buffer_cancelled(log, daddr, bb_per_cluster))
cancel_count++;
}
/*
* We currently only use icreate for a single allocation at a time. This
* means we should expect either all or none of the buffers to be
* cancelled. Be conservative and skip replay if at least one buffer is
* cancelled, but warn the user that something is awry if the buffers
* are not consistent.
*
* XXX: This must be refined to only skip cancelled clusters once we use
* icreate for multiple chunk allocations.
*/
ASSERT(!cancel_count || cancel_count == nbufs);
if (cancel_count) {
if (cancel_count != nbufs)
xfs_warn(mp,
"WARNING: partial inode chunk cancellation, skipped icreate.");
trace_xfs_log_recover_icreate_cancel(log, icl);
return 0;
}
trace_xfs_log_recover_icreate_recover(log, icl);
return xfs_ialloc_inode_init(mp, NULL, buffer_list, count, agno, agbno,
length, be32_to_cpu(icl->icl_gen));
}
const struct xlog_recover_item_ops xlog_icreate_item_ops = {
.item_type = XFS_LI_ICREATE,
.reorder = xlog_recover_icreate_reorder,
.commit_pass2 = xlog_recover_icreate_commit_pass2,
};