mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
![Carlos Maiolino](/assets/img/avatar_default.png)
Forcing the log to disk after reading the agf is wrong, we might be calling xfs_log_force with XFS_LOG_SYNC with a metadata lock held. This can cause a deadlock when racing a fstrim with a filesystem shutdown. The deadlock has been identified due a miscalculation bug in device-mapper dm-thin, which returns lack of space to its users earlier than the device itself really runs out of space, changing the device-mapper volume into an error state. The problem happened while filling the filesystem with a single file, triggering the bug in device-mapper, consequently causing an IO error and shutting down the filesystem. If such file is removed, and fstrim executed before the XFS finishes the shut down process, the fstrim process will end up holding the buffer lock, and going to sleep on the cil wait queue. At this point, the shut down process will try to wake up all the threads waiting on the cil wait queue, but for this, it will try to hold the same buffer log already held my the fstrim, locking up the filesystem. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
218 lines
5.9 KiB
C
218 lines
5.9 KiB
C
/*
|
|
* Copyright (C) 2010 Red Hat, Inc.
|
|
* All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it would be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
#include "xfs.h"
|
|
#include "xfs_format.h"
|
|
#include "xfs_log_format.h"
|
|
#include "xfs_trans_resv.h"
|
|
#include "xfs_sb.h"
|
|
#include "xfs_mount.h"
|
|
#include "xfs_quota.h"
|
|
#include "xfs_inode.h"
|
|
#include "xfs_btree.h"
|
|
#include "xfs_alloc_btree.h"
|
|
#include "xfs_alloc.h"
|
|
#include "xfs_error.h"
|
|
#include "xfs_extent_busy.h"
|
|
#include "xfs_discard.h"
|
|
#include "xfs_trace.h"
|
|
#include "xfs_log.h"
|
|
|
|
STATIC int
|
|
xfs_trim_extents(
|
|
struct xfs_mount *mp,
|
|
xfs_agnumber_t agno,
|
|
xfs_daddr_t start,
|
|
xfs_daddr_t end,
|
|
xfs_daddr_t minlen,
|
|
uint64_t *blocks_trimmed)
|
|
{
|
|
struct block_device *bdev = mp->m_ddev_targp->bt_bdev;
|
|
struct xfs_btree_cur *cur;
|
|
struct xfs_buf *agbp;
|
|
struct xfs_perag *pag;
|
|
int error;
|
|
int i;
|
|
|
|
pag = xfs_perag_get(mp, agno);
|
|
|
|
/*
|
|
* Force out the log. This means any transactions that might have freed
|
|
* space before we take the AGF buffer lock are now on disk, and the
|
|
* volatile disk cache is flushed.
|
|
*/
|
|
xfs_log_force(mp, XFS_LOG_SYNC);
|
|
|
|
error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
|
|
if (error || !agbp)
|
|
goto out_put_perag;
|
|
|
|
cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
|
|
|
|
/*
|
|
* Look up the longest btree in the AGF and start with it.
|
|
*/
|
|
error = xfs_alloc_lookup_ge(cur, 0,
|
|
be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest), &i);
|
|
if (error)
|
|
goto out_del_cursor;
|
|
|
|
/*
|
|
* Loop until we are done with all extents that are large
|
|
* enough to be worth discarding.
|
|
*/
|
|
while (i) {
|
|
xfs_agblock_t fbno;
|
|
xfs_extlen_t flen;
|
|
xfs_daddr_t dbno;
|
|
xfs_extlen_t dlen;
|
|
|
|
error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
|
|
if (error)
|
|
goto out_del_cursor;
|
|
XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_del_cursor);
|
|
ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
|
|
|
|
/*
|
|
* use daddr format for all range/len calculations as that is
|
|
* the format the range/len variables are supplied in by
|
|
* userspace.
|
|
*/
|
|
dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
|
|
dlen = XFS_FSB_TO_BB(mp, flen);
|
|
|
|
/*
|
|
* Too small? Give up.
|
|
*/
|
|
if (dlen < minlen) {
|
|
trace_xfs_discard_toosmall(mp, agno, fbno, flen);
|
|
goto out_del_cursor;
|
|
}
|
|
|
|
/*
|
|
* If the extent is entirely outside of the range we are
|
|
* supposed to discard skip it. Do not bother to trim
|
|
* down partially overlapping ranges for now.
|
|
*/
|
|
if (dbno + dlen < start || dbno > end) {
|
|
trace_xfs_discard_exclude(mp, agno, fbno, flen);
|
|
goto next_extent;
|
|
}
|
|
|
|
/*
|
|
* If any blocks in the range are still busy, skip the
|
|
* discard and try again the next time.
|
|
*/
|
|
if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
|
|
trace_xfs_discard_busy(mp, agno, fbno, flen);
|
|
goto next_extent;
|
|
}
|
|
|
|
trace_xfs_discard_extent(mp, agno, fbno, flen);
|
|
error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
|
|
if (error)
|
|
goto out_del_cursor;
|
|
*blocks_trimmed += flen;
|
|
|
|
next_extent:
|
|
error = xfs_btree_decrement(cur, 0, &i);
|
|
if (error)
|
|
goto out_del_cursor;
|
|
|
|
if (fatal_signal_pending(current)) {
|
|
error = -ERESTARTSYS;
|
|
goto out_del_cursor;
|
|
}
|
|
}
|
|
|
|
out_del_cursor:
|
|
xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
|
|
xfs_buf_relse(agbp);
|
|
out_put_perag:
|
|
xfs_perag_put(pag);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* trim a range of the filesystem.
|
|
*
|
|
* Note: the parameters passed from userspace are byte ranges into the
|
|
* filesystem which does not match to the format we use for filesystem block
|
|
* addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
|
|
* is a linear address range. Hence we need to use DADDR based conversions and
|
|
* comparisons for determining the correct offset and regions to trim.
|
|
*/
|
|
int
|
|
xfs_ioc_trim(
|
|
struct xfs_mount *mp,
|
|
struct fstrim_range __user *urange)
|
|
{
|
|
struct request_queue *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
|
|
unsigned int granularity = q->limits.discard_granularity;
|
|
struct fstrim_range range;
|
|
xfs_daddr_t start, end, minlen;
|
|
xfs_agnumber_t start_agno, end_agno, agno;
|
|
uint64_t blocks_trimmed = 0;
|
|
int error, last_error = 0;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
if (!blk_queue_discard(q))
|
|
return -EOPNOTSUPP;
|
|
if (copy_from_user(&range, urange, sizeof(range)))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* Truncating down the len isn't actually quite correct, but using
|
|
* BBTOB would mean we trivially get overflows for values
|
|
* of ULLONG_MAX or slightly lower. And ULLONG_MAX is the default
|
|
* used by the fstrim application. In the end it really doesn't
|
|
* matter as trimming blocks is an advisory interface.
|
|
*/
|
|
if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
|
|
range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
|
|
range.len < mp->m_sb.sb_blocksize)
|
|
return -EINVAL;
|
|
|
|
start = BTOBB(range.start);
|
|
end = start + BTOBBT(range.len) - 1;
|
|
minlen = BTOBB(max_t(u64, granularity, range.minlen));
|
|
|
|
if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
|
|
end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
|
|
|
|
start_agno = xfs_daddr_to_agno(mp, start);
|
|
end_agno = xfs_daddr_to_agno(mp, end);
|
|
|
|
for (agno = start_agno; agno <= end_agno; agno++) {
|
|
error = xfs_trim_extents(mp, agno, start, end, minlen,
|
|
&blocks_trimmed);
|
|
if (error) {
|
|
last_error = error;
|
|
if (error == -ERESTARTSYS)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (last_error)
|
|
return last_error;
|
|
|
|
range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
|
|
if (copy_to_user(urange, &range, sizeof(range)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|