Hi Greg,
This backport series contains mostly fixes from v5.14 release along with one fix deferred from the first joint 5.10/5.15 series [1].
The upstream commit f8d92a66e810 ("xfs: prevent UAF in xfs_log_item_in_current_chkpt") was already applied to 5.15.y, but its 5.10.y backport was more involved (required two non trivial dependency patches), so it needed more time for review and testing.
Per Darrick's recommendation, on top of the usual regression tests, I also ran the "recoveryloop" tests group for an extended period of time to test for rare regressions.
Some recoveryloop tests were failing at rates less frequent than 1/100, but no change in failure rate was observed between baseline (v5.10.131) and the backport branch.
There was one exceptional test, xfs/455, that was reporting data corruptions after crash at very low rate - less frequent than 1/1000 on both baseline and backport branch.
It is hard to draw solid conclusions with such rare failures, but the test was run >10,000 times on baseline and >20,000 times on backport branch, so as far as our test coverage can attest, these backports are not introducing any obvious xfs regressions to 5.10.y.
Thanks, Amir.
Changes from [v1]: - Survived a week of crash recovery loop - Added Acked-by Darrick - CC stable
[1] https://lore.kernel.org/linux-xfs/20220623203641.1710377-1-leah.rumancik@gma... [v1] https://lore.kernel.org/linux-xfs/20220726092125.3899077-1-amir73il@gmail.co...
Brian Foster (2): xfs: hold buffer across unpin and potential shutdown processing xfs: remove dead stale buf unpin handling code
Christoph Hellwig (1): xfs: refactor xfs_file_fsync
Darrick J. Wong (3): xfs: prevent UAF in xfs_log_item_in_current_chkpt xfs: fix log intent recovery ENOSPC shutdowns when inactivating inodes xfs: force the log offline when log intent item recovery fails
Dave Chinner (3): xfs: xfs_log_force_lsn isn't passed a LSN xfs: logging the on disk inode LSN can make it go backwards xfs: Enforce attr3 buffer recovery order
fs/xfs/libxfs/xfs_log_format.h | 11 ++++- fs/xfs/libxfs/xfs_types.h | 1 + fs/xfs/xfs_buf_item.c | 60 ++++++++++-------------- fs/xfs/xfs_buf_item_recover.c | 1 + fs/xfs/xfs_dquot_item.c | 2 +- fs/xfs/xfs_file.c | 81 ++++++++++++++++++++------------- fs/xfs/xfs_inode.c | 10 ++-- fs/xfs/xfs_inode_item.c | 4 +- fs/xfs/xfs_inode_item.h | 2 +- fs/xfs/xfs_inode_item_recover.c | 39 ++++++++++++---- fs/xfs/xfs_log.c | 30 ++++++------ fs/xfs/xfs_log.h | 4 +- fs/xfs/xfs_log_cil.c | 32 +++++-------- fs/xfs/xfs_log_priv.h | 15 +++--- fs/xfs/xfs_log_recover.c | 5 +- fs/xfs/xfs_mount.c | 10 +++- fs/xfs/xfs_trans.c | 6 +-- fs/xfs/xfs_trans.h | 4 +- 18 files changed, 179 insertions(+), 138 deletions(-)
From: Christoph Hellwig hch@lst.de
commit f22c7f87777361f94aa17f746fbadfa499248dc8 upstream.
[backported for dependency]
Factor out the log syncing logic into two helpers to make the code easier to read and more maintainable.
Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: Brian Foster bfoster@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Dave Chinner dchinner@redhat.com Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_file.c | 81 +++++++++++++++++++++++++++++------------------ 1 file changed, 50 insertions(+), 31 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 5b0f93f73837..414d856e2e75 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -118,6 +118,54 @@ xfs_dir_fsync( return xfs_log_force_inode(ip); }
+static xfs_lsn_t +xfs_fsync_lsn( + struct xfs_inode *ip, + bool datasync) +{ + if (!xfs_ipincount(ip)) + return 0; + if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) + return 0; + return ip->i_itemp->ili_last_lsn; +} + +/* + * All metadata updates are logged, which means that we just have to flush the + * log up to the latest LSN that touched the inode. + * + * If we have concurrent fsync/fdatasync() calls, we need them to all block on + * the log force before we clear the ili_fsync_fields field. This ensures that + * we don't get a racing sync operation that does not wait for the metadata to + * hit the journal before returning. If we race with clearing ili_fsync_fields, + * then all that will happen is the log force will do nothing as the lsn will + * already be on disk. We can't race with setting ili_fsync_fields because that + * is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock + * shared until after the ili_fsync_fields is cleared. + */ +static int +xfs_fsync_flush_log( + struct xfs_inode *ip, + bool datasync, + int *log_flushed) +{ + int error = 0; + xfs_lsn_t lsn; + + xfs_ilock(ip, XFS_ILOCK_SHARED); + lsn = xfs_fsync_lsn(ip, datasync); + if (lsn) { + error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, + log_flushed); + + spin_lock(&ip->i_itemp->ili_lock); + ip->i_itemp->ili_fsync_fields = 0; + spin_unlock(&ip->i_itemp->ili_lock); + } + xfs_iunlock(ip, XFS_ILOCK_SHARED); + return error; +} + STATIC int xfs_file_fsync( struct file *file, @@ -125,13 +173,10 @@ xfs_file_fsync( loff_t end, int datasync) { - struct inode *inode = file->f_mapping->host; - struct xfs_inode *ip = XFS_I(inode); - struct xfs_inode_log_item *iip = ip->i_itemp; + struct xfs_inode *ip = XFS_I(file->f_mapping->host); struct xfs_mount *mp = ip->i_mount; int error = 0; int log_flushed = 0; - xfs_lsn_t lsn = 0;
trace_xfs_file_fsync(ip);
@@ -155,33 +200,7 @@ xfs_file_fsync( else if (mp->m_logdev_targp != mp->m_ddev_targp) xfs_blkdev_issue_flush(mp->m_ddev_targp);
- /* - * All metadata updates are logged, which means that we just have to - * flush the log up to the latest LSN that touched the inode. If we have - * concurrent fsync/fdatasync() calls, we need them to all block on the - * log force before we clear the ili_fsync_fields field. This ensures - * that we don't get a racing sync operation that does not wait for the - * metadata to hit the journal before returning. If we race with - * clearing the ili_fsync_fields, then all that will happen is the log - * force will do nothing as the lsn will already be on disk. We can't - * race with setting ili_fsync_fields because that is done under - * XFS_ILOCK_EXCL, and that can't happen because we hold the lock shared - * until after the ili_fsync_fields is cleared. - */ - xfs_ilock(ip, XFS_ILOCK_SHARED); - if (xfs_ipincount(ip)) { - if (!datasync || - (iip->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) - lsn = iip->ili_last_lsn; - } - - if (lsn) { - error = xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed); - spin_lock(&iip->ili_lock); - iip->ili_fsync_fields = 0; - spin_unlock(&iip->ili_lock); - } - xfs_iunlock(ip, XFS_ILOCK_SHARED); + error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
/* * If we only have a single device, and the log force about was
From: Dave Chinner dchinner@redhat.com
commit 5f9b4b0de8dc2fb8eb655463b438001c111570fe upstream.
[backported from CIL scalability series for dependency]
In doing an investigation into AIL push stalls, I was looking at the log force code to see if an async CIL push could be done instead. This lead me to xfs_log_force_lsn() and looking at how it works.
xfs_log_force_lsn() is only called from inode synchronisation contexts such as fsync(), and it takes the ip->i_itemp->ili_last_lsn value as the LSN to sync the log to. This gets passed to xlog_cil_force_lsn() via xfs_log_force_lsn() to flush the CIL to the journal, and then used by xfs_log_force_lsn() to flush the iclogs to the journal.
The problem is that ip->i_itemp->ili_last_lsn does not store a log sequence number. What it stores is passed to it from the ->iop_committing method, which is called by xfs_log_commit_cil(). The value this passes to the iop_committing method is the CIL context sequence number that the item was committed to.
As it turns out, xlog_cil_force_lsn() converts the sequence to an actual commit LSN for the related context and returns that to xfs_log_force_lsn(). xfs_log_force_lsn() overwrites it's "lsn" variable that contained a sequence with an actual LSN and then uses that to sync the iclogs.
This caused me some confusion for a while, even though I originally wrote all this code a decade ago. ->iop_committing is only used by a couple of log item types, and only inode items use the sequence number it is passed.
Let's clean up the API, CIL structures and inode log item to call it a sequence number, and make it clear that the high level code is using CIL sequence numbers and not on-disk LSNs for integrity synchronisation purposes.
Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Brian Foster bfoster@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Allison Henderson allison.henderson@oracle.com Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/libxfs/xfs_types.h | 1 + fs/xfs/xfs_buf_item.c | 2 +- fs/xfs/xfs_dquot_item.c | 2 +- fs/xfs/xfs_file.c | 14 +++++++------- fs/xfs/xfs_inode.c | 10 +++++----- fs/xfs/xfs_inode_item.c | 4 ++-- fs/xfs/xfs_inode_item.h | 2 +- fs/xfs/xfs_log.c | 27 ++++++++++++++------------- fs/xfs/xfs_log.h | 4 +--- fs/xfs/xfs_log_cil.c | 30 +++++++++++------------------- fs/xfs/xfs_log_priv.h | 15 +++++++-------- fs/xfs/xfs_trans.c | 6 +++--- fs/xfs/xfs_trans.h | 4 ++-- 13 files changed, 56 insertions(+), 65 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h index 397d94775440..1ce06173c2f5 100644 --- a/fs/xfs/libxfs/xfs_types.h +++ b/fs/xfs/libxfs/xfs_types.h @@ -21,6 +21,7 @@ typedef int32_t xfs_suminfo_t; /* type of bitmap summary info */ typedef uint32_t xfs_rtword_t; /* word type for bitmap manipulations */
typedef int64_t xfs_lsn_t; /* log sequence number */ +typedef int64_t xfs_csn_t; /* CIL sequence number */
typedef uint32_t xfs_dablk_t; /* dir/attr block number (in file) */ typedef uint32_t xfs_dahash_t; /* dir/attr hash value */ diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index 8c6e26d62ef2..5d6535370f87 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -632,7 +632,7 @@ xfs_buf_item_release( STATIC void xfs_buf_item_committing( struct xfs_log_item *lip, - xfs_lsn_t commit_lsn) + xfs_csn_t seq) { return xfs_buf_item_release(lip); } diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c index 8c1fdf37ee8f..8ed47b739b6c 100644 --- a/fs/xfs/xfs_dquot_item.c +++ b/fs/xfs/xfs_dquot_item.c @@ -188,7 +188,7 @@ xfs_qm_dquot_logitem_release( STATIC void xfs_qm_dquot_logitem_committing( struct xfs_log_item *lip, - xfs_lsn_t commit_lsn) + xfs_csn_t seq) { return xfs_qm_dquot_logitem_release(lip); } diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 414d856e2e75..4d6bf8d4974f 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -118,8 +118,8 @@ xfs_dir_fsync( return xfs_log_force_inode(ip); }
-static xfs_lsn_t -xfs_fsync_lsn( +static xfs_csn_t +xfs_fsync_seq( struct xfs_inode *ip, bool datasync) { @@ -127,7 +127,7 @@ xfs_fsync_lsn( return 0; if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) return 0; - return ip->i_itemp->ili_last_lsn; + return ip->i_itemp->ili_commit_seq; }
/* @@ -150,12 +150,12 @@ xfs_fsync_flush_log( int *log_flushed) { int error = 0; - xfs_lsn_t lsn; + xfs_csn_t seq;
xfs_ilock(ip, XFS_ILOCK_SHARED); - lsn = xfs_fsync_lsn(ip, datasync); - if (lsn) { - error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, + seq = xfs_fsync_seq(ip, datasync); + if (seq) { + error = xfs_log_force_seq(ip->i_mount, seq, XFS_LOG_SYNC, log_flushed);
spin_lock(&ip->i_itemp->ili_lock); diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 03497741aef7..1f61e085676b 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -2754,7 +2754,7 @@ xfs_iunpin( trace_xfs_inode_unpin_nowait(ip, _RET_IP_);
/* Give the log a push to start the unpinning I/O */ - xfs_log_force_lsn(ip->i_mount, ip->i_itemp->ili_last_lsn, 0, NULL); + xfs_log_force_seq(ip->i_mount, ip->i_itemp->ili_commit_seq, 0, NULL);
}
@@ -3716,16 +3716,16 @@ int xfs_log_force_inode( struct xfs_inode *ip) { - xfs_lsn_t lsn = 0; + xfs_csn_t seq = 0;
xfs_ilock(ip, XFS_ILOCK_SHARED); if (xfs_ipincount(ip)) - lsn = ip->i_itemp->ili_last_lsn; + seq = ip->i_itemp->ili_commit_seq; xfs_iunlock(ip, XFS_ILOCK_SHARED);
- if (!lsn) + if (!seq) return 0; - return xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, NULL); + return xfs_log_force_seq(ip->i_mount, seq, XFS_LOG_SYNC, NULL); }
/* diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c index 6ff91e5bf3cd..3aba4559469f 100644 --- a/fs/xfs/xfs_inode_item.c +++ b/fs/xfs/xfs_inode_item.c @@ -617,9 +617,9 @@ xfs_inode_item_committed( STATIC void xfs_inode_item_committing( struct xfs_log_item *lip, - xfs_lsn_t commit_lsn) + xfs_csn_t seq) { - INODE_ITEM(lip)->ili_last_lsn = commit_lsn; + INODE_ITEM(lip)->ili_commit_seq = seq; return xfs_inode_item_release(lip); }
diff --git a/fs/xfs/xfs_inode_item.h b/fs/xfs/xfs_inode_item.h index 4b926e32831c..403b45ab9aa2 100644 --- a/fs/xfs/xfs_inode_item.h +++ b/fs/xfs/xfs_inode_item.h @@ -33,7 +33,7 @@ struct xfs_inode_log_item { unsigned int ili_fields; /* fields to be logged */ unsigned int ili_fsync_fields; /* logged since last fsync */ xfs_lsn_t ili_flush_lsn; /* lsn at last flush */ - xfs_lsn_t ili_last_lsn; /* lsn at last transaction */ + xfs_csn_t ili_commit_seq; /* last transaction commit */ };
static inline int xfs_inode_clean(struct xfs_inode *ip) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index b445e63cbc3c..05791456adbb 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -3210,14 +3210,13 @@ xfs_log_force( }
static int -__xfs_log_force_lsn( - struct xfs_mount *mp, +xlog_force_lsn( + struct xlog *log, xfs_lsn_t lsn, uint flags, int *log_flushed, bool already_slept) { - struct xlog *log = mp->m_log; struct xlog_in_core *iclog;
spin_lock(&log->l_icloglock); @@ -3250,8 +3249,6 @@ __xfs_log_force_lsn( if (!already_slept && (iclog->ic_prev->ic_state == XLOG_STATE_WANT_SYNC || iclog->ic_prev->ic_state == XLOG_STATE_SYNCING)) { - XFS_STATS_INC(mp, xs_log_force_sleep); - xlog_wait(&iclog->ic_prev->ic_write_wait, &log->l_icloglock); return -EAGAIN; @@ -3289,25 +3286,29 @@ __xfs_log_force_lsn( * to disk, that thread will wake up all threads waiting on the queue. */ int -xfs_log_force_lsn( +xfs_log_force_seq( struct xfs_mount *mp, - xfs_lsn_t lsn, + xfs_csn_t seq, uint flags, int *log_flushed) { + struct xlog *log = mp->m_log; + xfs_lsn_t lsn; int ret; - ASSERT(lsn != 0); + ASSERT(seq != 0);
XFS_STATS_INC(mp, xs_log_force); - trace_xfs_log_force(mp, lsn, _RET_IP_); + trace_xfs_log_force(mp, seq, _RET_IP_);
- lsn = xlog_cil_force_lsn(mp->m_log, lsn); + lsn = xlog_cil_force_seq(log, seq); if (lsn == NULLCOMMITLSN) return 0;
- ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, false); - if (ret == -EAGAIN) - ret = __xfs_log_force_lsn(mp, lsn, flags, log_flushed, true); + ret = xlog_force_lsn(log, lsn, flags, log_flushed, false); + if (ret == -EAGAIN) { + XFS_STATS_INC(mp, xs_log_force_sleep); + ret = xlog_force_lsn(log, lsn, flags, log_flushed, true); + } return ret; }
diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h index 98c913da7587..a1089f8b7169 100644 --- a/fs/xfs/xfs_log.h +++ b/fs/xfs/xfs_log.h @@ -106,7 +106,7 @@ struct xfs_item_ops; struct xfs_trans;
int xfs_log_force(struct xfs_mount *mp, uint flags); -int xfs_log_force_lsn(struct xfs_mount *mp, xfs_lsn_t lsn, uint flags, +int xfs_log_force_seq(struct xfs_mount *mp, xfs_csn_t seq, uint flags, int *log_forced); int xfs_log_mount(struct xfs_mount *mp, struct xfs_buftarg *log_target, @@ -132,8 +132,6 @@ bool xfs_log_writable(struct xfs_mount *mp); struct xlog_ticket *xfs_log_ticket_get(struct xlog_ticket *ticket); void xfs_log_ticket_put(struct xlog_ticket *ticket);
-void xfs_log_commit_cil(struct xfs_mount *mp, struct xfs_trans *tp, - xfs_lsn_t *commit_lsn, bool regrant); void xlog_cil_process_committed(struct list_head *list); bool xfs_log_item_in_current_chkpt(struct xfs_log_item *lip);
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index cd5c04dabe2e..88730883bb70 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -777,7 +777,7 @@ xlog_cil_push_work( * that higher sequences will wait for us to write out a commit record * before they do. * - * xfs_log_force_lsn requires us to mirror the new sequence into the cil + * xfs_log_force_seq requires us to mirror the new sequence into the cil * structure atomically with the addition of this sequence to the * committing list. This also ensures that we can do unlocked checks * against the current sequence in log forces without risking @@ -1020,16 +1020,14 @@ xlog_cil_empty( * allowed again. */ void -xfs_log_commit_cil( - struct xfs_mount *mp, +xlog_cil_commit( + struct xlog *log, struct xfs_trans *tp, - xfs_lsn_t *commit_lsn, + xfs_csn_t *commit_seq, bool regrant) { - struct xlog *log = mp->m_log; struct xfs_cil *cil = log->l_cilp; struct xfs_log_item *lip, *next; - xfs_lsn_t xc_commit_lsn;
/* * Do all necessary memory allocation before we lock the CIL. @@ -1043,10 +1041,6 @@ xfs_log_commit_cil(
xlog_cil_insert_items(log, tp);
- xc_commit_lsn = cil->xc_ctx->sequence; - if (commit_lsn) - *commit_lsn = xc_commit_lsn; - if (regrant && !XLOG_FORCED_SHUTDOWN(log)) xfs_log_ticket_regrant(log, tp->t_ticket); else @@ -1069,8 +1063,10 @@ xfs_log_commit_cil( list_for_each_entry_safe(lip, next, &tp->t_items, li_trans) { xfs_trans_del_item(lip); if (lip->li_ops->iop_committing) - lip->li_ops->iop_committing(lip, xc_commit_lsn); + lip->li_ops->iop_committing(lip, cil->xc_ctx->sequence); } + if (commit_seq) + *commit_seq = cil->xc_ctx->sequence;
/* xlog_cil_push_background() releases cil->xc_ctx_lock */ xlog_cil_push_background(log); @@ -1087,9 +1083,9 @@ xfs_log_commit_cil( * iclog flush is necessary following this call. */ xfs_lsn_t -xlog_cil_force_lsn( +xlog_cil_force_seq( struct xlog *log, - xfs_lsn_t sequence) + xfs_csn_t sequence) { struct xfs_cil *cil = log->l_cilp; struct xfs_cil_ctx *ctx; @@ -1185,21 +1181,17 @@ bool xfs_log_item_in_current_chkpt( struct xfs_log_item *lip) { - struct xfs_cil_ctx *ctx; + struct xfs_cil_ctx *ctx = lip->li_mountp->m_log->l_cilp->xc_ctx;
if (list_empty(&lip->li_cil)) return false;
- ctx = lip->li_mountp->m_log->l_cilp->xc_ctx; - /* * li_seq is written on the first commit of a log item to record the * first checkpoint it is written to. Hence if it is different to the * current sequence, we're in a new checkpoint. */ - if (XFS_LSN_CMP(lip->li_seq, ctx->sequence) != 0) - return false; - return true; + return lip->li_seq == ctx->sequence; }
/* diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index 1c6fdbf3d506..42cd1602ac25 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -230,7 +230,7 @@ struct xfs_cil;
struct xfs_cil_ctx { struct xfs_cil *cil; - xfs_lsn_t sequence; /* chkpt sequence # */ + xfs_csn_t sequence; /* chkpt sequence # */ xfs_lsn_t start_lsn; /* first LSN of chkpt commit */ xfs_lsn_t commit_lsn; /* chkpt commit record lsn */ struct xlog_ticket *ticket; /* chkpt ticket */ @@ -268,10 +268,10 @@ struct xfs_cil { struct xfs_cil_ctx *xc_ctx;
spinlock_t xc_push_lock ____cacheline_aligned_in_smp; - xfs_lsn_t xc_push_seq; + xfs_csn_t xc_push_seq; struct list_head xc_committing; wait_queue_head_t xc_commit_wait; - xfs_lsn_t xc_current_sequence; + xfs_csn_t xc_current_sequence; struct work_struct xc_push_work; wait_queue_head_t xc_push_wait; /* background push throttle */ } ____cacheline_aligned_in_smp; @@ -547,19 +547,18 @@ int xlog_cil_init(struct xlog *log); void xlog_cil_init_post_recovery(struct xlog *log); void xlog_cil_destroy(struct xlog *log); bool xlog_cil_empty(struct xlog *log); +void xlog_cil_commit(struct xlog *log, struct xfs_trans *tp, + xfs_csn_t *commit_seq, bool regrant);
/* * CIL force routines */ -xfs_lsn_t -xlog_cil_force_lsn( - struct xlog *log, - xfs_lsn_t sequence); +xfs_lsn_t xlog_cil_force_seq(struct xlog *log, xfs_csn_t sequence);
static inline void xlog_cil_force(struct xlog *log) { - xlog_cil_force_lsn(log, log->l_cilp->xc_current_sequence); + xlog_cil_force_seq(log, log->l_cilp->xc_current_sequence); }
/* diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index 36166bae24a6..73a1de7ceefc 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -832,7 +832,7 @@ __xfs_trans_commit( bool regrant) { struct xfs_mount *mp = tp->t_mountp; - xfs_lsn_t commit_lsn = -1; + xfs_csn_t commit_seq = 0; int error = 0; int sync = tp->t_flags & XFS_TRANS_SYNC;
@@ -874,7 +874,7 @@ __xfs_trans_commit( xfs_trans_apply_sb_deltas(tp); xfs_trans_apply_dquot_deltas(tp);
- xfs_log_commit_cil(mp, tp, &commit_lsn, regrant); + xlog_cil_commit(mp->m_log, tp, &commit_seq, regrant);
xfs_trans_free(tp);
@@ -883,7 +883,7 @@ __xfs_trans_commit( * log out now and wait for it. */ if (sync) { - error = xfs_log_force_lsn(mp, commit_lsn, XFS_LOG_SYNC, NULL); + error = xfs_log_force_seq(mp, commit_seq, XFS_LOG_SYNC, NULL); XFS_STATS_INC(mp, xs_trans_sync); } else { XFS_STATS_INC(mp, xs_trans_async); diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h index 075eeade4f7d..97485559008b 100644 --- a/fs/xfs/xfs_trans.h +++ b/fs/xfs/xfs_trans.h @@ -43,7 +43,7 @@ struct xfs_log_item { struct list_head li_cil; /* CIL pointers */ struct xfs_log_vec *li_lv; /* active log vector */ struct xfs_log_vec *li_lv_shadow; /* standby vector */ - xfs_lsn_t li_seq; /* CIL commit seq */ + xfs_csn_t li_seq; /* CIL commit seq */ };
/* @@ -69,7 +69,7 @@ struct xfs_item_ops { void (*iop_pin)(struct xfs_log_item *); void (*iop_unpin)(struct xfs_log_item *, int remove); uint (*iop_push)(struct xfs_log_item *, struct list_head *); - void (*iop_committing)(struct xfs_log_item *, xfs_lsn_t commit_lsn); + void (*iop_committing)(struct xfs_log_item *lip, xfs_csn_t seq); void (*iop_release)(struct xfs_log_item *); xfs_lsn_t (*iop_committed)(struct xfs_log_item *, xfs_lsn_t); int (*iop_recover)(struct xfs_log_item *lip,
From: "Darrick J. Wong" djwong@kernel.org
commit f8d92a66e810acbef6ddbc0bd0cbd9b117ce8acd upstream.
While I was running with KASAN and lockdep enabled, I stumbled upon an KASAN report about a UAF to a freed CIL checkpoint. Looking at the comment for xfs_log_item_in_current_chkpt, it seems pretty obvious to me that the original patch to xfs_defer_finish_noroll should have done something to lock the CIL to prevent it from switching the CIL contexts while the predicate runs.
For upper level code that needs to know if a given log item is new enough not to need relogging, add a new wrapper that takes the CIL context lock long enough to sample the current CIL context. This is kind of racy in that the CIL can switch the contexts immediately after sampling, but that's ok because the consequence is that the defer ops code is a little slow to relog items.
================================================================== BUG: KASAN: use-after-free in xfs_log_item_in_current_chkpt+0x139/0x160 [xfs] Read of size 8 at addr ffff88804ea5f608 by task fsstress/527999
CPU: 1 PID: 527999 Comm: fsstress Tainted: G D 5.16.0-rc4-xfsx #rc4 Call Trace: <TASK> dump_stack_lvl+0x45/0x59 print_address_description.constprop.0+0x1f/0x140 kasan_report.cold+0x83/0xdf xfs_log_item_in_current_chkpt+0x139/0x160 xfs_defer_finish_noroll+0x3bb/0x1e30 __xfs_trans_commit+0x6c8/0xcf0 xfs_reflink_remap_extent+0x66f/0x10e0 xfs_reflink_remap_blocks+0x2dd/0xa90 xfs_file_remap_range+0x27b/0xc30 vfs_dedupe_file_range_one+0x368/0x420 vfs_dedupe_file_range+0x37c/0x5d0 do_vfs_ioctl+0x308/0x1260 __x64_sys_ioctl+0xa1/0x170 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2c71a2950b Code: 0f 1e fa 48 8b 05 85 39 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 55 39 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe8c0e03c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00005600862a8740 RCX: 00007f2c71a2950b RDX: 00005600862a7be0 RSI: 00000000c0189436 RDI: 0000000000000004 RBP: 000000000000000b R08: 0000000000000027 R09: 0000000000000003 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000005a R13: 00005600862804a8 R14: 0000000000016000 R15: 00005600862a8a20 </TASK>
Allocated by task 464064: kasan_save_stack+0x1e/0x50 __kasan_kmalloc+0x81/0xa0 kmem_alloc+0xcd/0x2c0 [xfs] xlog_cil_ctx_alloc+0x17/0x1e0 [xfs] xlog_cil_push_work+0x141/0x13d0 [xfs] process_one_work+0x7f6/0x1380 worker_thread+0x59d/0x1040 kthread+0x3b0/0x490 ret_from_fork+0x1f/0x30
Freed by task 51: kasan_save_stack+0x1e/0x50 kasan_set_track+0x21/0x30 kasan_set_free_info+0x20/0x30 __kasan_slab_free+0xed/0x130 slab_free_freelist_hook+0x7f/0x160 kfree+0xde/0x340 xlog_cil_committed+0xbfd/0xfe0 [xfs] xlog_cil_process_committed+0x103/0x1c0 [xfs] xlog_state_do_callback+0x45d/0xbd0 [xfs] xlog_ioend_work+0x116/0x1c0 [xfs] process_one_work+0x7f6/0x1380 worker_thread+0x59d/0x1040 kthread+0x3b0/0x490 ret_from_fork+0x1f/0x30
Last potentially related work creation: kasan_save_stack+0x1e/0x50 __kasan_record_aux_stack+0xb7/0xc0 insert_work+0x48/0x2e0 __queue_work+0x4e7/0xda0 queue_work_on+0x69/0x80 xlog_cil_push_now.isra.0+0x16b/0x210 [xfs] xlog_cil_force_seq+0x1b7/0x850 [xfs] xfs_log_force_seq+0x1c7/0x670 [xfs] xfs_file_fsync+0x7c1/0xa60 [xfs] __x64_sys_fsync+0x52/0x80 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88804ea5f600 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 8 bytes inside of 256-byte region [ffff88804ea5f600, ffff88804ea5f700) The buggy address belongs to the page: page:ffffea00013a9780 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88804ea5ea00 pfn:0x4ea5e head:ffffea00013a9780 order:1 compound_mapcount:0 flags: 0x4fff80000010200(slab|head|node=1|zone=1|lastcpupid=0xfff) raw: 04fff80000010200 ffffea0001245908 ffffea00011bd388 ffff888004c42b40 raw: ffff88804ea5ea00 0000000000100009 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff88804ea5f500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804ea5f580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88804ea5f600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^ ffff88804ea5f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804ea5f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================
Fixes: 4e919af7827a ("xfs: periodically relog deferred intent items") Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Dave Chinner dchinner@redhat.com Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_log_cil.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index 88730883bb70..fbe160d5e9b9 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -1179,9 +1179,9 @@ xlog_cil_force_seq( */ bool xfs_log_item_in_current_chkpt( - struct xfs_log_item *lip) + struct xfs_log_item *lip) { - struct xfs_cil_ctx *ctx = lip->li_mountp->m_log->l_cilp->xc_ctx; + struct xfs_cil *cil = lip->li_mountp->m_log->l_cilp;
if (list_empty(&lip->li_cil)) return false; @@ -1191,7 +1191,7 @@ xfs_log_item_in_current_chkpt( * first checkpoint it is written to. Hence if it is different to the * current sequence, we're in a new checkpoint. */ - return lip->li_seq == ctx->sequence; + return lip->li_seq == READ_ONCE(cil->xc_current_sequence); }
/*
From: "Darrick J. Wong" djwong@kernel.org
commit 81ed94751b1513fcc5978dcc06eb1f5b4e55a785 upstream.
During regular operation, the xfs_inactive operations create transactions with zero block reservation because in general we're freeing space, not asking for more. The per-AG space reservations created at mount time enable us to handle expansions of the refcount btree without needing to reserve blocks to the transaction.
Unfortunately, log recovery doesn't create the per-AG space reservations when intent items are being recovered. This isn't an issue for intent item recovery itself because they explicitly request blocks, but any inode inactivation that can happen during log recovery uses the same xfs_inactive paths as regular runtime. If a refcount btree expansion happens, the transaction will fail due to blk_res_used > blk_res, and we shut down the filesystem unnecessarily.
Fix this problem by making per-AG reservations temporarily so that we can handle the inactivations, and releasing them at the end. This brings the recovery environment closer to the runtime environment.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_mount.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 44b05e1d5d32..a2a5a0fd9233 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -968,9 +968,17 @@ xfs_mountfs( /* * Finish recovering the file system. This part needed to be delayed * until after the root and real-time bitmap inodes were consistently - * read in. + * read in. Temporarily create per-AG space reservations for metadata + * btree shape changes because space freeing transactions (for inode + * inactivation) require the per-AG reservation in lieu of reserving + * blocks. */ + error = xfs_fs_reserve_ag_blocks(mp); + if (error && error == -ENOSPC) + xfs_warn(mp, + "ENOSPC reserving per-AG metadata pool, log recovery may fail."); error = xfs_log_mount_finish(mp); + xfs_fs_unreserve_ag_blocks(mp); if (error) { xfs_warn(mp, "log mount finish failed"); goto out_rtunmount;
From: "Darrick J. Wong" djwong@kernel.org
commit 4e6b8270c820c8c57a73f869799a0af2b56eff3e upstream.
If any part of log intent item recovery fails, we should shut down the log immediately to stop the log from writing a clean unmount record to disk, because the metadata is not consistent. The inability to cancel a dirty transaction catches most of these cases, but there are a few things that have slipped through the cracks, such as ENOSPC from a transaction allocation, or runtime errors that result in cancellation of a non-dirty transaction.
This solves some weird behaviors reported by customers where a system goes down, the first mount fails, the second succeeds, but then the fs goes down later because of inconsistent metadata.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_log.c | 3 +++ fs/xfs/xfs_log_recover.c | 5 ++++- 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 05791456adbb..22d7d74231d4 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -765,6 +765,9 @@ xfs_log_mount_finish( if (readonly) mp->m_flags |= XFS_MOUNT_RDONLY;
+ /* Make sure the log is dead if we're returning failure. */ + ASSERT(!error || (mp->m_log->l_flags & XLOG_IO_ERROR)); + return error; }
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index 87886b7f77da..69408782019e 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -2457,8 +2457,10 @@ xlog_finish_defer_ops(
error = xfs_trans_alloc(mp, &resv, dfc->dfc_blkres, dfc->dfc_rtxres, XFS_TRANS_RESERVE, &tp); - if (error) + if (error) { + xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR); return error; + }
/* * Transfer to this new transaction all the dfops we captured @@ -3454,6 +3456,7 @@ xlog_recover_finish( * this) before we get around to xfs_log_mount_cancel. */ xlog_recover_cancel_intents(log); + xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR); xfs_alert(log->l_mp, "Failed to recover intents"); return error; }
From: Brian Foster bfoster@redhat.com
commit 84d8949e770745b16a7e8a68dcb1d0f3687bdee9 upstream.
The special processing used to simulate a buffer I/O failure on fs shutdown has a difficult to reproduce race that can result in a use after free of the associated buffer. Consider a buffer that has been committed to the on-disk log and thus is AIL resident. The buffer lands on the writeback delwri queue, but is subsequently locked, committed and pinned by another transaction before submitted for I/O. At this point, the buffer is stuck on the delwri queue as it cannot be submitted for I/O until it is unpinned. A log checkpoint I/O failure occurs sometime later, which aborts the bli. The unpin handler is called with the aborted log item, drops the bli reference count, the pin count, and falls into the I/O failure simulation path.
The potential problem here is that once the pin count falls to zero in ->iop_unpin(), xfsaild is free to retry delwri submission of the buffer at any time, before the unpin handler even completes. If delwri queue submission wins the race to the buffer lock, it observes the shutdown state and simulates the I/O failure itself. This releases both the bli and delwri queue holds and frees the buffer while xfs_buf_item_unpin() sits on xfs_buf_lock() waiting to run through the same failure sequence. This problem is rare and requires many iterations of fstest generic/019 (which simulates disk I/O failures) to reproduce.
To avoid this problem, grab a hold on the buffer before the log item is unpinned if the associated item has been aborted and will require a simulated I/O failure. The hold is already required for the simulated I/O failure, so the ordering simply guarantees the unpin handler access to the buffer before it is unpinned and thus processed by the AIL. This particular ordering is required so long as the AIL does not acquire a reference on the bli, which is the long term solution to this problem.
Signed-off-by: Brian Foster bfoster@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_buf_item.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-)
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index 5d6535370f87..452af57731ed 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -393,17 +393,8 @@ xfs_buf_item_pin( }
/* - * This is called to unpin the buffer associated with the buf log - * item which was previously pinned with a call to xfs_buf_item_pin(). - * - * Also drop the reference to the buf item for the current transaction. - * If the XFS_BLI_STALE flag is set and we are the last reference, - * then free up the buf log item and unlock the buffer. - * - * If the remove flag is set we are called from uncommit in the - * forced-shutdown path. If that is true and the reference count on - * the log item is going to drop to zero we need to free the item's - * descriptor in the transaction. + * This is called to unpin the buffer associated with the buf log item which + * was previously pinned with a call to xfs_buf_item_pin(). */ STATIC void xfs_buf_item_unpin( @@ -420,12 +411,26 @@ xfs_buf_item_unpin(
trace_xfs_buf_item_unpin(bip);
+ /* + * Drop the bli ref associated with the pin and grab the hold required + * for the I/O simulation failure in the abort case. We have to do this + * before the pin count drops because the AIL doesn't acquire a bli + * reference. Therefore if the refcount drops to zero, the bli could + * still be AIL resident and the buffer submitted for I/O (and freed on + * completion) at any point before we return. This can be removed once + * the AIL properly holds a reference on the bli. + */ freed = atomic_dec_and_test(&bip->bli_refcount); - + if (freed && !stale && remove) + xfs_buf_hold(bp); if (atomic_dec_and_test(&bp->b_pin_count)) wake_up_all(&bp->b_waiters);
- if (freed && stale) { + /* nothing to do but drop the pin count if the bli is active */ + if (!freed) + return; + + if (stale) { ASSERT(bip->bli_flags & XFS_BLI_STALE); ASSERT(xfs_buf_islocked(bp)); ASSERT(bp->b_flags & XBF_STALE); @@ -468,13 +473,13 @@ xfs_buf_item_unpin( ASSERT(bp->b_log_item == NULL); } xfs_buf_relse(bp); - } else if (freed && remove) { + } else if (remove) { /* * The buffer must be locked and held by the caller to simulate - * an async I/O failure. + * an async I/O failure. We acquired the hold for this case + * before the buffer was unpinned. */ xfs_buf_lock(bp); - xfs_buf_hold(bp); bp->b_flags |= XBF_ASYNC; xfs_buf_ioend_fail(bp); }
From: Brian Foster bfoster@redhat.com
commit e53d3aa0b605c49d780e1b2fd0b49dba4154f32b upstream.
This code goes back to a time when transaction commits wrote directly to iclogs. The associated log items were pinned, written to the log, and then "uncommitted" if some part of the log write had failed. This uncommit sequence called an ->iop_unpin_remove() handler that was eventually folded into ->iop_unpin() via the remove parameter. The log subsystem has since changed significantly in that transactions commit to the CIL instead of direct to iclogs, though log items must still be aborted in the event of an eventual log I/O error. However, the context for a log item abort is now asynchronous from transaction commit, which means the committing transaction has been freed by this point in time and the transaction uncommit sequence of events is no longer relevant.
Further, since stale buffers remain locked at transaction commit through unpin, we can be certain that the buffer is not associated with any transaction when the unpin callback executes. Remove this unused hunk of code and replace it with an assertion that the buffer is disassociated from transaction context.
Signed-off-by: Brian Foster bfoster@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_buf_item.c | 21 ++------------------- 1 file changed, 2 insertions(+), 19 deletions(-)
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index 452af57731ed..a3d5ecccfc2c 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -435,28 +435,11 @@ xfs_buf_item_unpin( ASSERT(xfs_buf_islocked(bp)); ASSERT(bp->b_flags & XBF_STALE); ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL); + ASSERT(list_empty(&lip->li_trans)); + ASSERT(!bp->b_transp);
trace_xfs_buf_item_unpin_stale(bip);
- if (remove) { - /* - * If we are in a transaction context, we have to - * remove the log item from the transaction as we are - * about to release our reference to the buffer. If we - * don't, the unlock that occurs later in - * xfs_trans_uncommit() will try to reference the - * buffer which we no longer have a hold on. - */ - if (!list_empty(&lip->li_trans)) - xfs_trans_del_item(lip); - - /* - * Since the transaction no longer refers to the buffer, - * the buffer should no longer refer to the transaction. - */ - bp->b_transp = NULL; - } - /* * If we get called here because of an IO error, we may or may * not have the item on the AIL. xfs_trans_ail_delete() will
From: Dave Chinner dchinner@redhat.com
commit 32baa63d82ee3f5ab3bd51bae6bf7d1c15aed8c7 upstream.
When we log an inode, we format the "log inode" core and set an LSN in that inode core. We do that via xfs_inode_item_format_core(), which calls:
xfs_inode_to_log_dinode(ip, dic, ip->i_itemp->ili_item.li_lsn);
to format the log inode. It writes the LSN from the inode item into the log inode, and if recovery decides the inode item needs to be replayed, it recovers the log inode LSN field and writes it into the on disk inode LSN field.
Now this might seem like a reasonable thing to do, but it is wrong on multiple levels. Firstly, if the item is not yet in the AIL, item->li_lsn is zero. i.e. the first time the inode it is logged and formatted, the LSN we write into the log inode will be zero. If we only log it once, recovery will run and can write this zero LSN into the inode.
This means that the next time the inode is logged and log recovery runs, it will *always* replay changes to the inode regardless of whether the inode is newer on disk than the version in the log and that violates the entire purpose of recording the LSN in the inode at writeback time (i.e. to stop it going backwards in time on disk during recovery).
Secondly, if we commit the CIL to the journal so the inode item moves to the AIL, and then relog the inode, the LSN that gets stamped into the log inode will be the LSN of the inode's current location in the AIL, not it's age on disk. And it's not the LSN that will be associated with the current change. That means when log recovery replays this inode item, the LSN that ends up on disk is the LSN for the previous changes in the log, not the current changes being replayed. IOWs, after recovery the LSN on disk is not in sync with the LSN of the modifications that were replayed into the inode. This, again, violates the recovery ordering semantics that on-disk writeback LSNs provide.
Hence the inode LSN in the log dinode is -always- invalid.
Thirdly, recovery actually has the LSN of the log transaction it is replaying right at hand - it uses it to determine if it should replay the inode by comparing it to the on-disk inode's LSN. But it doesn't use that LSN to stamp the LSN into the inode which will be written back when the transaction is fully replayed. It uses the one in the log dinode, which we know is always going to be incorrect.
Looking back at the change history, the inode logging was broken by commit 93f958f9c41f ("xfs: cull unnecessary icdinode fields") way back in 2016 by a stupid idiot who thought he knew how this code worked. i.e. me. That commit replaced an in memory di_lsn field that was updated only at inode writeback time from the inode item.li_lsn value - and hence always contained the same LSN that appeared in the on-disk inode - with a read of the inode item LSN at inode format time. CLearly these are not the same thing.
Before 93f958f9c41f, the log recovery behaviour was irrelevant, because the LSN in the log inode always matched the on-disk LSN at the time the inode was logged, hence recovery of the transaction would never make the on-disk LSN in the inode go backwards or get out of sync.
A symptom of the problem is this, caught from a failure of generic/482. Before log recovery, the inode has been allocated but never used:
xfs_db> inode 393388 xfs_db> p core.magic = 0x494e core.mode = 0 .... v3.crc = 0x99126961 (correct) v3.change_count = 0 v3.lsn = 0 v3.flags2 = 0 v3.cowextsize = 0 v3.crtime.sec = Thu Jan 1 10:00:00 1970 v3.crtime.nsec = 0
After log recovery:
xfs_db> p core.magic = 0x494e core.mode = 020444 .... v3.crc = 0x23e68f23 (correct) v3.change_count = 2 v3.lsn = 0 v3.flags2 = 0 v3.cowextsize = 0 v3.crtime.sec = Thu Jul 22 17:03:03 2021 v3.crtime.nsec = 751000000 ...
You can see that the LSN of the on-disk inode is 0, even though it clearly has been written to disk. I point out this inode, because the generic/482 failure occurred because several adjacent inodes in this specific inode cluster were not replayed correctly and still appeared to be zero on disk when all the other metadata (inobt, finobt, directories, etc) indicated they should be allocated and written back.
The fix for this is two-fold. The first is that we need to either revert the LSN changes in 93f958f9c41f or stop logging the inode LSN altogether. If we do the former, log recovery does not need to change but we add 8 bytes of memory per inode to store what is largely a write-only inode field. If we do the latter, log recovery needs to stamp the on-disk inode in the same manner that inode writeback does.
I prefer the latter, because we shouldn't really be trying to log and replay changes to the on disk LSN as the on-disk value is the canonical source of the on-disk version of the inode. It also matches the way we recover buffer items - we create a buf_log_item that carries the current recovery transaction LSN that gets stamped into the buffer by the write verifier when it gets written back when the transaction is fully recovered.
However, this might break log recovery on older kernels even more, so I'm going to simply ignore the logged value in recovery and stamp the on-disk inode with the LSN of the transaction being recovered that will trigger writeback on transaction recovery completion. This will ensure that the on-disk inode LSN always reflects the LSN of the last change that was written to disk, regardless of whether it comes from log recovery or runtime writeback.
Fixes: 93f958f9c41f ("xfs: cull unnecessary icdinode fields") Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/libxfs/xfs_log_format.h | 11 +++++++++- fs/xfs/xfs_inode_item_recover.c | 39 ++++++++++++++++++++++++--------- 2 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h index 8bd00da6d2a4..2f46ef3800aa 100644 --- a/fs/xfs/libxfs/xfs_log_format.h +++ b/fs/xfs/libxfs/xfs_log_format.h @@ -414,7 +414,16 @@ struct xfs_log_dinode { /* start of the extended dinode, writable fields */ uint32_t di_crc; /* CRC of the inode */ uint64_t di_changecount; /* number of attribute changes */ - xfs_lsn_t di_lsn; /* flush sequence */ + + /* + * The LSN we write to this field during formatting is not a reflection + * of the current on-disk LSN. It should never be used for recovery + * sequencing, nor should it be recovered into the on-disk inode at all. + * See xlog_recover_inode_commit_pass2() and xfs_log_dinode_to_disk() + * for details. + */ + xfs_lsn_t di_lsn; + uint64_t di_flags2; /* more random flags */ uint32_t di_cowextsize; /* basic cow extent size for file */ uint8_t di_pad2[12]; /* more padding for future expansion */ diff --git a/fs/xfs/xfs_inode_item_recover.c b/fs/xfs/xfs_inode_item_recover.c index cb44f7653f03..538724f9f85c 100644 --- a/fs/xfs/xfs_inode_item_recover.c +++ b/fs/xfs/xfs_inode_item_recover.c @@ -145,7 +145,8 @@ xfs_log_dinode_to_disk_ts( STATIC void xfs_log_dinode_to_disk( struct xfs_log_dinode *from, - struct xfs_dinode *to) + struct xfs_dinode *to, + xfs_lsn_t lsn) { to->di_magic = cpu_to_be16(from->di_magic); to->di_mode = cpu_to_be16(from->di_mode); @@ -182,7 +183,7 @@ xfs_log_dinode_to_disk( to->di_flags2 = cpu_to_be64(from->di_flags2); to->di_cowextsize = cpu_to_be32(from->di_cowextsize); to->di_ino = cpu_to_be64(from->di_ino); - to->di_lsn = cpu_to_be64(from->di_lsn); + to->di_lsn = cpu_to_be64(lsn); memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2)); uuid_copy(&to->di_uuid, &from->di_uuid); to->di_flushiter = 0; @@ -261,16 +262,25 @@ xlog_recover_inode_commit_pass2( }
/* - * If the inode has an LSN in it, recover the inode only if it's less - * than the lsn of the transaction we are replaying. Note: we still - * need to replay an owner change even though the inode is more recent - * than the transaction as there is no guarantee that all the btree - * blocks are more recent than this transaction, too. + * If the inode has an LSN in it, recover the inode only if the on-disk + * inode's LSN is older than the lsn of the transaction we are + * replaying. We can have multiple checkpoints with the same start LSN, + * so the current LSN being equal to the on-disk LSN doesn't necessarily + * mean that the on-disk inode is more recent than the change being + * replayed. + * + * We must check the current_lsn against the on-disk inode + * here because the we can't trust the log dinode to contain a valid LSN + * (see comment below before replaying the log dinode for details). + * + * Note: we still need to replay an owner change even though the inode + * is more recent than the transaction as there is no guarantee that all + * the btree blocks are more recent than this transaction, too. */ if (dip->di_version >= 3) { xfs_lsn_t lsn = be64_to_cpu(dip->di_lsn);
- if (lsn && lsn != -1 && XFS_LSN_CMP(lsn, current_lsn) >= 0) { + if (lsn && lsn != -1 && XFS_LSN_CMP(lsn, current_lsn) > 0) { trace_xfs_log_recover_inode_skip(log, in_f); error = 0; goto out_owner_change; @@ -368,8 +378,17 @@ xlog_recover_inode_commit_pass2( goto out_release; }
- /* recover the log dinode inode into the on disk inode */ - xfs_log_dinode_to_disk(ldip, dip); + /* + * Recover the log dinode inode into the on disk inode. + * + * The LSN in the log dinode is garbage - it can be zero or reflect + * stale in-memory runtime state that isn't coherent with the changes + * logged in this transaction or the changes written to the on-disk + * inode. Hence we write the current lSN into the inode because that + * matches what xfs_iflush() would write inode the inode when flushing + * the changes in this transaction. + */ + xfs_log_dinode_to_disk(ldip, dip, current_lsn);
fields = in_f->ilf_fields; if (fields & XFS_ILOG_DEV)
From: Dave Chinner dchinner@redhat.com
commit d8f4c2d0398fa1d92cacf854daf80d21a46bfefc upstream.
From the department of "WTAF? How did we miss that!?"...
When we are recovering a buffer, the first thing we do is check the buffer magic number and extract the LSN from the buffer. If the LSN is older than the current LSN, we replay the modification to it. If the metadata on disk is newer than the transaction in the log, we skip it. This is a fundamental v5 filesystem metadata recovery behaviour.
generic/482 failed with an attribute writeback failure during log recovery. The write verifier caught the corruption before it got written to disk, and the attr buffer dump looked like:
XFS (dm-3): Metadata corruption detected at xfs_attr3_leaf_verify+0x275/0x2e0, xfs_attr3_leaf block 0x19be8 XFS (dm-3): Unmount and run xfs_repair XFS (dm-3): First 128 bytes of corrupted metadata buffer: 00000000: 00 00 00 00 00 00 00 00 3b ee 00 00 4d 2a 01 e1 ........;...M*.. 00000010: 00 00 00 00 00 01 9b e8 00 00 00 01 00 00 05 38 ...............8 ^^^^^^^^^^^^^^^^^^^^^^^ 00000020: df 39 5e 51 58 ac 44 b6 8d c5 e7 10 44 09 bc 17 .9^QX.D.....D... 00000030: 00 00 00 00 00 02 00 83 00 03 00 cc 0f 24 01 00 .............$.. 00000040: 00 68 0e bc 0f c8 00 10 00 00 00 00 00 00 00 00 .h.............. 00000050: 00 00 3c 31 0f 24 01 00 00 00 3c 32 0f 88 01 00 ..<1.$....<2.... 00000060: 00 00 3c 33 0f d8 01 00 00 00 00 00 00 00 00 00 ..<3............ 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ .....
The highlighted bytes are the LSN that was replayed into the buffer: 0x100000538. This is cycle 1, block 0x538. Prior to replay, that block on disk looks like this:
$ sudo xfs_db -c "fsb 0x417d" -c "type attr3" -c p /dev/mapper/thin-vol hdr.info.hdr.forw = 0 hdr.info.hdr.back = 0 hdr.info.hdr.magic = 0x3bee hdr.info.crc = 0xb5af0bc6 (correct) hdr.info.bno = 105448 hdr.info.lsn = 0x100000900 ^^^^^^^^^^^ hdr.info.uuid = df395e51-58ac-44b6-8dc5-e7104409bc17 hdr.info.owner = 131203 hdr.count = 2 hdr.usedbytes = 120 hdr.firstused = 3796 hdr.holes = 1 hdr.freemap[0-2] = [base,size]
Note the LSN stamped into the buffer on disk: 1/0x900. The version on disk is much newer than the log transaction that was being replayed. That's a bug, and should -never- happen.
So I immediately went to look at xlog_recover_get_buf_lsn() to check that we handled the LSN correctly. I was wondering if there was a similar "two commits with the same start LSN skips the second replay" problem with buffers. I didn't get that far, because I found a much more basic, rudimentary bug: xlog_recover_get_buf_lsn() doesn't recognise buffers with XFS_ATTR3_LEAF_MAGIC set in them!!!
IOWs, attr3 leaf buffers fall through the magic number checks unrecognised, so trigger the "recover immediately" behaviour instead of undergoing an LSN check. IOWs, we incorrectly replay ATTR3 leaf buffers and that causes silent on disk corruption of inode attribute forks and potentially other things....
Git history shows this is *another* zero day bug, this time introduced in commit 50d5c8d8e938 ("xfs: check LSN ordering for v5 superblocks during recovery") which failed to handle the attr3 leaf buffers in recovery. And we've failed to handle them ever since...
Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/xfs_buf_item_recover.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c index 1d649462d731..b374c9cee117 100644 --- a/fs/xfs/xfs_buf_item_recover.c +++ b/fs/xfs/xfs_buf_item_recover.c @@ -796,6 +796,7 @@ xlog_recover_get_buf_lsn( switch (magicda) { case XFS_DIR3_LEAF1_MAGIC: case XFS_DIR3_LEAFN_MAGIC: + case XFS_ATTR3_LEAF_MAGIC: case XFS_DA3_NODE_MAGIC: lsn = be64_to_cpu(((struct xfs_da3_blkinfo *)blk)->lsn); uuid = &((struct xfs_da3_blkinfo *)blk)->uuid;
On Fri, Jul 29, 2022 at 06:16:00PM +0200, Amir Goldstein wrote:
Hi Greg,
This backport series contains mostly fixes from v5.14 release along with one fix deferred from the first joint 5.10/5.15 series [1].
The upstream commit f8d92a66e810 ("xfs: prevent UAF in xfs_log_item_in_current_chkpt") was already applied to 5.15.y, but its 5.10.y backport was more involved (required two non trivial dependency patches), so it needed more time for review and testing.
Per Darrick's recommendation, on top of the usual regression tests, I also ran the "recoveryloop" tests group for an extended period of time to test for rare regressions.
Some recoveryloop tests were failing at rates less frequent than 1/100, but no change in failure rate was observed between baseline (v5.10.131) and the backport branch.
There was one exceptional test, xfs/455, that was reporting data corruptions after crash at very low rate - less frequent than 1/1000 on both baseline and backport branch.
It is hard to draw solid conclusions with such rare failures, but the test was run >10,000 times on baseline and >20,000 times on backport branch, so as far as our test coverage can attest, these backports are not introducing any obvious xfs regressions to 5.10.y.
Now queued up, thanks!
greg k-h
linux-stable-mirror@lists.linaro.org
-
Amir Goldstein -
Greg Kroah-Hartman