diff options
| author | Christoph Hellwig | 2024-10-23 15:37:22 +0200 |
|---|---|---|
| committer | Carlos Maiolino | 2024-10-30 11:27:18 +0100 |
| commit | dc60992ce76fbc2f71c2674f435ff6bde2108028 (patch) | |
| tree | 0491b2bac78836237d49bb0f00b5bb75146c4e36 | |
| parent | 3ef22684038aa577c10972ee9c6a2455f5fac941 (diff) | |
xfs: fix finding a last resort AG in xfs_filestream_pick_ag
When the main loop in xfs_filestream_pick_ag fails to find a suitable
AG it tries to just pick the online AG. But the loop for that uses
args->pag as loop iterator while the later code expects pag to be
set. Fix this by reusing the max_pag case for this last resort, and
also add a check for impossible case of no AG just to make sure that
the uninitialized pag doesn't even escape in theory.
Reported-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com
Fixes: f8f1ed1ab3baba ("xfs: return a referenced perag from filestreams allocator")
Cc: <stable@vger.kernel.org> # v6.3
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
| -rw-r--r-- | fs/xfs/xfs_filestream.c | 23 | ||||
| -rw-r--r-- | fs/xfs/xfs_trace.h | 15 |
2 files changed, 17 insertions, 21 deletions
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c index e3aaa0555597..88bd23ce74cd 100644 --- a/fs/xfs/xfs_filestream.c +++ b/fs/xfs/xfs_filestream.c @@ -64,7 +64,7 @@ xfs_filestream_pick_ag( struct xfs_perag *pag; struct xfs_perag *max_pag = NULL; xfs_extlen_t minlen = *longest; - xfs_extlen_t free = 0, minfree, maxfree = 0; + xfs_extlen_t minfree, maxfree = 0; xfs_agnumber_t agno; bool first_pass = true; int err; @@ -107,7 +107,6 @@ restart: !(flags & XFS_PICK_USERDATA) || (flags & XFS_PICK_LOWSPACE))) { /* Break out, retaining the reference on the AG. */ - free = pag->pagf_freeblks; break; } } @@ -150,23 +149,25 @@ restart: * grab. */ if (!max_pag) { - for_each_perag_wrap(args->mp, 0, start_agno, args->pag) + for_each_perag_wrap(args->mp, 0, start_agno, pag) { + max_pag = pag; break; - atomic_inc(&args->pag->pagf_fstrms); - *longest = 0; - } else { - pag = max_pag; - free = maxfree; - atomic_inc(&pag->pagf_fstrms); + } + + /* Bail if there are no AGs at all to select from. */ + if (!max_pag) + return -ENOSPC; } + + pag = max_pag; + atomic_inc(&pag->pagf_fstrms); } else if (max_pag) { xfs_perag_rele(max_pag); } - trace_xfs_filestream_pick(pag, pino, free); + trace_xfs_filestream_pick(pag, pino); args->pag = pag; return 0; - } static struct xfs_inode * diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index ee9f0b1f548d..fcb2bad4f76e 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -691,8 +691,8 @@ DEFINE_FILESTREAM_EVENT(xfs_filestream_lookup); DEFINE_FILESTREAM_EVENT(xfs_filestream_scan); TRACE_EVENT(xfs_filestream_pick, - TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino, xfs_extlen_t free), - TP_ARGS(pag, ino, free), + TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino), + TP_ARGS(pag, ino), TP_STRUCT__entry( __field(dev_t, dev) __field(xfs_ino_t, ino) @@ -703,14 +703,9 @@ TRACE_EVENT(xfs_filestream_pick, TP_fast_assign( __entry->dev = pag->pag_mount->m_super->s_dev; __entry->ino = ino; - if (pag) { - __entry->agno = pag->pag_agno; - __entry->streams = atomic_read(&pag->pagf_fstrms); - } else { - __entry->agno = NULLAGNUMBER; - __entry->streams = 0; - } - __entry->free = free; + __entry->agno = pag->pag_agno; + __entry->streams = atomic_read(&pag->pagf_fstrms); + __entry->free = pag->pagf_freeblks; ), TP_printk("dev %d:%d ino 0x%llx agno 0x%x streams %d free %d", MAJOR(__entry->dev), MINOR(__entry->dev), |