From: NeilBrown Date: Tue, 27 Feb 2024 23:23:31 +0000 (+1100) Subject: NFS: Fix data corruption caused by congestion. X-Git-Tag: v6.6.21~30 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be8a177250b2ba387a55ce37dd4a8046a0ccab55;p=thirdparty%2Fkernel%2Fstable.git NFS: Fix data corruption caused by congestion. when AOP_WRITEPAGE_ACTIVATE is returned (as NFS does when it detects congestion) it is important that the folio is redirtied. nfs_writepage_locked() doesn't do this, so files can become corrupted as writes can be lost. Note that this is not needed in v6.8 as AOP_WRITEPAGE_ACTIVATE cannot be returned. It is needed for kernels v5.18..v6.7. Prior to 6.3 the patch is different as it needs to mention "page", not "folio". Reported-and-tested-by: Jacek Tomaka Fixes: 6df25e58532b ("nfs: remove reliance on bdi congestion") Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 9d82d50ce0b12..4a250f65fa759 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -668,8 +668,10 @@ static int nfs_writepage_locked(struct folio *folio, int err; if (wbc->sync_mode == WB_SYNC_NONE && - NFS_SERVER(inode)->write_congested) + NFS_SERVER(inode)->write_congested) { + folio_redirty_for_writepage(wbc, folio); return AOP_WRITEPAGE_ACTIVATE; + } nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE); nfs_pageio_init_write(&pgio, inode, 0, false,