The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 14abcb0bf59a30cf65a74f6c6f53974cd7224bc6 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Date: Sat, 19 Aug 2017 10:10:34 -0400 Subject: [PATCH] NFSv4: Fix up mirror allocation There are a number of callers of nfs_pageio_complete() that want to continue using the nfs_pageio_descriptor without needing to call nfs_pageio_init() again. Examples include nfs_pageio_resend() and nfs_pageio_cond_complete(). The problem is that nfs_pageio_complete() also calls nfs_pageio_cleanup_mirroring(), which frees up the array of mirrors. This can lead to writeback errors, in the next call to nfs_pageio_setup_mirroring(). Fix by simply moving the allocation of the mirrors to nfs_pageio_setup_mirroring(). Link: https://bugzilla.kernel.org/show_bug.cgi?id=196709 Reported-by: JianhongYin <yin-jianhong@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 4.0+ Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index de9066a92c0d..b7d193e2a243 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -714,9 +714,6 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, int io_flags, gfp_t gfp_flags) { - struct nfs_pgio_mirror *new; - int i; - desc->pg_moreio = 0; desc->pg_inode = inode; desc->pg_ops = pg_ops; @@ -732,21 +729,9 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, desc->pg_mirror_count = 1; desc->pg_mirror_idx = 0; - if (pg_ops->pg_get_mirror_count) { - /* until we have a request, we don't have an lseg and no - * idea how many mirrors there will be */ - new = kcalloc(NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX, - sizeof(struct nfs_pgio_mirror), gfp_flags); - desc->pg_mirrors_dynamic = new; - desc->pg_mirrors = new; - - for (i = 0; i < NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX; i++) - nfs_pageio_mirror_init(&desc->pg_mirrors[i], bsize); - } else { - desc->pg_mirrors_dynamic = NULL; - desc->pg_mirrors = desc->pg_mirrors_static; - nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize); - } + desc->pg_mirrors_dynamic = NULL; + desc->pg_mirrors = desc->pg_mirrors_static; + nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize); } EXPORT_SYMBOL_GPL(nfs_pageio_init); @@ -865,32 +850,52 @@ static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc) return ret; } +static struct nfs_pgio_mirror * +nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc, + unsigned int mirror_count) +{ + struct nfs_pgio_mirror *ret; + unsigned int i; + + kfree(desc->pg_mirrors_dynamic); + desc->pg_mirrors_dynamic = NULL; + if (mirror_count == 1) + return desc->pg_mirrors_static; + ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_NOFS); + if (ret != NULL) { + for (i = 0; i < mirror_count; i++) + nfs_pageio_mirror_init(&ret[i], desc->pg_bsize); + desc->pg_mirrors_dynamic = ret; + } + return ret; +} + /* * nfs_pageio_setup_mirroring - determine if mirroring is to be used * by calling the pg_get_mirror_count op */ -static int nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio, +static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) { - int mirror_count = 1; + unsigned int mirror_count = 1; - if (!pgio->pg_ops->pg_get_mirror_count) - return 0; - - mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req); - - if (pgio->pg_error < 0) - return pgio->pg_error; - - if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) - return -EINVAL; + if (pgio->pg_ops->pg_get_mirror_count) + mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req); + if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0) + return; - if (WARN_ON_ONCE(!pgio->pg_mirrors_dynamic)) - return -EINVAL; + if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) { + pgio->pg_error = -EINVAL; + return; + } + pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count); + if (pgio->pg_mirrors == NULL) { + pgio->pg_error = -ENOMEM; + pgio->pg_mirrors = pgio->pg_mirrors_static; + mirror_count = 1; + } pgio->pg_mirror_count = mirror_count; - - return 0; } /*