5.15-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Coddington bcodding@redhat.com
[ Upstream commit 99765233ab42bf7a4950377ad7894dce8a5c0e60 ]
If the NFS client is doing writeback from a workqueue context, avoid using __GFP_NORETRY for allocations if the task has set PF_MEMALLOC_NOIO or PF_MEMALLOC_NOFS. The combination of these flags makes memory allocation failures much more likely.
We've seen those allocation failures show up when the loopback driver is doing writeback from a workqueue to a file on NFS, where memory allocation failure results in errors or corruption within the loopback device's filesystem.
Suggested-by: Trond Myklebust trondmy@kernel.org Fixes: 0bae835b63c5 ("NFS: Avoid writeback threads getting stuck in mempool_alloc()") Signed-off-by: Benjamin Coddington bcodding@redhat.com Reviewed-by: Laurence Oberman loberman@redhat.com Tested-by: Laurence Oberman loberman@redhat.com Reviewed-by: Jeff Layton jlayton@kernel.org Link: https://lore.kernel.org/r/f83ac1155a4bc670f2663959a7a068571e06afd9.175211162... Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/internal.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index a6d0b64dda36..76605eb93609 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -581,9 +581,12 @@ nfs_write_match_verf(const struct nfs_writeverf *verf,
static inline gfp_t nfs_io_gfp_mask(void) { - if (current->flags & PF_WQ_WORKER) - return GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN; - return GFP_KERNEL; + gfp_t ret = current_gfp_context(GFP_KERNEL); + + /* For workers __GFP_NORETRY only with __GFP_IO or __GFP_FS */ + if ((current->flags & PF_WQ_WORKER) && ret == GFP_KERNEL) + ret |= __GFP_NORETRY | __GFP_NOWARN; + return ret; }
/* unlink.c */