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c=1 sm=1 tr=0 ts=6a61c1dc cx=c_pps a=KcDtNT9Y7DbXMZTh6VQ3dg==:117 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=bi6dqmuHe4P4UrxVR6um:22 a=iKiJcTA2PjBS6x5JeXcw:22 a=ItIgLucf9a_KYlnWXAYA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: rrVxK79actBxAV5CL_FJAMkxkcjfg0pq X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-23_02,2026-07-22_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 malwarescore=0 bulkscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 impostorscore=0 phishscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607230073 On 7/23/26 12:59, Christoph Hellwig wrote: > On Tue, Jul 07, 2026 at 01:25:55PM +0800, Yun Zhou wrote: >> When netfs_create_write_req() fails with -ENOMEM in netfs_writepages(), >> the couldnt_start error path redirties and unlocks the first folio, > > writeback must use mempools to back resoures, or __GFP_NOFAIL if it > can't for some reason. -ENOMEM must not happend in writeback paths > or your toast. So please fix the cause of this error and not the > symptoms. > Thanks for the review. You're right - writeback should not fail with ENOMEM. I'll follow your suggestion and use __GFP_NOFAIL for the allocation in the writeback path. The ENOMEM here comes from rolling_buffer_init() which uses plain GFP_NOFS for its folio_queue allocation. Using mempools would be the more robust approach, but it requires adding a new mempool, modifying the rolling_buffer_init() signature and all its callers, plus the init/destroy lifecycle - a much larger change. __GFP_NOFAIL is a minimal fix that achieves the same goal for the writeback path. Will send v2 shortly.