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Petersen" Cc: Shin'ichiro Kawasaki , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Tal Zussman X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=ed25519-sha256; t=1790207813; l=1162; i=tz2294@columbia.edu; s=20250528; h=from:subject:message-id; bh=eekIRUkO6xctJzh0LDxpTW7f45r0xCkvZKYTjeZsvDw=; b=2YSDeglgyk07rr4XCceLzHJrMpahC9wn5HyPBCzFyGWpB4A7Jm0LwTpK53X+wg/uOg2P5jPVn EO951ZjrUh1C4yifGSMaj539bji3K60vVy92ozbmJFDFa2hZoDofx44 X-Developer-Key: i=tz2294@columbia.edu; a=ed25519; pk=BIj5KdACscEOyAC0oIkeZqLB3L94fzBnDccEooxeM5Y= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTIzMDEwMCBTYWx0ZWRfX34IyYmp7kWV7 gR0UBoNwBiFdciRI7eSyMapvyRri9KP2g+jx4vFaCBD7JhaL9iQ+TECgN8E68tYkS9OJ4/NAT1U igPCxYhDjNFa0i9vuwl4nYplTyZYW9+bdI3IcyuIgnraH8np9bsCKDOehHoN+4QSprfCLZFITb8 MADWdDh/xvrQimN0A6NIlQsXPfHxVlvxZ1roElthw1dFgd2uK763/3LDExjLkHa0avz/r1fYNGH laNrCRBiuLtNC8JaovhSS9RPqWa29pK8Fn8ju4+KO+BeXoSSyxOeCzQqGgIY4X3EHVCpHkz6viW ncqMzsASQMgh98BYe/CONIsF0jzNm073BluYh8Ci/eP9Ceg9ziAelWOcNchUC2uMQCU2yg9DNZb YQE8r5oettSHs+RTpF44ViTJ26/bpc5PFlfq85hU33alMf17mBprjM9vQoCp3lk+zglr8qP0TOF TV0oNVJjJpCVrhK6pqw== X-Proofpoint-GUID: eWVdv1MGYzaTHvprttgWkYNXex-lzPov X-Proofpoint-ORIG-GUID: eWVdv1MGYzaTHvprttgWkYNXex-lzPov X-Authority-Analysis: v=2.4 cv=LtYHWXdc c=1 sm=1 tr=0 ts=6ab46752 cx=c_pps a=0uOsjrqzRL749jD1oC5vDA==:117 a=6aZ3Ysb2zzbY2sELL/OBJw==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=x7bEGLp0ZPQA:10 a=A0y_DWxS2BwA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Da8U98TiO7q1upZEImrf:22 a=SsB-OO3BMngHh3ZO9fOt:22 a=ASVHLkjgWNnnwhGXR8EA:9 a=QEXdDO2ut3YA:10 a=mQ_c8vxmzFEMiUWkPHU9:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTIzMDEwMCBTYWx0ZWRfX5Ma1tQ31J0RH CL2KmtqRl8ZJBL2vyiYR4lSGDuWMSpbdOa4sBFCLD2j1wV44xexuPuwtN91gcBMQx548WnvDPdj bC+HycpG2B+Qtle1UaolVSAEQ/jhVmjJIANdem3jU5+GOzUwdpeB X-Proofpoint-Virus-Version: vendor=nai engine=6900 definitions=11914 signatures=596817 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 suspectscore=0 spamscore=0 lowpriorityscore=10 clxscore=1015 malwarescore=0 bulkscore=10 adultscore=0 impostorscore=10 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609230100 Buffered atomic writes are not currently supported. The page cache writes folios back independently, so it cannot guarantee that a range is written atomically. iomap_file_buffered_write() does not check for IOCB_ATOMIC, so a direct write that falls back to it would complete an atomic write without atomicity. While no such case currently exists, fail IOCB_ATOMIC writes with -EOPNOTSUPP, so that a future fallback cannot complete an atomic write non-atomically. Suggested-by: John Garry Signed-off-by: Tal Zussman --- fs/iomap/buffered-io.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 0a5ebfda90f1..e6654cfe1cbf 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1304,6 +1304,10 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, }; ssize_t ret; + /* Buffered atomic writes are not supported */ + if (iocb->ki_flags & IOCB_ATOMIC) + return -EOPNOTSUPP; + if (iocb->ki_flags & IOCB_NOWAIT) iter.flags |= IOMAP_NOWAIT; if (iocb->ki_flags & IOCB_DONTCACHE) -- 2.39.5