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Wed, 1 Nov 2023 16:38:14 +0000 (GMT) From: Ojaswin Mujoo To: linux-ext4@vger.kernel.org, "Theodore Ts'o" Cc: Ritesh Harjani , linux-kernel@vger.kernel.org, Jan Kara Subject: [PATCH v2 0/2] Document handing of unwritten bh in ext4_block_zero_page_range() Date: Wed, 1 Nov 2023 22:08:09 +0530 Message-Id: X-Mailer: git-send-email 2.39.3 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: suN64p_AwKzoTaWsCCF2QtP4gC8wGVXV X-Proofpoint-GUID: Xi_vsV5XsktoosfggeVP1s2DI3yTzQu- Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-01_15,2023-11-01_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 mlxscore=0 adultscore=0 suspectscore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 phishscore=0 bulkscore=0 clxscore=1015 malwarescore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2310240000 definitions=main-2311010131 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ** Changes v1 -> v2 ** * Instead of exiting early in ext4_block_zero_page_range() for unwrit bhs like in v1, lets let the current logic be as it is and instead document the handing of unwritten buffer heads to make the intent clear v1: https://lore.kernel.org/linux-ext4/20231019165546.norapdphdyx7g3ob@quack3/T/#mbd0ab69d55487493edbd465b3882051e5bc2365d ** Original Cover Letter ** As per discussion with Jan here [1], this patchset intends to exit early from __ext4_block_zero_page_range() incase the block we are about to zero (partially) is unwritten and unmapped, since such a block doesn't require zeroing. Further, also make sure that calls to ext4_zero_partial_blocks() truncate the page cache completely beforehand, so that they don't rely on ext4_zero_partial_block() -> __ext4_block_zero_page_range() to zero out non block aligned edges of pagecache. Reviews and comments are appreciated! Regards, ojaswin [1] https://lore.kernel.org/linux-ext4/20230914141920.lw2nlpzhcxwuz2y6@quack3/ Ojaswin Mujoo (2): ext4: treat end of range as exclusive in ext4_zero_range() ext4: Clarify handling of unwritten bh in __ext4_block_zero_page_range() fs/ext4/extents.c | 6 ++++-- fs/ext4/inode.c | 6 ++++++ 2 files changed, 10 insertions(+), 2 deletions(-) -- 2.39.3