From: Li Chen Date: Thu, 11 Dec 2025 11:51:40 +0000 (+0800) Subject: ext4: mark move extents fast-commit ineligible X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=690558921d9f9388c6bc83610451d8cb393e4d88;p=thirdparty%2Flinux.git ext4: mark move extents fast-commit ineligible Fast commits only log operations that have dedicated replay support. EXT4_IOC_MOVE_EXT swaps extents between regular files and may copy data, rewriting the affected inodes' block mapping layout without going through the fast commit tracking paths. In practice these operations are rare and usually followed by further updates, but mixing them into a fast commit makes the overall semantics harder to reason about and risks replay gaps if new call sites appear. Teach ext4 to mark the filesystem fast-commit ineligible for the journal transactions used by move_extent_per_page() when EXT4_IOC_MOVE_EXT runs. This forces those transactions to fall back to a full commit, ensuring that these multi-inode extent swaps are captured by the normal journal rather than partially encoded in fast commit TLVs. This change should not affect common workloads but makes online defragmentation safer and easier to reason about under fast commit. Testing: 1. prepare: dd if=/dev/zero of=/root/fc_move.img bs=1M count=0 seek=256 mkfs.ext4 -O fast_commit -F /root/fc_move.img mkdir -p /mnt/fc_move && mount -t ext4 -o loop \ /root/fc_move.img /mnt/fc_move 2. Created two files, ran EXT4_IOC_MOVE_EXT via e4defrag, and checked the ineligible reason statistics: fallocate -l 64M /mnt/fc_move/file1 cp /mnt/fc_move/file1 /mnt/fc_move/file2 e4defrag /mnt/fc_move/file1 cat /proc/fs/ext4/loop0/fc_info shows "Move extents": > 0 and fc stats ineligible > 0. Signed-off-by: Li Chen Link: https://patch.msgid.link/20251211115146.897420-4-me@linux.beauty Signed-off-by: Theodore Ts'o --- diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index 242b69e5fe130..0ef2154a2b1f5 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -2304,6 +2304,7 @@ static const char * const fc_ineligible_reasons[] = { [EXT4_FC_REASON_ENCRYPTED_FILENAME] = "Encrypted filename", [EXT4_FC_REASON_MIGRATE] = "Inode format migration", [EXT4_FC_REASON_VERITY] = "fs-verity enable", + [EXT4_FC_REASON_MOVE_EXT] = "Move extents", }; int ext4_fc_info_show(struct seq_file *seq, void *v) diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h index 20f65135208fa..2f77a37fb1018 100644 --- a/fs/ext4/fast_commit.h +++ b/fs/ext4/fast_commit.h @@ -99,6 +99,7 @@ enum { EXT4_FC_REASON_ENCRYPTED_FILENAME, EXT4_FC_REASON_MIGRATE, EXT4_FC_REASON_VERITY, + EXT4_FC_REASON_MOVE_EXT, EXT4_FC_REASON_MAX }; diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 635fb8a52e0c2..ce1f738dff938 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -321,6 +321,8 @@ static int mext_move_extent(struct mext_data *mext, u64 *m_len) ret = PTR_ERR(handle); goto out; } + ext4_fc_mark_ineligible(orig_inode->i_sb, EXT4_FC_REASON_MOVE_EXT, + handle); ret = mext_move_begin(mext, folio, &move_type); if (ret) diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h index 726705bce9d36..a3e8fe414df85 100644 --- a/include/trace/events/ext4.h +++ b/include/trace/events/ext4.h @@ -104,6 +104,7 @@ TRACE_DEFINE_ENUM(EXT4_FC_REASON_INODE_JOURNAL_DATA); TRACE_DEFINE_ENUM(EXT4_FC_REASON_ENCRYPTED_FILENAME); TRACE_DEFINE_ENUM(EXT4_FC_REASON_MIGRATE); TRACE_DEFINE_ENUM(EXT4_FC_REASON_VERITY); +TRACE_DEFINE_ENUM(EXT4_FC_REASON_MOVE_EXT); TRACE_DEFINE_ENUM(EXT4_FC_REASON_MAX); #define show_fc_reason(reason) \ @@ -119,7 +120,8 @@ TRACE_DEFINE_ENUM(EXT4_FC_REASON_MAX); { EXT4_FC_REASON_INODE_JOURNAL_DATA, "INODE_JOURNAL_DATA"}, \ { EXT4_FC_REASON_ENCRYPTED_FILENAME, "ENCRYPTED_FILENAME"}, \ { EXT4_FC_REASON_MIGRATE, "MIGRATE"}, \ - { EXT4_FC_REASON_VERITY, "VERITY"}) + { EXT4_FC_REASON_VERITY, "VERITY"}, \ + { EXT4_FC_REASON_MOVE_EXT, "MOVE_EXT"}) TRACE_DEFINE_ENUM(CR_POWER2_ALIGNED); TRACE_DEFINE_ENUM(CR_GOAL_LEN_FAST);