From: John Garry <john.g.garry@oracle.com> mainline inclusion from mainline-v6.15-rc2 commit b1e09178b73adf10dc87fba9aee7787a7ad26874 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ID2HML CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When completing a CoW-based write, each extent range mapping update is covered by a separate transaction. For a CoW-based atomic write, all mappings must be changed at once, so change to use a single transaction. Note that there is a limit on the amount of log intent items which can be fit into a single transaction, but this is being ignored for now since the count of items for a typical atomic write would be much less than is typically supported. A typical atomic write would be expected to be 64KB or less, which means only 16 possible extents unmaps, which is quite small. Reviewed-by: Darrick J. Wong <djwong@kernel.org> [djwong: add tr_atomic_ioend] Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: John Garry <john.g.garry@oracle.com> Conflicts: fs/xfs/libxfs/xfs_log_rlimit.c fs/xfs/libxfs/xfs_trans_resv.c Signed-off-by: Long Li <leo.lilong@huawei.com> --- fs/xfs/libxfs/xfs_log_rlimit.c | 3 ++ fs/xfs/libxfs/xfs_trans_resv.c | 15 +++++++++ fs/xfs/libxfs/xfs_trans_resv.h | 1 + fs/xfs/xfs_file.c | 5 ++- fs/xfs/xfs_reflink.c | 56 ++++++++++++++++++++++++++++++++++ fs/xfs/xfs_reflink.h | 2 ++ 6 files changed, 81 insertions(+), 1 deletion(-) diff --git a/fs/xfs/libxfs/xfs_log_rlimit.c b/fs/xfs/libxfs/xfs_log_rlimit.c index 9975b93a7412..ba9e0ca6e381 100644 --- a/fs/xfs/libxfs/xfs_log_rlimit.c +++ b/fs/xfs/libxfs/xfs_log_rlimit.c @@ -61,6 +61,9 @@ xfs_log_calc_trans_resv_for_minlogblocks( xfs_trans_resv_calc(mp, resv); + /* Copy the dynamic transaction reservation types from the running fs */ + resv->tr_atomic_ioend = M_RES(mp)->tr_atomic_ioend; + if (xfs_has_reflink(mp)) { /* * In the early days of reflink, typical log operation counts diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index 1bb2891b26ff..58fea92b94da 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.c +++ b/fs/xfs/libxfs/xfs_trans_resv.c @@ -909,6 +909,15 @@ xfs_calc_sb_reservation( return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize); } +STATIC void +xfs_calc_default_atomic_ioend_reservation( + struct xfs_mount *mp, + struct xfs_trans_resv *resp) +{ + /* Pick a default that will scale reasonably for the log size. */ + resp->tr_atomic_ioend = resp->tr_itruncate; +} + void xfs_trans_resv_calc( struct xfs_mount *mp, @@ -1025,4 +1034,10 @@ xfs_trans_resv_calc( resp->tr_itruncate.tr_logcount += logcount_adj; resp->tr_write.tr_logcount += logcount_adj; resp->tr_qm_dqalloc.tr_logcount += logcount_adj; + + /* + * Now that we've finished computing the static reservations, we can + * compute the dynamic reservation for atomic writes. + */ + xfs_calc_default_atomic_ioend_reservation(mp, resp); } diff --git a/fs/xfs/libxfs/xfs_trans_resv.h b/fs/xfs/libxfs/xfs_trans_resv.h index 0554b9d775d2..5ae6a5d46b33 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.h +++ b/fs/xfs/libxfs/xfs_trans_resv.h @@ -48,6 +48,7 @@ struct xfs_trans_resv { struct xfs_trans_res tr_qm_dqalloc; /* allocate quota on disk */ struct xfs_trans_res tr_sb; /* modify superblock */ struct xfs_trans_res tr_fsyncts; /* update timestamps on fsync */ + struct xfs_trans_res tr_atomic_ioend; /* untorn write completion */ }; /* shorthand way of accessing reservation structure */ diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 1285c121531e..99815cdc4ca5 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -516,7 +516,10 @@ xfs_dio_write_end_io( nofs_flag = memalloc_nofs_save(); if (flags & IOMAP_DIO_COW) { - error = xfs_reflink_end_cow(ip, offset, size); + if (iocb->ki_flags & IOCB_ATOMIC) + error = xfs_reflink_end_atomic_cow(ip, offset, size); + else + error = xfs_reflink_end_cow(ip, offset, size); if (error) goto out; } diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index dbd5dc38c83f..8b48f9c5d0f9 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -903,6 +903,62 @@ xfs_reflink_end_cow( return error; } +/* + * Fully remap all of the file's data fork at once, which is the critical part + * in achieving atomic behaviour. + * The regular CoW end path does not use function as to keep the block + * reservation per transaction as low as possible. + */ +int +xfs_reflink_end_atomic_cow( + struct xfs_inode *ip, + xfs_off_t offset, + xfs_off_t count) +{ + xfs_fileoff_t offset_fsb; + xfs_fileoff_t end_fsb; + int error = 0; + struct xfs_mount *mp = ip->i_mount; + struct xfs_trans *tp; + unsigned int resblks; + + trace_xfs_reflink_end_cow(ip, offset, count); + + offset_fsb = XFS_B_TO_FSBT(mp, offset); + end_fsb = XFS_B_TO_FSB(mp, offset + count); + + /* + * Each remapping operation could cause a btree split, so in the worst + * case that's one for each block. + */ + resblks = (end_fsb - offset_fsb) * + XFS_NEXTENTADD_SPACE_RES(mp, 1, XFS_DATA_FORK); + + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_atomic_ioend, resblks, 0, + XFS_TRANS_RESERVE, &tp); + if (error) + return error; + + xfs_ilock(ip, XFS_ILOCK_EXCL); + xfs_trans_ijoin(tp, ip, 0); + + while (end_fsb > offset_fsb && !error) { + error = xfs_reflink_end_cow_extent_locked(tp, ip, &offset_fsb, + end_fsb); + } + if (error) { + trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_); + goto out_cancel; + } + error = xfs_trans_commit(tp); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + return error; +out_cancel: + xfs_trans_cancel(tp); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + return error; +} + /* * Free all CoW staging blocks that are still referenced by the ondisk refcount * metadata. The ondisk metadata does not track which inode created the diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h index 31f01d5c229b..36fb7ee6c9b6 100644 --- a/fs/xfs/xfs_reflink.h +++ b/fs/xfs/xfs_reflink.h @@ -36,6 +36,8 @@ extern int xfs_reflink_cancel_cow_range(struct xfs_inode *ip, xfs_off_t offset, xfs_off_t count, bool cancel_real); extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset, xfs_off_t count); +int xfs_reflink_end_atomic_cow(struct xfs_inode *ip, xfs_off_t offset, + xfs_off_t count); extern int xfs_reflink_recover_cow(struct xfs_mount *mp); extern loff_t xfs_reflink_remap_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t len, -- 2.39.2