From ccd4c4a104c0f0c37b9068f3210d6f4cc2a59b58 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Wed, 3 Jul 2024 14:21:43 -0700 Subject: [PATCH] libfrog: add support for commit range ioctl family Add some library code to support the new file range commit ioctls. This will be used to test the atomic file commit functionality in fstests. Signed-off-by: Darrick J. Wong --- libfrog/file_exchange.c | 194 ++++++++++++++++++++++++++++++++++++++++ libfrog/file_exchange.h | 10 +++ 2 files changed, 204 insertions(+) diff --git a/libfrog/file_exchange.c b/libfrog/file_exchange.c index 29fdc17e5..e6c3f486b 100644 --- a/libfrog/file_exchange.c +++ b/libfrog/file_exchange.c @@ -50,3 +50,197 @@ xfrog_exchangerange( return 0; } + +/* + * Prepare for committing a file contents exchange if nobody changes file2 in + * the meantime by asking the kernel to sample file2's change attributes. + * + * Returns 0 for success or a negative errno. + */ +int +xfrog_commitrange_prep( + struct xfs_commit_range *xcr, + int file2_fd, + off_t file2_offset, + int file1_fd, + off_t file1_offset, + uint64_t length) +{ + int ret; + + memset(xcr, 0, sizeof(*xcr)); + + xcr->file1_fd = file1_fd; + xcr->file1_offset = file1_offset; + xcr->length = length; + xcr->file2_offset = file2_offset; + + ret = ioctl(file2_fd, XFS_IOC_START_COMMIT, xcr); + if (ret) + return -errno; + + return 0; +} + +/* + * Execute an exchange-commit operation. Returns 0 for success or a negative + * errno. + */ +int +xfrog_commitrange( + int file2_fd, + struct xfs_commit_range *xcr, + uint64_t flags) +{ + int ret; + + xcr->flags = flags; + + ret = ioctl(file2_fd, XFS_IOC_COMMIT_RANGE, xcr); + if (ret) + return -errno; + + return 0; +} + +/* Opaque freshness blob for XFS_IOC_COMMIT_RANGE */ +struct xfs_commit_range_fresh { + xfs_fsid_t fsid; /* m_fixedfsid */ + __u64 file2_ino; /* inode number */ + __s64 file2_mtime; /* modification time */ + __s64 file2_ctime; /* change time */ + __s32 file2_mtime_nsec; /* mod time, nsec */ + __s32 file2_ctime_nsec; /* change time, nsec */ + __u32 file2_gen; /* inode generation */ + __u32 magic; /* zero */ +}; + +/* magic flag to force use of swapext */ +#define XCR_SWAPEXT_MAGIC 0x43524150 /* CRAP */ + +/* + * Import file2 freshness information for a XFS_IOC_SWAPEXT call from bulkstat + * information. We can skip the fsid and file2_gen members because old swapext + * did not verify those things. + */ +static void +xfrog_swapext_prep( + struct xfs_commit_range *xdf, + const struct xfs_bulkstat *file2_stat) +{ + struct xfs_commit_range_fresh *f; + + f = (struct xfs_commit_range_fresh *)&xdf->file2_freshness; + f->file2_ino = file2_stat->bs_ino; + f->file2_mtime = file2_stat->bs_mtime; + f->file2_mtime_nsec = file2_stat->bs_mtime_nsec; + f->file2_ctime = file2_stat->bs_ctime; + f->file2_ctime_nsec = file2_stat->bs_ctime_nsec; + f->magic = XCR_SWAPEXT_MAGIC; +} + +/* Invoke the old swapext ioctl. */ +static int +xfrog_ioc_swapext( + int file2_fd, + struct xfs_commit_range *xdf) +{ + struct xfs_swapext args = { + .sx_version = XFS_SX_VERSION, + .sx_fdtarget = file2_fd, + .sx_length = xdf->length, + .sx_fdtmp = xdf->file1_fd, + }; + struct xfs_commit_range_fresh *f; + int ret; + + BUILD_BUG_ON(sizeof(struct xfs_commit_range_fresh) != + sizeof(xdf->file2_freshness)); + + f = (struct xfs_commit_range_fresh *)&xdf->file2_freshness; + args.sx_stat.bs_ino = f->file2_ino; + args.sx_stat.bs_mtime.tv_sec = f->file2_mtime; + args.sx_stat.bs_mtime.tv_nsec = f->file2_mtime_nsec; + args.sx_stat.bs_ctime.tv_sec = f->file2_ctime; + args.sx_stat.bs_ctime.tv_nsec = f->file2_ctime_nsec; + + ret = ioctl(file2_fd, XFS_IOC_SWAPEXT, &args); + if (ret) { + /* + * Old swapext returns EFAULT if file1 or file2 length doesn't + * match. The new new COMMIT_RANGE doesn't check the file + * length, but the freshness checks will trip and return EBUSY. + * If we see EFAULT from the old ioctl, turn that into EBUSY. + */ + if (errno == EFAULT) + return -EBUSY; + return -errno; + } + + return 0; +} + +/* + * Prepare for defragmenting a file by committing a file contents exchange if + * if nobody changes file2 in the meantime by asking the kernel to sample + * file2's change attributes. + * + * If the kernel supports only the old XFS_IOC_SWAPEXT ioctl, the @file2_stat + * information will be used to sample the change attributes. + * + * Returns 0 or a negative errno. + */ +int +xfrog_defragrange_prep( + struct xfs_commit_range *xdf, + int file2_fd, + const struct xfs_bulkstat *file2_stat, + int file1_fd) +{ + int ret; + + memset(xdf, 0, sizeof(*xdf)); + + xdf->file1_fd = file1_fd; + xdf->length = file2_stat->bs_size; + + ret = ioctl(file2_fd, XFS_IOC_START_COMMIT, xdf); + if (ret && (errno == EOPNOTSUPP || errno == ENOTTY)) { + xfrog_swapext_prep(xdf, file2_stat); + return 0; + } + if (ret) + return -errno; + + return 0; +} + +/* Execute an exchange operation. Returns 0 for success or a negative errno. */ +int +xfrog_defragrange( + int file2_fd, + struct xfs_commit_range *xdf) +{ + struct xfs_commit_range_fresh *f; + int ret; + + f = (struct xfs_commit_range_fresh *)&xdf->file2_freshness; + if (f->magic == XCR_SWAPEXT_MAGIC) + goto legacy_fallback; + + ret = ioctl(file2_fd, XFS_IOC_COMMIT_RANGE, xdf); + if (ret) { + if (errno == EOPNOTSUPP || errno != ENOTTY) + goto legacy_fallback; + return -errno; + } + + return 0; + +legacy_fallback: + ret = xfrog_ioc_swapext(file2_fd, xdf); + if (ret) + return -errno; + + return 0; +} diff --git a/libfrog/file_exchange.h b/libfrog/file_exchange.h index b6f6f9f69..98d3b867c 100644 --- a/libfrog/file_exchange.h +++ b/libfrog/file_exchange.h @@ -12,4 +12,14 @@ void xfrog_exchangerange_prep(struct xfs_exchange_range *fxr, int xfrog_exchangerange(int file2_fd, struct xfs_exchange_range *fxr, uint64_t flags); +int xfrog_commitrange_prep(struct xfs_commit_range *xcr, int file2_fd, + off_t file2_offset, int file1_fd, off_t file1_offset, + uint64_t length); +int xfrog_commitrange(int file2_fd, struct xfs_commit_range *xcr, + uint64_t flags); + +int xfrog_defragrange_prep(struct xfs_commit_range *xdf, int file2_fd, + const struct xfs_bulkstat *file2_stat, int file1_fd); +int xfrog_defragrange(int file2_fd, struct xfs_commit_range *xdf); + #endif /* __LIBFROG_FILE_EXCHANGE_H__ */ -- 2.50.1