From: Darrick J. Wong <djwong@xxxxxxxxxx> So far, we've constructed the front end of the file range exchange code that does all the checking; and the back end of the file mapping exchange code that actually does the work. Glue these two pieces together so that we can turn on the functionality. Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> --- fs/xfs/xfs_exchrange.c | 364 ++++++++++++++++++++++++++++++++++++++++++++++++ fs/xfs/xfs_exchrange.h | 1 fs/xfs/xfs_mount.h | 5 + fs/xfs/xfs_trace.c | 1 fs/xfs/xfs_trace.h | 163 +++++++++++++++++++++ 5 files changed, 532 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_exchrange.c b/fs/xfs/xfs_exchrange.c index ff8a2712f657c..1642ea1bd7b30 100644 --- a/fs/xfs/xfs_exchrange.c +++ b/fs/xfs/xfs_exchrange.c @@ -12,8 +12,15 @@ #include "xfs_defer.h" #include "xfs_inode.h" #include "xfs_trans.h" +#include "xfs_quota.h" +#include "xfs_bmap_util.h" +#include "xfs_reflink.h" +#include "xfs_trace.h" #include "xfs_exchrange.h" #include "xfs_exchmaps.h" +#include "xfs_sb.h" +#include "xfs_icache.h" +#include "xfs_log.h" #include <linux/fsnotify.h> /* @@ -47,6 +54,34 @@ xfs_exchrange_possible( xfs_can_add_incompat_log_features(mp, false); } +/* + * Get permission to use log-assisted atomic exchange of file mappings. + * Callers must not be running any transactions or hold any ILOCKs. + */ +int +xfs_exchrange_enable( + struct xfs_mount *mp) +{ + int error = 0; + + /* Mapping exchange log intent items are already enabled */ + if (xfs_sb_version_haslogexchmaps(&mp->m_sb)) + return 0; + + if (!xfs_exchrange_upgradeable(mp)) + return -EOPNOTSUPP; + + error = xfs_add_incompat_log_feature(mp, + XFS_SB_FEAT_INCOMPAT_LOG_EXCHMAPS); + if (error) + return error; + + xfs_warn_mount(mp, XFS_OPSTATE_WARNED_EXCHMAPS, + "EXPERIMENTAL atomic file range exchange feature in use. Use at your own risk!"); + + return 0; +} + /* Lock (and optionally join) two inodes for a file range exchange. */ void xfs_exchrange_ilock( @@ -95,6 +130,207 @@ xfs_exchrange_estimate( return error; } +#define QRETRY_IP1 (0x1) +#define QRETRY_IP2 (0x2) + +/* + * Obtain a quota reservation to make sure we don't hit EDQUOT. We can skip + * this if quota enforcement is disabled or if both inodes' dquots are the + * same. The qretry structure must be initialized to zeroes before the first + * call to this function. + */ +STATIC int +xfs_exchrange_reserve_quota( + struct xfs_trans *tp, + const struct xfs_exchmaps_req *req, + unsigned int *qretry) +{ + int64_t ddelta, rdelta; + int ip1_error = 0; + int error; + + /* + * Don't bother with a quota reservation if we're not enforcing them + * or the two inodes have the same dquots. + */ + if (!XFS_IS_QUOTA_ON(tp->t_mountp) || req->ip1 == req->ip2 || + (req->ip1->i_udquot == req->ip2->i_udquot && + req->ip1->i_gdquot == req->ip2->i_gdquot && + req->ip1->i_pdquot == req->ip2->i_pdquot)) + return 0; + + *qretry = 0; + + /* + * For each file, compute the net gain in the number of regular blocks + * that will be mapped into that file and reserve that much quota. The + * quota counts must be able to absorb at least that much space. + */ + ddelta = req->ip2_bcount - req->ip1_bcount; + rdelta = req->ip2_rtbcount - req->ip1_rtbcount; + if (ddelta > 0 || rdelta > 0) { + error = xfs_trans_reserve_quota_nblks(tp, req->ip1, + ddelta > 0 ? ddelta : 0, + rdelta > 0 ? rdelta : 0, + false); + if (error == -EDQUOT || error == -ENOSPC) { + /* + * Save this error and see what happens if we try to + * reserve quota for ip2. Then report both. + */ + *qretry |= QRETRY_IP1; + ip1_error = error; + error = 0; + } + if (error) + return error; + } + if (ddelta < 0 || rdelta < 0) { + error = xfs_trans_reserve_quota_nblks(tp, req->ip2, + ddelta < 0 ? -ddelta : 0, + rdelta < 0 ? -rdelta : 0, + false); + if (error == -EDQUOT || error == -ENOSPC) + *qretry |= QRETRY_IP2; + if (error) + return error; + } + if (ip1_error) + return ip1_error; + + /* + * For each file, forcibly reserve the gross gain in mapped blocks so + * that we don't trip over any quota block reservation assertions. + * We must reserve the gross gain because the quota code subtracts from + * bcount the number of blocks that we unmap; it does not add that + * quantity back to the quota block reservation. + */ + error = xfs_trans_reserve_quota_nblks(tp, req->ip1, req->ip1_bcount, + req->ip1_rtbcount, true); + if (error) + return error; + + return xfs_trans_reserve_quota_nblks(tp, req->ip2, req->ip2_bcount, + req->ip2_rtbcount, true); +} + +/* Exchange the mappings (and hence the contents) of two files' forks. */ +STATIC int +xfs_exchrange_mappings( + const struct xfs_exchrange *fxr, + struct xfs_inode *ip1, + struct xfs_inode *ip2) +{ + struct xfs_mount *mp = ip1->i_mount; + struct xfs_exchmaps_req req = { + .ip1 = ip1, + .ip2 = ip2, + .startoff1 = XFS_B_TO_FSBT(mp, fxr->file1_offset), + .startoff2 = XFS_B_TO_FSBT(mp, fxr->file2_offset), + .blockcount = XFS_B_TO_FSB(mp, fxr->length), + }; + struct xfs_trans *tp; + unsigned int qretry; + bool retried = false; + int error; + + trace_xfs_exchrange_mappings(fxr, ip1, ip2); + + if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) + req.flags |= XFS_EXCHMAPS_SET_SIZES; + if (fxr->flags & XFS_EXCHANGE_RANGE_FILE1_WRITTEN) + req.flags |= XFS_EXCHMAPS_INO1_WRITTEN; + + error = xfs_exchrange_estimate(&req); + if (error) + return error; + +retry: + /* Allocate the transaction, lock the inodes, and join them. */ + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, req.resblks, 0, + XFS_TRANS_RES_FDBLKS, &tp); + if (error) + return error; + + xfs_exchrange_ilock(tp, ip1, ip2); + + trace_xfs_exchrange_before(ip2, 2); + trace_xfs_exchrange_before(ip1, 1); + + error = xfs_exchmaps_check_forks(mp, &req); + if (error) + goto out_trans_cancel; + + /* + * Reserve ourselves some quota if any of them are in enforcing mode. + * In theory we only need enough to satisfy the change in the number + * of blocks between the two ranges being remapped. + */ + error = xfs_exchrange_reserve_quota(tp, &req, &qretry); + if ((error == -EDQUOT || error == -ENOSPC) && !retried) { + xfs_trans_cancel(tp); + xfs_exchrange_iunlock(ip1, ip2); + if (qretry & QRETRY_IP1) + xfs_blockgc_free_quota(ip1, 0); + if (qretry & QRETRY_IP2) + xfs_blockgc_free_quota(ip2, 0); + retried = true; + goto retry; + } + if (error) + goto out_trans_cancel; + + /* If we got this far on a dry run, all parameters are ok. */ + if (fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN) + goto out_trans_cancel; + + /* Update the mtime and ctime of both files. */ + if (fxr->flags & __XFS_EXCHANGE_RANGE_UPD_CMTIME1) + xfs_trans_ichgtime(tp, ip1, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); + if (fxr->flags & __XFS_EXCHANGE_RANGE_UPD_CMTIME2) + xfs_trans_ichgtime(tp, ip2, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); + + xfs_exchange_mappings(tp, &req); + + /* + * Force the log to persist metadata updates if the caller or the + * administrator requires this. The generic prep function already + * flushed the relevant parts of the page cache. + */ + if (xfs_has_wsync(mp) || (fxr->flags & XFS_EXCHANGE_RANGE_DSYNC)) + xfs_trans_set_sync(tp); + + error = xfs_trans_commit(tp); + + trace_xfs_exchrange_after(ip2, 2); + trace_xfs_exchrange_after(ip1, 1); + + if (error) + goto out_unlock; + + /* + * If the caller wanted us to exchange the contents of two complete + * files of unequal length, exchange the incore sizes now. This should + * be safe because we flushed both files' page caches, exchanged all + * the mappings, and updated the ondisk sizes. + */ + if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) { + loff_t temp; + + temp = i_size_read(VFS_I(ip2)); + i_size_write(VFS_I(ip2), i_size_read(VFS_I(ip1))); + i_size_write(VFS_I(ip1), temp); + } + +out_unlock: + xfs_exchrange_iunlock(ip1, ip2); + return error; + +out_trans_cancel: + xfs_trans_cancel(tp); + goto out_unlock; +} + /* * Generic code for exchanging ranges of two files via XFS_IOC_EXCHANGE_RANGE. * This part deals with struct file objects and byte ranges and does not deal @@ -318,6 +554,132 @@ xfs_exchange_range_finish( return file_remove_privs(fxr->file2); } +/* Prepare two files to have their data exchanged. */ +STATIC int +xfs_exchrange_prep( + struct xfs_exchrange *fxr, + struct xfs_inode *ip1, + struct xfs_inode *ip2) +{ + unsigned int alloc_unit = xfs_inode_alloc_unitsize(ip2); + int error; + + trace_xfs_exchrange_prep(fxr, ip1, ip2); + + /* Verify both files are either real-time or non-realtime */ + if (XFS_IS_REALTIME_INODE(ip1) != XFS_IS_REALTIME_INODE(ip2)) + return -EINVAL; + + /* + * The alignment checks in the generic helpers cannot deal with + * allocation units that are not powers of 2. This can happen with the + * realtime volume if the extent size is set. + */ + if (!is_power_of_2(alloc_unit)) + return -EOPNOTSUPP; + + error = xfs_exchange_range_prep(fxr, alloc_unit); + if (error || fxr->length == 0) + return error; + + /* Attach dquots to both inodes before changing block maps. */ + error = xfs_qm_dqattach(ip2); + if (error) + return error; + error = xfs_qm_dqattach(ip1); + if (error) + return error; + + trace_xfs_exchrange_flush(fxr, ip1, ip2); + + /* Flush the relevant ranges of both files. */ + error = xfs_flush_unmap_range(ip2, fxr->file2_offset, fxr->length); + if (error) + return error; + error = xfs_flush_unmap_range(ip1, fxr->file1_offset, fxr->length); + if (error) + return error; + + /* + * Cancel CoW fork preallocations for the ranges of both files. The + * prep function should have flushed all the dirty data, so the only + * CoW mappings remaining should be speculative. + */ + if (xfs_inode_has_cow_data(ip1)) { + error = xfs_reflink_cancel_cow_range(ip1, fxr->file1_offset, + fxr->length, true); + if (error) + return error; + } + + if (xfs_inode_has_cow_data(ip2)) { + error = xfs_reflink_cancel_cow_range(ip2, fxr->file2_offset, + fxr->length, true); + if (error) + return error; + } + + return 0; +} + +/* + * Exchange contents of files. This is the binding between the generic + * file-level concepts and the XFS inode-specific implementation. + */ +STATIC int +xfs_exchrange_contents( + struct xfs_exchrange *fxr) +{ + struct inode *inode1 = file_inode(fxr->file1); + struct inode *inode2 = file_inode(fxr->file2); + struct xfs_inode *ip1 = XFS_I(inode1); + struct xfs_inode *ip2 = XFS_I(inode2); + struct xfs_mount *mp = ip1->i_mount; + int error; + + if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS | + XFS_EXCHANGE_RANGE_PRIV_FLAGS)) + return -EINVAL; + + if (xfs_is_shutdown(mp)) + return -EIO; + + /* Lock both files against IO */ + error = xfs_ilock2_io_mmap(ip1, ip2); + if (error) + goto out_err; + + /* Get permission to use log-assisted file mapping exchanges. */ + error = xfs_exchrange_enable(mp); + if (error) + goto out_unlock; + + /* Prepare and then exchange file contents. */ + error = xfs_exchrange_prep(fxr, ip1, ip2); + if (error) + goto out_unlock; + + error = xfs_exchrange_mappings(fxr, ip1, ip2); + if (error) + goto out_unlock; + + /* + * Finish the exchange by removing special file privileges like any + * other file write would do. This may involve turning on support for + * logged xattrs if either file has security capabilities. + */ + error = xfs_exchange_range_finish(fxr); + if (error) + goto out_unlock; + +out_unlock: + xfs_iunlock2_io_mmap(ip1, ip2); +out_err: + if (error) + trace_xfs_exchrange_error(ip2, error, _RET_IP_); + return error; +} + /* Exchange parts of two files. */ int xfs_exchange_range( @@ -372,7 +734,7 @@ xfs_exchange_range( fxr->flags |= __XFS_EXCHANGE_RANGE_UPD_CMTIME2; file_start_write(fxr->file2); - ret = -EOPNOTSUPP; /* XXX call out to lower level code */ + ret = xfs_exchrange_contents(fxr); file_end_write(fxr->file2); if (ret) return ret; diff --git a/fs/xfs/xfs_exchrange.h b/fs/xfs/xfs_exchrange.h index 3d7779cdd0815..804bb92cb5c29 100644 --- a/fs/xfs/xfs_exchrange.h +++ b/fs/xfs/xfs_exchrange.h @@ -7,6 +7,7 @@ #define __XFS_EXCHRANGE_H__ bool xfs_exchrange_possible(struct xfs_mount *mp); +int xfs_exchrange_enable(struct xfs_mount *mp); /* Update the mtime/cmtime of file1 and file2 */ #define __XFS_EXCHANGE_RANGE_UPD_CMTIME1 (1ULL << 63) diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 654d282234b1e..a567a1ac24134 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -417,6 +417,8 @@ __XFS_HAS_FEAT(nouuid, NOUUID) #define XFS_OPSTATE_QUOTACHECK_RUNNING 10 /* Do we want to clear log incompat flags? */ #define XFS_OPSTATE_UNSET_LOG_INCOMPAT 11 +/* Kernel has logged a warning about logged file mapping exchanges being used. */ +#define XFS_OPSTATE_WARNED_EXCHMAPS 12 #define __XFS_IS_OPSTATE(name, NAME) \ static inline bool xfs_is_ ## name (struct xfs_mount *mp) \ @@ -464,7 +466,8 @@ xfs_should_warn(struct xfs_mount *mp, long nr) { (1UL << XFS_OPSTATE_WARNED_SHRINK), "wshrink" }, \ { (1UL << XFS_OPSTATE_WARNED_LARP), "wlarp" }, \ { (1UL << XFS_OPSTATE_QUOTACHECK_RUNNING), "quotacheck" }, \ - { (1UL << XFS_OPSTATE_UNSET_LOG_INCOMPAT), "unset_log_incompat" } + { (1UL << XFS_OPSTATE_UNSET_LOG_INCOMPAT), "unset_log_incompat" }, \ + { (1UL << XFS_OPSTATE_WARNED_EXCHMAPS), "wexchmaps" } /* * Max and min values for mount-option defined I/O diff --git a/fs/xfs/xfs_trace.c b/fs/xfs/xfs_trace.c index 9f38e69f1ce40..cf92a3bd56c79 100644 --- a/fs/xfs/xfs_trace.c +++ b/fs/xfs/xfs_trace.c @@ -40,6 +40,7 @@ #include "xfs_btree_mem.h" #include "xfs_bmap.h" #include "xfs_exchmaps.h" +#include "xfs_exchrange.h" /* * We include this last to have the helpers above available for the trace diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 7c17d1f80fec3..e18480109e08c 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -84,6 +84,7 @@ struct xfs_btree_ops; struct xfs_bmap_intent; struct xfs_exchmaps_intent; struct xfs_exchmaps_req; +struct xfs_exchrange; #define XFS_ATTR_FILTER_FLAGS \ { XFS_ATTR_ROOT, "ROOT" }, \ @@ -4785,6 +4786,168 @@ DEFINE_INODE_IREC_EVENT(xfs_exchmaps_mapping1); DEFINE_INODE_IREC_EVENT(xfs_exchmaps_mapping2); DEFINE_ITRUNC_EVENT(xfs_exchmaps_update_inode_size); +#define XFS_EXCHRANGE_INODES \ + { 1, "file1" }, \ + { 2, "file2" } + +DECLARE_EVENT_CLASS(xfs_exchrange_inode_class, + TP_PROTO(struct xfs_inode *ip, int whichfile), + TP_ARGS(ip, whichfile), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(int, whichfile) + __field(xfs_ino_t, ino) + __field(int, format) + __field(xfs_extnum_t, nex) + __field(int, broot_size) + __field(int, fork_off) + ), + TP_fast_assign( + __entry->dev = VFS_I(ip)->i_sb->s_dev; + __entry->whichfile = whichfile; + __entry->ino = ip->i_ino; + __entry->format = ip->i_df.if_format; + __entry->nex = ip->i_df.if_nextents; + __entry->fork_off = xfs_inode_fork_boff(ip); + ), + TP_printk("dev %d:%d ino 0x%llx whichfile %s format %s num_extents %llu forkoff 0x%x", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + __print_symbolic(__entry->whichfile, XFS_EXCHRANGE_INODES), + __print_symbolic(__entry->format, XFS_INODE_FORMAT_STR), + __entry->nex, + __entry->fork_off) +) + +#define DEFINE_EXCHRANGE_INODE_EVENT(name) \ +DEFINE_EVENT(xfs_exchrange_inode_class, name, \ + TP_PROTO(struct xfs_inode *ip, int whichfile), \ + TP_ARGS(ip, whichfile)) + +DEFINE_EXCHRANGE_INODE_EVENT(xfs_exchrange_before); +DEFINE_EXCHRANGE_INODE_EVENT(xfs_exchrange_after); +DEFINE_INODE_ERROR_EVENT(xfs_exchrange_error); + +#define XFS_EXCHANGE_RANGE_FLAGS_STRS \ + { XFS_EXCHANGE_RANGE_TO_EOF, "TO_EOF" }, \ + { XFS_EXCHANGE_RANGE_DSYNC , "DSYNC" }, \ + { XFS_EXCHANGE_RANGE_DRY_RUN, "DRY_RUN" }, \ + { XFS_EXCHANGE_RANGE_FILE1_WRITTEN, "F1_WRITTEN" }, \ + { __XFS_EXCHANGE_RANGE_UPD_CMTIME1, "CMTIME1" }, \ + { __XFS_EXCHANGE_RANGE_UPD_CMTIME2, "CMTIME2" } + +/* file exchange-range tracepoint class */ +DECLARE_EVENT_CLASS(xfs_exchrange_class, + TP_PROTO(const struct xfs_exchrange *fxr, struct xfs_inode *ip1, + struct xfs_inode *ip2), + TP_ARGS(fxr, ip1, ip2), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(xfs_ino_t, ip1_ino) + __field(loff_t, ip1_isize) + __field(loff_t, ip1_disize) + __field(xfs_ino_t, ip2_ino) + __field(loff_t, ip2_isize) + __field(loff_t, ip2_disize) + + __field(loff_t, file1_offset) + __field(loff_t, file2_offset) + __field(unsigned long long, length) + __field(unsigned long long, flags) + ), + TP_fast_assign( + __entry->dev = VFS_I(ip1)->i_sb->s_dev; + __entry->ip1_ino = ip1->i_ino; + __entry->ip1_isize = VFS_I(ip1)->i_size; + __entry->ip1_disize = ip1->i_disk_size; + __entry->ip2_ino = ip2->i_ino; + __entry->ip2_isize = VFS_I(ip2)->i_size; + __entry->ip2_disize = ip2->i_disk_size; + + __entry->file1_offset = fxr->file1_offset; + __entry->file2_offset = fxr->file2_offset; + __entry->length = fxr->length; + __entry->flags = fxr->flags; + ), + TP_printk("dev %d:%d flags %s bytecount 0x%llx " + "ino1 0x%llx isize 0x%llx disize 0x%llx pos 0x%llx -> " + "ino2 0x%llx isize 0x%llx disize 0x%llx pos 0x%llx", + MAJOR(__entry->dev), MINOR(__entry->dev), + __print_flags_u64(__entry->flags, "|", XFS_EXCHANGE_RANGE_FLAGS_STRS), + __entry->length, + __entry->ip1_ino, + __entry->ip1_isize, + __entry->ip1_disize, + __entry->file1_offset, + __entry->ip2_ino, + __entry->ip2_isize, + __entry->ip2_disize, + __entry->file2_offset) +) + +#define DEFINE_EXCHRANGE_EVENT(name) \ +DEFINE_EVENT(xfs_exchrange_class, name, \ + TP_PROTO(const struct xfs_exchrange *fxr, struct xfs_inode *ip1, \ + struct xfs_inode *ip2), \ + TP_ARGS(fxr, ip1, ip2)) +DEFINE_EXCHRANGE_EVENT(xfs_exchrange_prep); +DEFINE_EXCHRANGE_EVENT(xfs_exchrange_flush); +DEFINE_EXCHRANGE_EVENT(xfs_exchrange_mappings); + +TRACE_EVENT(xfs_exchrange_freshness, + TP_PROTO(const struct xfs_exchrange *fxr, struct xfs_inode *ip2), + TP_ARGS(fxr, ip2), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(xfs_ino_t, ip2_ino) + __field(long long, ip2_mtime) + __field(long long, ip2_ctime) + __field(int, ip2_mtime_nsec) + __field(int, ip2_ctime_nsec) + + __field(xfs_ino_t, file2_ino) + __field(long long, file2_mtime) + __field(long long, file2_ctime) + __field(int, file2_mtime_nsec) + __field(int, file2_ctime_nsec) + ), + TP_fast_assign( + struct timespec64 ts64; + struct inode *inode2 = VFS_I(ip2); + + __entry->dev = inode2->i_sb->s_dev; + __entry->ip2_ino = ip2->i_ino; + + ts64 = inode_get_ctime(inode2); + __entry->ip2_ctime = ts64.tv_sec; + __entry->ip2_ctime_nsec = ts64.tv_nsec; + + ts64 = inode_get_mtime(inode2); + __entry->ip2_mtime = ts64.tv_sec; + __entry->ip2_mtime_nsec = ts64.tv_nsec; + + __entry->file2_ino = fxr->file2_ino; + __entry->file2_mtime = fxr->file2_mtime.tv_sec; + __entry->file2_ctime = fxr->file2_ctime.tv_sec; + __entry->file2_mtime_nsec = fxr->file2_mtime.tv_nsec; + __entry->file2_ctime_nsec = fxr->file2_ctime.tv_nsec; + ), + TP_printk("dev %d:%d " + "ino 0x%llx mtime %lld:%d ctime %lld:%d -> " + "file 0x%llx mtime %lld:%d ctime %lld:%d", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ip2_ino, + __entry->ip2_mtime, + __entry->ip2_mtime_nsec, + __entry->ip2_ctime, + __entry->ip2_ctime_nsec, + __entry->file2_ino, + __entry->file2_mtime, + __entry->file2_mtime_nsec, + __entry->file2_ctime, + __entry->file2_ctime_nsec) +); + TRACE_EVENT(xfs_exchmaps_overhead, TP_PROTO(struct xfs_mount *mp, unsigned long long bmbt_blocks, unsigned long long rmapbt_blocks),