On Fri, Feb 17, 2017 at 05:17:49PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Introduce a new ioctl that uses the reverse mapping btree to return
> information about the physical layout of the filesystem.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
Mostly looks good, though there's a decent amount of indirection here so
I'll probably need another pass through it. Mostly minor comments, a
couple potential issues and some questions..
> fs/xfs/Makefile | 1
> fs/xfs/libxfs/xfs_fs.h | 13 +
> fs/xfs/xfs_fsmap.c | 782 ++++++++++++++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_fsmap.h | 51 +++
> fs/xfs/xfs_ioctl.c | 103 ++++++
> fs/xfs/xfs_ioctl32.c | 2
> fs/xfs/xfs_trace.h | 85 +++++
> fs/xfs/xfs_trans.c | 22 +
> fs/xfs/xfs_trans.h | 2
> 9 files changed, 1061 insertions(+)
> create mode 100644 fs/xfs/xfs_fsmap.c
> create mode 100644 fs/xfs/xfs_fsmap.h
>
>
> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
> index c7515d4..0e7ee30 100644
> --- a/fs/xfs/Makefile
> +++ b/fs/xfs/Makefile
> @@ -80,6 +80,7 @@ xfs-y += xfs_aops.o \
> xfs_extent_busy.o \
> xfs_file.o \
> xfs_filestream.o \
> + xfs_fsmap.o \
> xfs_fsops.o \
> xfs_globals.o \
> xfs_icache.o \
> diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> index b72dc82..095bdf0 100644
> --- a/fs/xfs/libxfs/xfs_fs.h
> +++ b/fs/xfs/libxfs/xfs_fs.h
> @@ -92,6 +92,18 @@ struct getbmapx {
> #define BMV_OF_LAST 0x4 /* segment is the last in the file */
> #define BMV_OF_SHARED 0x8 /* segment shared with another file */
>
> +/* fmr_owner special values for FS_IOC_GETFSMAP */
> +#define XFS_FMR_OWN_FREE FMR_OWN_FREE /* free space */
> +#define XFS_FMR_OWN_UNKNOWN FMR_OWN_UNKNOWN /* unknown owner */
> +#define XFS_FMR_OWN_FS FMR_OWNER('X', 1) /* static fs metadata */
> +#define XFS_FMR_OWN_LOG FMR_OWNER('X', 2) /* journalling log */
> +#define XFS_FMR_OWN_AG FMR_OWNER('X', 3) /* per-AG metadata */
> +#define XFS_FMR_OWN_INOBT FMR_OWNER('X', 4) /* inode btree blocks */
> +#define XFS_FMR_OWN_INODES FMR_OWNER('X', 5) /* inodes */
> +#define XFS_FMR_OWN_REFC FMR_OWNER('X', 6) /* refcount tree */
> +#define XFS_FMR_OWN_COW FMR_OWNER('X', 7) /* cow staging */
> +#define XFS_FMR_OWN_DEFECTIVE FMR_OWNER('X', 8) /* bad blocks */
> +
> /*
> * Structure for XFS_IOC_FSSETDM.
> * For use by backup and restore programs to set the XFS on-disk inode
> @@ -502,6 +514,7 @@ typedef struct xfs_swapext
> #define XFS_IOC_GETBMAPX _IOWR('X', 56, struct getbmap)
> #define XFS_IOC_ZERO_RANGE _IOW ('X', 57, struct xfs_flock64)
> #define XFS_IOC_FREE_EOFBLOCKS _IOR ('X', 58, struct xfs_fs_eofblocks)
> +/* XFS_IOC_GETFSMAP ------ hoisted 59 */
>
> /*
> * ioctl commands that replace IRIX syssgi()'s
> diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
> new file mode 100644
> index 0000000..09d6b92
> --- /dev/null
> +++ b/fs/xfs/xfs_fsmap.c
> @@ -0,0 +1,782 @@
> +/*
> + * Copyright (C) 2017 Oracle. All Rights Reserved.
> + *
> + * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
> + */
> +#include "xfs.h"
> +#include "xfs_fs.h"
> +#include "xfs_shared.h"
> +#include "xfs_format.h"
> +#include "xfs_log_format.h"
> +#include "xfs_trans_resv.h"
> +#include "xfs_sb.h"
> +#include "xfs_mount.h"
> +#include "xfs_defer.h"
> +#include "xfs_inode.h"
> +#include "xfs_trans.h"
> +#include "xfs_error.h"
> +#include "xfs_btree.h"
> +#include "xfs_rmap_btree.h"
> +#include "xfs_trace.h"
> +#include "xfs_log.h"
> +#include "xfs_rmap.h"
> +#include "xfs_alloc.h"
> +#include "xfs_bit.h"
> +#include <linux/fsmap.h>
> +#include "xfs_fsmap.h"
> +#include "xfs_refcount.h"
> +#include "xfs_refcount_btree.h"
> +
> +/* Convert an xfs_fsmap to an fsmap. */
> +void
> +xfs_fsmap_from_internal(
> + struct fsmap *dest,
> + struct xfs_fsmap *src)
> +{
> + dest->fmr_device = src->fmr_device;
> + dest->fmr_flags = src->fmr_flags;
> + dest->fmr_physical = BBTOB(src->fmr_physical);
> + dest->fmr_owner = src->fmr_owner;
> + dest->fmr_offset = BBTOB(src->fmr_offset);
> + dest->fmr_length = BBTOB(src->fmr_length);
> + dest->fmr_reserved[0] = 0;
> + dest->fmr_reserved[1] = 0;
> + dest->fmr_reserved[2] = 0;
> +}
> +
> +/* Convert an fsmap to an xfs_fsmap. */
> +void
> +xfs_fsmap_to_internal(
> + struct xfs_fsmap *dest,
> + struct fsmap *src)
> +{
> + dest->fmr_device = src->fmr_device;
> + dest->fmr_flags = src->fmr_flags;
> + dest->fmr_physical = BTOBBT(src->fmr_physical);
> + dest->fmr_owner = src->fmr_owner;
> + dest->fmr_offset = BTOBBT(src->fmr_offset);
> + dest->fmr_length = BTOBBT(src->fmr_length);
> +}
> +
> +/* Convert an fsmap owner into an rmapbt owner. */
> +static int
> +xfs_fsmap_owner_to_rmap(
> + struct xfs_fsmap *fmr,
> + struct xfs_rmap_irec *rm)
I find the inconsistent semantics a little confusing here. E.g., the
xfs_fsmap_[to|from]_*() helpers use consistent dest, src parameter
ordering. Here we use the opposite. I don't care much which way we go,
but could we use the same semantics between all of such helpers?
> +{
> + if (!(fmr->fmr_flags & FMR_OF_SPECIAL_OWNER)) {
> + rm->rm_owner = fmr->fmr_owner;
> + return 0;
> + }
> +
> + switch (fmr->fmr_owner) {
> + case 0: /* "lowest owner id possible" */
> + case -1ULL: /* "highest owner id possible" */
> + rm->rm_owner = 0;
> + break;
> + case XFS_FMR_OWN_FREE:
> + rm->rm_owner = XFS_RMAP_OWN_NULL;
> + break;
> + case XFS_FMR_OWN_UNKNOWN:
> + rm->rm_owner = XFS_RMAP_OWN_UNKNOWN;
> + break;
> + case XFS_FMR_OWN_FS:
> + rm->rm_owner = XFS_RMAP_OWN_FS;
> + break;
> + case XFS_FMR_OWN_LOG:
> + rm->rm_owner = XFS_RMAP_OWN_LOG;
> + break;
> + case XFS_FMR_OWN_AG:
> + rm->rm_owner = XFS_RMAP_OWN_AG;
> + break;
> + case XFS_FMR_OWN_INOBT:
> + rm->rm_owner = XFS_RMAP_OWN_INOBT;
> + break;
> + case XFS_FMR_OWN_INODES:
> + rm->rm_owner = XFS_RMAP_OWN_INODES;
> + break;
> + case XFS_FMR_OWN_REFC:
> + rm->rm_owner = XFS_RMAP_OWN_REFC;
> + break;
> + case XFS_FMR_OWN_COW:
> + rm->rm_owner = XFS_RMAP_OWN_COW;
> + break;
> + case XFS_FMR_OWN_DEFECTIVE: /* not implemented */
> + /* fall through */
> + default:
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +/* Convert an rmapbt owner into an fsmap owner. */
> +static int
> +xfs_fsmap_owner_from_rmap(
> + struct xfs_rmap_irec *rm,
> + struct xfs_fsmap *fmr)
> +{
> + fmr->fmr_flags = 0;
> + if (!XFS_RMAP_NON_INODE_OWNER(rm->rm_owner)) {
> + fmr->fmr_owner = rm->rm_owner;
> + return 0;
> + }
> + fmr->fmr_flags |= FMR_OF_SPECIAL_OWNER;
> +
> + switch (rm->rm_owner) {
> + case XFS_RMAP_OWN_FS:
> + fmr->fmr_owner = XFS_FMR_OWN_FS;
> + break;
> + case XFS_RMAP_OWN_LOG:
> + fmr->fmr_owner = XFS_FMR_OWN_LOG;
> + break;
> + case XFS_RMAP_OWN_AG:
> + fmr->fmr_owner = XFS_FMR_OWN_AG;
> + break;
> + case XFS_RMAP_OWN_INOBT:
> + fmr->fmr_owner = XFS_FMR_OWN_INOBT;
> + break;
> + case XFS_RMAP_OWN_INODES:
> + fmr->fmr_owner = XFS_FMR_OWN_INODES;
> + break;
> + case XFS_RMAP_OWN_REFC:
> + fmr->fmr_owner = XFS_FMR_OWN_REFC;
> + break;
> + case XFS_RMAP_OWN_COW:
> + fmr->fmr_owner = XFS_FMR_OWN_COW;
> + break;
> + default:
> + return -EFSCORRUPTED;
> + }
> + return 0;
> +}
> +
> +/* getfsmap query state */
> +struct xfs_getfsmap_info {
> + struct xfs_fsmap_head *head;
> + struct xfs_fsmap *rkey_low; /* lowest key */
> + xfs_fsmap_format_t formatter; /* formatting fn */
> + void *format_arg; /* format buffer */
> + bool last; /* last extent? */
> + xfs_daddr_t next_daddr; /* next daddr we expect */
> + u32 dev; /* device id */
> + u64 missing_owner; /* owner of holes */
> +
> + xfs_agnumber_t agno; /* AG number, if applicable */
> + struct xfs_buf *agf_bp; /* AGF, for refcount queries */
> + struct xfs_rmap_irec low; /* low rmap key */
> + struct xfs_rmap_irec high; /* high rmap key */
> +};
> +
> +/* Associate a device with a getfsmap handler. */
> +struct xfs_getfsmap_dev {
> + u32 dev;
> + int (*fn)(struct xfs_trans *tp,
> + struct xfs_fsmap *keys,
> + struct xfs_getfsmap_info *info);
> +};
> +
> +/* Compare two getfsmap device handlers. */
> +static int
> +xfs_getfsmap_dev_compare(
> + const void *p1,
> + const void *p2)
> +{
> + const struct xfs_getfsmap_dev *d1 = p1;
> + const struct xfs_getfsmap_dev *d2 = p2;
> +
> + return d1->dev - d2->dev;
> +}
> +
> +/* Compare a record against our starting point */
> +static bool
> +xfs_getfsmap_rec_before_low_key(
> + struct xfs_getfsmap_info *info,
> + struct xfs_rmap_irec *rec)
> +{
> + uint64_t x, y;
> +
> + if (rec->rm_startblock < info->low.rm_startblock)
> + return true;
> + if (rec->rm_startblock > info->low.rm_startblock)
> + return false;
> +
> + if (rec->rm_owner < info->low.rm_owner)
> + return true;
> + if (rec->rm_owner > info->low.rm_owner)
> + return false;
> +
> + x = xfs_rmap_irec_offset_pack(rec);
> + y = xfs_rmap_irec_offset_pack(&info->low);
It looks like these functions incorporate flags bits into the offset. Is
that intentional? If so.. comment?
> + if (x < y)
> + return true;
> + return false;
> +}
> +
> +/* Decide if this mapping is shared. */
> +STATIC int
> +xfs_getfsmap_is_shared(
> + struct xfs_trans *tp,
> + struct xfs_getfsmap_info *info,
> + struct xfs_rmap_irec *rec,
> + bool *stat)
> +{
> + struct xfs_mount *mp = tp->t_mountp;
> + struct xfs_btree_cur *cur;
> + xfs_agblock_t fbno;
> + xfs_extlen_t flen;
> + int error;
> +
> + *stat = false;
> + if (!xfs_sb_version_hasreflink(&mp->m_sb))
> + return 0;
> + /* rt files will have agno set to NULLAGNUMBER */
> + if (info->agno == NULLAGNUMBER)
> + return 0;
> +
> + /* Are there any shared blocks here? */
> + flen = 0;
> + cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp,
> + info->agno, NULL);
> +
> + error = xfs_refcount_find_shared(cur, rec->rm_startblock,
> + rec->rm_blockcount, &fbno, &flen, false);
> +
> + xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
> + if (error)
> + return error;
> +
> + *stat = flen > 0;
> + return 0;
> +}
> +
> +/*
> + * Format a reverse mapping for getfsmap, having translated rm_startblock
> + * into the appropriate daddr units.
> + */
> +STATIC int
> +xfs_getfsmap_helper(
> + struct xfs_trans *tp,
> + struct xfs_getfsmap_info *info,
> + struct xfs_rmap_irec *rec,
> + xfs_daddr_t rec_daddr)
> +{
> + struct xfs_fsmap fmr;
> + struct xfs_mount *mp = tp->t_mountp;
> + xfs_daddr_t key_end;
> + bool shared;
> + int error;
> +
> + if (fatal_signal_pending(current))
> + return -EAGAIN;
> +
I wonder if -EINTR is more appropriate here..?
> + /*
> + * Filter out records that start before our startpoint, if the
> + * caller requested that.
> + */
> + if (xfs_getfsmap_rec_before_low_key(info, rec)) {
> + rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
> + if (info->next_daddr < rec_daddr)
> + info->next_daddr = rec_daddr;
> + return XFS_BTREE_QUERY_RANGE_CONTINUE;
> + }
> +
> + /*
> + * If the caller passed in a length with the low record and
> + * the record represents a file data extent, we incremented
> + * the offset in the low key by the length in the hopes of
> + * finding reverse mappings for the physical blocks we just
> + * saw. We did /not/ increment next_daddr by the length
> + * because the range query would not be able to find shared
> + * extents within the same physical block range.
> + *
> + * However, the extent we've been fed could have a startblock
> + * past the passed-in low record. If this is the case,
> + * advance next_daddr to the end of the passed-in low record
> + * so we don't report the extent prior to this extent as
> + * free.
> + */
> + key_end = info->rkey_low->fmr_physical + info->rkey_low->fmr_length;
> + if (info->dev == info->rkey_low->fmr_device &&
> + info->next_daddr < key_end && rec_daddr >= key_end)
> + info->next_daddr = key_end;
> +
Hmm, so I think I follow what this is trying to do..
In the case where we left off on a file mapping, we bump the offset of
the passed in low key but next_daddr remains at the same physical block
because we could have more mappings there. If we don't, however, and the
next mapping occurs at a higher physical block, we need to make sure we
don't map the previous range as free space. So we bump next_daddr here
to make sure that if free space does exist, it shown to start at the end
of the previous mapping. Yes?
If I'm following that correctly, what about the case where we have
bumped fmr_physical? It doesn't look like we've reset fmr_length, so
couldn't this cause us to skip legitimate free space if for e.g. the
current record is much farther ahead?
> + /* Are we just counting mappings? */
> + if (info->head->fmh_count == 0) {
> + if (rec_daddr > info->next_daddr)
> + info->head->fmh_entries++;
> +
> + if (info->last)
> + return XFS_BTREE_QUERY_RANGE_CONTINUE;
> +
> + info->head->fmh_entries++;
> +
> + rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
> + if (info->next_daddr < rec_daddr)
> + info->next_daddr = rec_daddr;
> + return XFS_BTREE_QUERY_RANGE_CONTINUE;
> + }
> +
> + /*
> + * If the record starts past the last physical block we saw,
> + * then we've found some free space. Report that too.
> + */
> + if (rec_daddr > info->next_daddr) {
> + if (info->head->fmh_entries >= info->head->fmh_count)
> + return XFS_BTREE_QUERY_RANGE_ABORT;
> +
> + trace_xfs_fsmap_mapping(mp, info->dev, info->agno,
> + XFS_DADDR_TO_FSB(mp, info->next_daddr),
> + XFS_DADDR_TO_FSB(mp, rec_daddr -
> + info->next_daddr),
> + info->missing_owner, 0);
> +
> + fmr.fmr_device = info->dev;
> + fmr.fmr_physical = info->next_daddr;
> + fmr.fmr_owner = info->missing_owner;
> + fmr.fmr_offset = 0;
> + fmr.fmr_length = rec_daddr - info->next_daddr;
> + fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
> + error = info->formatter(&fmr, info->format_arg);
> + if (error)
> + return error;
> + info->head->fmh_entries++;
> + }
> +
> + if (info->last)
> + goto out;
> +
> + /* Fill out the extent we found */
> + if (info->head->fmh_entries >= info->head->fmh_count)
> + return XFS_BTREE_QUERY_RANGE_ABORT;
> +
> + trace_xfs_fsmap_mapping(mp, info->dev, info->agno,
> + rec->rm_startblock, rec->rm_blockcount, rec->rm_owner,
> + rec->rm_offset);
> +
> + fmr.fmr_device = info->dev;
> + fmr.fmr_physical = rec_daddr;
> + error = xfs_fsmap_owner_from_rmap(rec, &fmr);
> + if (error)
> + return error;
> + fmr.fmr_offset = XFS_FSB_TO_BB(mp, rec->rm_offset);
> + fmr.fmr_length = XFS_FSB_TO_BB(mp, rec->rm_blockcount);
> + if (rec->rm_flags & XFS_RMAP_UNWRITTEN)
> + fmr.fmr_flags |= FMR_OF_PREALLOC;
> + if (rec->rm_flags & XFS_RMAP_ATTR_FORK)
> + fmr.fmr_flags |= FMR_OF_ATTR_FORK;
> + if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
> + fmr.fmr_flags |= FMR_OF_EXTENT_MAP;
> + if (fmr.fmr_flags == 0) {
> + error = xfs_getfsmap_is_shared(tp, info, rec, &shared);
> + if (error)
> + return error;
> + if (shared)
> + fmr.fmr_flags |= FMR_OF_SHARED;
> + }
> + error = info->formatter(&fmr, info->format_arg);
> + if (error)
> + return error;
> + info->head->fmh_entries++;
> +
> +out:
> + rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
> + if (info->next_daddr < rec_daddr)
> + info->next_daddr = rec_daddr;
> + return XFS_BTREE_QUERY_RANGE_CONTINUE;
> +}
> +
> +/* Transform a rmapbt irec into a fsmap */
> +STATIC int
> +xfs_getfsmap_datadev_helper(
> + struct xfs_btree_cur *cur,
> + struct xfs_rmap_irec *rec,
> + void *priv)
> +{
> + struct xfs_mount *mp = cur->bc_mp;
> + struct xfs_getfsmap_info *info = priv;
> + xfs_fsblock_t fsb;
> + xfs_daddr_t rec_daddr;
> +
> + fsb = XFS_AGB_TO_FSB(mp, cur->bc_private.a.agno, rec->rm_startblock);
> + rec_daddr = XFS_FSB_TO_DADDR(mp, fsb);
> +
> + return xfs_getfsmap_helper(cur->bc_tp, info, rec, rec_daddr);
> +}
> +
> +/* Transform a absolute-startblock rmap (rtdev, logdev) into a fsmap */
> +STATIC int
> +xfs_getfsmap_rtdev_helper(
> + struct xfs_btree_cur *cur,
> + struct xfs_rmap_irec *rec,
> + void *priv)
> +{
> + struct xfs_mount *mp = cur->bc_mp;
> + struct xfs_getfsmap_info *info = priv;
> + xfs_daddr_t rec_daddr;
> +
> + rec_daddr = XFS_FSB_TO_BB(mp, rec->rm_startblock);
> +
> + return xfs_getfsmap_helper(cur->bc_tp, info, rec, rec_daddr);
> +}
> +
> +/* Set rmap flags based on the getfsmap flags */
> +static void
> +xfs_getfsmap_set_irec_flags(
> + struct xfs_rmap_irec *irec,
> + struct xfs_fsmap *fmr)
> +{
> + irec->rm_flags = 0;
> + if (fmr->fmr_flags & FMR_OF_ATTR_FORK)
> + irec->rm_flags |= XFS_RMAP_ATTR_FORK;
> + if (fmr->fmr_flags & FMR_OF_EXTENT_MAP)
> + irec->rm_flags |= XFS_RMAP_BMBT_BLOCK;
> + if (fmr->fmr_flags & FMR_OF_PREALLOC)
> + irec->rm_flags |= XFS_RMAP_UNWRITTEN;
> +}
> +
> +/* Execute a getfsmap query against the log device. */
> +STATIC int
> +xfs_getfsmap_logdev(
> + struct xfs_trans *tp,
> + struct xfs_fsmap *keys,
> + struct xfs_getfsmap_info *info)
> +{
> + struct xfs_mount *mp = tp->t_mountp;
> + struct xfs_fsmap *dkey_low = keys;
> + struct xfs_btree_cur cur;
> + struct xfs_rmap_irec rmap;
> + int error;
> +
> + /* Set up search keys */
> + info->low.rm_startblock = XFS_BB_TO_FSBT(mp, dkey_low->fmr_physical);
> + info->low.rm_offset = XFS_BB_TO_FSBT(mp, dkey_low->fmr_offset);
> + error = xfs_fsmap_owner_to_rmap(keys, &info->low);
> + if (error)
> + return error;
> + info->low.rm_blockcount = 0;
> + xfs_getfsmap_set_irec_flags(&info->low, dkey_low);
> +
> + error = xfs_fsmap_owner_to_rmap(keys + 1, &info->high);
> + if (error)
> + return error;
> + info->high.rm_startblock = -1U;
> + info->high.rm_owner = ULLONG_MAX;
> + info->high.rm_offset = ULLONG_MAX;
> + info->high.rm_blockcount = 0;
> + info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
> + info->missing_owner = XFS_FMR_OWN_FREE;
> +
> + trace_xfs_fsmap_low_key(mp, info->dev, info->agno,
> + info->low.rm_startblock,
> + info->low.rm_blockcount,
> + info->low.rm_owner,
> + info->low.rm_offset);
> +
> + trace_xfs_fsmap_high_key(mp, info->dev, info->agno,
> + info->high.rm_startblock,
> + info->high.rm_blockcount,
> + info->high.rm_owner,
> + info->high.rm_offset);
> +
> +
> + if (dkey_low->fmr_physical > 0)
> + return 0;
> +
A comment to point out we're fabricating an rmap record here would be
nice. Also, (how) do we handle/report internal log blocks?
> + rmap.rm_startblock = 0;
> + rmap.rm_blockcount = mp->m_sb.sb_logblocks;
> + rmap.rm_owner = XFS_RMAP_OWN_LOG;
> + rmap.rm_offset = 0;
> + rmap.rm_flags = 0;
> +
> + cur.bc_mp = mp;
> + cur.bc_tp = tp;
> + return xfs_getfsmap_rtdev_helper(&cur, &rmap, info);
> +}
> +
> +/* Execute a getfsmap query against the regular data device. */
> +STATIC int
> +xfs_getfsmap_datadev(
> + struct xfs_trans *tp,
> + struct xfs_fsmap *keys,
> + struct xfs_getfsmap_info *info)
> +{
> + struct xfs_mount *mp = tp->t_mountp;
> + struct xfs_btree_cur *bt_cur = NULL;
> + struct xfs_fsmap *dkey_low;
> + struct xfs_fsmap *dkey_high;
> + xfs_fsblock_t start_fsb;
> + xfs_fsblock_t end_fsb;
> + xfs_agnumber_t start_ag;
> + xfs_agnumber_t end_ag;
> + xfs_daddr_t eofs;
> + int error = 0;
> +
> + dkey_low = keys;
> + dkey_high = keys + 1;
> + eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
> + if (dkey_low->fmr_physical >= eofs)
> + return 0;
> + if (dkey_high->fmr_physical >= eofs)
> + dkey_high->fmr_physical = eofs - 1;
> + start_fsb = XFS_DADDR_TO_FSB(mp, dkey_low->fmr_physical);
> + end_fsb = XFS_DADDR_TO_FSB(mp, dkey_high->fmr_physical);
> +
> + /* Set up search keys */
I think we could use slightly better comments here and below just to
point out why we set low/high to these values. E.g., something like:
/*
* Convert the fsmap low/high keys to AG based keys. Initialize low to
* the fsmap low key and max out the high key to the end of the AG.
*/
> + info->low.rm_startblock = XFS_FSB_TO_AGBNO(mp, start_fsb);
> + info->low.rm_offset = XFS_BB_TO_FSBT(mp, dkey_low->fmr_offset);
> + error = xfs_fsmap_owner_to_rmap(dkey_low, &info->low);
> + if (error)
> + return error;
> + info->low.rm_blockcount = 0;
> + xfs_getfsmap_set_irec_flags(&info->low, dkey_low);
> +
> + info->high.rm_startblock = -1U;
> + info->high.rm_owner = ULLONG_MAX;
> + info->high.rm_offset = ULLONG_MAX;
> + info->high.rm_blockcount = 0;
> + info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
> + info->missing_owner = XFS_FMR_OWN_FREE;
> +
> + start_ag = XFS_FSB_TO_AGNO(mp, start_fsb);
> + end_ag = XFS_FSB_TO_AGNO(mp, end_fsb);
> +
> + /* Query each AG */
> + for (info->agno = start_ag; info->agno <= end_ag; info->agno++) {
/*
* Incorporate the fsmap high key for the last AG.
*/
> + if (info->agno == end_ag) {
> + info->high.rm_startblock = XFS_FSB_TO_AGBNO(mp,
> + end_fsb);
> + info->high.rm_offset = XFS_BB_TO_FSBT(mp,
> + dkey_high->fmr_offset);
> + error = xfs_fsmap_owner_to_rmap(dkey_high, &info->high);
> + if (error)
> + goto err;
> + xfs_getfsmap_set_irec_flags(&info->high, dkey_high);
> + }
> +
> + if (bt_cur) {
> + xfs_btree_del_cursor(bt_cur, XFS_BTREE_NOERROR);
> + bt_cur = NULL;
> + info->agf_bp = NULL;
> + }
> +
> + error = xfs_alloc_read_agf(mp, tp, info->agno, 0,
> + &info->agf_bp);
> + if (error)
> + goto err;
> +
> + trace_xfs_fsmap_low_key(mp, info->dev, info->agno,
> + info->low.rm_startblock,
> + info->low.rm_blockcount,
> + info->low.rm_owner,
> + info->low.rm_offset);
> +
> + trace_xfs_fsmap_high_key(mp, info->dev, info->agno,
> + info->high.rm_startblock,
> + info->high.rm_blockcount,
> + info->high.rm_owner,
> + info->high.rm_offset);
> +
> + bt_cur = xfs_rmapbt_init_cursor(mp, tp, info->agf_bp,
> + info->agno);
> + error = xfs_rmap_query_range(bt_cur, &info->low, &info->high,
> + xfs_getfsmap_datadev_helper, info);
> + if (error)
> + goto err;
> +
/*
* Reset the low key for the start of the next AG.
*/
> + if (info->agno == start_ag) {
> + info->low.rm_startblock = 0;
> + info->low.rm_owner = 0;
> + info->low.rm_offset = 0;
> + info->low.rm_flags = 0;
> + }
> + }
Do I follow this loop correctly in that we lock each AGF buffer as we
progress through the fs, holding the locks until we've traversed the
entire fs? If so, is that really necessary or can we release the
previous previous buffer once we move on to the next AG? Not doing so
seems like it makes this a very heavyweight operation...
> +
> + /* Report any free space at the end of the AG */
> + info->last = true;
> + error = xfs_getfsmap_datadev_helper(bt_cur, &info->high, info);
> + if (error)
> + goto err;
> +
> +err:
> + if (bt_cur)
> + xfs_btree_del_cursor(bt_cur, error < 0 ? XFS_BTREE_ERROR :
> + XFS_BTREE_NOERROR);
> + if (info->agf_bp)
> + info->agf_bp = NULL;
> +
> + return error;
> +}
> +
> +/* Do we recognize the device? */
> +STATIC bool
> +xfs_getfsmap_is_valid_device(
> + struct xfs_mount *mp,
> + struct xfs_fsmap *fm)
> +{
> + if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
> + fm->fmr_device == new_encode_dev(mp->m_ddev_targp->bt_dev))
> + return true;
> + if (mp->m_logdev_targp &&
> + fm->fmr_device == new_encode_dev(mp->m_logdev_targp->bt_dev))
> + return true;
> + return false;
> +}
> +
> +/* Ensure that the low key is less than the high key. */
> +STATIC bool
> +xfs_getfsmap_check_keys(
> + struct xfs_fsmap *low_key,
> + struct xfs_fsmap *high_key)
> +{
> + if (low_key->fmr_device > high_key->fmr_device)
> + return false;
> + if (low_key->fmr_device < high_key->fmr_device)
> + return true;
> +
> + if (low_key->fmr_physical > high_key->fmr_physical)
> + return false;
> + if (low_key->fmr_physical < high_key->fmr_physical)
> + return true;
> +
> + if (low_key->fmr_owner > high_key->fmr_owner)
> + return false;
> + if (low_key->fmr_owner < high_key->fmr_owner)
> + return true;
> +
> + if (low_key->fmr_offset > high_key->fmr_offset)
> + return false;
> + if (low_key->fmr_offset < high_key->fmr_offset)
> + return true;
> +
> + return false;
> +}
> +
> +#define XFS_GETFSMAP_DEVS 3
Why 3 (looks like we use 2 below)?
> +/*
> + * Get filesystem's extents as described in head, and format for
> + * output. Calls formatter to fill the user's buffer until all
> + * extents are mapped, until the passed-in head->fmh_count slots have
> + * been filled, or until the formatter short-circuits the loop, if it
> + * is tracking filled-in extents on its own.
> + */
> +int
> +xfs_getfsmap(
> + struct xfs_mount *mp,
> + struct xfs_fsmap_head *head,
> + xfs_fsmap_format_t formatter,
> + void *arg)
> +{
> + struct xfs_trans *tp = NULL;
> + struct xfs_fsmap *rkey_low; /* request keys */
> + struct xfs_fsmap *rkey_high;
> + struct xfs_fsmap dkeys[2]; /* per-dev keys */
> + struct xfs_getfsmap_dev handlers[XFS_GETFSMAP_DEVS];
> + struct xfs_getfsmap_info info = {0};
> + int i;
> + int error = 0;
> +
> + if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
> + return -EOPNOTSUPP;
> + if (head->fmh_iflags & ~FMH_IF_VALID)
> + return -EINVAL;
> + rkey_low = head->fmh_keys;
> + rkey_high = rkey_low + 1;
This is more clear IMO if we just use fmh_keys[0] and fmh_keys[1] (the
same pattern exists in one or two other places as well..).
> + if (!xfs_getfsmap_is_valid_device(mp, rkey_low) ||
> + !xfs_getfsmap_is_valid_device(mp, rkey_high))
> + return -EINVAL;
> +
> + head->fmh_entries = 0;
> +
> + /* Set up our device handlers. */
> + memset(handlers, 0, sizeof(handlers));
> + handlers[0].dev = new_encode_dev(mp->m_ddev_targp->bt_dev);
> + handlers[0].fn = xfs_getfsmap_datadev;
> + if (mp->m_logdev_targp != mp->m_ddev_targp) {
> + handlers[1].dev = new_encode_dev(mp->m_logdev_targp->bt_dev);
> + handlers[1].fn = xfs_getfsmap_logdev;
> + }
> +
> + xfs_sort(handlers, XFS_GETFSMAP_DEVS, sizeof(struct xfs_getfsmap_dev),
> + xfs_getfsmap_dev_compare);
> +
> + /*
> + * Since we allow the user to copy the last mapping from a previous
> + * call into the low key slot, we have to advance the low key by
> + * whatever the reported length is. If the offset field doesn't apply,
> + * move up the start block to the next extent and start over with the
> + * lowest owner/offset possible; otherwise it's file data, so move up
> + * the offset only.
> + */
> + dkeys[0] = *rkey_low;
> + if (dkeys[0].fmr_flags & (FMR_OF_SPECIAL_OWNER | FMR_OF_EXTENT_MAP)) {
> + dkeys[0].fmr_physical += dkeys[0].fmr_length;
> + dkeys[0].fmr_owner = 0;
> + dkeys[0].fmr_offset = 0;
Should these values already be zero in this case?
> + } else
> + dkeys[0].fmr_offset += dkeys[0].fmr_length;
> + memset(&dkeys[1], 0xFF, sizeof(struct xfs_fsmap));
Ok, it took me a bit to grok this hunk for some reason. I had to come
back to it after reading deeper into the code. It could just be me, but
something like the following comment helps me understand it a bit better
(feel free to take it entirely, reword/update the existing comment or
just ignore):
/*
* To continue where we left off, we allow userspace to use the last
* mapping from a previous call as the low key of the next. This is
* identified by a non-zero length in the low key. We have to increment
* the low key in this scenario to ensure we don't return the same
* mapping again, and instead return the very next mapping.
*
* If the low key mapping refers to fs owned blocks, bump the physical
* offset as there can be no other mapping for the same physical block
* range. If the mapping refers to file data, however, the same physical
* blocks could be mapped to several other files/offsets. According to
* rmapbt record ordering, the minimal next possible record for the
* block range is the next starting offset in the same inode. Therefore,
* bump the file offset to continue the search appropriately.
*/
> +
> + if (!xfs_getfsmap_check_keys(dkeys, rkey_high))
> + return -EINVAL;
> +
> + info.rkey_low = rkey_low;
> + info.formatter = formatter;
> + info.format_arg = arg;
> + info.head = head;
> +
> + /* For each device we support... */
> + for (i = 0; i < XFS_GETFSMAP_DEVS; i++) {
> + /* Is this device within the range the user asked for? */
> + if (!handlers[i].fn)
> + continue;
> + if (rkey_low->fmr_device > handlers[i].dev)
> + continue;
> + if (rkey_high->fmr_device < handlers[i].dev)
> + break;
> +
> + /*
> + * If this device number matches the high key, we have
> + * to pass the high key to the handler to limit the
> + * query results. If the device number exceeds the
> + * low key, zero out the low key so that we get
> + * everything from the beginning.
> + */
> + if (handlers[i].dev == rkey_high->fmr_device)
> + dkeys[1] = *rkey_high;
> + if (handlers[i].dev > rkey_low->fmr_device)
> + memset(&dkeys[0], 0, sizeof(struct xfs_fsmap));
> +
> + error = xfs_trans_alloc_empty(mp, &tp);
> + if (error)
> + break;
> +
> + info.next_daddr = dkeys[0].fmr_physical;
> + info.dev = handlers[i].dev;
> + info.last = false;
> + info.agno = NULLAGNUMBER;
> + error = handlers[i].fn(tp, dkeys, &info);
> + if (error)
> + break;
> + xfs_trans_cancel(tp);
> + tp = NULL;
> + }
> +
> + if (tp)
> + xfs_trans_cancel(tp);
> + head->fmh_oflags = FMH_OF_DEV_T;
> + return error;
> +}
> diff --git a/fs/xfs/xfs_fsmap.h b/fs/xfs/xfs_fsmap.h
> new file mode 100644
> index 0000000..1943047
> --- /dev/null
> +++ b/fs/xfs/xfs_fsmap.h
> @@ -0,0 +1,51 @@
> +/*
> + * Copyright (C) 2017 Oracle. All Rights Reserved.
> + *
> + * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
> + */
> +#ifndef __XFS_FSMAP_H__
> +#define __XFS_FSMAP_H__
> +
> +/* internal fsmap representation */
> +struct xfs_fsmap {
> + dev_t fmr_device; /* device id */
> + uint32_t fmr_flags; /* mapping flags */
> + uint64_t fmr_physical; /* device offset of segment */
> + uint64_t fmr_owner; /* owner id */
> + xfs_fileoff_t fmr_offset; /* file offset of segment */
> + xfs_filblks_t fmr_length; /* length of segment, blocks */
> +};
> +
> +struct xfs_fsmap_head {
> + uint32_t fmh_iflags; /* control flags */
> + uint32_t fmh_oflags; /* output flags */
> + unsigned int fmh_count; /* # of entries in array incl. input */
> + unsigned int fmh_entries; /* # of entries filled in (output). */
> +
> + struct xfs_fsmap fmh_keys[2]; /* low and high keys */
> +};
> +
> +void xfs_fsmap_from_internal(struct fsmap *dest, struct xfs_fsmap *src);
> +void xfs_fsmap_to_internal(struct xfs_fsmap *dest, struct fsmap *src);
> +
> +/* fsmap to userspace formatter - copy to user & advance pointer */
> +typedef int (*xfs_fsmap_format_t)(struct xfs_fsmap *, void *);
> +
> +int xfs_getfsmap(struct xfs_mount *mp, struct xfs_fsmap_head *head,
> + xfs_fsmap_format_t formatter, void *arg);
> +
> +#endif /* __XFS_FSMAP_H__ */
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index c67cfb4..bbe1b58 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -41,6 +41,9 @@
> #include "xfs_trans.h"
> #include "xfs_pnfs.h"
> #include "xfs_acl.h"
> +#include "xfs_btree.h"
> +#include <linux/fsmap.h>
> +#include "xfs_fsmap.h"
>
> #include <linux/capability.h>
> #include <linux/dcache.h>
> @@ -1607,6 +1610,103 @@ xfs_ioc_getbmapx(
> return 0;
> }
>
> +struct getfsmap_info {
> + struct xfs_mount *mp;
> + struct fsmap __user *data;
> + __u32 last_flags;
> +};
> +
> +STATIC int
> +xfs_getfsmap_format(struct xfs_fsmap *xfm, void *priv)
> +{
> + struct getfsmap_info *info = priv;
> + struct fsmap fm;
> +
> + trace_xfs_getfsmap_mapping(info->mp, xfm->fmr_device, xfm->fmr_physical,
> + xfm->fmr_length, xfm->fmr_owner, xfm->fmr_offset,
> + xfm->fmr_flags);
> +
> + info->last_flags = xfm->fmr_flags;
> + xfs_fsmap_from_internal(&fm, xfm);
> + if (copy_to_user(info->data, &fm, sizeof(struct fsmap)))
> + return -EFAULT;
> +
> + info->data++;
> + return 0;
> +}
> +
> +STATIC int
> +xfs_ioc_getfsmap(
> + struct xfs_inode *ip,
> + void __user *arg)
> +{
> + struct getfsmap_info info;
> + struct xfs_fsmap_head xhead = {0};
> + struct fsmap_head head;
> + bool aborted = false;
> + int error;
> +
> + if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
> + return -EFAULT;
> + if (head.fmh_reserved[0] || head.fmh_reserved[1] ||
> + head.fmh_reserved[2] || head.fmh_reserved[3] ||
> + head.fmh_reserved[4] || head.fmh_reserved[5] ||
> + head.fmh_keys[0].fmr_reserved[0] ||
> + head.fmh_keys[0].fmr_reserved[1] ||
> + head.fmh_keys[0].fmr_reserved[2] ||
> + head.fmh_keys[1].fmr_reserved[0] ||
> + head.fmh_keys[1].fmr_reserved[1] ||
> + head.fmh_keys[1].fmr_reserved[2])
> + return -EINVAL;
Probably better to use memchr_inv() here.
> +
> + xhead.fmh_iflags = head.fmh_iflags;
> + xhead.fmh_count = head.fmh_count;
> + xfs_fsmap_to_internal(&xhead.fmh_keys[0], &head.fmh_keys[0]);
> + xfs_fsmap_to_internal(&xhead.fmh_keys[1], &head.fmh_keys[1]);
> +
> + trace_xfs_getfsmap_low_key(ip->i_mount,
> + xhead.fmh_keys[0].fmr_device,
> + xhead.fmh_keys[0].fmr_physical,
> + xhead.fmh_keys[0].fmr_length,
> + xhead.fmh_keys[0].fmr_owner,
> + xhead.fmh_keys[0].fmr_offset,
> + xhead.fmh_keys[0].fmr_flags);
> +
> + trace_xfs_getfsmap_high_key(ip->i_mount,
> + xhead.fmh_keys[1].fmr_device,
> + xhead.fmh_keys[1].fmr_physical,
> + xhead.fmh_keys[1].fmr_length,
> + xhead.fmh_keys[1].fmr_owner,
> + xhead.fmh_keys[1].fmr_offset,
> + xhead.fmh_keys[1].fmr_flags);
> +
Hmm.. could we combine these into one call that looks like:
trace_xfs_getfsmap(mp, &fmh_keys[0], &fmh_keys[1]);
... and has the trace handler pull the relevant data out of the key
structure (same comment for the similar trace_xfs_fsmap*())?
> + info.mp = ip->i_mount;
> + info.data = ((__force struct fsmap_head *)arg)->fmh_recs;
> + error = xfs_getfsmap(ip->i_mount, &xhead, xfs_getfsmap_format, &info);
> + if (error == XFS_BTREE_QUERY_RANGE_ABORT) {
> + error = 0;
> + aborted = true;
> + } else if (error)
> + return error;
> +
> + /* If we didn't abort, set the "last" flag in the last fmx */
> + if (!aborted && xhead.fmh_entries) {
> + info.data--;
> + info.last_flags |= FMR_OF_LAST;
Isn't this kind of implied by a short return? It looks like if a real
error occurs at any point during the search, we just return the error. I
guess there is still the case where the remaining mappings exactly match
the number of entries in the data structure passed in and you'd have to
make another call to identify EOF. If we do want the flag, I'm also
wondering why we couldn't stuff it in oflags in the header. Is there
some reason I'm not yet aware of why we want the LAST flag in the flags
of the last entry?
Brian
> + if (copy_to_user(&info.data->fmr_flags, &info.last_flags,
> + sizeof(info.last_flags)))
> + return -EFAULT;
> + }
> +
> + /* copy back header */
> + head.fmh_entries = xhead.fmh_entries;
> + head.fmh_oflags = xhead.fmh_oflags;
> + if (copy_to_user(arg, &head, sizeof(struct fsmap_head)))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> int
> xfs_ioc_swapext(
> xfs_swapext_t *sxp)
> @@ -1787,6 +1887,9 @@ xfs_file_ioctl(
> case XFS_IOC_GETBMAPX:
> return xfs_ioc_getbmapx(ip, arg);
>
> + case FS_IOC_GETFSMAP:
> + return xfs_ioc_getfsmap(ip, arg);
> +
> case XFS_IOC_FD_TO_HANDLE:
> case XFS_IOC_PATH_TO_HANDLE:
> case XFS_IOC_PATH_TO_FSHANDLE: {
> diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
> index 7c49938..fa0bc4d 100644
> --- a/fs/xfs/xfs_ioctl32.c
> +++ b/fs/xfs/xfs_ioctl32.c
> @@ -20,6 +20,7 @@
> #include <linux/mount.h>
> #include <linux/slab.h>
> #include <linux/uaccess.h>
> +#include <linux/fsmap.h>
> #include "xfs.h"
> #include "xfs_fs.h"
> #include "xfs_format.h"
> @@ -554,6 +555,7 @@ xfs_file_compat_ioctl(
> case XFS_IOC_GOINGDOWN:
> case XFS_IOC_ERROR_INJECTION:
> case XFS_IOC_ERROR_CLEARALL:
> + case FS_IOC_GETFSMAP:
> return xfs_file_ioctl(filp, cmd, p);
> #ifndef BROKEN_X86_ALIGNMENT
> /* These are handled fine if no alignment issues */
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index d3d11905..125d568 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -3270,6 +3270,91 @@ DEFINE_INODE_IREC_EVENT(xfs_swap_extent_rmap_remap);
> DEFINE_INODE_IREC_EVENT(xfs_swap_extent_rmap_remap_piece);
> DEFINE_INODE_ERROR_EVENT(xfs_swap_extent_rmap_error);
>
> +/* fsmap traces */
> +DECLARE_EVENT_CLASS(xfs_fsmap_class,
> + TP_PROTO(struct xfs_mount *mp, u32 keydev, xfs_agnumber_t agno,
> + xfs_fsblock_t bno, xfs_filblks_t len, __uint64_t owner,
> + __uint64_t offset),
> + TP_ARGS(mp, keydev, agno, bno, len, owner, offset),
> + TP_STRUCT__entry(
> + __field(dev_t, dev)
> + __field(dev_t, keydev)
> + __field(xfs_agnumber_t, agno)
> + __field(xfs_fsblock_t, bno)
> + __field(xfs_filblks_t, len)
> + __field(__uint64_t, owner)
> + __field(__uint64_t, offset)
> + ),
> + TP_fast_assign(
> + __entry->dev = mp->m_super->s_dev;
> + __entry->keydev = new_decode_dev(keydev);
> + __entry->agno = agno;
> + __entry->bno = bno;
> + __entry->len = len;
> + __entry->owner = owner;
> + __entry->offset = offset;
> + ),
> + TP_printk("dev %d:%d keydev %d:%d agno %u bno %llu len %llu owner %lld offset 0x%llx\n",
> + MAJOR(__entry->dev), MINOR(__entry->dev),
> + MAJOR(__entry->keydev), MINOR(__entry->keydev),
> + __entry->agno,
> + __entry->bno,
> + __entry->len,
> + __entry->owner,
> + __entry->offset)
> +)
> +#define DEFINE_FSMAP_EVENT(name) \
> +DEFINE_EVENT(xfs_fsmap_class, name, \
> + TP_PROTO(struct xfs_mount *mp, u32 keydev, xfs_agnumber_t agno, \
> + xfs_fsblock_t bno, xfs_filblks_t len, __uint64_t owner, \
> + __uint64_t offset), \
> + TP_ARGS(mp, keydev, agno, bno, len, owner, offset))
> +DEFINE_FSMAP_EVENT(xfs_fsmap_low_key);
> +DEFINE_FSMAP_EVENT(xfs_fsmap_high_key);
> +DEFINE_FSMAP_EVENT(xfs_fsmap_mapping);
> +
> +DECLARE_EVENT_CLASS(xfs_getfsmap_class,
> + TP_PROTO(struct xfs_mount *mp, u32 keydev, xfs_daddr_t block,
> + xfs_daddr_t len, __uint64_t owner, __uint64_t offset,
> + __uint64_t flags),
> + TP_ARGS(mp, keydev, block, len, owner, offset, flags),
> + TP_STRUCT__entry(
> + __field(dev_t, dev)
> + __field(dev_t, keydev)
> + __field(xfs_daddr_t, block)
> + __field(xfs_daddr_t, len)
> + __field(__uint64_t, owner)
> + __field(__uint64_t, offset)
> + __field(__uint64_t, flags)
> + ),
> + TP_fast_assign(
> + __entry->dev = mp->m_super->s_dev;
> + __entry->keydev = new_decode_dev(keydev);
> + __entry->block = block;
> + __entry->len = len;
> + __entry->owner = owner;
> + __entry->offset = offset;
> + __entry->flags = flags;
> + ),
> + TP_printk("dev %d:%d keydev %d:%d block %llu len %llu owner %lld offset %llu flags 0x%llx\n",
> + MAJOR(__entry->dev), MINOR(__entry->dev),
> + MAJOR(__entry->keydev), MINOR(__entry->keydev),
> + __entry->block,
> + __entry->len,
> + __entry->owner,
> + __entry->offset,
> + __entry->flags)
> +)
> +#define DEFINE_GETFSMAP_EVENT(name) \
> +DEFINE_EVENT(xfs_getfsmap_class, name, \
> + TP_PROTO(struct xfs_mount *mp, u32 keydev, xfs_daddr_t block, \
> + xfs_daddr_t len, __uint64_t owner, __uint64_t offset, \
> + __uint64_t flags), \
> + TP_ARGS(mp, keydev, block, len, owner, offset, flags))
> +DEFINE_GETFSMAP_EVENT(xfs_getfsmap_low_key);
> +DEFINE_GETFSMAP_EVENT(xfs_getfsmap_high_key);
> +DEFINE_GETFSMAP_EVENT(xfs_getfsmap_mapping);
> +
> #endif /* _TRACE_XFS_H */
>
> #undef TRACE_INCLUDE_PATH
> diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
> index 70f42ea..a280e12 100644
> --- a/fs/xfs/xfs_trans.c
> +++ b/fs/xfs/xfs_trans.c
> @@ -263,6 +263,28 @@ xfs_trans_alloc(
> }
>
> /*
> + * Create an empty transaction with no reservation. This is a defensive
> + * mechanism for routines that query metadata without actually modifying
> + * them -- if the metadata being queried is somehow cross-linked (think a
> + * btree block pointer that points higher in the tree), we risk deadlock.
> + * However, blocks grabbed as part of a transaction can be re-grabbed.
> + * The verifiers will notice the corrupt block and the operation will fail
> + * back to userspace without deadlocking.
> + *
> + * Note the zero-length reservation; this transaction MUST be cancelled
> + * without any dirty data.
> + */
> +int
> +xfs_trans_alloc_empty(
> + struct xfs_mount *mp,
> + struct xfs_trans **tpp)
> +{
> + struct xfs_trans_res resv = {0};
> +
> + return xfs_trans_alloc(mp, &resv, 0, 0, XFS_TRANS_NO_WRITECOUNT, tpp);
> +}
> +
> +/*
> * Record the indicated change to the given field for application
> * to the file system's superblock when the transaction commits.
> * For now, just store the change in the transaction structure.
> diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
> index 61b7fbd..98024cb 100644
> --- a/fs/xfs/xfs_trans.h
> +++ b/fs/xfs/xfs_trans.h
> @@ -159,6 +159,8 @@ typedef struct xfs_trans {
> int xfs_trans_alloc(struct xfs_mount *mp, struct xfs_trans_res *resp,
> uint blocks, uint rtextents, uint flags,
> struct xfs_trans **tpp);
> +int xfs_trans_alloc_empty(struct xfs_mount *mp,
> + struct xfs_trans **tpp);
> void xfs_trans_mod_sb(xfs_trans_t *, uint, int64_t);
>
> struct xfs_buf *xfs_trans_get_buf_map(struct xfs_trans *tp,
>
> --
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