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linux-next/fs/xfs/xfs_fsmap.c
Darrick J. Wong a440a28ddb xfs: fix off-by-one error in fsmap's end_daddr usage 
In commit ca6448aed4, we created an "end_daddr" variable to fix
fsmap reporting when the end of the range requested falls in the middle
of an unknown (aka free on the rmapbt) region.  Unfortunately, I didn't
notice that the the code sets end_daddr to the last sector of the device
but then uses that quantity to compute the length of the synthesized
mapping.

Zizhi Wo later observed that when end_daddr isn't set, we still don't
report the last fsblock on a device because in that case (aka when
info->last is true), the info->high mapping that we pass to
xfs_getfsmap_group_helper has a startblock that points to the last
fsblock.  This is also wrong because the code uses startblock to
compute the length of the synthesized mapping.

Fix the second problem by setting end_daddr unconditionally, and fix the
first problem by setting start_daddr to one past the end of the range to
query.

Cc: <stable@vger.kernel.org> # v6.11
Fixes: ca6448aed4 ("xfs: Fix missing interval for missing_owner in xfs fsmap")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reported-by: Zizhi Wo <wozizhi@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-12-12 17:45:08 -08:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#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_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_btree.h"
#include "xfs_rmap_btree.h"
#include "xfs_trace.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"
#include "xfs_alloc_btree.h"
#include "xfs_rtbitmap.h"
#include "xfs_ag.h"
#include "xfs_rtgroup.h"
/* Convert an xfs_fsmap to an fsmap. */
static 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. */
static 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_rmap_irec *dest,
const struct xfs_fsmap *src)
{
if (!(src->fmr_flags & FMR_OF_SPECIAL_OWNER)) {
dest->rm_owner = src->fmr_owner;
return 0;
}
switch (src->fmr_owner) {
case 0: /* "lowest owner id possible" */
case -1ULL: /* "highest owner id possible" */
dest->rm_owner = src->fmr_owner;
break;
case XFS_FMR_OWN_FREE:
dest->rm_owner = XFS_RMAP_OWN_NULL;
break;
case XFS_FMR_OWN_UNKNOWN:
dest->rm_owner = XFS_RMAP_OWN_UNKNOWN;
break;
case XFS_FMR_OWN_FS:
dest->rm_owner = XFS_RMAP_OWN_FS;
break;
case XFS_FMR_OWN_LOG:
dest->rm_owner = XFS_RMAP_OWN_LOG;
break;
case XFS_FMR_OWN_AG:
dest->rm_owner = XFS_RMAP_OWN_AG;
break;
case XFS_FMR_OWN_INOBT:
dest->rm_owner = XFS_RMAP_OWN_INOBT;
break;
case XFS_FMR_OWN_INODES:
dest->rm_owner = XFS_RMAP_OWN_INODES;
break;
case XFS_FMR_OWN_REFC:
dest->rm_owner = XFS_RMAP_OWN_REFC;
break;
case XFS_FMR_OWN_COW:
dest->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_frec(
struct xfs_fsmap *dest,
const struct xfs_fsmap_irec *frec)
{
dest->fmr_flags = 0;
if (!XFS_RMAP_NON_INODE_OWNER(frec->owner)) {
dest->fmr_owner = frec->owner;
return 0;
}
dest->fmr_flags |= FMR_OF_SPECIAL_OWNER;
switch (frec->owner) {
case XFS_RMAP_OWN_FS:
dest->fmr_owner = XFS_FMR_OWN_FS;
break;
case XFS_RMAP_OWN_LOG:
dest->fmr_owner = XFS_FMR_OWN_LOG;
break;
case XFS_RMAP_OWN_AG:
dest->fmr_owner = XFS_FMR_OWN_AG;
break;
case XFS_RMAP_OWN_INOBT:
dest->fmr_owner = XFS_FMR_OWN_INOBT;
break;
case XFS_RMAP_OWN_INODES:
dest->fmr_owner = XFS_FMR_OWN_INODES;
break;
case XFS_RMAP_OWN_REFC:
dest->fmr_owner = XFS_FMR_OWN_REFC;
break;
case XFS_RMAP_OWN_COW:
dest->fmr_owner = XFS_FMR_OWN_COW;
break;
case XFS_RMAP_OWN_NULL: /* "free" */
dest->fmr_owner = XFS_FMR_OWN_FREE;
break;
default:
ASSERT(0);
return -EFSCORRUPTED;
}
return 0;
}
/* getfsmap query state */
struct xfs_getfsmap_info {
struct xfs_fsmap_head *head;
struct fsmap *fsmap_recs; /* mapping records */
struct xfs_buf *agf_bp; /* AGF, for refcount queries */
struct xfs_group *group; /* group info, if applicable */
xfs_daddr_t next_daddr; /* next daddr we expect */
/* daddr of low fsmap key when we're using the rtbitmap */
xfs_daddr_t low_daddr;
/* daddr of high fsmap key, or the last daddr on the device */
xfs_daddr_t end_daddr;
u64 missing_owner; /* owner of holes */
u32 dev; /* device id */
/*
* Low rmap key for the query. If low.rm_blockcount is nonzero, this
* is the second (or later) call to retrieve the recordset in pieces.
* xfs_getfsmap_rec_before_start will compare all records retrieved
* by the rmapbt query to filter out any records that start before
* the last record.
*/
struct xfs_rmap_irec low;
struct xfs_rmap_irec high; /* high rmap key */
bool last; /* last extent? */
};
/* Associate a device with a getfsmap handler. */
struct xfs_getfsmap_dev {
u32 dev;
int (*fn)(struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info);
sector_t nr_sectors;
};
/* 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;
}
/* Decide if this mapping is shared. */
STATIC int
xfs_getfsmap_is_shared(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
const struct xfs_fsmap_irec *frec,
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_has_reflink(mp))
return 0;
/* rt files will have no perag structure */
if (!info->group)
return 0;
/* Are there any shared blocks here? */
flen = 0;
cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp,
to_perag(info->group));
error = xfs_refcount_find_shared(cur, frec->rec_key,
XFS_BB_TO_FSBT(mp, frec->len_daddr), &fbno, &flen,
false);
xfs_btree_del_cursor(cur, error);
if (error)
return error;
*stat = flen > 0;
return 0;
}
static inline void
xfs_getfsmap_format(
struct xfs_mount *mp,
struct xfs_fsmap *xfm,
struct xfs_getfsmap_info *info)
{
struct fsmap *rec;
trace_xfs_getfsmap_mapping(mp, xfm);
rec = &info->fsmap_recs[info->head->fmh_entries++];
xfs_fsmap_from_internal(rec, xfm);
}
static inline bool
xfs_getfsmap_frec_before_start(
struct xfs_getfsmap_info *info,
const struct xfs_fsmap_irec *frec)
{
if (info->low_daddr != XFS_BUF_DADDR_NULL)
return frec->start_daddr < info->low_daddr;
if (info->low.rm_blockcount) {
struct xfs_rmap_irec rec = {
.rm_startblock = frec->rec_key,
.rm_owner = frec->owner,
.rm_flags = frec->rm_flags,
};
return xfs_rmap_compare(&rec, &info->low) < 0;
}
return false;
}
/*
* Format a reverse mapping for getfsmap, having translated rm_startblock
* into the appropriate daddr units. Pass in a nonzero @len_daddr if the
* length could be larger than rm_blockcount in struct xfs_rmap_irec.
*/
STATIC int
xfs_getfsmap_helper(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
const struct xfs_fsmap_irec *frec)
{
struct xfs_fsmap fmr;
struct xfs_mount *mp = tp->t_mountp;
bool shared;
int error = 0;
if (fatal_signal_pending(current))
return -EINTR;
/*
* Filter out records that start before our startpoint, if the
* caller requested that.
*/
if (xfs_getfsmap_frec_before_start(info, frec))
goto out;
/* Are we just counting mappings? */
if (info->head->fmh_count == 0) {
if (info->head->fmh_entries == UINT_MAX)
return -ECANCELED;
if (frec->start_daddr > info->next_daddr)
info->head->fmh_entries++;
if (info->last)
return 0;
info->head->fmh_entries++;
goto out;
}
/*
* If the record starts past the last physical block we saw,
* then we've found a gap. Report the gap as being owned by
* whatever the caller specified is the missing owner.
*/
if (frec->start_daddr > info->next_daddr) {
if (info->head->fmh_entries >= info->head->fmh_count)
return -ECANCELED;
fmr.fmr_device = info->dev;
fmr.fmr_physical = info->next_daddr;
fmr.fmr_owner = info->missing_owner;
fmr.fmr_offset = 0;
fmr.fmr_length = frec->start_daddr - info->next_daddr;
fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
xfs_getfsmap_format(mp, &fmr, info);
}
if (info->last)
goto out;
/* Fill out the extent we found */
if (info->head->fmh_entries >= info->head->fmh_count)
return -ECANCELED;
trace_xfs_fsmap_mapping(mp, info->dev,
info->group ? info->group->xg_gno : NULLAGNUMBER,
frec);
fmr.fmr_device = info->dev;
fmr.fmr_physical = frec->start_daddr;
error = xfs_fsmap_owner_from_frec(&fmr, frec);
if (error)
return error;
fmr.fmr_offset = XFS_FSB_TO_BB(mp, frec->offset);
fmr.fmr_length = frec->len_daddr;
if (frec->rm_flags & XFS_RMAP_UNWRITTEN)
fmr.fmr_flags |= FMR_OF_PREALLOC;
if (frec->rm_flags & XFS_RMAP_ATTR_FORK)
fmr.fmr_flags |= FMR_OF_ATTR_FORK;
if (frec->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, frec, &shared);
if (error)
return error;
if (shared)
fmr.fmr_flags |= FMR_OF_SHARED;
}
xfs_getfsmap_format(mp, &fmr, info);
out:
info->next_daddr = max(info->next_daddr,
frec->start_daddr + frec->len_daddr);
return 0;
}
static inline int
xfs_getfsmap_group_helper(
struct xfs_getfsmap_info *info,
struct xfs_trans *tp,
struct xfs_group *xg,
xfs_agblock_t startblock,
xfs_extlen_t blockcount,
struct xfs_fsmap_irec *frec)
{
/*
* For an info->last query, we're looking for a gap between the last
* mapping emitted and the high key specified by userspace. If the
* user's query spans less than 1 fsblock, then info->high and
* info->low will have the same rm_startblock, which causes rec_daddr
* and next_daddr to be the same. Therefore, use the end_daddr that
* we calculated from userspace's high key to synthesize the record.
* Note that if the btree query found a mapping, there won't be a gap.
*/
if (info->last)
frec->start_daddr = info->end_daddr + 1;
else
frec->start_daddr = xfs_gbno_to_daddr(xg, startblock);
frec->len_daddr = XFS_FSB_TO_BB(xg->xg_mount, blockcount);
return xfs_getfsmap_helper(tp, info, frec);
}
/* Transform a rmapbt irec into a fsmap */
STATIC int
xfs_getfsmap_rmapbt_helper(
struct xfs_btree_cur *cur,
const struct xfs_rmap_irec *rec,
void *priv)
{
struct xfs_fsmap_irec frec = {
.owner = rec->rm_owner,
.offset = rec->rm_offset,
.rm_flags = rec->rm_flags,
.rec_key = rec->rm_startblock,
};
struct xfs_getfsmap_info *info = priv;
return xfs_getfsmap_group_helper(info, cur->bc_tp, cur->bc_group,
rec->rm_startblock, rec->rm_blockcount, &frec);
}
/* Transform a bnobt irec into a fsmap */
STATIC int
xfs_getfsmap_datadev_bnobt_helper(
struct xfs_btree_cur *cur,
const struct xfs_alloc_rec_incore *rec,
void *priv)
{
struct xfs_fsmap_irec frec = {
.owner = XFS_RMAP_OWN_NULL, /* "free" */
.rec_key = rec->ar_startblock,
};
struct xfs_getfsmap_info *info = priv;
return xfs_getfsmap_group_helper(info, cur->bc_tp, cur->bc_group,
rec->ar_startblock, rec->ar_blockcount, &frec);
}
/* Set rmap flags based on the getfsmap flags */
static void
xfs_getfsmap_set_irec_flags(
struct xfs_rmap_irec *irec,
const 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;
}
static inline bool
rmap_not_shareable(struct xfs_mount *mp, const struct xfs_rmap_irec *r)
{
if (!xfs_has_reflink(mp))
return true;
if (XFS_RMAP_NON_INODE_OWNER(r->rm_owner))
return true;
if (r->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK |
XFS_RMAP_UNWRITTEN))
return true;
return false;
}
/* Execute a getfsmap query against the regular data device. */
STATIC int
__xfs_getfsmap_datadev(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info,
int (*query_fn)(struct xfs_trans *,
struct xfs_getfsmap_info *,
struct xfs_btree_cur **,
void *),
void *priv)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_perag *pag = NULL;
struct xfs_btree_cur *bt_cur = NULL;
xfs_fsblock_t start_fsb;
xfs_fsblock_t end_fsb;
xfs_agnumber_t start_ag, end_ag;
uint64_t eofs;
int error = 0;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
start_fsb = XFS_DADDR_TO_FSB(mp, keys[0].fmr_physical);
end_fsb = XFS_DADDR_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
/*
* 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_offset = XFS_BB_TO_FSBT(mp, keys[0].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->low, &keys[0]);
if (error)
return error;
info->low.rm_blockcount = XFS_BB_TO_FSBT(mp, keys[0].fmr_length);
xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
/* Adjust the low key if we are continuing from where we left off. */
if (info->low.rm_blockcount == 0) {
/* No previous record from which to continue */
} else if (rmap_not_shareable(mp, &info->low)) {
/* Last record seen was an unshareable extent */
info->low.rm_owner = 0;
info->low.rm_offset = 0;
start_fsb += info->low.rm_blockcount;
if (XFS_FSB_TO_DADDR(mp, start_fsb) >= eofs)
return 0;
} else {
/* Last record seen was a shareable file data extent */
info->low.rm_offset += info->low.rm_blockcount;
}
info->low.rm_startblock = XFS_FSB_TO_AGBNO(mp, start_fsb);
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;
start_ag = XFS_FSB_TO_AGNO(mp, start_fsb);
end_ag = XFS_FSB_TO_AGNO(mp, end_fsb);
while ((pag = xfs_perag_next_range(mp, pag, start_ag, end_ag))) {
/*
* Set the AG high key from the fsmap high key if this
* is the last AG that we're querying.
*/
info->group = pag_group(pag);
if (pag_agno(pag) == end_ag) {
info->high.rm_startblock = XFS_FSB_TO_AGBNO(mp,
end_fsb);
info->high.rm_offset = XFS_BB_TO_FSBT(mp,
keys[1].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->high, &keys[1]);
if (error)
break;
xfs_getfsmap_set_irec_flags(&info->high, &keys[1]);
}
if (bt_cur) {
xfs_btree_del_cursor(bt_cur, XFS_BTREE_NOERROR);
bt_cur = NULL;
xfs_trans_brelse(tp, info->agf_bp);
info->agf_bp = NULL;
}
error = xfs_alloc_read_agf(pag, tp, 0, &info->agf_bp);
if (error)
break;
trace_xfs_fsmap_low_group_key(mp, info->dev, pag_agno(pag),
&info->low);
trace_xfs_fsmap_high_group_key(mp, info->dev, pag_agno(pag),
&info->high);
error = query_fn(tp, info, &bt_cur, priv);
if (error)
break;
/*
* Set the AG low key to the start of the AG prior to
* moving on to the next AG.
*/
if (pag_agno(pag) == start_ag)
memset(&info->low, 0, sizeof(info->low));
/*
* If this is the last AG, report any gap at the end of it
* before we drop the reference to the perag when the loop
* terminates.
*/
if (pag_agno(pag) == end_ag) {
info->last = true;
error = query_fn(tp, info, &bt_cur, priv);
if (error)
break;
}
info->group = NULL;
}
if (bt_cur)
xfs_btree_del_cursor(bt_cur, error < 0 ? XFS_BTREE_ERROR :
XFS_BTREE_NOERROR);
if (info->agf_bp) {
xfs_trans_brelse(tp, info->agf_bp);
info->agf_bp = NULL;
}
if (info->group) {
xfs_perag_rele(pag);
info->group = NULL;
} else if (pag) {
/* loop termination case */
xfs_perag_rele(pag);
}
return error;
}
/* Actually query the rmap btree. */
STATIC int
xfs_getfsmap_datadev_rmapbt_query(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
struct xfs_btree_cur **curpp,
void *priv)
{
/* Report any gap at the end of the last AG. */
if (info->last)
return xfs_getfsmap_rmapbt_helper(*curpp, &info->high, info);
/* Allocate cursor for this AG and query_range it. */
*curpp = xfs_rmapbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
to_perag(info->group));
return xfs_rmap_query_range(*curpp, &info->low, &info->high,
xfs_getfsmap_rmapbt_helper, info);
}
/* Execute a getfsmap query against the regular data device rmapbt. */
STATIC int
xfs_getfsmap_datadev_rmapbt(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
info->missing_owner = XFS_FMR_OWN_FREE;
return __xfs_getfsmap_datadev(tp, keys, info,
xfs_getfsmap_datadev_rmapbt_query, NULL);
}
/* Actually query the bno btree. */
STATIC int
xfs_getfsmap_datadev_bnobt_query(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
struct xfs_btree_cur **curpp,
void *priv)
{
struct xfs_alloc_rec_incore *key = priv;
/* Report any gap at the end of the last AG. */
if (info->last)
return xfs_getfsmap_datadev_bnobt_helper(*curpp, &key[1], info);
/* Allocate cursor for this AG and query_range it. */
*curpp = xfs_bnobt_init_cursor(tp->t_mountp, tp, info->agf_bp,
to_perag(info->group));
key->ar_startblock = info->low.rm_startblock;
key[1].ar_startblock = info->high.rm_startblock;
return xfs_alloc_query_range(*curpp, key, &key[1],
xfs_getfsmap_datadev_bnobt_helper, info);
}
/* Execute a getfsmap query against the regular data device's bnobt. */
STATIC int
xfs_getfsmap_datadev_bnobt(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_alloc_rec_incore akeys[2];
memset(akeys, 0, sizeof(akeys));
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
return __xfs_getfsmap_datadev(tp, keys, info,
xfs_getfsmap_datadev_bnobt_query, &akeys[0]);
}
/* Execute a getfsmap query against the log device. */
STATIC int
xfs_getfsmap_logdev(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_fsmap_irec frec = {
.start_daddr = 0,
.rec_key = 0,
.owner = XFS_RMAP_OWN_LOG,
};
struct xfs_mount *mp = tp->t_mountp;
xfs_fsblock_t start_fsb, end_fsb;
uint64_t eofs;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
start_fsb = XFS_BB_TO_FSBT(mp,
keys[0].fmr_physical + keys[0].fmr_length);
end_fsb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
/* Adjust the low key if we are continuing from where we left off. */
if (keys[0].fmr_length > 0)
info->low_daddr = XFS_FSB_TO_BB(mp, start_fsb);
trace_xfs_fsmap_low_linear_key(mp, info->dev, start_fsb);
trace_xfs_fsmap_high_linear_key(mp, info->dev, end_fsb);
if (start_fsb > 0)
return 0;
/* Fabricate an rmap entry for the external log device. */
frec.len_daddr = XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
return xfs_getfsmap_helper(tp, info, &frec);
}
#ifdef CONFIG_XFS_RT
/* Transform a rtbitmap "record" into a fsmap */
STATIC int
xfs_getfsmap_rtdev_rtbitmap_helper(
struct xfs_rtgroup *rtg,
struct xfs_trans *tp,
const struct xfs_rtalloc_rec *rec,
void *priv)
{
struct xfs_fsmap_irec frec = {
.owner = XFS_RMAP_OWN_NULL, /* "free" */
};
struct xfs_mount *mp = rtg_mount(rtg);
struct xfs_getfsmap_info *info = priv;
xfs_rtblock_t start_rtb =
xfs_rtx_to_rtb(rtg, rec->ar_startext);
uint64_t rtbcount =
xfs_rtbxlen_to_blen(mp, rec->ar_extcount);
/*
* For an info->last query, we're looking for a gap between the last
* mapping emitted and the high key specified by userspace. If the
* user's query spans less than 1 fsblock, then info->high and
* info->low will have the same rm_startblock, which causes rec_daddr
* and next_daddr to be the same. Therefore, use the end_daddr that
* we calculated from userspace's high key to synthesize the record.
* Note that if the btree query found a mapping, there won't be a gap.
*/
if (info->last)
frec.start_daddr = info->end_daddr + 1;
else
frec.start_daddr = xfs_rtb_to_daddr(mp, start_rtb);
frec.len_daddr = XFS_FSB_TO_BB(mp, rtbcount);
return xfs_getfsmap_helper(tp, info, &frec);
}
/* Execute a getfsmap query against the realtime device rtbitmap. */
STATIC int
xfs_getfsmap_rtdev_rtbitmap(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_mount *mp = tp->t_mountp;
xfs_rtblock_t start_rtbno, end_rtbno;
xfs_rtxnum_t start_rtx, end_rtx;
xfs_rgnumber_t start_rgno, end_rgno;
struct xfs_rtgroup *rtg = NULL;
uint64_t eofs;
int error;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
/* Adjust the low key if we are continuing from where we left off. */
start_rtbno = xfs_daddr_to_rtb(mp,
keys[0].fmr_physical + keys[0].fmr_length);
if (keys[0].fmr_length > 0) {
info->low_daddr = xfs_rtb_to_daddr(mp, start_rtbno);
if (info->low_daddr >= eofs)
return 0;
}
start_rtx = xfs_rtb_to_rtx(mp, start_rtbno);
start_rgno = xfs_rtb_to_rgno(mp, start_rtbno);
end_rtbno = xfs_daddr_to_rtb(mp, min(eofs - 1, keys[1].fmr_physical));
end_rgno = xfs_rtb_to_rgno(mp, end_rtbno);
trace_xfs_fsmap_low_linear_key(mp, info->dev, start_rtbno);
trace_xfs_fsmap_high_linear_key(mp, info->dev, end_rtbno);
end_rtx = -1ULL;
while ((rtg = xfs_rtgroup_next_range(mp, rtg, start_rgno, end_rgno))) {
if (rtg_rgno(rtg) == end_rgno)
end_rtx = xfs_rtb_to_rtx(mp,
end_rtbno + mp->m_sb.sb_rextsize - 1);
info->group = rtg_group(rtg);
xfs_rtgroup_lock(rtg, XFS_RTGLOCK_BITMAP_SHARED);
error = xfs_rtalloc_query_range(rtg, tp, start_rtx, end_rtx,
xfs_getfsmap_rtdev_rtbitmap_helper, info);
if (error)
break;
/*
* Report any gaps at the end of the rtbitmap by simulating a
* zero-length free extent starting at the rtx after the end
* of the query range.
*/
if (rtg_rgno(rtg) == end_rgno) {
struct xfs_rtalloc_rec ahigh = {
.ar_startext = min(end_rtx + 1,
rtg->rtg_extents),
};
info->last = true;
error = xfs_getfsmap_rtdev_rtbitmap_helper(rtg, tp,
&ahigh, info);
if (error)
break;
}
xfs_rtgroup_unlock(rtg, XFS_RTGLOCK_BITMAP_SHARED);
info->group = NULL;
start_rtx = 0;
}
/* loop termination case */
if (rtg) {
if (info->group) {
xfs_rtgroup_unlock(rtg, XFS_RTGLOCK_BITMAP_SHARED);
info->group = NULL;
}
xfs_rtgroup_rele(rtg);
}
return error;
}
#endif /* CONFIG_XFS_RT */
/* 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;
if (mp->m_rtdev_targp &&
fm->fmr_device == new_encode_dev(mp->m_rtdev_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_flags & (FMR_OF_SPECIAL_OWNER | FMR_OF_EXTENT_MAP)) {
if (low_key->fmr_offset)
return false;
}
if (high_key->fmr_flags != -1U &&
(high_key->fmr_flags & (FMR_OF_SPECIAL_OWNER |
FMR_OF_EXTENT_MAP))) {
if (high_key->fmr_offset && high_key->fmr_offset != -1ULL)
return false;
}
if (high_key->fmr_length && high_key->fmr_length != -1ULL)
return false;
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;
}
/*
* There are only two devices if we didn't configure RT devices at build time.
*/
#ifdef CONFIG_XFS_RT
#define XFS_GETFSMAP_DEVS 3
#else
#define XFS_GETFSMAP_DEVS 2
#endif /* CONFIG_XFS_RT */
/*
* Get filesystem's extents as described in head, and format for output. Fills
* in the supplied records array until there are no more reverse mappings to
* return or head.fmh_entries == head.fmh_count. In the second case, this
* function returns -ECANCELED to indicate that more records would have been
* returned.
*
* Key to Confusion
* ----------------
* There are multiple levels of keys and counters at work here:
* xfs_fsmap_head.fmh_keys -- low and high fsmap keys passed in;
* these reflect fs-wide sector addrs.
* dkeys -- fmh_keys used to query each device;
* these are fmh_keys but w/ the low key
* bumped up by fmr_length.
* xfs_getfsmap_info.next_daddr -- next disk addr we expect to see; this
* is how we detect gaps in the fsmap
records and report them.
* xfs_getfsmap_info.low/high -- per-AG low/high keys computed from
* dkeys; used to query the metadata.
*/
STATIC int
xfs_getfsmap(
struct xfs_mount *mp,
struct xfs_fsmap_head *head,
struct fsmap *fsmap_recs)
{
struct xfs_trans *tp = NULL;
struct xfs_fsmap dkeys[2]; /* per-dev keys */
struct xfs_getfsmap_dev handlers[XFS_GETFSMAP_DEVS];
struct xfs_getfsmap_info info = {
.fsmap_recs = fsmap_recs,
.head = head,
};
bool use_rmap;
int i;
int error = 0;
if (head->fmh_iflags & ~FMH_IF_VALID)
return -EINVAL;
if (!xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[0]) ||
!xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[1]))
return -EINVAL;
if (!xfs_getfsmap_check_keys(&head->fmh_keys[0], &head->fmh_keys[1]))
return -EINVAL;
use_rmap = xfs_has_rmapbt(mp) &&
has_capability_noaudit(current, CAP_SYS_ADMIN);
head->fmh_entries = 0;
/* Set up our device handlers. */
memset(handlers, 0, sizeof(handlers));
handlers[0].nr_sectors = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
handlers[0].dev = new_encode_dev(mp->m_ddev_targp->bt_dev);
if (use_rmap)
handlers[0].fn = xfs_getfsmap_datadev_rmapbt;
else
handlers[0].fn = xfs_getfsmap_datadev_bnobt;
if (mp->m_logdev_targp != mp->m_ddev_targp) {
handlers[1].nr_sectors = XFS_FSB_TO_BB(mp,
mp->m_sb.sb_logblocks);
handlers[1].dev = new_encode_dev(mp->m_logdev_targp->bt_dev);
handlers[1].fn = xfs_getfsmap_logdev;
}
#ifdef CONFIG_XFS_RT
if (mp->m_rtdev_targp) {
handlers[2].nr_sectors = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
handlers[2].dev = new_encode_dev(mp->m_rtdev_targp->bt_dev);
handlers[2].fn = xfs_getfsmap_rtdev_rtbitmap;
}
#endif /* CONFIG_XFS_RT */
xfs_sort(handlers, XFS_GETFSMAP_DEVS, sizeof(struct xfs_getfsmap_dev),
xfs_getfsmap_dev_compare);
/*
* 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 file data, 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, each fsmap backend bumps
* the file offset to continue the search appropriately. For
* all other low key mapping types (attr blocks, metadata), each
* fsmap backend bumps the physical offset as there can be no
* other mapping for the same physical block range.
*/
dkeys[0] = head->fmh_keys[0];
memset(&dkeys[1], 0xFF, sizeof(struct xfs_fsmap));
info.next_daddr = head->fmh_keys[0].fmr_physical +
head->fmh_keys[0].fmr_length;
/* 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 (head->fmh_keys[0].fmr_device > handlers[i].dev)
continue;
if (head->fmh_keys[1].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, and
* set the end_daddr so that we can synthesize records at the
* end of the query range or device.
*/
if (handlers[i].dev == head->fmh_keys[1].fmr_device) {
dkeys[1] = head->fmh_keys[1];
info.end_daddr = min(handlers[i].nr_sectors - 1,
dkeys[1].fmr_physical);
} else {
info.end_daddr = handlers[i].nr_sectors - 1;
}
/*
* 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 > head->fmh_keys[0].fmr_device)
memset(&dkeys[0], 0, sizeof(struct xfs_fsmap));
/*
* Grab an empty transaction so that we can use its recursive
* buffer locking abilities to detect cycles in the rmapbt
* without deadlocking.
*/
error = xfs_trans_alloc_empty(mp, &tp);
if (error)
break;
info.dev = handlers[i].dev;
info.last = false;
info.group = NULL;
info.low_daddr = XFS_BUF_DADDR_NULL;
info.low.rm_blockcount = 0;
error = handlers[i].fn(tp, dkeys, &info);
if (error)
break;
xfs_trans_cancel(tp);
tp = NULL;
info.next_daddr = 0;
}
if (tp)
xfs_trans_cancel(tp);
head->fmh_oflags = FMH_OF_DEV_T;
return error;
}
int
xfs_ioc_getfsmap(
struct xfs_inode *ip,
struct fsmap_head __user *arg)
{
struct xfs_fsmap_head xhead = {0};
struct fsmap_head head;
struct fsmap *recs;
unsigned int count;
__u32 last_flags = 0;
bool done = false;
int error;
if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
return -EFAULT;
if (memchr_inv(head.fmh_reserved, 0, sizeof(head.fmh_reserved)) ||
memchr_inv(head.fmh_keys[0].fmr_reserved, 0,
sizeof(head.fmh_keys[0].fmr_reserved)) ||
memchr_inv(head.fmh_keys[1].fmr_reserved, 0,
sizeof(head.fmh_keys[1].fmr_reserved)))
return -EINVAL;
/*
* Use an internal memory buffer so that we don't have to copy fsmap
* data to userspace while holding locks. Start by trying to allocate
* up to 128k for the buffer, but fall back to a single page if needed.
*/
count = min_t(unsigned int, head.fmh_count,
131072 / sizeof(struct fsmap));
recs = kvcalloc(count, sizeof(struct fsmap), GFP_KERNEL);
if (!recs) {
count = min_t(unsigned int, head.fmh_count,
PAGE_SIZE / sizeof(struct fsmap));
recs = kvcalloc(count, sizeof(struct fsmap), GFP_KERNEL);
if (!recs)
return -ENOMEM;
}
xhead.fmh_iflags = head.fmh_iflags;
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]);
trace_xfs_getfsmap_high_key(ip->i_mount, &xhead.fmh_keys[1]);
head.fmh_entries = 0;
do {
struct fsmap __user *user_recs;
struct fsmap *last_rec;
user_recs = &arg->fmh_recs[head.fmh_entries];
xhead.fmh_entries = 0;
xhead.fmh_count = min_t(unsigned int, count,
head.fmh_count - head.fmh_entries);
/* Run query, record how many entries we got. */
error = xfs_getfsmap(ip->i_mount, &xhead, recs);
switch (error) {
case 0:
/*
* There are no more records in the result set. Copy
* whatever we got to userspace and break out.
*/
done = true;
break;
case -ECANCELED:
/*
* The internal memory buffer is full. Copy whatever
* records we got to userspace and go again if we have
* not yet filled the userspace buffer.
*/
error = 0;
break;
default:
goto out_free;
}
head.fmh_entries += xhead.fmh_entries;
head.fmh_oflags = xhead.fmh_oflags;
/*
* If the caller wanted a record count or there aren't any
* new records to return, we're done.
*/
if (head.fmh_count == 0 || xhead.fmh_entries == 0)
break;
/* Copy all the records we got out to userspace. */
if (copy_to_user(user_recs, recs,
xhead.fmh_entries * sizeof(struct fsmap))) {
error = -EFAULT;
goto out_free;
}
/* Remember the last record flags we copied to userspace. */
last_rec = &recs[xhead.fmh_entries - 1];
last_flags = last_rec->fmr_flags;
/* Set up the low key for the next iteration. */
xfs_fsmap_to_internal(&xhead.fmh_keys[0], last_rec);
trace_xfs_getfsmap_low_key(ip->i_mount, &xhead.fmh_keys[0]);
} while (!done && head.fmh_entries < head.fmh_count);
/*
* If there are no more records in the query result set and we're not
* in counting mode, mark the last record returned with the LAST flag.
*/
if (done && head.fmh_count > 0 && head.fmh_entries > 0) {
struct fsmap __user *user_rec;
last_flags |= FMR_OF_LAST;
user_rec = &arg->fmh_recs[head.fmh_entries - 1];
if (copy_to_user(&user_rec->fmr_flags, &last_flags,
sizeof(last_flags))) {
error = -EFAULT;
goto out_free;
}
}
/* copy back header */
if (copy_to_user(arg, &head, sizeof(struct fsmap_head))) {
error = -EFAULT;
goto out_free;
}
out_free:
kvfree(recs);
return error;
}
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