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linux/fs/xfs/xfs_fsmap.c
Darrick J. Wong ea9a46e1c4 xfs: only return detailed fsmap info if the caller has CAP_SYS_ADMIN 
There were a number of handwaving complaints that one could "possibly"
use inode numbers and extent maps to fingerprint a filesystem hosting
multiple containers and somehow use the information to guess at the
contents of other containers and attack them.  Despite the total lack of
any demonstration that this is actually possible, it's easier to
restrict access now and broaden it later, so use the rmapbt fsmap
backends only if the caller has CAP_SYS_ADMIN.  Unprivileged users will
just have to make do with only getting the free space and static
metadata placement information.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
2017-05-16 12:26:16 -07:00

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/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*
* 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"
#include "xfs_alloc_btree.h"
#include "xfs_rtalloc.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_rmap_irec *dest,
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 = 0;
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_rmap(
struct xfs_fsmap *dest,
struct xfs_rmap_irec *src)
{
dest->fmr_flags = 0;
if (!XFS_RMAP_NON_INODE_OWNER(src->rm_owner)) {
dest->fmr_owner = src->rm_owner;
return 0;
}
dest->fmr_flags |= FMR_OF_SPECIAL_OWNER;
switch (src->rm_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:
return -EFSCORRUPTED;
}
return 0;
}
/* getfsmap query state */
struct xfs_getfsmap_info {
struct xfs_fsmap_head *head;
xfs_fsmap_format_t formatter; /* formatting fn */
void *format_arg; /* format buffer */
struct xfs_buf *agf_bp; /* AGF, for refcount queries */
xfs_daddr_t next_daddr; /* next daddr we expect */
u64 missing_owner; /* owner of holes */
u32 dev; /* device id */
xfs_agnumber_t agno; /* AG number, if applicable */
struct xfs_rmap_irec low; /* low rmap key */
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,
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;
}
/* 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;
bool shared;
int error;
if (fatal_signal_pending(current))
return -EINTR;
/*
* Filter out records that start before our startpoint, if the
* caller requested that.
*/
if (xfs_rmap_compare(rec, &info->low) < 0) {
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;
}
/* 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 a gap. Report the gap as being owned by
* whatever the caller specified is the missing owner.
*/
if (rec_daddr > info->next_daddr) {
if (info->head->fmh_entries >= info->head->fmh_count)
return XFS_BTREE_QUERY_RANGE_ABORT;
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);
fmr.fmr_device = info->dev;
fmr.fmr_physical = rec_daddr;
error = xfs_fsmap_owner_from_rmap(&fmr, rec);
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 rtbitmap "record" into a fsmap */
STATIC int
xfs_getfsmap_rtdev_rtbitmap_helper(
struct xfs_trans *tp,
struct xfs_rtalloc_rec *rec,
void *priv)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_getfsmap_info *info = priv;
struct xfs_rmap_irec irec;
xfs_daddr_t rec_daddr;
rec_daddr = XFS_FSB_TO_BB(mp, rec->ar_startblock);
irec.rm_startblock = rec->ar_startblock;
irec.rm_blockcount = rec->ar_blockcount;
irec.rm_owner = XFS_RMAP_OWN_NULL; /* "free" */
irec.rm_offset = 0;
irec.rm_flags = 0;
return xfs_getfsmap_helper(tp, info, &irec, rec_daddr);
}
/* Transform a bnobt irec into a fsmap */
STATIC int
xfs_getfsmap_datadev_bnobt_helper(
struct xfs_btree_cur *cur,
struct xfs_alloc_rec_incore *rec,
void *priv)
{
struct xfs_mount *mp = cur->bc_mp;
struct xfs_getfsmap_info *info = priv;
struct xfs_rmap_irec irec;
xfs_daddr_t rec_daddr;
rec_daddr = XFS_AGB_TO_DADDR(mp, cur->bc_private.a.agno,
rec->ar_startblock);
irec.rm_startblock = rec->ar_startblock;
irec.rm_blockcount = rec->ar_blockcount;
irec.rm_owner = XFS_RMAP_OWN_NULL; /* "free" */
irec.rm_offset = 0;
irec.rm_flags = 0;
return xfs_getfsmap_helper(cur->bc_tp, info, &irec, 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_rmap_irec rmap;
int error;
/* Set up search keys */
info->low.rm_startblock = XFS_BB_TO_FSBT(mp, keys[0].fmr_physical);
info->low.rm_offset = XFS_BB_TO_FSBT(mp, keys[0].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->low, keys);
if (error)
return error;
info->low.rm_blockcount = 0;
xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
error = xfs_fsmap_owner_to_rmap(&info->high, keys + 1);
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);
trace_xfs_fsmap_high_key(mp, info->dev, info->agno, &info->high);
if (keys[0].fmr_physical > 0)
return 0;
/* Fabricate an rmap entry for the external log device. */
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;
return xfs_getfsmap_helper(tp, info, &rmap, 0);
}
/* Execute a getfsmap query against the realtime device. */
STATIC int
__xfs_getfsmap_rtdev(
struct xfs_trans *tp,
struct xfs_fsmap *keys,
int (*query_fn)(struct xfs_trans *,
struct xfs_getfsmap_info *),
struct xfs_getfsmap_info *info)
{
struct xfs_mount *mp = tp->t_mountp;
xfs_fsblock_t start_fsb;
xfs_fsblock_t end_fsb;
xfs_daddr_t eofs;
int error = 0;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
if (keys[1].fmr_physical >= eofs)
keys[1].fmr_physical = eofs - 1;
start_fsb = XFS_BB_TO_FSBT(mp, keys[0].fmr_physical);
end_fsb = XFS_BB_TO_FSB(mp, keys[1].fmr_physical);
/* Set up search keys */
info->low.rm_startblock = start_fsb;
error = xfs_fsmap_owner_to_rmap(&info->low, &keys[0]);
if (error)
return error;
info->low.rm_offset = XFS_BB_TO_FSBT(mp, keys[0].fmr_offset);
info->low.rm_blockcount = 0;
xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
info->high.rm_startblock = end_fsb;
error = xfs_fsmap_owner_to_rmap(&info->high, &keys[1]);
if (error)
return error;
info->high.rm_offset = XFS_BB_TO_FSBT(mp, keys[1].fmr_offset);
info->high.rm_blockcount = 0;
xfs_getfsmap_set_irec_flags(&info->high, &keys[1]);
trace_xfs_fsmap_low_key(mp, info->dev, info->agno, &info->low);
trace_xfs_fsmap_high_key(mp, info->dev, info->agno, &info->high);
return query_fn(tp, info);
}
/* Actually query the realtime bitmap. */
STATIC int
xfs_getfsmap_rtdev_rtbitmap_query(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info)
{
struct xfs_rtalloc_rec alow;
struct xfs_rtalloc_rec ahigh;
int error;
xfs_ilock(tp->t_mountp->m_rbmip, XFS_ILOCK_SHARED);
alow.ar_startblock = info->low.rm_startblock;
ahigh.ar_startblock = info->high.rm_startblock;
error = xfs_rtalloc_query_range(tp, &alow, &ahigh,
xfs_getfsmap_rtdev_rtbitmap_helper, info);
if (error)
goto err;
/* Report any gaps at the end of the rtbitmap */
info->last = true;
error = xfs_getfsmap_rtdev_rtbitmap_helper(tp, &ahigh, info);
if (error)
goto err;
err:
xfs_iunlock(tp->t_mountp->m_rbmip, XFS_ILOCK_SHARED);
return error;
}
/* Execute a getfsmap query against the realtime device rtbitmap. */
STATIC int
xfs_getfsmap_rtdev_rtbitmap(
struct xfs_trans *tp,
struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
return __xfs_getfsmap_rtdev(tp, keys, xfs_getfsmap_rtdev_rtbitmap_query,
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,
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_btree_cur *bt_cur = NULL;
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;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
if (keys[1].fmr_physical >= eofs)
keys[1].fmr_physical = eofs - 1;
start_fsb = XFS_DADDR_TO_FSB(mp, keys[0].fmr_physical);
end_fsb = XFS_DADDR_TO_FSB(mp, 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_startblock = XFS_FSB_TO_AGBNO(mp, start_fsb);
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 = 0;
xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
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);
/* Query each AG */
for (info->agno = start_ag; info->agno <= end_ag; info->agno++) {
/*
* Set the AG high key from the fsmap high key if this
* is the last AG that we're querying.
*/
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,
keys[1].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->high, &keys[1]);
if (error)
goto err;
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(mp, tp, info->agno, 0,
&info->agf_bp);
if (error)
goto err;
trace_xfs_fsmap_low_key(mp, info->dev, info->agno, &info->low);
trace_xfs_fsmap_high_key(mp, info->dev, info->agno,
&info->high);
error = query_fn(tp, info, &bt_cur, priv);
if (error)
goto err;
/*
* Set the AG low key to the start of the AG prior to
* moving on to 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;
}
}
/* Report any gap at the end of the AG */
info->last = true;
error = query_fn(tp, info, &bt_cur, priv);
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) {
xfs_trans_brelse(tp, info->agf_bp);
info->agf_bp = NULL;
}
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_datadev_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,
info->agno);
return xfs_rmap_query_range(*curpp, &info->low, &info->high,
xfs_getfsmap_datadev_helper, info);
}
/* Execute a getfsmap query against the regular data device rmapbt. */
STATIC int
xfs_getfsmap_datadev_rmapbt(
struct xfs_trans *tp,
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_allocbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
info->agno, XFS_BTNUM_BNO);
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,
struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_alloc_rec_incore akeys[2];
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
return __xfs_getfsmap_datadev(tp, keys, info,
xfs_getfsmap_datadev_bnobt_query, &akeys[0]);
}
/* 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_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
/*
* 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.
*
* 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.
*/
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 dkeys[2]; /* per-dev keys */
struct xfs_getfsmap_dev handlers[XFS_GETFSMAP_DEVS];
struct xfs_getfsmap_info info = { NULL };
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;
use_rmap = capable(CAP_SYS_ADMIN) &&
xfs_sb_version_hasrmapbt(&mp->m_sb);
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);
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].dev = new_encode_dev(mp->m_logdev_targp->bt_dev);
handlers[1].fn = xfs_getfsmap_logdev;
}
if (mp->m_rtdev_targp) {
handlers[2].dev = new_encode_dev(mp->m_rtdev_targp->bt_dev);
handlers[2].fn = xfs_getfsmap_rtdev_rtbitmap;
}
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, bump the file offset to
* continue the search appropriately. For all other low key
* mapping types (attr blocks, metadata), bump the physical
* offset as there can be no other mapping for the same physical
* block range.
*/
dkeys[0] = head->fmh_keys[0];
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;
if (dkeys[0].fmr_offset)
return -EINVAL;
} else
dkeys[0].fmr_offset += dkeys[0].fmr_length;
dkeys[0].fmr_length = 0;
memset(&dkeys[1], 0xFF, sizeof(struct xfs_fsmap));
if (!xfs_getfsmap_check_keys(dkeys, &head->fmh_keys[1]))
return -EINVAL;
info.next_daddr = head->fmh_keys[0].fmr_physical +
head->fmh_keys[0].fmr_length;
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 (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. 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[1].fmr_device)
dkeys[1] = head->fmh_keys[1];
if (handlers[i].dev > head->fmh_keys[0].fmr_device)
memset(&dkeys[0], 0, sizeof(struct xfs_fsmap));
error = xfs_trans_alloc_empty(mp, &tp);
if (error)
break;
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;
info.next_daddr = 0;
}
if (tp)
xfs_trans_cancel(tp);
head->fmh_oflags = FMH_OF_DEV_T;
return error;
}
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