linux/fs/xfs/xfs_fsmap.c

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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_rtalloc.h"
#include "xfs_ag.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. */
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 = 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,
const 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:
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_perag *pag; /* AG 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;
u64 missing_owner; /* owner of holes */
u32 dev; /* device id */
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
/*
* 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);
};
/* 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_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_has_reflink(mp))
return 0;
/* rt files will have no perag structure */
if (!info->pag)
return 0;
/* Are there any shared blocks here? */
flen = 0;
cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp, info->pag);
error = xfs_refcount_find_shared(cur, rec->rm_startblock,
rec->rm_blockcount, &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);
}
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
static inline bool
xfs_getfsmap_rec_before_start(
struct xfs_getfsmap_info *info,
const struct xfs_rmap_irec *rec,
xfs_daddr_t rec_daddr)
{
if (info->low_daddr != -1ULL)
return rec_daddr < info->low_daddr;
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
if (info->low.rm_blockcount)
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_rmap_irec *rec,
xfs_daddr_t rec_daddr,
xfs_daddr_t len_daddr)
{
struct xfs_fsmap fmr;
struct xfs_mount *mp = tp->t_mountp;
bool shared;
int error;
if (fatal_signal_pending(current))
return -EINTR;
if (len_daddr == 0)
len_daddr = XFS_FSB_TO_BB(mp, rec->rm_blockcount);
/*
* Filter out records that start before our startpoint, if the
* caller requested that.
*/
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
if (xfs_getfsmap_rec_before_start(info, rec, rec_daddr)) {
rec_daddr += len_daddr;
if (info->next_daddr < rec_daddr)
info->next_daddr = rec_daddr;
return 0;
}
/* Are we just counting mappings? */
if (info->head->fmh_count == 0) {
if (info->head->fmh_entries == UINT_MAX)
return -ECANCELED;
if (rec_daddr > info->next_daddr)
info->head->fmh_entries++;
if (info->last)
return 0;
info->head->fmh_entries++;
rec_daddr += len_daddr;
if (info->next_daddr < rec_daddr)
info->next_daddr = rec_daddr;
return 0;
}
/*
* 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 -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 = rec_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->pag ? info->pag->pag_agno : NULLAGNUMBER, 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 = len_daddr;
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;
}
xfs_getfsmap_format(mp, &fmr, info);
out:
rec_daddr += len_daddr;
if (info->next_daddr < rec_daddr)
info->next_daddr = rec_daddr;
return 0;
}
/* Transform a rmapbt irec into a fsmap */
STATIC int
xfs_getfsmap_datadev_helper(
struct xfs_btree_cur *cur,
const 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_ag.pag->pag_agno, rec->rm_startblock);
rec_daddr = XFS_FSB_TO_DADDR(mp, fsb);
return xfs_getfsmap_helper(cur->bc_tp, info, rec, rec_daddr, 0);
}
/* 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_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_ag.pag->pag_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, 0);
}
/* 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;
}
/* 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_mount *mp = tp->t_mountp;
struct xfs_rmap_irec rmap;
xfs_daddr_t rec_daddr, len_daddr;
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_key_linear(mp, info->dev, start_fsb);
trace_xfs_fsmap_high_key_linear(mp, info->dev, end_fsb);
if (start_fsb > 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;
rec_daddr = XFS_FSB_TO_BB(mp, rmap.rm_startblock);
len_daddr = XFS_FSB_TO_BB(mp, rmap.rm_blockcount);
return xfs_getfsmap_helper(tp, info, &rmap, rec_daddr, len_daddr);
}
#ifdef CONFIG_XFS_RT
/* Transform a rtbitmap "record" into a fsmap */
STATIC int
xfs_getfsmap_rtdev_rtbitmap_helper(
struct xfs_mount *mp,
struct xfs_trans *tp,
const struct xfs_rtalloc_rec *rec,
void *priv)
{
struct xfs_getfsmap_info *info = priv;
struct xfs_rmap_irec irec;
xfs_rtblock_t rtbno;
xfs_daddr_t rec_daddr, len_daddr;
rtbno = rec->ar_startext * mp->m_sb.sb_rextsize;
rec_daddr = XFS_FSB_TO_BB(mp, rtbno);
irec.rm_startblock = rtbno;
rtbno = rec->ar_extcount * mp->m_sb.sb_rextsize;
len_daddr = XFS_FSB_TO_BB(mp, rtbno);
irec.rm_blockcount = rtbno;
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, len_daddr);
}
/* 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_rtalloc_rec alow = { 0 };
struct xfs_rtalloc_rec ahigh = { 0 };
struct xfs_mount *mp = tp->t_mountp;
xfs_rtblock_t start_rtb;
xfs_rtblock_t end_rtb;
uint64_t eofs;
int error;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rextents * mp->m_sb.sb_rextsize);
if (keys[0].fmr_physical >= eofs)
return 0;
start_rtb = XFS_BB_TO_FSBT(mp,
keys[0].fmr_physical + keys[0].fmr_length);
end_rtb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
/* 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_rtb);
if (info->low_daddr >= eofs)
return 0;
}
trace_xfs_fsmap_low_key_linear(mp, info->dev, start_rtb);
trace_xfs_fsmap_high_key_linear(mp, info->dev, end_rtb);
xfs_ilock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
/*
* Set up query parameters to return free rtextents covering the range
* we want.
*/
alow.ar_startext = start_rtb;
ahigh.ar_startext = end_rtb;
do_div(alow.ar_startext, mp->m_sb.sb_rextsize);
if (do_div(ahigh.ar_startext, mp->m_sb.sb_rextsize))
ahigh.ar_startext++;
error = xfs_rtalloc_query_range(mp, tp, &alow, &ahigh,
xfs_getfsmap_rtdev_rtbitmap_helper, info);
if (error)
goto err;
/*
* Report any gaps at the end of the rtbitmap by simulating a null
* rmap starting at the block after the end of the query range.
*/
info->last = true;
ahigh.ar_startext = min(mp->m_sb.sb_rextents, ahigh.ar_startext);
error = xfs_getfsmap_rtdev_rtbitmap_helper(mp, tp, &ahigh, info);
if (error)
goto err;
err:
xfs_iunlock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
return error;
}
#endif /* CONFIG_XFS_RT */
/* 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;
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;
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_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;
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
info->low.rm_blockcount = XFS_BB_TO_FSBT(mp, keys[0].fmr_length);
xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
/* Adjust the low key if we are continuing from where we left off. */
if (info->low.rm_blockcount == 0) {
/* empty */
} else if (XFS_RMAP_NON_INODE_OWNER(info->low.rm_owner) ||
(info->low.rm_flags & (XFS_RMAP_ATTR_FORK |
XFS_RMAP_BMBT_BLOCK |
XFS_RMAP_UNWRITTEN))) {
info->low.rm_startblock += info->low.rm_blockcount;
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 {
info->low.rm_offset += info->low.rm_blockcount;
}
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);
for_each_perag_range(mp, start_ag, end_ag, pag) {
/*
* Set the AG high key from the fsmap high key if this
* is the last AG that we're querying.
*/
info->pag = pag;
if (pag->pag_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)
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_key(mp, info->dev, pag->pag_agno,
&info->low);
trace_xfs_fsmap_high_key(mp, info->dev, pag->pag_agno,
&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.
*/
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
if (pag->pag_agno == 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->pag_agno == end_ag) {
info->last = true;
error = query_fn(tp, info, &bt_cur, priv);
if (error)
break;
}
info->pag = 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->pag) {
xfs: active perag reference counting We need to be able to dynamically remove instantiated AGs from memory safely, either for shrinking the filesystem or paging AG state in and out of memory (e.g. supporting millions of AGs). This means we need to be able to safely exclude operations from accessing perags while dynamic removal is in progress. To do this, introduce the concept of active and passive references. Active references are required for high level operations that make use of an AG for a given operation (e.g. allocation) and pin the perag in memory for the duration of the operation that is operating on the perag (e.g. transaction scope). This means we can fail to get an active reference to an AG, hence callers of the new active reference API must be able to handle lookup failure gracefully. Passive references are used in low level code, where we might need to access the perag structure for the purposes of completing high level operations. For example, buffers need to use passive references because: - we need to be able to do metadata IO during operations like grow and shrink transactions where high level active references to the AG have already been blocked - buffers need to pin the perag until they are reclaimed from memory, something that high level code has no direct control over. - unused cached buffers should not prevent a shrink from being started. Hence we have active references that will form exclusion barriers for operations to be performed on an AG, and passive references that will prevent reclaim of the perag until all objects with passive references have been reclaimed themselves. This patch introduce xfs_perag_grab()/xfs_perag_rele() as the API for active AG reference functionality. We also need to convert the for_each_perag*() iterators to use active references, which will start the process of converting high level code over to using active references. Conversion of non-iterator based code to active references will be done in followup patches. Note that the implementation using reference counting is really just a development vehicle for the API to ensure we don't have any leaks in the callers. Once we need to remove perag structures from memory dyanmically, we will need a much more robust per-ag state transition mechanism for preventing new references from being taken while we wait for existing references to drain before removal from memory can occur.... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-02-12 22:14:42 +00:00
xfs_perag_rele(info->pag);
info->pag = NULL;
} else if (pag) {
/* loop termination case */
xfs: active perag reference counting We need to be able to dynamically remove instantiated AGs from memory safely, either for shrinking the filesystem or paging AG state in and out of memory (e.g. supporting millions of AGs). This means we need to be able to safely exclude operations from accessing perags while dynamic removal is in progress. To do this, introduce the concept of active and passive references. Active references are required for high level operations that make use of an AG for a given operation (e.g. allocation) and pin the perag in memory for the duration of the operation that is operating on the perag (e.g. transaction scope). This means we can fail to get an active reference to an AG, hence callers of the new active reference API must be able to handle lookup failure gracefully. Passive references are used in low level code, where we might need to access the perag structure for the purposes of completing high level operations. For example, buffers need to use passive references because: - we need to be able to do metadata IO during operations like grow and shrink transactions where high level active references to the AG have already been blocked - buffers need to pin the perag until they are reclaimed from memory, something that high level code has no direct control over. - unused cached buffers should not prevent a shrink from being started. Hence we have active references that will form exclusion barriers for operations to be performed on an AG, and passive references that will prevent reclaim of the perag until all objects with passive references have been reclaimed themselves. This patch introduce xfs_perag_grab()/xfs_perag_rele() as the API for active AG reference functionality. We also need to convert the for_each_perag*() iterators to use active references, which will start the process of converting high level code over to using active references. Conversion of non-iterator based code to active references will be done in followup patches. Note that the implementation using reference counting is really just a development vehicle for the API to ensure we don't have any leaks in the callers. Once we need to remove perag structures from memory dyanmically, we will need a much more robust per-ag state transition mechanism for preventing new references from being taken while we wait for existing references to drain before removal from memory can occur.... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-02-12 22:14:42 +00:00
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_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->pag);
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,
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_allocbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
info->pag, 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,
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]);
}
/* 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.
*/
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 = { 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;
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].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;
}
#ifdef CONFIG_XFS_RT
if (mp->m_rtdev_targp) {
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
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
* 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;
info.fsmap_recs = fsmap_recs;
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));
/*
* 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.pag = NULL;
info.low_daddr = -1ULL;
xfs: fix interval filtering in multi-step fsmap queries I noticed a bug in ranged GETFSMAP queries: # xfs_io -c 'fsmap -vvvv' /opt EXT: DEV BLOCK-RANGE OWNER FILE-OFFSET AG AG-OFFSET TOTAL 0: 8:80 [0..7]: static fs metadata 0 (0..7) 8 <snip> 9: 8:80 [192..223]: 137 0..31 0 (192..223) 32 # xfs_io -c 'fsmap -vvvv -d 208 208' /opt # That's not right -- we asked what block maps block 208, and we should've received a mapping for inode 137 offset 16. Instead, we get nothing. The root cause of this problem is a mis-interaction between the fsmap code and how btree ranged queries work. xfs_btree_query_range returns any btree record that overlaps with the query interval, even if the record starts before or ends after the interval. Similarly, GETFSMAP is supposed to return a recordset containing all records that overlap the range queried. However, it's possible that the recordset is larger than the buffer that the caller provided to convey mappings to userspace. In /that/ case, userspace is supposed to copy the last record returned to fmh_keys[0] and call GETFSMAP again. In this case, we do not want to return mappings that we have already supplied to the caller. The call to xfs_btree_query_range is the same, but now we ignore any records that start before fmh_keys[0]. Unfortunately, we didn't implement the filtering predicate correctly. The predicate should only be called when we're calling back for more records. Accomplish this by setting info->low.rm_blockcount to a nonzero value and ensuring that it is cleared as necessary. As a result, we no longer want to adjust dkeys[0] in the main setup function because that's confusing. This patch doesn't touch the logdev/rtbitmap backends because they have bigger problems that will be addressed by subsequent patches. Found via xfs/556 with parent pointers enabled. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-06-30 00:39:43 +00:00
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;
}