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linux/fs/xfs/libxfs/xfs_bmap.h
Christoph Hellwig 0c1d9e4a61 xfs: simplify validation of the unwritten extent bit 
XFS only supports the unwritten extent bit in the data fork, and only if
the file system has a version 5 superblock or the unwritten extent
feature bit.

We currently have two routines that validate the invariant:
xfs_check_nostate_extents which return -EFSCORRUPTED when it's not met,
and xfs_validate_extent that triggers and assert in debug build.

Both of them iterate over all extents of an inode fork when called,
which isn't very efficient.

This patch instead adds a new helper that verifies the invariant one
extent at a time, and calls it from the places where we iterate over
all extents to converted them from or two the in-memory format.  The
callers then return -EFSCORRUPTED when reading invalid extents from
disk, or trigger an assert when writing them to disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-04-25 09:40:41 -07:00

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/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* All Rights Reserved.
*
* 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.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_BMAP_H__
#define __XFS_BMAP_H__
struct getbmap;
struct xfs_bmbt_irec;
struct xfs_ifork;
struct xfs_inode;
struct xfs_mount;
struct xfs_trans;
extern kmem_zone_t *xfs_bmap_free_item_zone;
/*
* Argument structure for xfs_bmap_alloc.
*/
struct xfs_bmalloca {
xfs_fsblock_t *firstblock; /* i/o first block allocated */
struct xfs_defer_ops *dfops; /* bmap freelist */
struct xfs_trans *tp; /* transaction pointer */
struct xfs_inode *ip; /* incore inode pointer */
struct xfs_bmbt_irec prev; /* extent before the new one */
struct xfs_bmbt_irec got; /* extent after, or delayed */
xfs_fileoff_t offset; /* offset in file filling in */
xfs_extlen_t length; /* i/o length asked/allocated */
xfs_fsblock_t blkno; /* starting block of new extent */
struct xfs_btree_cur *cur; /* btree cursor */
xfs_extnum_t idx; /* current extent index */
int nallocs;/* number of extents alloc'd */
int logflags;/* flags for transaction logging */
xfs_extlen_t total; /* total blocks needed for xaction */
xfs_extlen_t minlen; /* minimum allocation size (blocks) */
xfs_extlen_t minleft; /* amount must be left after alloc */
bool eof; /* set if allocating past last extent */
bool wasdel; /* replacing a delayed allocation */
bool aeof; /* allocated space at eof */
bool conv; /* overwriting unwritten extents */
int datatype;/* data type being allocated */
int flags;
};
/*
* List of extents to be free "later".
* The list is kept sorted on xbf_startblock.
*/
struct xfs_extent_free_item
{
xfs_fsblock_t xefi_startblock;/* starting fs block number */
xfs_extlen_t xefi_blockcount;/* number of blocks in extent */
struct list_head xefi_list;
struct xfs_owner_info xefi_oinfo; /* extent owner */
};
#define XFS_BMAP_MAX_NMAP 4
/*
* Flags for xfs_bmapi_*
*/
#define XFS_BMAPI_ENTIRE 0x001 /* return entire extent, not trimmed */
#define XFS_BMAPI_METADATA 0x002 /* mapping metadata not user data */
#define XFS_BMAPI_ATTRFORK 0x004 /* use attribute fork not data */
#define XFS_BMAPI_PREALLOC 0x008 /* preallocation op: unwritten space */
#define XFS_BMAPI_IGSTATE 0x010 /* Ignore state - */
/* combine contig. space */
#define XFS_BMAPI_CONTIG 0x020 /* must allocate only one extent */
/*
* unwritten extent conversion - this needs write cache flushing and no additional
* allocation alignments. When specified with XFS_BMAPI_PREALLOC it converts
* from written to unwritten, otherwise convert from unwritten to written.
*/
#define XFS_BMAPI_CONVERT 0x040
/*
* allocate zeroed extents - this requires all newly allocated user data extents
* to be initialised to zero. It will be ignored if XFS_BMAPI_METADATA is set.
* Use in conjunction with XFS_BMAPI_CONVERT to convert unwritten extents found
* during the allocation range to zeroed written extents.
*/
#define XFS_BMAPI_ZERO 0x080
/*
* Map the inode offset to the block given in ap->firstblock. Primarily
* used for reflink. The range must be in a hole, and this flag cannot be
* turned on with PREALLOC or CONVERT, and cannot be used on the attr fork.
*
* For bunmapi, this flag unmaps the range without adjusting quota, reducing
* refcount, or freeing the blocks.
*/
#define XFS_BMAPI_REMAP 0x100
/* Map something in the CoW fork. */
#define XFS_BMAPI_COWFORK 0x200
/* Only convert delalloc space, don't allocate entirely new extents */
#define XFS_BMAPI_DELALLOC 0x400
#define XFS_BMAPI_FLAGS \
{ XFS_BMAPI_ENTIRE, "ENTIRE" }, \
{ XFS_BMAPI_METADATA, "METADATA" }, \
{ XFS_BMAPI_ATTRFORK, "ATTRFORK" }, \
{ XFS_BMAPI_PREALLOC, "PREALLOC" }, \
{ XFS_BMAPI_IGSTATE, "IGSTATE" }, \
{ XFS_BMAPI_CONTIG, "CONTIG" }, \
{ XFS_BMAPI_CONVERT, "CONVERT" }, \
{ XFS_BMAPI_ZERO, "ZERO" }, \
{ XFS_BMAPI_REMAP, "REMAP" }, \
{ XFS_BMAPI_COWFORK, "COWFORK" }, \
{ XFS_BMAPI_DELALLOC, "DELALLOC" }
static inline int xfs_bmapi_aflag(int w)
{
return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK :
(w == XFS_COW_FORK ? XFS_BMAPI_COWFORK : 0));
}
static inline int xfs_bmapi_whichfork(int bmapi_flags)
{
if (bmapi_flags & XFS_BMAPI_COWFORK)
return XFS_COW_FORK;
else if (bmapi_flags & XFS_BMAPI_ATTRFORK)
return XFS_ATTR_FORK;
return XFS_DATA_FORK;
}
/*
* Special values for xfs_bmbt_irec_t br_startblock field.
*/
#define DELAYSTARTBLOCK ((xfs_fsblock_t)-1LL)
#define HOLESTARTBLOCK ((xfs_fsblock_t)-2LL)
/*
* Flags for xfs_bmap_add_extent*.
*/
#define BMAP_LEFT_CONTIG (1 << 0)
#define BMAP_RIGHT_CONTIG (1 << 1)
#define BMAP_LEFT_FILLING (1 << 2)
#define BMAP_RIGHT_FILLING (1 << 3)
#define BMAP_LEFT_DELAY (1 << 4)
#define BMAP_RIGHT_DELAY (1 << 5)
#define BMAP_LEFT_VALID (1 << 6)
#define BMAP_RIGHT_VALID (1 << 7)
#define BMAP_ATTRFORK (1 << 8)
#define BMAP_COWFORK (1 << 9)
#define XFS_BMAP_EXT_FLAGS \
{ BMAP_LEFT_CONTIG, "LC" }, \
{ BMAP_RIGHT_CONTIG, "RC" }, \
{ BMAP_LEFT_FILLING, "LF" }, \
{ BMAP_RIGHT_FILLING, "RF" }, \
{ BMAP_ATTRFORK, "ATTR" }, \
{ BMAP_COWFORK, "COW" }
/*
* Return true if the extent is a real, allocated extent, or false if it is a
* delayed allocation, and unwritten extent or a hole.
*/
static inline bool xfs_bmap_is_real_extent(struct xfs_bmbt_irec *irec)
{
return irec->br_state != XFS_EXT_UNWRITTEN &&
irec->br_startblock != HOLESTARTBLOCK &&
irec->br_startblock != DELAYSTARTBLOCK &&
!isnullstartblock(irec->br_startblock);
}
/*
* This macro is used to determine how many extents will be shifted
* in one write transaction. We could require two splits,
* an extent move on the first and an extent merge on the second,
* So it is proper that one extent is shifted inside write transaction
* at a time.
*/
#define XFS_BMAP_MAX_SHIFT_EXTENTS 1
enum shift_direction {
SHIFT_LEFT = 0,
SHIFT_RIGHT,
};
#ifdef DEBUG
void xfs_bmap_trace_exlist(struct xfs_inode *ip, xfs_extnum_t cnt,
int whichfork, unsigned long caller_ip);
#define XFS_BMAP_TRACE_EXLIST(ip,c,w) \
xfs_bmap_trace_exlist(ip,c,w, _THIS_IP_)
#else
#define XFS_BMAP_TRACE_EXLIST(ip,c,w)
#endif
void xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
xfs_filblks_t len);
int xfs_bmap_add_attrfork(struct xfs_inode *ip, int size, int rsvd);
void xfs_bmap_local_to_extents_empty(struct xfs_inode *ip, int whichfork);
void xfs_bmap_add_free(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
xfs_fsblock_t bno, xfs_filblks_t len,
struct xfs_owner_info *oinfo);
void xfs_bmap_compute_maxlevels(struct xfs_mount *mp, int whichfork);
int xfs_bmap_first_unused(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_extlen_t len, xfs_fileoff_t *unused, int whichfork);
int xfs_bmap_last_before(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t *last_block, int whichfork);
int xfs_bmap_last_offset(struct xfs_inode *ip, xfs_fileoff_t *unused,
int whichfork);
int xfs_bmap_one_block(struct xfs_inode *ip, int whichfork);
int xfs_bmap_read_extents(struct xfs_trans *tp, struct xfs_inode *ip,
int whichfork);
int xfs_bmapi_read(struct xfs_inode *ip, xfs_fileoff_t bno,
xfs_filblks_t len, struct xfs_bmbt_irec *mval,
int *nmap, int flags);
int xfs_bmapi_write(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t bno, xfs_filblks_t len, int flags,
xfs_fsblock_t *firstblock, xfs_extlen_t total,
struct xfs_bmbt_irec *mval, int *nmap,
struct xfs_defer_ops *dfops);
int __xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t bno, xfs_filblks_t *rlen, int flags,
xfs_extnum_t nexts, xfs_fsblock_t *firstblock,
struct xfs_defer_ops *dfops);
int xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t bno, xfs_filblks_t len, int flags,
xfs_extnum_t nexts, xfs_fsblock_t *firstblock,
struct xfs_defer_ops *dfops, int *done);
int xfs_bmap_del_extent_delay(struct xfs_inode *ip, int whichfork,
xfs_extnum_t *idx, struct xfs_bmbt_irec *got,
struct xfs_bmbt_irec *del);
void xfs_bmap_del_extent_cow(struct xfs_inode *ip, xfs_extnum_t *idx,
struct xfs_bmbt_irec *got, struct xfs_bmbt_irec *del);
uint xfs_default_attroffset(struct xfs_inode *ip);
int xfs_bmap_shift_extents(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t *next_fsb, xfs_fileoff_t offset_shift_fsb,
int *done, xfs_fileoff_t stop_fsb, xfs_fsblock_t *firstblock,
struct xfs_defer_ops *dfops, enum shift_direction direction,
int num_exts);
int xfs_bmap_split_extent(struct xfs_inode *ip, xfs_fileoff_t split_offset);
int xfs_bmapi_reserve_delalloc(struct xfs_inode *ip, int whichfork,
xfs_fileoff_t off, xfs_filblks_t len, xfs_filblks_t prealloc,
struct xfs_bmbt_irec *got, xfs_extnum_t *lastx, int eof);
enum xfs_bmap_intent_type {
XFS_BMAP_MAP = 1,
XFS_BMAP_UNMAP,
};
struct xfs_bmap_intent {
struct list_head bi_list;
enum xfs_bmap_intent_type bi_type;
struct xfs_inode *bi_owner;
int bi_whichfork;
struct xfs_bmbt_irec bi_bmap;
};
int xfs_bmap_finish_one(struct xfs_trans *tp, struct xfs_defer_ops *dfops,
struct xfs_inode *ip, enum xfs_bmap_intent_type type,
int whichfork, xfs_fileoff_t startoff, xfs_fsblock_t startblock,
xfs_filblks_t blockcount, xfs_exntst_t state);
int xfs_bmap_map_extent(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
struct xfs_inode *ip, struct xfs_bmbt_irec *imap);
int xfs_bmap_unmap_extent(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
struct xfs_inode *ip, struct xfs_bmbt_irec *imap);
#endif /* __XFS_BMAP_H__ */
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