kernel-ark/fs/xfs/xfs_bmap.h
Dave Chinner c726de4409 xfs: fix failed write truncation handling.
Since the move to the new truncate sequence we call xfs_setattr to
truncate down excessively instanciated blocks.  As shown by the testcase
in kernel.org BZ #22452 that doesn't work too well.  Due to the confusion
of the internal inode size, and the VFS inode i_size it zeroes data that
it shouldn't.

But full blown truncate seems like overkill here.  We only instanciate
delayed allocations in the write path, and given that we never released
the iolock we can't have converted them to real allocations yet either.

The only nasty case is pre-existing preallocation which we need to skip.
We already do this for page discard during writeback, so make the delayed
allocation block punching a generic function and call it from the failed
write path as well as xfs_aops_discard_page. The callers are
responsible for ensuring that partial blocks are not truncated away,
and that they hold the ilock.

Based on a fix originally from Christoph Hellwig. This version used
filesystem blocks as the range unit.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-12-01 07:40:19 -06:00

405 lines
13 KiB
C

/*
* 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;
/*
* List of extents to be free "later".
* The list is kept sorted on xbf_startblock.
*/
typedef struct xfs_bmap_free_item
{
xfs_fsblock_t xbfi_startblock;/* starting fs block number */
xfs_extlen_t xbfi_blockcount;/* number of blocks in extent */
struct xfs_bmap_free_item *xbfi_next; /* link to next entry */
} xfs_bmap_free_item_t;
/*
* Header for free extent list.
*
* xbf_low is used by the allocator to activate the lowspace algorithm -
* when free space is running low the extent allocator may choose to
* allocate an extent from an AG without leaving sufficient space for
* a btree split when inserting the new extent. In this case the allocator
* will enable the lowspace algorithm which is supposed to allow further
* allocations (such as btree splits and newroots) to allocate from
* sequential AGs. In order to avoid locking AGs out of order the lowspace
* algorithm will start searching for free space from AG 0. If the correct
* transaction reservations have been made then this algorithm will eventually
* find all the space it needs.
*/
typedef struct xfs_bmap_free
{
xfs_bmap_free_item_t *xbf_first; /* list of to-be-free extents */
int xbf_count; /* count of items on list */
int xbf_low; /* alloc in low mode */
} xfs_bmap_free_t;
#define XFS_BMAP_MAX_NMAP 4
/*
* Flags for xfs_bmapi
*/
#define XFS_BMAPI_WRITE 0x001 /* write operation: allocate space */
#define XFS_BMAPI_DELAY 0x002 /* delayed write operation */
#define XFS_BMAPI_ENTIRE 0x004 /* return entire extent, not trimmed */
#define XFS_BMAPI_METADATA 0x008 /* mapping metadata not user data */
#define XFS_BMAPI_ATTRFORK 0x010 /* use attribute fork not data */
#define XFS_BMAPI_RSVBLOCKS 0x020 /* OK to alloc. reserved data blocks */
#define XFS_BMAPI_PREALLOC 0x040 /* preallocation op: unwritten space */
#define XFS_BMAPI_IGSTATE 0x080 /* Ignore state - */
/* combine contig. space */
#define XFS_BMAPI_CONTIG 0x100 /* 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 0x200
#define XFS_BMAPI_FLAGS \
{ XFS_BMAPI_WRITE, "WRITE" }, \
{ XFS_BMAPI_DELAY, "DELAY" }, \
{ XFS_BMAPI_ENTIRE, "ENTIRE" }, \
{ XFS_BMAPI_METADATA, "METADATA" }, \
{ XFS_BMAPI_ATTRFORK, "ATTRFORK" }, \
{ XFS_BMAPI_RSVBLOCKS, "RSVBLOCKS" }, \
{ XFS_BMAPI_PREALLOC, "PREALLOC" }, \
{ XFS_BMAPI_IGSTATE, "IGSTATE" }, \
{ XFS_BMAPI_CONTIG, "CONTIG" }, \
{ XFS_BMAPI_CONVERT, "CONVERT" }
static inline int xfs_bmapi_aflag(int w)
{
return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0);
}
/*
* Special values for xfs_bmbt_irec_t br_startblock field.
*/
#define DELAYSTARTBLOCK ((xfs_fsblock_t)-1LL)
#define HOLESTARTBLOCK ((xfs_fsblock_t)-2LL)
static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
{
((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \
(flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK);
}
/*
* Argument structure for xfs_bmap_alloc.
*/
typedef struct xfs_bmalloca {
xfs_fsblock_t firstblock; /* i/o first block allocated */
xfs_fsblock_t rval; /* starting block of new extent */
xfs_fileoff_t off; /* offset in file filling in */
struct xfs_trans *tp; /* transaction pointer */
struct xfs_inode *ip; /* incore inode pointer */
struct xfs_bmbt_irec *prevp; /* extent before the new one */
struct xfs_bmbt_irec *gotp; /* extent after, or delayed */
xfs_extlen_t alen; /* i/o length asked/allocated */
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 */
char eof; /* set if allocating past last extent */
char wasdel; /* replacing a delayed allocation */
char userdata;/* set if is user data */
char low; /* low on space, using seq'l ags */
char aeof; /* allocated space at eof */
char conv; /* overwriting unwritten extents */
} xfs_bmalloca_t;
/*
* 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 XFS_BMAP_EXT_FLAGS \
{ BMAP_LEFT_CONTIG, "LC" }, \
{ BMAP_RIGHT_CONTIG, "RC" }, \
{ BMAP_LEFT_FILLING, "LF" }, \
{ BMAP_RIGHT_FILLING, "RF" }, \
{ BMAP_ATTRFORK, "ATTR" }
/*
* Add bmap trace insert entries for all the contents of the extent list.
*
* Quite excessive tracing. Only do this for debug builds.
*/
#if defined(__KERNEL) && defined(DEBUG)
void
xfs_bmap_trace_exlist(
struct xfs_inode *ip, /* incore inode pointer */
xfs_extnum_t cnt, /* count of entries in list */
int whichfork,
unsigned long caller_ip); /* data or attr fork */
#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
/*
* Convert inode from non-attributed to attributed.
* Must not be in a transaction, ip must not be locked.
*/
int /* error code */
xfs_bmap_add_attrfork(
struct xfs_inode *ip, /* incore inode pointer */
int size, /* space needed for new attribute */
int rsvd); /* flag for reserved block allocation */
/*
* Add the extent to the list of extents to be free at transaction end.
* The list is maintained sorted (by block number).
*/
void
xfs_bmap_add_free(
xfs_fsblock_t bno, /* fs block number of extent */
xfs_filblks_t len, /* length of extent */
xfs_bmap_free_t *flist, /* list of extents */
struct xfs_mount *mp); /* mount point structure */
/*
* Routine to clean up the free list data structure when
* an error occurs during a transaction.
*/
void
xfs_bmap_cancel(
xfs_bmap_free_t *flist); /* free list to clean up */
/*
* Compute and fill in the value of the maximum depth of a bmap btree
* in this filesystem. Done once, during mount.
*/
void
xfs_bmap_compute_maxlevels(
struct xfs_mount *mp, /* file system mount structure */
int whichfork); /* data or attr fork */
/*
* Returns the file-relative block number of the first unused block in the file.
* This is the lowest-address hole if the file has holes, else the first block
* past the end of file.
*/
int /* error */
xfs_bmap_first_unused(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
xfs_extlen_t len, /* size of hole to find */
xfs_fileoff_t *unused, /* unused block num */
int whichfork); /* data or attr fork */
/*
* Returns the file-relative block number of the last block + 1 before
* last_block (input value) in the file.
* This is not based on i_size, it is based on the extent list.
* Returns 0 for local files, as they do not have an extent list.
*/
int /* error */
xfs_bmap_last_before(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
xfs_fileoff_t *last_block, /* last block */
int whichfork); /* data or attr fork */
/*
* Returns the file-relative block number of the first block past eof in
* the file. This is not based on i_size, it is based on the extent list.
* Returns 0 for local files, as they do not have an extent list.
*/
int /* error */
xfs_bmap_last_offset(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
xfs_fileoff_t *unused, /* last block num */
int whichfork); /* data or attr fork */
/*
* Returns whether the selected fork of the inode has exactly one
* block or not. For the data fork we check this matches di_size,
* implying the file's range is 0..bsize-1.
*/
int
xfs_bmap_one_block(
struct xfs_inode *ip, /* incore inode */
int whichfork); /* data or attr fork */
/*
* Read in the extents to iu_extents.
* All inode fields are set up by caller, we just traverse the btree
* and copy the records in.
*/
int /* error */
xfs_bmap_read_extents(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
int whichfork); /* data or attr fork */
/*
* Map file blocks to filesystem blocks.
* File range is given by the bno/len pair.
* Adds blocks to file if a write ("flags & XFS_BMAPI_WRITE" set)
* into a hole or past eof.
* Only allocates blocks from a single allocation group,
* to avoid locking problems.
* The returned value in "firstblock" from the first call in a transaction
* must be remembered and presented to subsequent calls in "firstblock".
* An upper bound for the number of blocks to be allocated is supplied to
* the first call in "total"; if no allocation group has that many free
* blocks then the call will fail (return NULLFSBLOCK in "firstblock").
*/
int /* error */
xfs_bmapi(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
xfs_fileoff_t bno, /* starting file offs. mapped */
xfs_filblks_t len, /* length to map in file */
int flags, /* XFS_BMAPI_... */
xfs_fsblock_t *firstblock, /* first allocated block
controls a.g. for allocs */
xfs_extlen_t total, /* total blocks needed */
struct xfs_bmbt_irec *mval, /* output: map values */
int *nmap, /* i/o: mval size/count */
xfs_bmap_free_t *flist); /* i/o: list extents to free */
/*
* Map file blocks to filesystem blocks, simple version.
* One block only, read-only.
* For flags, only the XFS_BMAPI_ATTRFORK flag is examined.
* For the other flag values, the effect is as if XFS_BMAPI_METADATA
* was set and all the others were clear.
*/
int /* error */
xfs_bmapi_single(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
int whichfork, /* data or attr fork */
xfs_fsblock_t *fsb, /* output: mapped block */
xfs_fileoff_t bno); /* starting file offs. mapped */
/*
* Unmap (remove) blocks from a file.
* If nexts is nonzero then the number of extents to remove is limited to
* that value. If not all extents in the block range can be removed then
* *done is set.
*/
int /* error */
xfs_bunmapi(
struct xfs_trans *tp, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
xfs_fileoff_t bno, /* starting offset to unmap */
xfs_filblks_t len, /* length to unmap in file */
int flags, /* XFS_BMAPI_... */
xfs_extnum_t nexts, /* number of extents max */
xfs_fsblock_t *firstblock, /* first allocated block
controls a.g. for allocs */
xfs_bmap_free_t *flist, /* i/o: list extents to free */
int *done); /* set if not done yet */
/*
* Check an extent list, which has just been read, for
* any bit in the extent flag field.
*/
int
xfs_check_nostate_extents(
struct xfs_ifork *ifp,
xfs_extnum_t idx,
xfs_extnum_t num);
uint
xfs_default_attroffset(
struct xfs_inode *ip);
#ifdef __KERNEL__
/*
* Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
* caller. Frees all the extents that need freeing, which must be done
* last due to locking considerations.
*
* Return 1 if the given transaction was committed and a new one allocated,
* and 0 otherwise.
*/
int /* error */
xfs_bmap_finish(
struct xfs_trans **tp, /* transaction pointer addr */
xfs_bmap_free_t *flist, /* i/o: list extents to free */
int *committed); /* xact committed or not */
/* bmap to userspace formatter - copy to user & advance pointer */
typedef int (*xfs_bmap_format_t)(void **, struct getbmapx *, int *);
/*
* Get inode's extents as described in bmv, and format for output.
*/
int /* error code */
xfs_getbmap(
xfs_inode_t *ip,
struct getbmapx *bmv, /* user bmap structure */
xfs_bmap_format_t formatter, /* format to user */
void *arg); /* formatter arg */
/*
* Check if the endoff is outside the last extent. If so the caller will grow
* the allocation to a stripe unit boundary
*/
int
xfs_bmap_eof(
struct xfs_inode *ip,
xfs_fileoff_t endoff,
int whichfork,
int *eof);
/*
* Count fsblocks of the given fork.
*/
int
xfs_bmap_count_blocks(
xfs_trans_t *tp,
struct xfs_inode *ip,
int whichfork,
int *count);
int
xfs_bmap_punch_delalloc_range(
struct xfs_inode *ip,
xfs_fileoff_t start_fsb,
xfs_fileoff_t length);
#endif /* __KERNEL__ */
#endif /* __XFS_BMAP_H__ */