Merge branch 'akpm'

[linux-2.6/next.git] / fs / xfs / xfs_bmap.h

/*
 * 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_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_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__ */