xfs: teach get_bmapx about shared extents and the CoW fork
Teach xfs_getbmapx how to report shared extents and CoW fork contents accurately in the bmap output by querying the refcount btree appropriately. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong
Родитель
cc714660bb
Коммит
f86f403794
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@ -81,14 +81,16 @@ struct getbmapx {
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#define BMV_IF_PREALLOC 0x4 /* rtn status BMV_OF_PREALLOC if req */
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#define BMV_IF_DELALLOC 0x8 /* rtn status BMV_OF_DELALLOC if req */
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#define BMV_IF_NO_HOLES 0x10 /* Do not return holes */
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#define BMV_IF_COWFORK 0x20 /* return CoW fork rather than data */
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#define BMV_IF_VALID \
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(BMV_IF_ATTRFORK|BMV_IF_NO_DMAPI_READ|BMV_IF_PREALLOC| \
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BMV_IF_DELALLOC|BMV_IF_NO_HOLES)
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BMV_IF_DELALLOC|BMV_IF_NO_HOLES|BMV_IF_COWFORK)
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/* bmv_oflags values - returned for each non-header segment */
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#define BMV_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */
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#define BMV_OF_DELALLOC 0x2 /* segment = delayed allocation */
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#define BMV_OF_LAST 0x4 /* segment is the last in the file */
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#define BMV_OF_SHARED 0x8 /* segment shared with another file */
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/*
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* Structure for XFS_IOC_FSSETDM.
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@ -42,6 +42,9 @@
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#include "xfs_icache.h"
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#include "xfs_log.h"
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#include "xfs_rmap_btree.h"
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#include "xfs_iomap.h"
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#include "xfs_reflink.h"
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#include "xfs_refcount.h"
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/* Kernel only BMAP related definitions and functions */
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@ -389,11 +392,13 @@ xfs_bmap_count_blocks(
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STATIC int
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xfs_getbmapx_fix_eof_hole(
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xfs_inode_t *ip, /* xfs incore inode pointer */
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int whichfork,
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struct getbmapx *out, /* output structure */
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int prealloced, /* this is a file with
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* preallocated data space */
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__int64_t end, /* last block requested */
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xfs_fsblock_t startblock)
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xfs_fsblock_t startblock,
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bool moretocome)
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{
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__int64_t fixlen;
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xfs_mount_t *mp; /* file system mount point */
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@ -418,8 +423,9 @@ xfs_getbmapx_fix_eof_hole(
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else
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out->bmv_block = xfs_fsb_to_db(ip, startblock);
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fileblock = XFS_BB_TO_FSB(ip->i_mount, out->bmv_offset);
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ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
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if (xfs_iext_bno_to_ext(ifp, fileblock, &lastx) &&
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ifp = XFS_IFORK_PTR(ip, whichfork);
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if (!moretocome &&
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xfs_iext_bno_to_ext(ifp, fileblock, &lastx) &&
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(lastx == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t))-1))
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out->bmv_oflags |= BMV_OF_LAST;
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}
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@ -427,6 +433,81 @@ xfs_getbmapx_fix_eof_hole(
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return 1;
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}
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/* Adjust the reported bmap around shared/unshared extent transitions. */
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STATIC int
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xfs_getbmap_adjust_shared(
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struct xfs_inode *ip,
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int whichfork,
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struct xfs_bmbt_irec *map,
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struct getbmapx *out,
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struct xfs_bmbt_irec *next_map)
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{
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struct xfs_mount *mp = ip->i_mount;
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xfs_agnumber_t agno;
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xfs_agblock_t agbno;
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xfs_agblock_t ebno;
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xfs_extlen_t elen;
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xfs_extlen_t nlen;
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int error;
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next_map->br_startblock = NULLFSBLOCK;
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next_map->br_startoff = NULLFILEOFF;
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next_map->br_blockcount = 0;
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/* Only written data blocks can be shared. */
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if (!xfs_is_reflink_inode(ip) || whichfork != XFS_DATA_FORK ||
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map->br_startblock == DELAYSTARTBLOCK ||
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map->br_startblock == HOLESTARTBLOCK ||
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ISUNWRITTEN(map))
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return 0;
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agno = XFS_FSB_TO_AGNO(mp, map->br_startblock);
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agbno = XFS_FSB_TO_AGBNO(mp, map->br_startblock);
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error = xfs_reflink_find_shared(mp, agno, agbno, map->br_blockcount,
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&ebno, &elen, true);
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if (error)
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return error;
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if (ebno == NULLAGBLOCK) {
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/* No shared blocks at all. */
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return 0;
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} else if (agbno == ebno) {
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/*
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* Shared extent at (agbno, elen). Shrink the reported
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* extent length and prepare to move the start of map[i]
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* to agbno+elen, with the aim of (re)formatting the new
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* map[i] the next time through the inner loop.
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*/
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out->bmv_length = XFS_FSB_TO_BB(mp, elen);
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out->bmv_oflags |= BMV_OF_SHARED;
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if (elen != map->br_blockcount) {
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*next_map = *map;
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next_map->br_startblock += elen;
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next_map->br_startoff += elen;
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next_map->br_blockcount -= elen;
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}
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map->br_blockcount -= elen;
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} else {
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/*
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* There's an unshared extent (agbno, ebno - agbno)
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* followed by shared extent at (ebno, elen). Shrink
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* the reported extent length to cover only the unshared
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* extent and prepare to move up the start of map[i] to
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* ebno, with the aim of (re)formatting the new map[i]
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* the next time through the inner loop.
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*/
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*next_map = *map;
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nlen = ebno - agbno;
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out->bmv_length = XFS_FSB_TO_BB(mp, nlen);
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next_map->br_startblock += nlen;
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next_map->br_startoff += nlen;
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next_map->br_blockcount -= nlen;
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map->br_blockcount -= nlen;
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}
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return 0;
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}
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/*
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* Get inode's extents as described in bmv, and format for output.
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* Calls formatter to fill the user's buffer until all extents
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@ -459,12 +540,28 @@ xfs_getbmap(
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int iflags; /* interface flags */
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int bmapi_flags; /* flags for xfs_bmapi */
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int cur_ext = 0;
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struct xfs_bmbt_irec inject_map;
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mp = ip->i_mount;
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iflags = bmv->bmv_iflags;
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whichfork = iflags & BMV_IF_ATTRFORK ? XFS_ATTR_FORK : XFS_DATA_FORK;
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if (whichfork == XFS_ATTR_FORK) {
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#ifndef DEBUG
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/* Only allow CoW fork queries if we're debugging. */
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if (iflags & BMV_IF_COWFORK)
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return -EINVAL;
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#endif
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if ((iflags & BMV_IF_ATTRFORK) && (iflags & BMV_IF_COWFORK))
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return -EINVAL;
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if (iflags & BMV_IF_ATTRFORK)
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whichfork = XFS_ATTR_FORK;
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else if (iflags & BMV_IF_COWFORK)
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whichfork = XFS_COW_FORK;
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else
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whichfork = XFS_DATA_FORK;
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switch (whichfork) {
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case XFS_ATTR_FORK:
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if (XFS_IFORK_Q(ip)) {
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if (ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS &&
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ip->i_d.di_aformat != XFS_DINODE_FMT_BTREE &&
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@ -480,7 +577,15 @@ xfs_getbmap(
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prealloced = 0;
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fixlen = 1LL << 32;
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} else {
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break;
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case XFS_COW_FORK:
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if (ip->i_cformat != XFS_DINODE_FMT_EXTENTS)
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return -EINVAL;
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prealloced = 0;
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fixlen = XFS_ISIZE(ip);
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break;
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default:
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if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS &&
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ip->i_d.di_format != XFS_DINODE_FMT_BTREE &&
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ip->i_d.di_format != XFS_DINODE_FMT_LOCAL)
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@ -494,6 +599,7 @@ xfs_getbmap(
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prealloced = 0;
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fixlen = XFS_ISIZE(ip);
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}
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break;
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}
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if (bmv->bmv_length == -1) {
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@ -520,7 +626,8 @@ xfs_getbmap(
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return -ENOMEM;
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xfs_ilock(ip, XFS_IOLOCK_SHARED);
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if (whichfork == XFS_DATA_FORK) {
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switch (whichfork) {
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case XFS_DATA_FORK:
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if (!(iflags & BMV_IF_DELALLOC) &&
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(ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_d.di_size)) {
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error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
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@ -538,8 +645,14 @@ xfs_getbmap(
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}
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lock = xfs_ilock_data_map_shared(ip);
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} else {
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break;
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case XFS_COW_FORK:
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lock = XFS_ILOCK_SHARED;
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xfs_ilock(ip, lock);
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break;
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case XFS_ATTR_FORK:
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lock = xfs_ilock_attr_map_shared(ip);
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break;
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}
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/*
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@ -581,7 +694,8 @@ xfs_getbmap(
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goto out_free_map;
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ASSERT(nmap <= subnex);
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for (i = 0; i < nmap && nexleft && bmv->bmv_length; i++) {
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for (i = 0; i < nmap && nexleft && bmv->bmv_length &&
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cur_ext < bmv->bmv_count; i++) {
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out[cur_ext].bmv_oflags = 0;
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if (map[i].br_state == XFS_EXT_UNWRITTEN)
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out[cur_ext].bmv_oflags |= BMV_OF_PREALLOC;
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@ -614,9 +728,16 @@ xfs_getbmap(
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goto out_free_map;
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}
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if (!xfs_getbmapx_fix_eof_hole(ip, &out[cur_ext],
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prealloced, bmvend,
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map[i].br_startblock))
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/* Is this a shared block? */
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error = xfs_getbmap_adjust_shared(ip, whichfork,
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&map[i], &out[cur_ext], &inject_map);
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if (error)
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goto out_free_map;
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if (!xfs_getbmapx_fix_eof_hole(ip, whichfork,
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&out[cur_ext], prealloced, bmvend,
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map[i].br_startblock,
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inject_map.br_startblock != NULLFSBLOCK))
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goto out_free_map;
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bmv->bmv_offset =
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@ -636,11 +757,16 @@ xfs_getbmap(
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continue;
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}
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nexleft--;
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if (inject_map.br_startblock != NULLFSBLOCK) {
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map[i] = inject_map;
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i--;
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} else
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nexleft--;
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bmv->bmv_entries++;
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cur_ext++;
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}
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} while (nmap && nexleft && bmv->bmv_length);
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} while (nmap && nexleft && bmv->bmv_length &&
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cur_ext < bmv->bmv_count);
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out_free_map:
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kmem_free(map);
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