diff options
author | Darrick J. Wong <darrick.wong@oracle.com> | 2016-10-03 19:11:32 +0300 |
---|---|---|
committer | Darrick J. Wong <darrick.wong@oracle.com> | 2016-10-05 04:06:40 +0300 |
commit | 3993baeb3c52f497d243a4a3b5510df97b22596b (patch) | |
tree | 2dab55892137a064012b352a0f9ac730797221fb /fs/xfs | |
parent | 11715a21bc3035440b853a0334685f1a55ca8c3c (diff) | |
download | linux-3993baeb3c52f497d243a4a3b5510df97b22596b.tar.xz |
xfs: introduce the CoW fork
Introduce a new in-core fork for storing copy-on-write delalloc
reservations and allocated extents that are in the process of being
written out.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs')
-rw-r--r-- | fs/xfs/Makefile | 1 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_bmap.c | 27 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_bmap.h | 22 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_bmap_btree.c | 1 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_inode_fork.c | 47 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_inode_fork.h | 28 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_rmap.c | 15 | ||||
-rw-r--r-- | fs/xfs/libxfs/xfs_types.h | 1 | ||||
-rw-r--r-- | fs/xfs/xfs_icache.c | 5 | ||||
-rw-r--r-- | fs/xfs/xfs_inode.h | 4 | ||||
-rw-r--r-- | fs/xfs/xfs_reflink.c | 114 | ||||
-rw-r--r-- | fs/xfs/xfs_reflink.h | 23 | ||||
-rw-r--r-- | fs/xfs/xfs_trace.h | 4 |
13 files changed, 264 insertions, 28 deletions
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile index 6afb2281bc01..26ef1958b65b 100644 --- a/fs/xfs/Makefile +++ b/fs/xfs/Makefile @@ -90,6 +90,7 @@ xfs-y += xfs_aops.o \ xfs_message.o \ xfs_mount.o \ xfs_mru_cache.o \ + xfs_reflink.o \ xfs_stats.o \ xfs_super.o \ xfs_symlink.o \ diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 2be1fd3fac47..dc24dd0e7128 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -2924,6 +2924,7 @@ xfs_bmap_add_extent_hole_real( ASSERT(!isnullstartblock(new->br_startblock)); ASSERT(!bma->cur || !(bma->cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL)); + ASSERT(whichfork != XFS_COW_FORK); XFS_STATS_INC(mp, xs_add_exlist); @@ -4072,12 +4073,11 @@ xfs_bmapi_read( int error; int eof; int n = 0; - int whichfork = (flags & XFS_BMAPI_ATTRFORK) ? - XFS_ATTR_FORK : XFS_DATA_FORK; + int whichfork = xfs_bmapi_whichfork(flags); ASSERT(*nmap >= 1); ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK|XFS_BMAPI_ENTIRE| - XFS_BMAPI_IGSTATE))); + XFS_BMAPI_IGSTATE|XFS_BMAPI_COWFORK))); ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)); if (unlikely(XFS_TEST_ERROR( @@ -4095,6 +4095,16 @@ xfs_bmapi_read( ifp = XFS_IFORK_PTR(ip, whichfork); + /* No CoW fork? Return a hole. */ + if (whichfork == XFS_COW_FORK && !ifp) { + mval->br_startoff = bno; + mval->br_startblock = HOLESTARTBLOCK; + mval->br_blockcount = len; + mval->br_state = XFS_EXT_NORM; + *nmap = 1; + return 0; + } + if (!(ifp->if_flags & XFS_IFEXTENTS)) { error = xfs_iread_extents(NULL, ip, whichfork); if (error) @@ -4368,8 +4378,7 @@ xfs_bmapi_convert_unwritten( xfs_filblks_t len, int flags) { - int whichfork = (flags & XFS_BMAPI_ATTRFORK) ? - XFS_ATTR_FORK : XFS_DATA_FORK; + int whichfork = xfs_bmapi_whichfork(flags); struct xfs_ifork *ifp = XFS_IFORK_PTR(bma->ip, whichfork); int tmp_logflags = 0; int error; @@ -4385,6 +4394,8 @@ xfs_bmapi_convert_unwritten( (XFS_BMAPI_PREALLOC | XFS_BMAPI_CONVERT)) return 0; + ASSERT(whichfork != XFS_COW_FORK); + /* * Modify (by adding) the state flag, if writing. */ @@ -4795,6 +4806,8 @@ xfs_bmap_del_extent( if (whichfork == XFS_ATTR_FORK) state |= BMAP_ATTRFORK; + else if (whichfork == XFS_COW_FORK) + state |= BMAP_COWFORK; ifp = XFS_IFORK_PTR(ip, whichfork); ASSERT((*idx >= 0) && (*idx < ifp->if_bytes / @@ -5133,8 +5146,8 @@ __xfs_bunmapi( trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_); - whichfork = (flags & XFS_BMAPI_ATTRFORK) ? - XFS_ATTR_FORK : XFS_DATA_FORK; + whichfork = xfs_bmapi_whichfork(flags); + ASSERT(whichfork != XFS_COW_FORK); ifp = XFS_IFORK_PTR(ip, whichfork); if (unlikely( XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS && diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h index 85e3b9d91ade..87741274c114 100644 --- a/fs/xfs/libxfs/xfs_bmap.h +++ b/fs/xfs/libxfs/xfs_bmap.h @@ -107,6 +107,9 @@ struct xfs_extent_free_item */ #define XFS_BMAPI_REMAP 0x100 +/* Map something in the CoW fork. */ +#define XFS_BMAPI_COWFORK 0x200 + #define XFS_BMAPI_FLAGS \ { XFS_BMAPI_ENTIRE, "ENTIRE" }, \ { XFS_BMAPI_METADATA, "METADATA" }, \ @@ -116,12 +119,23 @@ struct xfs_extent_free_item { XFS_BMAPI_CONTIG, "CONTIG" }, \ { XFS_BMAPI_CONVERT, "CONVERT" }, \ { XFS_BMAPI_ZERO, "ZERO" }, \ - { XFS_BMAPI_REMAP, "REMAP" } + { XFS_BMAPI_REMAP, "REMAP" }, \ + { XFS_BMAPI_COWFORK, "COWFORK" } static inline int xfs_bmapi_aflag(int w) { - return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0); + 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; } /* @@ -142,13 +156,15 @@ static inline int xfs_bmapi_aflag(int w) #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_ATTRFORK, "ATTR" }, \ + { BMAP_COWFORK, "COW" } /* diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c index cd85274e810c..37f0d9daafce 100644 --- a/fs/xfs/libxfs/xfs_bmap_btree.c +++ b/fs/xfs/libxfs/xfs_bmap_btree.c @@ -777,6 +777,7 @@ xfs_bmbt_init_cursor( { struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork); struct xfs_btree_cur *cur; + ASSERT(whichfork != XFS_COW_FORK); cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP); diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c index 7699a033dd3c..5dd56d3dbb3a 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.c +++ b/fs/xfs/libxfs/xfs_inode_fork.c @@ -206,9 +206,14 @@ xfs_iformat_fork( XFS_ERROR_REPORT("xfs_iformat(7)", XFS_ERRLEVEL_LOW, ip->i_mount); return -EFSCORRUPTED; } - if (error) { + if (error) return error; + + if (xfs_is_reflink_inode(ip)) { + ASSERT(ip->i_cowfp == NULL); + xfs_ifork_init_cow(ip); } + if (!XFS_DFORK_Q(dip)) return 0; @@ -247,6 +252,9 @@ xfs_iformat_fork( if (error) { kmem_zone_free(xfs_ifork_zone, ip->i_afp); ip->i_afp = NULL; + if (ip->i_cowfp) + kmem_zone_free(xfs_ifork_zone, ip->i_cowfp); + ip->i_cowfp = NULL; xfs_idestroy_fork(ip, XFS_DATA_FORK); } return error; @@ -761,6 +769,9 @@ xfs_idestroy_fork( if (whichfork == XFS_ATTR_FORK) { kmem_zone_free(xfs_ifork_zone, ip->i_afp); ip->i_afp = NULL; + } else if (whichfork == XFS_COW_FORK) { + kmem_zone_free(xfs_ifork_zone, ip->i_cowfp); + ip->i_cowfp = NULL; } } @@ -948,6 +959,19 @@ xfs_iext_get_ext( } } +/* Convert bmap state flags to an inode fork. */ +struct xfs_ifork * +xfs_iext_state_to_fork( + struct xfs_inode *ip, + int state) +{ + if (state & BMAP_COWFORK) + return ip->i_cowfp; + else if (state & BMAP_ATTRFORK) + return ip->i_afp; + return &ip->i_df; +} + /* * Insert new item(s) into the extent records for incore inode * fork 'ifp'. 'count' new items are inserted at index 'idx'. @@ -960,7 +984,7 @@ xfs_iext_insert( xfs_bmbt_irec_t *new, /* items to insert */ int state) /* type of extent conversion */ { - xfs_ifork_t *ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df; + xfs_ifork_t *ifp = xfs_iext_state_to_fork(ip, state); xfs_extnum_t i; /* extent record index */ trace_xfs_iext_insert(ip, idx, new, state, _RET_IP_); @@ -1210,7 +1234,7 @@ xfs_iext_remove( int ext_diff, /* number of extents to remove */ int state) /* type of extent conversion */ { - xfs_ifork_t *ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df; + xfs_ifork_t *ifp = xfs_iext_state_to_fork(ip, state); xfs_extnum_t nextents; /* number of extents in file */ int new_size; /* size of extents after removal */ @@ -1955,3 +1979,20 @@ xfs_iext_irec_update_extoffs( ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff; } } + +/* + * Initialize an inode's copy-on-write fork. + */ +void +xfs_ifork_init_cow( + struct xfs_inode *ip) +{ + if (ip->i_cowfp) + return; + + ip->i_cowfp = kmem_zone_zalloc(xfs_ifork_zone, + KM_SLEEP | KM_NOFS); + ip->i_cowfp->if_flags = XFS_IFEXTENTS; + ip->i_cformat = XFS_DINODE_FMT_EXTENTS; + ip->i_cnextents = 0; +} diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h index f95e072ae646..c9476f50e32d 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.h +++ b/fs/xfs/libxfs/xfs_inode_fork.h @@ -92,7 +92,9 @@ typedef struct xfs_ifork { #define XFS_IFORK_PTR(ip,w) \ ((w) == XFS_DATA_FORK ? \ &(ip)->i_df : \ - (ip)->i_afp) + ((w) == XFS_ATTR_FORK ? \ + (ip)->i_afp : \ + (ip)->i_cowfp)) #define XFS_IFORK_DSIZE(ip) \ (XFS_IFORK_Q(ip) ? \ XFS_IFORK_BOFF(ip) : \ @@ -105,26 +107,38 @@ typedef struct xfs_ifork { #define XFS_IFORK_SIZE(ip,w) \ ((w) == XFS_DATA_FORK ? \ XFS_IFORK_DSIZE(ip) : \ - XFS_IFORK_ASIZE(ip)) + ((w) == XFS_ATTR_FORK ? \ + XFS_IFORK_ASIZE(ip) : \ + 0)) #define XFS_IFORK_FORMAT(ip,w) \ ((w) == XFS_DATA_FORK ? \ (ip)->i_d.di_format : \ - (ip)->i_d.di_aformat) + ((w) == XFS_ATTR_FORK ? \ + (ip)->i_d.di_aformat : \ + (ip)->i_cformat)) #define XFS_IFORK_FMT_SET(ip,w,n) \ ((w) == XFS_DATA_FORK ? \ ((ip)->i_d.di_format = (n)) : \ - ((ip)->i_d.di_aformat = (n))) + ((w) == XFS_ATTR_FORK ? \ + ((ip)->i_d.di_aformat = (n)) : \ + ((ip)->i_cformat = (n)))) #define XFS_IFORK_NEXTENTS(ip,w) \ ((w) == XFS_DATA_FORK ? \ (ip)->i_d.di_nextents : \ - (ip)->i_d.di_anextents) + ((w) == XFS_ATTR_FORK ? \ + (ip)->i_d.di_anextents : \ + (ip)->i_cnextents)) #define XFS_IFORK_NEXT_SET(ip,w,n) \ ((w) == XFS_DATA_FORK ? \ ((ip)->i_d.di_nextents = (n)) : \ - ((ip)->i_d.di_anextents = (n))) + ((w) == XFS_ATTR_FORK ? \ + ((ip)->i_d.di_anextents = (n)) : \ + ((ip)->i_cnextents = (n)))) #define XFS_IFORK_MAXEXT(ip, w) \ (XFS_IFORK_SIZE(ip, w) / sizeof(xfs_bmbt_rec_t)) +struct xfs_ifork *xfs_iext_state_to_fork(struct xfs_inode *ip, int state); + int xfs_iformat_fork(struct xfs_inode *, struct xfs_dinode *); void xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *, struct xfs_inode_log_item *, int); @@ -169,4 +183,6 @@ void xfs_iext_irec_update_extoffs(struct xfs_ifork *, int, int); extern struct kmem_zone *xfs_ifork_zone; +extern void xfs_ifork_init_cow(struct xfs_inode *ip); + #endif /* __XFS_INODE_FORK_H__ */ diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c index 73d05407d663..1c40b851a21d 100644 --- a/fs/xfs/libxfs/xfs_rmap.c +++ b/fs/xfs/libxfs/xfs_rmap.c @@ -1263,9 +1263,10 @@ out_cur: */ static bool xfs_rmap_update_is_needed( - struct xfs_mount *mp) + struct xfs_mount *mp, + int whichfork) { - return xfs_sb_version_hasrmapbt(&mp->m_sb); + return xfs_sb_version_hasrmapbt(&mp->m_sb) && whichfork != XFS_COW_FORK; } /* @@ -1311,7 +1312,7 @@ xfs_rmap_map_extent( int whichfork, struct xfs_bmbt_irec *PREV) { - if (!xfs_rmap_update_is_needed(mp)) + if (!xfs_rmap_update_is_needed(mp, whichfork)) return 0; return __xfs_rmap_add(mp, dfops, XFS_RMAP_MAP, ip->i_ino, @@ -1327,7 +1328,7 @@ xfs_rmap_unmap_extent( int whichfork, struct xfs_bmbt_irec *PREV) { - if (!xfs_rmap_update_is_needed(mp)) + if (!xfs_rmap_update_is_needed(mp, whichfork)) return 0; return __xfs_rmap_add(mp, dfops, XFS_RMAP_UNMAP, ip->i_ino, @@ -1343,7 +1344,7 @@ xfs_rmap_convert_extent( int whichfork, struct xfs_bmbt_irec *PREV) { - if (!xfs_rmap_update_is_needed(mp)) + if (!xfs_rmap_update_is_needed(mp, whichfork)) return 0; return __xfs_rmap_add(mp, dfops, XFS_RMAP_CONVERT, ip->i_ino, @@ -1362,7 +1363,7 @@ xfs_rmap_alloc_extent( { struct xfs_bmbt_irec bmap; - if (!xfs_rmap_update_is_needed(mp)) + if (!xfs_rmap_update_is_needed(mp, XFS_DATA_FORK)) return 0; bmap.br_startblock = XFS_AGB_TO_FSB(mp, agno, bno); @@ -1386,7 +1387,7 @@ xfs_rmap_free_extent( { struct xfs_bmbt_irec bmap; - if (!xfs_rmap_update_is_needed(mp)) + if (!xfs_rmap_update_is_needed(mp, XFS_DATA_FORK)) return 0; bmap.br_startblock = XFS_AGB_TO_FSB(mp, agno, bno); diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h index be7b6de5137d..8d74870468c2 100644 --- a/fs/xfs/libxfs/xfs_types.h +++ b/fs/xfs/libxfs/xfs_types.h @@ -90,6 +90,7 @@ typedef __int64_t xfs_sfiloff_t; /* signed block number in a file */ */ #define XFS_DATA_FORK 0 #define XFS_ATTR_FORK 1 +#define XFS_COW_FORK 2 /* * Min numbers of data/attr fork btree root pointers. diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index 65b2e3f85f52..2d3de02f3529 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -76,6 +76,9 @@ xfs_inode_alloc( ip->i_mount = mp; memset(&ip->i_imap, 0, sizeof(struct xfs_imap)); ip->i_afp = NULL; + ip->i_cowfp = NULL; + ip->i_cnextents = 0; + ip->i_cformat = XFS_DINODE_FMT_EXTENTS; memset(&ip->i_df, 0, sizeof(xfs_ifork_t)); ip->i_flags = 0; ip->i_delayed_blks = 0; @@ -101,6 +104,8 @@ xfs_inode_free_callback( if (ip->i_afp) xfs_idestroy_fork(ip, XFS_ATTR_FORK); + if (ip->i_cowfp) + xfs_idestroy_fork(ip, XFS_COW_FORK); if (ip->i_itemp) { ASSERT(!(ip->i_itemp->ili_item.li_flags & XFS_LI_IN_AIL)); diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index 4be32036e16a..ff6fc03c0092 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -47,6 +47,7 @@ typedef struct xfs_inode { /* Extent information. */ xfs_ifork_t *i_afp; /* attribute fork pointer */ + xfs_ifork_t *i_cowfp; /* copy on write extents */ xfs_ifork_t i_df; /* data fork */ /* operations vectors */ @@ -65,6 +66,9 @@ typedef struct xfs_inode { struct xfs_icdinode i_d; /* most of ondisk inode */ + xfs_extnum_t i_cnextents; /* # of extents in cow fork */ + unsigned int i_cformat; /* format of cow fork */ + /* VFS inode */ struct inode i_vnode; /* embedded VFS inode */ } xfs_inode_t; diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c new file mode 100644 index 000000000000..7adbb83df040 --- /dev/null +++ b/fs/xfs/xfs_reflink.c @@ -0,0 +1,114 @@ +/* + * Copyright (C) 2016 Oracle. All Rights Reserved. + * + * Author: Darrick J. Wong <darrick.wong@oracle.com> + * + * 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; either version 2 + * of the License, or (at your option) any later version. + * + * 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. + */ +#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_defer.h" +#include "xfs_da_format.h" +#include "xfs_da_btree.h" +#include "xfs_inode.h" +#include "xfs_trans.h" +#include "xfs_inode_item.h" +#include "xfs_bmap.h" +#include "xfs_bmap_util.h" +#include "xfs_error.h" +#include "xfs_dir2.h" +#include "xfs_dir2_priv.h" +#include "xfs_ioctl.h" +#include "xfs_trace.h" +#include "xfs_log.h" +#include "xfs_icache.h" +#include "xfs_pnfs.h" +#include "xfs_refcount_btree.h" +#include "xfs_refcount.h" +#include "xfs_bmap_btree.h" +#include "xfs_trans_space.h" +#include "xfs_bit.h" +#include "xfs_alloc.h" +#include "xfs_quota_defs.h" +#include "xfs_quota.h" +#include "xfs_btree.h" +#include "xfs_bmap_btree.h" +#include "xfs_reflink.h" + +/* + * Copy on Write of Shared Blocks + * + * XFS must preserve "the usual" file semantics even when two files share + * the same physical blocks. This means that a write to one file must not + * alter the blocks in a different file; the way that we'll do that is + * through the use of a copy-on-write mechanism. At a high level, that + * means that when we want to write to a shared block, we allocate a new + * block, write the data to the new block, and if that succeeds we map the + * new block into the file. + * + * XFS provides a "delayed allocation" mechanism that defers the allocation + * of disk blocks to dirty-but-not-yet-mapped file blocks as long as + * possible. This reduces fragmentation by enabling the filesystem to ask + * for bigger chunks less often, which is exactly what we want for CoW. + * + * The delalloc mechanism begins when the kernel wants to make a block + * writable (write_begin or page_mkwrite). If the offset is not mapped, we + * create a delalloc mapping, which is a regular in-core extent, but without + * a real startblock. (For delalloc mappings, the startblock encodes both + * a flag that this is a delalloc mapping, and a worst-case estimate of how + * many blocks might be required to put the mapping into the BMBT.) delalloc + * mappings are a reservation against the free space in the filesystem; + * adjacent mappings can also be combined into fewer larger mappings. + * + * When dirty pages are being written out (typically in writepage), the + * delalloc reservations are converted into real mappings by allocating + * blocks and replacing the delalloc mapping with real ones. A delalloc + * mapping can be replaced by several real ones if the free space is + * fragmented. + * + * We want to adapt the delalloc mechanism for copy-on-write, since the + * write paths are similar. The first two steps (creating the reservation + * and allocating the blocks) are exactly the same as delalloc except that + * the mappings must be stored in a separate CoW fork because we do not want + * to disturb the mapping in the data fork until we're sure that the write + * succeeded. IO completion in this case is the process of removing the old + * mapping from the data fork and moving the new mapping from the CoW fork to + * the data fork. This will be discussed shortly. + * + * For now, unaligned directio writes will be bounced back to the page cache. + * Block-aligned directio writes will use the same mechanism as buffered + * writes. + * + * CoW remapping must be done after the data block write completes, + * because we don't want to destroy the old data fork map until we're sure + * the new block has been written. Since the new mappings are kept in a + * separate fork, we can simply iterate these mappings to find the ones + * that cover the file blocks that we just CoW'd. For each extent, simply + * unmap the corresponding range in the data fork, map the new range into + * the data fork, and remove the extent from the CoW fork. + * + * Since the remapping operation can be applied to an arbitrary file + * range, we record the need for the remap step as a flag in the ioend + * instead of declaring a new IO type. This is required for direct io + * because we only have ioend for the whole dio, and we have to be able to + * remember the presence of unwritten blocks and CoW blocks with a single + * ioend structure. Better yet, the more ground we can cover with one + * ioend, the better. + */ diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h new file mode 100644 index 000000000000..820b151c8206 --- /dev/null +++ b/fs/xfs/xfs_reflink.h @@ -0,0 +1,23 @@ +/* + * Copyright (C) 2016 Oracle. All Rights Reserved. + * + * Author: Darrick J. Wong <darrick.wong@oracle.com> + * + * 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; either version 2 + * of the License, or (at your option) any later version. + * + * 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_REFLINK_H +#define __XFS_REFLINK_H 1 + +#endif /* __XFS_REFLINK_H */ diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 476bf2b54aeb..ae59c3c5b417 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -269,10 +269,10 @@ DECLARE_EVENT_CLASS(xfs_bmap_class, __field(unsigned long, caller_ip) ), TP_fast_assign( - struct xfs_ifork *ifp = (state & BMAP_ATTRFORK) ? - ip->i_afp : &ip->i_df; + struct xfs_ifork *ifp; struct xfs_bmbt_irec r; + ifp = xfs_iext_state_to_fork(ip, state); xfs_bmbt_get_all(xfs_iext_get_ext(ifp, idx), &r); __entry->dev = VFS_I(ip)->i_sb->s_dev; __entry->ino = ip->i_ino; |