xfs: abstract the differences in dir2/dir3 via an ops vector

Lots of the dir code now goes through switches to determine what is
the correct on-disk format to parse. It generally involves a
"xfs_sbversion_hasfoo" check, deferencing the superblock version and
feature fields and hence touching several cache lines per operation
in the process. Some operations do multiple checks because they nest
conditional operations and they don't pass the information in a
direct fashion between each other.

Hence, add an ops vector to the xfs_inode structure that is
configured when the inode is initialised to point to all the correct
decode and encoding operations.  This will significantly reduce the
branchiness and cacheline footprint of the directory object decoding
and encoding.

This is the first patch in a series of conversion patches. It will
introduce the ops structure, the setup of it and add the first
operation to the vector. Subsequent patches will convert directory
ops one at a time to keep the changes simple and obvious.

Just this patch shows the benefit of such an approach on code size.
Just converting the two shortform dir operations as this patch does
decreases the built binary size by ~1500 bytes:

$ size fs/xfs/xfs.o.orig fs/xfs/xfs.o.p1
   text    data     bss     dec     hex filename
 794490   96802    1096  892388   d9de4 fs/xfs/xfs.o.orig
 792986   96802    1096  890884   d9804 fs/xfs/xfs.o.p1
$

That's a significant decrease in the instruction cache footprint of
the directory code for such a simple change, and indicates that this
approach is definitely worth pursuing further.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 33a69fabfd83306b8f6b7fb7f48d328f3e81fa75..c21f4350666112c4222b33ad7c268e1d759d540c 100644 (file)
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -66,6 +66,7 @@ xfs-y                         += xfs_alloc.o \
                                   xfs_bmap_btree.o \
                                   xfs_btree.o \
                                   xfs_da_btree.o \
+                                  xfs_da_format.o \
                                   xfs_dir2.o \
                                   xfs_dir2_block.o \
                                   xfs_dir2_data.o \

diff --git a/fs/xfs/xfs_da_btree.h b/fs/xfs/xfs_da_btree.h
index e492dcadd0322dc00c4c156b4556811bef200890..6e95ea79f5d73aa2447fc49eb0e4c7e9bb73a25d 100644 (file)
--- a/fs/xfs/xfs_da_btree.h
+++ b/fs/xfs/xfs_da_btree.h
@@ -23,6 +23,7 @@ struct xfs_bmap_free;
 struct xfs_inode;
 struct xfs_trans;
 struct zone;
+struct xfs_dir_ops;
 
 /*========================================================================
  * Btree searching and modification structure definitions.

diff --git a/fs/xfs/xfs_da_format.c b/fs/xfs/xfs_da_format.c
new file mode 100644 (file)
index 0000000..982d105
--- /dev/null
+++ b/fs/xfs/xfs_da_format.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2013 Red Hat, 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
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_da_format.h"
+#include "xfs_inode.h"
+#include "xfs_dir2.h"
+
+
+static int
+xfs_dir2_sf_entsize(
+       struct xfs_dir2_sf_hdr  *hdr,
+       int                     len)
+{
+       int count = sizeof(struct xfs_dir2_sf_entry);   /* namelen + offset */
+
+       count += len;                                   /* name */
+       count += hdr->i8count ? sizeof(xfs_dir2_ino8_t) :
+                               sizeof(xfs_dir2_ino4_t); /* ino # */
+       return count;
+}
+
+static int
+xfs_dir3_sf_entsize(
+       struct xfs_dir2_sf_hdr  *hdr,
+       int                     len)
+{
+       return xfs_dir2_sf_entsize(hdr, len) + sizeof(__uint8_t);
+}
+
+static struct xfs_dir2_sf_entry *
+xfs_dir2_sf_nextentry(
+       struct xfs_dir2_sf_hdr  *hdr,
+       struct xfs_dir2_sf_entry *sfep)
+{
+       return (struct xfs_dir2_sf_entry *)
+               ((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
+}
+
+static struct xfs_dir2_sf_entry *
+xfs_dir3_sf_nextentry(
+       struct xfs_dir2_sf_hdr  *hdr,
+       struct xfs_dir2_sf_entry *sfep)
+{
+       return (struct xfs_dir2_sf_entry *)
+               ((char *)sfep + xfs_dir3_sf_entsize(hdr, sfep->namelen));
+}
+
+
+const struct xfs_dir_ops xfs_dir2_ops = {
+       .sf_entsize = xfs_dir2_sf_entsize,
+       .sf_nextentry = xfs_dir2_sf_nextentry,
+};
+
+const struct xfs_dir_ops xfs_dir2_ftype_ops = {
+       .sf_entsize = xfs_dir3_sf_entsize,
+       .sf_nextentry = xfs_dir3_sf_nextentry,
+};
+
+const struct xfs_dir_ops xfs_dir3_ops = {
+       .sf_entsize = xfs_dir3_sf_entsize,
+       .sf_nextentry = xfs_dir3_sf_nextentry,
+};

diff --git a/fs/xfs/xfs_da_format.h b/fs/xfs/xfs_da_format.h
index 89a1a219c8ff57cc35a6e8c10f2309fff8ee183f..d54726d0fc10bd3bbcae4d9e26495d7c22591eb3 100644 (file)
--- a/fs/xfs/xfs_da_format.h
+++ b/fs/xfs/xfs_da_format.h
@@ -329,32 +329,6 @@ xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
                ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
 }
 
-static inline int
-xfs_dir3_sf_entsize(
-       struct xfs_mount        *mp,
-       struct xfs_dir2_sf_hdr  *hdr,
-       int                     len)
-{
-       int count = sizeof(struct xfs_dir2_sf_entry);   /* namelen + offset */
-
-       count += len;                                   /* name */
-       count += hdr->i8count ? sizeof(xfs_dir2_ino8_t) :
-                               sizeof(xfs_dir2_ino4_t); /* ino # */
-       if (xfs_sb_version_hasftype(&mp->m_sb))
-               count += sizeof(__uint8_t);             /* file type */
-       return count;
-}
-
-static inline struct xfs_dir2_sf_entry *
-xfs_dir3_sf_nextentry(
-       struct xfs_mount        *mp,
-       struct xfs_dir2_sf_hdr  *hdr,
-       struct xfs_dir2_sf_entry *sfep)
-{
-       return (struct xfs_dir2_sf_entry *)
-               ((char *)sfep + xfs_dir3_sf_entsize(mp, hdr, sfep->namelen));
-}
-
 /*
  * in dir3 shortform directories, the file type field is stored at a variable
  * offset after the inode number. Because it's only a single byte, endian

diff --git a/fs/xfs/xfs_dir2.c b/fs/xfs/xfs_dir2.c
index 38bf9324302c497aadf73d22524c1271b80f18a5..7911136453cd61e10c48ab241d41f6eec26e3a98 100644 (file)
--- a/fs/xfs/xfs_dir2.c
+++ b/fs/xfs/xfs_dir2.c
@@ -112,6 +112,13 @@ xfs_dir_mount(
                mp->m_dirnameops = &xfs_ascii_ci_nameops;
        else
                mp->m_dirnameops = &xfs_default_nameops;
+
+       if (xfs_sb_version_hascrc(&mp->m_sb))
+               mp->m_dir_inode_ops = &xfs_dir3_ops;
+       else if (xfs_sb_version_hasftype(&mp->m_sb))
+               mp->m_dir_inode_ops = &xfs_dir2_ftype_ops;
+       else
+               mp->m_dir_inode_ops = &xfs_dir2_ops;
 }
 
 /*

diff --git a/fs/xfs/xfs_dir2.h b/fs/xfs/xfs_dir2.h
index 9910401327d45c788586b2e0953309b81c8c7c6d..1909d9faff7140dde936c0faae3b35efa968d649 100644 (file)
--- a/fs/xfs/xfs_dir2.h
+++ b/fs/xfs/xfs_dir2.h
@@ -31,6 +31,20 @@ struct xfs_dir2_data_unused;
 
 extern struct xfs_name xfs_name_dotdot;
 
+/*
+ * directory operations vector for encode/decode routines
+ */
+struct xfs_dir_ops {
+       int     (*sf_entsize)(struct xfs_dir2_sf_hdr *hdr, int len);
+       struct xfs_dir2_sf_entry *
+               (*sf_nextentry)(struct xfs_dir2_sf_hdr *hdr,
+                               struct xfs_dir2_sf_entry *sfep);
+};
+
+extern const struct xfs_dir_ops xfs_dir2_ops;
+extern const struct xfs_dir_ops xfs_dir2_ftype_ops;
+extern const struct xfs_dir_ops xfs_dir3_ops;
+
 /*
  * Generic directory interface routines
  */

diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index 9f3f83a5e2da9db832e2dc22b6e74a7eb8655350..9d86b6f9e80fd6029075ef53228a4f37f05b4ebc 100644 (file)
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -1240,7 +1240,7 @@ xfs_dir2_sf_to_block(
                if (++i == sfp->count)
                        sfep = NULL;
                else
-                       sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
+                       sfep = dp->d_ops->sf_nextentry(sfp, sfep);
        }
        /* Done with the temporary buffer */
        kmem_free(sfp);

diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index 45c9ce8cdb28110a4e1436d5b48ad7d30807c650..80333055df34334e503068c124ff3057775e8579 100644 (file)
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -153,7 +153,7 @@ xfs_dir2_sf_getdents(
                                xfs_dir2_sf_get_offset(sfep));
 
                if (ctx->pos > off) {
-                       sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
+                       sfep = dp->d_ops->sf_nextentry(sfp, sfep);
                        continue;
                }
 
@@ -163,7 +163,7 @@ xfs_dir2_sf_getdents(
                if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
                            xfs_dir3_get_dtype(mp, filetype)))
                        return 0;
-               sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
+               sfep = dp->d_ops->sf_nextentry(sfp, sfep);
        }
 
        ctx->pos = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0) &

diff --git a/fs/xfs/xfs_dir2_sf.c b/fs/xfs/xfs_dir2_sf.c
index 8811ee5eaec65e7762d261781a6f0c2f7303c64b..73881c9f40d67d21c7d5063394d64ca64ed38f81 100644 (file)
--- a/fs/xfs/xfs_dir2_sf.c
+++ b/fs/xfs/xfs_dir2_sf.c
@@ -336,7 +336,7 @@ xfs_dir2_block_to_sf(
                        xfs_dir3_sfe_put_ftype(mp, sfp, sfep,
                                        xfs_dir3_dirent_get_ftype(mp, dep));
 
-                       sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
+                       sfep = dp->d_ops->sf_nextentry(sfp, sfep);
                }
                ptr += xfs_dir3_data_entsize(mp, dep->namelen);
        }
@@ -389,7 +389,7 @@ xfs_dir2_sf_addname(
        /*
         * Compute entry (and change in) size.
         */
-       add_entsize = xfs_dir3_sf_entsize(dp->i_mount, sfp, args->namelen);
+       add_entsize = dp->d_ops->sf_entsize(sfp, args->namelen);
        incr_isize = add_entsize;
        objchange = 0;
 #if XFS_BIG_INUMS
@@ -483,8 +483,7 @@ xfs_dir2_sf_addname_easy(
        /*
         * Grow the in-inode space.
         */
-       xfs_idata_realloc(dp,
-                         xfs_dir3_sf_entsize(dp->i_mount, sfp, args->namelen),
+       xfs_idata_realloc(dp, dp->d_ops->sf_entsize(sfp, args->namelen),
                          XFS_DATA_FORK);
        /*
         * Need to set up again due to realloc of the inode data.
@@ -563,7 +562,7 @@ xfs_dir2_sf_addname_hard(
              eof = (char *)oldsfep == &buf[old_isize];
             !eof;
             offset = new_offset + xfs_dir3_data_entsize(mp, oldsfep->namelen),
-             oldsfep = xfs_dir3_sf_nextentry(mp, oldsfp, oldsfep),
+             oldsfep = dp->d_ops->sf_nextentry(oldsfp, oldsfep),
              eof = (char *)oldsfep == &buf[old_isize]) {
                new_offset = xfs_dir2_sf_get_offset(oldsfep);
                if (offset + add_datasize <= new_offset)
@@ -603,7 +602,7 @@ xfs_dir2_sf_addname_hard(
         * If there's more left to copy, do that.
         */
        if (!eof) {
-               sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
+               sfep = dp->d_ops->sf_nextentry(sfp, sfep);
                memcpy(sfep, oldsfep, old_isize - nbytes);
        }
        kmem_free(buf);
@@ -653,7 +652,7 @@ xfs_dir2_sf_addname_pick(
                        holefit = offset + size <= xfs_dir2_sf_get_offset(sfep);
                offset = xfs_dir2_sf_get_offset(sfep) +
                         xfs_dir3_data_entsize(mp, sfep->namelen);
-               sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep);
+               sfep = dp->d_ops->sf_nextentry(sfp, sfep);
        }
        /*
         * Calculate data bytes used excluding the new entry, if this
@@ -719,7 +718,7 @@ xfs_dir2_sf_check(
 
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp);
             i < sfp->count;
-            i++, sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep)) {
+            i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                ASSERT(xfs_dir2_sf_get_offset(sfep) >= offset);
                ino = xfs_dir3_sfe_get_ino(mp, sfp, sfep);
                i8count += ino > XFS_DIR2_MAX_SHORT_INUM;
@@ -848,7 +847,7 @@ xfs_dir2_sf_lookup(
         */
        ci_sfep = NULL;
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
-            i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep)) {
+            i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                /*
                 * Compare name and if it's an exact match, return the inode
                 * number. If it's the first case-insensitive match, store the
@@ -917,7 +916,7 @@ xfs_dir2_sf_removename(
         * Find the one we're deleting.
         */
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
-            i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep)) {
+            i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                if (xfs_da_compname(args, sfep->name, sfep->namelen) ==
                                                                XFS_CMP_EXACT) {
                        ASSERT(xfs_dir3_sfe_get_ino(dp->i_mount, sfp, sfep) ==
@@ -934,7 +933,7 @@ xfs_dir2_sf_removename(
         * Calculate sizes.
         */
        byteoff = (int)((char *)sfep - (char *)sfp);
-       entsize = xfs_dir3_sf_entsize(dp->i_mount, sfp, args->namelen);
+       entsize = dp->d_ops->sf_entsize(sfp, args->namelen);
        newsize = oldsize - entsize;
        /*
         * Copy the part if any after the removed entry, sliding it down.
@@ -1051,7 +1050,7 @@ xfs_dir2_sf_replace(
         */
        else {
                for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
-                    i++, sfep = xfs_dir3_sf_nextentry(dp->i_mount, sfp, sfep)) {
+                    i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                        if (xfs_da_compname(args, sfep->name, sfep->namelen) ==
                                                                XFS_CMP_EXACT) {
 #if XFS_BIG_INUMS || defined(DEBUG)
@@ -1172,8 +1171,8 @@ xfs_dir2_sf_toino4(
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp),
                    oldsfep = xfs_dir2_sf_firstentry(oldsfp);
             i < sfp->count;
-            i++, sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep),
-                 oldsfep = xfs_dir3_sf_nextentry(mp, oldsfp, oldsfep)) {
+            i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep),
+                 oldsfep = dp->d_ops->sf_nextentry(oldsfp, oldsfep)) {
                sfep->namelen = oldsfep->namelen;
                sfep->offset = oldsfep->offset;
                memcpy(sfep->name, oldsfep->name, sfep->namelen);
@@ -1251,8 +1250,8 @@ xfs_dir2_sf_toino8(
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp),
                    oldsfep = xfs_dir2_sf_firstentry(oldsfp);
             i < sfp->count;
-            i++, sfep = xfs_dir3_sf_nextentry(mp, sfp, sfep),
-                 oldsfep = xfs_dir3_sf_nextentry(mp, oldsfp, oldsfep)) {
+            i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep),
+                 oldsfep = dp->d_ops->sf_nextentry(oldsfp, oldsfep)) {
                sfep->namelen = oldsfep->namelen;
                sfep->offset = oldsfep->offset;
                memcpy(sfep->name, oldsfep->name, sfep->namelen);

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 66675877f38cd273d7b9fe51e10d93980b9f8422..9e6efccbae04f23f86581767e09f61304dc55ac4 100644 (file)
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -49,6 +49,9 @@ typedef struct xfs_inode {
        xfs_ifork_t             *i_afp;         /* attribute fork pointer */
        xfs_ifork_t             i_df;           /* data fork */
 
+       /* operations vectors */
+       const struct xfs_dir_ops *d_ops;                /* directory ops vector */
+
        /* Transaction and locking information. */
        struct xfs_inode_log_item *i_itemp;     /* logging information */
        mrlock_t                i_lock;         /* inode lock */

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 718b62b0fe05165d3749249869dddc0eebede87e..0493587ea6bcfa778f558046d1e9c41c729b1e5d 100644 (file)
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1215,6 +1215,7 @@ xfs_setup_inode(
                else
                        inode->i_op = &xfs_dir_inode_operations;
                inode->i_fop = &xfs_dir_file_operations;
+               ip->d_ops = ip->i_mount->m_dir_inode_ops;
                break;
        case S_IFLNK:
                inode->i_op = &xfs_symlink_inode_operations;

diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 1fa0584b5627830c77e4bf0fa02db9c55c066a2d..973397f66c6b9e8242974dde9f77180bdf49299c 100644 (file)
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -26,6 +26,7 @@ struct xfs_mru_cache;
 struct xfs_nameops;
 struct xfs_ail;
 struct xfs_quotainfo;
+struct xfs_dir_ops;
 
 #ifdef HAVE_PERCPU_SB
 
@@ -148,6 +149,7 @@ typedef struct xfs_mount {
        int                     m_dir_magicpct; /* 37% of the dir blocksize */
        __uint8_t               m_sectbb_log;   /* sectlog - BBSHIFT */
        const struct xfs_nameops *m_dirnameops; /* vector of dir name ops */
+       const struct xfs_dir_ops *m_dir_inode_ops; /* vector of dir inode ops */
        int                     m_dirblksize;   /* directory block sz--bytes */
        int                     m_dirblkfsbs;   /* directory block sz--fsbs */
        xfs_dablk_t             m_dirdatablk;   /* blockno of dir data v2 */