src/patches/suse-2.6.27.31/patches.suse/ocfs2-Make-cached-block-reads-the-common-case.patch

   1 From: Joel Becker <joel.becker@oracle.com>
   2 Subject: ocfs2: Make cached block reads the common case.
   3 Patch-mainline: 2.6.28
   4
   5 ocfs2_read_blocks() currently requires the CACHED flag for cached I/O.
   6 However, that's the common case.  Let's flip it around and provide an
   7 IGNORE_CACHE flag for the special users.  This has the added benefit of
   8 cleaning up the code some (ignore_cache takes on its special meaning
   9 earlier in the loop).
  10
  11 Signed-off-by: Joel Becker <joel.becker@oracle.com>
  12 Signed-off-by: Mark Fasheh <mfasheh@suse.com>
  13 ---
  14  fs/ocfs2/buffer_head_io.c |   19 +++++++++++--------
  15  fs/ocfs2/buffer_head_io.h |    4 ++--
  16  fs/ocfs2/dir.c            |    2 +-
  17  fs/ocfs2/inode.c          |    3 ++-
  18  fs/ocfs2/journal.c        |    3 ++-
  19  fs/ocfs2/localalloc.c     |    4 ++--
  20  fs/ocfs2/slot_map.c       |    6 ++++--
  21  7 files changed, 24 insertions(+), 17 deletions(-)
  22
  23 Index: linux-2.6.27/fs/ocfs2/buffer_head_io.c
  24 ===================================================================
  25 --- linux-2.6.27.orig/fs/ocfs2/buffer_head_io.c
  26 +++ linux-2.6.27/fs/ocfs2/buffer_head_io.c
  27 @@ -181,7 +181,8 @@ int ocfs2_read_blocks(struct inode *inod
  28                    inode, (unsigned long long)block, nr, flags);
  29
  30         BUG_ON(!inode);
  31 -       BUG_ON((flags & OCFS2_BH_READAHEAD) && !(flags & OCFS2_BH_CACHED));
  32 +       BUG_ON((flags & OCFS2_BH_READAHEAD) &&
  33 +              (flags & OCFS2_BH_IGNORE_CACHE));
  34
  35         if (bhs == NULL) {
  36                 status = -EINVAL;
  37 @@ -214,7 +215,7 @@ int ocfs2_read_blocks(struct inode *inod
  38                         }
  39                 }
  40                 bh = bhs[i];
  41 -               ignore_cache = 0;
  42 +               ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE);
  43
  44                 /* There are three read-ahead cases here which we need to
  45                  * be concerned with. All three assume a buffer has
  46 @@ -240,26 +241,27 @@ int ocfs2_read_blocks(struct inode *inod
  47                  *    before our is-it-in-flight check.
  48                  */
  49
  50 -               if (flags & OCFS2_BH_CACHED &&
  51 -                   !ocfs2_buffer_uptodate(inode, bh)) {
  52 +               if (!ignore_cache && !ocfs2_buffer_uptodate(inode, bh)) {
  53                         mlog(ML_UPTODATE,
  54                              "bh (%llu), inode %llu not uptodate\n",
  55                              (unsigned long long)bh->b_blocknr,
  56                              (unsigned long long)OCFS2_I(inode)->ip_blkno);
  57 +                       /* We're using ignore_cache here to say
  58 +                        * "go to disk" */
  59                         ignore_cache = 1;
  60                 }
  61
  62                 /* XXX: Can we ever get this and *not* have the cached
  63                  * flag set? */
  64                 if (buffer_jbd(bh)) {
  65 -                       if (!(flags & OCFS2_BH_CACHED) || ignore_cache)
  66 +                       if (ignore_cache)
  67                                 mlog(ML_BH_IO, "trying to sync read a jbd "
  68                                                "managed bh (blocknr = %llu)\n",
  69                                      (unsigned long long)bh->b_blocknr);
  70                         continue;
  71                 }
  72
  73 -               if (!(flags & OCFS2_BH_CACHED) || ignore_cache) {
  74 +               if (ignore_cache) {
  75                         if (buffer_dirty(bh)) {
  76                                 /* This should probably be a BUG, or
  77                                  * at least return an error. */
  78 @@ -294,7 +296,7 @@ int ocfs2_read_blocks(struct inode *inod
  79                          * previously read-ahead buffer may have
  80                          * completed I/O while we were waiting for the
  81                          * buffer lock. */
  82 -                       if ((flags & OCFS2_BH_CACHED)
  83 +                       if (!(flags & OCFS2_BH_IGNORE_CACHE)
  84                             && !(flags & OCFS2_BH_READAHEAD)
  85                             && ocfs2_buffer_uptodate(inode, bh)) {
  86                                 unlock_buffer(bh);
  87 @@ -344,7 +346,8 @@ int ocfs2_read_blocks(struct inode *inod
  88
  89         mlog(ML_BH_IO, "block=(%llu), nr=(%d), cached=%s, flags=0x%x\n",
  90              (unsigned long long)block, nr,
  91 -            (!(flags & OCFS2_BH_CACHED) || ignore_cache) ? "no" : "yes", flags);
  92 +            ((flags & OCFS2_BH_IGNORE_CACHE) || ignore_cache) ? "no" : "yes",
  93 +            flags);
  94
  95  bail:
  96
  97 Index: linux-2.6.27/fs/ocfs2/buffer_head_io.h
  98 ===================================================================
  99 --- linux-2.6.27.orig/fs/ocfs2/buffer_head_io.h
 100 +++ linux-2.6.27/fs/ocfs2/buffer_head_io.h
 101 @@ -49,7 +49,7 @@ int ocfs2_read_blocks_sync(struct ocfs2_
 102  int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
 103                                 struct buffer_head *bh);
 104
 105 -#define OCFS2_BH_CACHED            1
 106 +#define OCFS2_BH_IGNORE_CACHE      1
 107  #define OCFS2_BH_READAHEAD         8
 108
 109  static inline int ocfs2_read_block(struct inode *inode, u64 off,
 110 @@ -63,7 +63,7 @@ static inline int ocfs2_read_block(struc
 111                 goto bail;
 112         }
 113
 114 -       status = ocfs2_read_blocks(inode, off, 1, bh, OCFS2_BH_CACHED);
 115 +       status = ocfs2_read_blocks(inode, off, 1, bh, 0);
 116
 117  bail:
 118         return status;
 119 Index: linux-2.6.27/fs/ocfs2/dir.c
 120 ===================================================================
 121 --- linux-2.6.27.orig/fs/ocfs2/dir.c
 122 +++ linux-2.6.27/fs/ocfs2/dir.c
 123 @@ -88,7 +88,7 @@ static struct buffer_head *ocfs2_bread(s
 124         struct buffer_head *bh = NULL;
 125         int tmperr;
 126         u64 p_blkno;
 127 -       int readflags = OCFS2_BH_CACHED;
 128 +       int readflags = 0;
 129
 130         if (reada)
 131                 readflags |= OCFS2_BH_READAHEAD;
 132 Index: linux-2.6.27/fs/ocfs2/inode.c
 133 ===================================================================
 134 --- linux-2.6.27.orig/fs/ocfs2/inode.c
 135 +++ linux-2.6.27/fs/ocfs2/inode.c
 136 @@ -461,7 +461,8 @@ static int ocfs2_read_locked_inode(struc
 137         }
 138
 139         if (can_lock)
 140 -               status = ocfs2_read_blocks(inode, args->fi_blkno, 1, &bh, 0);
 141 +               status = ocfs2_read_blocks(inode, args->fi_blkno, 1, &bh,
 142 +                                          OCFS2_BH_IGNORE_CACHE);
 143         else
 144                 status = ocfs2_read_blocks_sync(osb, args->fi_blkno, 1, &bh);
 145         if (status < 0) {
 146 Index: linux-2.6.27/fs/ocfs2/journal.c
 147 ===================================================================
 148 --- linux-2.6.27.orig/fs/ocfs2/journal.c
 149 +++ linux-2.6.27/fs/ocfs2/journal.c
 150 @@ -1134,7 +1134,8 @@ static int ocfs2_read_journal_inode(stru
 151         }
 152         SET_INODE_JOURNAL(inode);
 153
 154 -       status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, bh, 0);
 155 +       status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, bh,
 156 +                                  OCFS2_BH_IGNORE_CACHE);
 157         if (status < 0) {
 158                 mlog_errno(status);
 159                 goto bail;
 160 Index: linux-2.6.27/fs/ocfs2/localalloc.c
 161 ===================================================================
 162 --- linux-2.6.27.orig/fs/ocfs2/localalloc.c
 163 +++ linux-2.6.27/fs/ocfs2/localalloc.c
 164 @@ -249,7 +249,7 @@ int ocfs2_load_local_alloc(struct ocfs2_
 165         }
 166
 167         status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1,
 168 -                                  &alloc_bh, 0);
 169 +                                  &alloc_bh, OCFS2_BH_IGNORE_CACHE);
 170         if (status < 0) {
 171                 mlog_errno(status);
 172                 goto bail;
 173 @@ -460,7 +460,7 @@ int ocfs2_begin_local_alloc_recovery(str
 174         mutex_lock(&inode->i_mutex);
 175
 176         status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1,
 177 -                                  &alloc_bh, 0);
 178 +                                  &alloc_bh, OCFS2_BH_IGNORE_CACHE);
 179         if (status < 0) {
 180                 mlog_errno(status);
 181                 goto bail;
 182 Index: linux-2.6.27/fs/ocfs2/slot_map.c
 183 ===================================================================
 184 --- linux-2.6.27.orig/fs/ocfs2/slot_map.c
 185 +++ linux-2.6.27/fs/ocfs2/slot_map.c
 186 @@ -150,7 +150,8 @@ int ocfs2_refresh_slot_info(struct ocfs2
 187          * be !NULL.  Thus, ocfs2_read_blocks() will ignore blocknr.  If
 188          * this is not true, the read of -1 (UINT64_MAX) will fail.
 189          */
 190 -       ret = ocfs2_read_blocks(si->si_inode, -1, si->si_blocks, si->si_bh, 0);
 191 +       ret = ocfs2_read_blocks(si->si_inode, -1, si->si_blocks, si->si_bh,
 192 +                               OCFS2_BH_IGNORE_CACHE);
 193         if (ret == 0) {
 194                 spin_lock(&osb->osb_lock);
 195                 ocfs2_update_slot_info(si);
 196 @@ -403,7 +404,8 @@ static int ocfs2_map_slot_buffers(struct
 197                      (unsigned long long)blkno);
 198
 199                 bh = NULL;  /* Acquire a fresh bh */
 200 -               status = ocfs2_read_blocks(si->si_inode, blkno, 1, &bh, 0);
 201 +               status = ocfs2_read_blocks(si->si_inode, blkno, 1, &bh,
 202 +                                          OCFS2_BH_IGNORE_CACHE);
 203                 if (status < 0) {
 204                         mlog_errno(status);
 205                         goto bail;