From 5163f95a08cbf058ae16452c2242c5600fedc32e Mon Sep 17 00:00:00 2001 From: Barry Naujok Date: Wed, 21 May 2008 16:41:01 +1000 Subject: [XFS] Name operation vector for hash and compare Adds two pieces of functionality for the basis of case-insensitive support in XFS: 1. A comparison result enumerated type: xfs_dacmp. It represents an exact match, case-insensitive match or no match at all. This patch only implements different and exact results. 2. xfs_nameops vector for specifying how to perform the hash generation of filenames and comparision methods. In this patch the hash vector points to the existing xfs_da_hashname function and the comparison method does a length compare, and if the same, does a memcmp and return the xfs_dacmp result. All filename functions that use the hash (create, lookup remove, rename, etc) now use the xfs_nameops.hashname function and all directory lookup functions also use the xfs_nameops.compname function. The lookup functions also handle case-insensitive results even though the default comparison function cannot return that. And important aspect of the lookup functions is that an exact match always has precedence over a case-insensitive. So while a case-insensitive match is found, we have to keep looking just in case there is an exact match. In the meantime, the info for the first case-insensitive match is retained if no exact match is found. SGI-PV: 981519 SGI-Modid: xfs-linux-melb:xfs-kern:31205a Signed-off-by: Barry Naujok Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_dir2_leaf.c | 60 ++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 43 insertions(+), 17 deletions(-) (limited to 'fs/xfs/xfs_dir2_leaf.c') diff --git a/fs/xfs/xfs_dir2_leaf.c b/fs/xfs/xfs_dir2_leaf.c index e33433408e4a..b52903bc0b14 100644 --- a/fs/xfs/xfs_dir2_leaf.c +++ b/fs/xfs/xfs_dir2_leaf.c @@ -1331,6 +1331,8 @@ xfs_dir2_leaf_lookup_int( xfs_mount_t *mp; /* filesystem mount point */ xfs_dir2_db_t newdb; /* new data block number */ xfs_trans_t *tp; /* transaction pointer */ + xfs_dabuf_t *cbp; /* case match data buffer */ + enum xfs_dacmp cmp; /* name compare result */ dp = args->dp; tp = args->trans; @@ -1354,9 +1356,11 @@ xfs_dir2_leaf_lookup_int( * Loop over all the entries with the right hash value * looking to match the name. */ + cbp = NULL; for (lep = &leaf->ents[index], dbp = NULL, curdb = -1; - index < be16_to_cpu(leaf->hdr.count) && be32_to_cpu(lep->hashval) == args->hashval; - lep++, index++) { + index < be16_to_cpu(leaf->hdr.count) && + be32_to_cpu(lep->hashval) == args->hashval; + lep++, index++) { /* * Skip over stale leaf entries. */ @@ -1371,12 +1375,12 @@ xfs_dir2_leaf_lookup_int( * need to pitch the old one and read the new one. */ if (newdb != curdb) { - if (dbp) + if (dbp != cbp) xfs_da_brelse(tp, dbp); - if ((error = - xfs_da_read_buf(tp, dp, - xfs_dir2_db_to_da(mp, newdb), -1, &dbp, - XFS_DATA_FORK))) { + error = xfs_da_read_buf(tp, dp, + xfs_dir2_db_to_da(mp, newdb), + -1, &dbp, XFS_DATA_FORK); + if (error) { xfs_da_brelse(tp, lbp); return error; } @@ -1386,24 +1390,46 @@ xfs_dir2_leaf_lookup_int( /* * Point to the data entry. */ - dep = (xfs_dir2_data_entry_t *) - ((char *)dbp->data + - xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address))); + dep = (xfs_dir2_data_entry_t *)((char *)dbp->data + + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address))); /* - * If it matches then return it. + * Compare name and if it's an exact match, return the index + * and buffer. If it's the first case-insensitive match, store + * the index and buffer and continue looking for an exact match. */ - if (dep->namelen == args->namelen && - dep->name[0] == args->name[0] && - memcmp(dep->name, args->name, args->namelen) == 0) { - *dbpp = dbp; + cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen); + if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) { + args->cmpresult = cmp; *indexp = index; - return 0; + /* + * case exact match: release the stored CI buffer if it + * exists and return the current buffer. + */ + if (cmp == XFS_CMP_EXACT) { + if (cbp && cbp != dbp) + xfs_da_brelse(tp, cbp); + *dbpp = dbp; + return 0; + } + cbp = dbp; } } + ASSERT(args->oknoent); + /* + * Here, we can only be doing a lookup (not a rename or replace). + * If a case-insensitive match was found earlier, release the current + * buffer and return the stored CI matching buffer. + */ + if (args->cmpresult == XFS_CMP_CASE) { + if (cbp != dbp) + xfs_da_brelse(tp, dbp); + *dbpp = cbp; + return 0; + } /* * No match found, return ENOENT. */ - ASSERT(args->oknoent); + ASSERT(cbp == NULL); if (dbp) xfs_da_brelse(tp, dbp); xfs_da_brelse(tp, lbp); -- cgit 1.4.1