From 384f3ced07efdddf6838f6527366089d37843c94 Mon Sep 17 00:00:00 2001 From: Barry Naujok Date: Wed, 21 May 2008 16:58:22 +1000 Subject: [XFS] Return case-insensitive match for dentry cache This implements the code to store the actual filename found during a lookup in the dentry cache and to avoid multiple entries in the dcache pointing to the same inode. To avoid polluting the dcache, we implement a new directory inode operations for lookup. xfs_vn_ci_lookup() stores the correct case name in the dcache. The "actual name" is only allocated and returned for a case- insensitive match and not an actual match. Another unusual interaction with the dcache is not storing negative dentries like other filesystems doing a d_add(dentry, NULL) when an ENOENT is returned. During the VFS lookup, if a dentry returned has no inode, dput is called and ENOENT is returned. By not doing a d_add, this actually removes it completely from the dcache to be reused. create/rename have to be modified to support unhashed dentries being passed in. SGI-PV: 981521 SGI-Modid: xfs-linux-melb:xfs-kern:31208a Signed-off-by: Barry Naujok Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_dir2.c | 40 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 38 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_dir2.c') diff --git a/fs/xfs/xfs_dir2.c b/fs/xfs/xfs_dir2.c index 3387acd3e47..882609c699c 100644 --- a/fs/xfs/xfs_dir2.c +++ b/fs/xfs/xfs_dir2.c @@ -192,15 +192,44 @@ xfs_dir_createname( return rval; } +/* + * If doing a CI lookup and case-insensitive match, dup actual name into + * args.value. Return EEXIST for success (ie. name found) or an error. + */ +int +xfs_dir_cilookup_result( + struct xfs_da_args *args, + const char *name, + int len) +{ + if (args->cmpresult == XFS_CMP_DIFFERENT) + return ENOENT; + if (args->cmpresult != XFS_CMP_CASE || + !(args->op_flags & XFS_DA_OP_CILOOKUP)) + return EEXIST; + + args->value = kmem_alloc(len, KM_MAYFAIL); + if (!args->value) + return ENOMEM; + + memcpy(args->value, name, len); + args->valuelen = len; + return EEXIST; +} + /* * Lookup a name in a directory, give back the inode number. + * If ci_name is not NULL, returns the actual name in ci_name if it differs + * to name, or ci_name->name is set to NULL for an exact match. */ + int xfs_dir_lookup( xfs_trans_t *tp, xfs_inode_t *dp, struct xfs_name *name, - xfs_ino_t *inum) /* out: inode number */ + xfs_ino_t *inum, /* out: inode number */ + struct xfs_name *ci_name) /* out: actual name if CI match */ { xfs_da_args_t args; int rval; @@ -217,6 +246,8 @@ xfs_dir_lookup( args.whichfork = XFS_DATA_FORK; args.trans = tp; args.op_flags = XFS_DA_OP_OKNOENT; + if (ci_name) + args.op_flags |= XFS_DA_OP_CILOOKUP; args.cmpresult = XFS_CMP_DIFFERENT; if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) @@ -233,8 +264,13 @@ xfs_dir_lookup( rval = xfs_dir2_node_lookup(&args); if (rval == EEXIST) rval = 0; - if (rval == 0) + if (!rval) { *inum = args.inumber; + if (ci_name) { + ci_name->name = args.value; + ci_name->len = args.valuelen; + } + } return rval; } -- cgit v1.2.3