Commit 5163f95a authored by Barry Naujok's avatar Barry Naujok Committed by Niv Sardi
Browse files

[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: default avatarBarry Naujok <bnaujok@sgi.com>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
parent 68f34d51

fs/xfs/xfs_da_btree.c

+22 −0
Original line number Diff line number Diff line
@@ -1530,6 +1530,28 @@ xfs_da_hashname(const uchar_t *name, int namelen) 
	}

}



enum xfs_dacmp

xfs_da_compname(

	struct xfs_da_args *args,

	const char 	*name,

	int 		len)

{

	return (args->namelen == len && memcmp(args->name, name, len) == 0) ?

					XFS_CMP_EXACT : XFS_CMP_DIFFERENT;

}



static xfs_dahash_t

xfs_default_hashname(

	struct xfs_name	*name)

{

	return xfs_da_hashname(name->name, name->len);

}



const struct xfs_nameops xfs_default_nameops = {

	.hashname	= xfs_default_hashname,

	.compname	= xfs_da_compname

};



/*

 * Add a block to the btree ahead of the file.

 * Return the new block number to the caller.

fs/xfs/xfs_da_btree.h

+22 −0
Original line number Diff line number Diff line
@@ -98,6 +98,15 @@ typedef struct xfs_da_node_entry xfs_da_node_entry_t; 
 * Btree searching and modification structure definitions.

 *========================================================================*/



/*

 * Search comparison results

 */

enum xfs_dacmp {

	XFS_CMP_DIFFERENT,	/* names are completely different */

	XFS_CMP_EXACT,		/* names are exactly the same */

	XFS_CMP_CASE		/* names are same but differ in case */

};



/*

 * Structure to ease passing around component names.

 */
@@ -127,6 +136,7 @@ typedef struct xfs_da_args { 
	unsigned char	rename;		/* T/F: this is an atomic rename op */

	unsigned char	addname;	/* T/F: this is an add operation */

	unsigned char	oknoent;	/* T/F: ok to return ENOENT, else die */

	enum xfs_dacmp	cmpresult;	/* name compare result for lookups */

} xfs_da_args_t;



/*
@@ -201,6 +211,14 @@ typedef struct xfs_da_state { 
		(uint)(XFS_DA_LOGOFF(BASE, ADDR)), \

		(uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)



/*

 * Name ops for directory and/or attr name operations

 */

struct xfs_nameops {

	xfs_dahash_t	(*hashname)(struct xfs_name *);

	enum xfs_dacmp	(*compname)(struct xfs_da_args *, const char *, int);

};





#ifdef __KERNEL__

/*========================================================================
@@ -249,6 +267,10 @@ int xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno, 
					  xfs_dabuf_t *dead_buf);



uint xfs_da_hashname(const uchar_t *name_string, int name_length);

enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,

				const char *name, int len);





xfs_da_state_t *xfs_da_state_alloc(void);

void xfs_da_state_free(xfs_da_state_t *state);

fs/xfs/xfs_dir2.c

+7 −5
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ xfs_dir_mount( 
		(mp->m_dirblksize - (uint)sizeof(xfs_da_node_hdr_t)) /

		(uint)sizeof(xfs_da_node_entry_t);

	mp->m_dir_magicpct = (mp->m_dirblksize * 37) / 100;

	mp->m_dirnameops = &xfs_default_nameops;

}



/*
@@ -164,7 +165,7 @@ xfs_dir_createname( 


	args.name = name->name;

	args.namelen = name->len;

	args.hashval = xfs_da_hashname(name->name, name->len);

	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

	args.inumber = inum;

	args.dp = dp;

	args.firstblock = first;
@@ -210,11 +211,12 @@ xfs_dir_lookup( 


	args.name = name->name;

	args.namelen = name->len;

	args.hashval = xfs_da_hashname(name->name, name->len);

	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

	args.dp = dp;

	args.whichfork = XFS_DATA_FORK;

	args.trans = tp;

	args.oknoent = 1;

	args.cmpresult = XFS_CMP_DIFFERENT;



	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)

		rval = xfs_dir2_sf_lookup(&args);
@@ -257,7 +259,7 @@ xfs_dir_removename( 


	args.name = name->name;

	args.namelen = name->len;

	args.hashval = xfs_da_hashname(name->name, name->len);

	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

	args.inumber = ino;

	args.dp = dp;

	args.firstblock = first;
@@ -340,7 +342,7 @@ xfs_dir_replace( 


	args.name = name->name;

	args.namelen = name->len;

	args.hashval = xfs_da_hashname(name->name, name->len);

	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

	args.inumber = inum;

	args.dp = dp;

	args.firstblock = first;
@@ -388,7 +390,7 @@ xfs_dir_canenter( 


	args.name = name->name;

	args.namelen = name->len;

	args.hashval = xfs_da_hashname(name->name, name->len);

	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

	args.dp = dp;

	args.whichfork = XFS_DATA_FORK;

	args.trans = tp;

fs/xfs/xfs_dir2_block.c

+24 −9
Original line number Diff line number Diff line
@@ -643,6 +643,7 @@ xfs_dir2_block_lookup_int( 
	int			mid;		/* binary search current idx */

	xfs_mount_t		*mp;		/* filesystem mount point */

	xfs_trans_t		*tp;		/* transaction pointer */

	enum xfs_dacmp		cmp;		/* comparison result */



	dp = args->dp;

	tp = args->trans;
@@ -697,20 +698,31 @@ xfs_dir2_block_lookup_int( 
		dep = (xfs_dir2_data_entry_t *)

			((char *)block + xfs_dir2_dataptr_to_off(mp, addr));

		/*

		 * Compare, if it's right give back buffer & entry number.

		 * 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) {

		cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);

		if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {

			args->cmpresult = cmp;

			*bpp = bp;

			*entno = mid;

			if (cmp == XFS_CMP_EXACT)

				return 0;

		}

	} while (++mid < be32_to_cpu(btp->count) && be32_to_cpu(blp[mid].hashval) == hash);

	} while (++mid < be32_to_cpu(btp->count) &&

			be32_to_cpu(blp[mid].hashval) == hash);



	ASSERT(args->oknoent);

	/*

	 * Here, we can only be doing a lookup (not a rename or replace).

	 * If a case-insensitive match was found earlier, return success.

	 */

	if (args->cmpresult == XFS_CMP_CASE)

		return 0;

	/*

	 * No match, release the buffer and return ENOENT.

	 */

	ASSERT(args->oknoent);

	xfs_da_brelse(tp, bp);

	return XFS_ERROR(ENOENT);

}
@@ -1033,6 +1045,7 @@ xfs_dir2_sf_to_block( 
	xfs_dir2_sf_t		*sfp;		/* shortform structure */

	__be16			*tagp;		/* end of data entry */

	xfs_trans_t		*tp;		/* transaction pointer */

	struct xfs_name		name;



	xfs_dir2_trace_args("sf_to_block", args);

	dp = args->dp;
@@ -1187,8 +1200,10 @@ xfs_dir2_sf_to_block( 
		tagp = xfs_dir2_data_entry_tag_p(dep);

		*tagp = cpu_to_be16((char *)dep - (char *)block);

		xfs_dir2_data_log_entry(tp, bp, dep);

		blp[2 + i].hashval = cpu_to_be32(xfs_da_hashname(

					(char *)sfep->name, sfep->namelen));

		name.name = sfep->name;

		name.len = sfep->namelen;

		blp[2 + i].hashval = cpu_to_be32(mp->m_dirnameops->

							hashname(&name));

		blp[2 + i].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,

						 (char *)dep - (char *)block));

		offset = (int)((char *)(tagp + 1) - (char *)block);

fs/xfs/xfs_dir2_data.c

+4 −1
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ xfs_dir2_data_check( 
	xfs_mount_t		*mp;		/* filesystem mount point */

	char			*p;		/* current data position */

	int			stale;		/* count of stale leaves */

	struct xfs_name		name;



	mp = dp->i_mount;

	d = bp->data;
@@ -140,7 +141,9 @@ xfs_dir2_data_check( 
			addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,

				(xfs_dir2_data_aoff_t)

				((char *)dep - (char *)d));

			hash = xfs_da_hashname((char *)dep->name, dep->namelen);

			name.name = dep->name;

			name.len = dep->namelen;

			hash = mp->m_dirnameops->hashname(&name);

			for (i = 0; i < be32_to_cpu(btp->count); i++) {

				if (be32_to_cpu(lep[i].address) == addr &&

				    be32_to_cpu(lep[i].hashval) == hash)

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