patch-2.4.20 linux-2.4.20/fs/jfs/xattr.c

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diff -urN linux-2.4.19/fs/jfs/xattr.c linux-2.4.20/fs/jfs/xattr.c
@@ -0,0 +1,937 @@
+/*
+ *   Copyright (c) International Business Machines  Corp., 2000-2002
+ *   Copyright (c) Christoph Hellwig, 2002
+ *
+ *   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; either version 2 of the License, or 
+ *   (at your option) any later version.
+ * 
+ *   This program is distributed in the hope that it will 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 to the Free Software 
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include "jfs_incore.h"
+#include "jfs_dmap.h"
+#include "jfs_debug.h"
+#include "jfs_dinode.h"
+#include "jfs_extent.h"
+#include "jfs_metapage.h"
+#include "jfs_xattr.h"
+
+/*
+ *	jfs_xattr.c: extended attribute service
+ *
+ * Overall design --
+ *
+ * Format:
+ *
+ *   Extended attribute lists (jfs_ea_list) consist of an overall size (32 bit
+ *   value) and a variable (0 or more) number of extended attribute
+ *   entries.  Each extended attribute entry (jfs_ea) is a <name,value> double
+ *   where <name> is constructed from a null-terminated ascii string
+ *   (1 ... 255 bytes in the name) and <value> is arbitrary 8 bit data
+ *   (1 ... 65535 bytes).  The in-memory format is
+ *
+ *   0       1        2        4                4 + namelen + 1
+ *   +-------+--------+--------+----------------+-------------------+
+ *   | Flags | Name   | Value  | Name String \0 | Data . . . .      |
+ *   |       | Length | Length |                |                   |
+ *   +-------+--------+--------+----------------+-------------------+
+ *
+ *   A jfs_ea_list then is structured as
+ *
+ *   0            4                   4 + EA_SIZE(ea1)
+ *   +------------+-------------------+--------------------+-----
+ *   | Overall EA | First FEA Element | Second FEA Element | ..... 
+ *   | List Size  |                   |                    |
+ *   +------------+-------------------+--------------------+-----
+ *
+ *   On-disk:
+ *
+ *     FEALISTs are stored on disk using blocks allocated by dbAlloc() and
+ *     written directly. An EA list may be in-lined in the inode if there is
+ *     sufficient room available.
+ */
+
+struct ea_buffer {
+	int flag;		/* Indicates what storage xattr points to */
+	int max_size;		/* largest xattr that fits in current buffer */
+	dxd_t new_ea;		/* dxd to replace ea when modifying xattr */
+	struct metapage *mp;	/* metapage containing ea list */
+	struct jfs_ea_list *xattr;	/* buffer containing ea list */
+};
+
+/*
+ * ea_buffer.flag values
+ */
+#define EA_INLINE	0x0001
+#define EA_EXTENT	0x0002
+#define EA_NEW		0x0004
+#define EA_MALLOC	0x0008
+
+/* Namespaces */
+#define XATTR_SYSTEM_PREFIX "system."
+#define XATTR_SYSTEM_PREFIX_LEN (sizeof (XATTR_SYSTEM_PREFIX) - 1)
+
+#define XATTR_USER_PREFIX "user."
+#define XATTR_USER_PREFIX_LEN (sizeof (XATTR_USER_PREFIX) - 1)
+
+#define XATTR_OS2_PREFIX "os2."
+#define XATTR_OS2_PREFIX_LEN (sizeof (XATTR_OS2_PREFIX) - 1)
+
+/*
+ * These three routines are used to recognize on-disk extended attributes
+ * that are in a recognized namespace.  If the attribute is not recognized,
+ * "os2." is prepended to the name
+ */
+static inline int is_os2_xattr(struct jfs_ea *ea)
+{
+	/*
+	 * Check for "system."
+	 */
+	if ((ea->namelen >= XATTR_SYSTEM_PREFIX_LEN) &&
+	    !strncmp(ea->name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return FALSE;
+	/*
+	 * Check for "user."
+	 */
+	if ((ea->namelen >= XATTR_USER_PREFIX_LEN) &&
+	    !strncmp(ea->name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
+		return FALSE;
+	/*
+	 * Add any other valid namespace prefixes here
+	 */
+
+	/*
+	 * We assume it's OS/2's flat namespace
+	 */
+	return TRUE;
+}
+
+static inline int name_size(struct jfs_ea *ea)
+{
+	if (is_os2_xattr(ea))
+		return ea->namelen + XATTR_OS2_PREFIX_LEN;
+	else
+		return ea->namelen;
+}
+
+static inline int copy_name(char *buffer, struct jfs_ea *ea)
+{
+	int len = ea->namelen;
+
+	if (is_os2_xattr(ea)) {
+		memcpy(buffer, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN);
+		buffer += XATTR_OS2_PREFIX_LEN;
+		len += XATTR_OS2_PREFIX_LEN;
+	}
+	memcpy(buffer, ea->name, ea->namelen);
+	buffer[ea->namelen] = 0;
+
+	return len;
+}
+
+/* Forward references */
+static void ea_release(struct inode *inode, struct ea_buffer *ea_buf);
+
+/*
+ * NAME: ea_write_inline
+ *                                                                    
+ * FUNCTION: Attempt to write an EA inline if area is available
+ *                                                                    
+ * PRE CONDITIONS:
+ *	Already verified that the specified EA is small enough to fit inline
+ *
+ * PARAMETERS:
+ *	ip	- Inode pointer
+ *	ealist	- EA list pointer
+ *	size	- size of ealist in bytes
+ *	ea	- dxd_t structure to be filled in with necessary EA information
+ *		  if we successfully copy the EA inline
+ *
+ * NOTES:
+ *	Checks if the inode's inline area is available.  If so, copies EA inline
+ *	and sets <ea> fields appropriately.  Otherwise, returns failure, EA will
+ *	have to be put into an extent.
+ *
+ * RETURNS: 0 for successful copy to inline area; -1 if area not available
+ */
+static int ea_write_inline(struct inode *ip, struct jfs_ea_list *ealist,
+			   int size, dxd_t * ea)
+{
+	struct jfs_inode_info *ji = JFS_IP(ip);
+
+	/*
+	 * Make sure we have an EA -- the NULL EA list is valid, but you
+	 * can't copy it!
+	 */
+	if (ealist && size > sizeof (struct jfs_ea_list)) {
+		assert(size <= sizeof (ji->i_inline_ea));
+
+		/*
+		 * See if the space is available or if it is already being
+		 * used for an inline EA.
+		 */
+		if (!(ji->mode2 & INLINEEA) && !(ji->ea.flag & DXD_INLINE))
+			return -1;
+
+		DXDsize(ea, size);
+		DXDlength(ea, 0);
+		DXDaddress(ea, 0);
+		memcpy(ji->i_inline_ea, ealist, size);
+		ea->flag = DXD_INLINE;
+		ji->mode2 &= ~INLINEEA;
+	} else {
+		ea->flag = 0;
+		DXDsize(ea, 0);
+		DXDlength(ea, 0);
+		DXDaddress(ea, 0);
+
+		/* Free up INLINE area */
+		if (ji->ea.flag & DXD_INLINE)
+			ji->mode2 |= INLINEEA;
+	}
+
+	mark_inode_dirty(ip);
+	return 0;
+}
+
+/*
+ * NAME: ea_write
+ *                                                                    
+ * FUNCTION: Write an EA for an inode
+ *                                                                    
+ * PRE CONDITIONS: EA has been verified 
+ *
+ * PARAMETERS:
+ *	ip	- Inode pointer
+ *	ealist	- EA list pointer
+ *	size	- size of ealist in bytes
+ *	ea	- dxd_t structure to be filled in appropriately with where the
+ *		  EA was copied
+ *
+ * NOTES: Will write EA inline if able to, otherwise allocates blocks for an
+ *	extent and synchronously writes it to those blocks.
+ *
+ * RETURNS: 0 for success; Anything else indicates failure
+ */
+static int ea_write(struct inode *ip, struct jfs_ea_list *ealist, int size,
+		       dxd_t * ea)
+{
+	struct super_block *sb = ip->i_sb;
+	struct jfs_inode_info *ji = JFS_IP(ip);
+	struct jfs_sb_info *sbi = JFS_SBI(sb);
+	int nblocks;
+	s64 blkno;
+	int rc = 0, i;
+	char *cp;
+	s32 nbytes, nb;
+	s32 bytes_to_write;
+	struct metapage *mp;
+
+	/*
+	 * Quick check to see if this is an in-linable EA.  Short EAs
+	 * and empty EAs are all in-linable, provided the space exists.
+	 */
+	if (!ealist || size <= sizeof (ji->i_inline_ea)) {
+		if (!ea_write_inline(ip, ealist, size, ea))
+			return 0;
+	}
+
+	/* figure out how many blocks we need */
+	nblocks = (size + (sb->s_blocksize - 1)) >> sb->s_blocksize_bits;
+
+	rc = dbAlloc(ip, INOHINT(ip), nblocks, &blkno);
+	if (rc)
+		return -rc;
+
+	/*
+	 * Now have nblocks worth of storage to stuff into the FEALIST.
+	 * loop over the FEALIST copying data into the buffer one page at
+	 * a time.
+	 */
+	cp = (char *) ealist;
+	nbytes = size;
+	for (i = 0; i < nblocks; i += sbi->nbperpage) {
+		/*
+		 * Determine how many bytes for this request, and round up to
+		 * the nearest aggregate block size
+		 */
+		nb = min(PSIZE, nbytes);
+		bytes_to_write =
+		    ((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
+		    << sb->s_blocksize_bits;
+
+		if (!(mp = get_metapage(ip, blkno + i, bytes_to_write, 1))) {
+			rc = -EIO;
+			goto failed;
+		}
+
+		memcpy(mp->data, cp, nb);
+
+		/*
+		 * We really need a way to propagate errors for
+		 * forced writes like this one.  --hch
+		 *
+		 * (__write_metapage => release_metapage => flush_metapage)
+		 */
+#ifdef _JFS_FIXME
+		if ((rc = flush_metapage(mp))) {
+			/*
+			 * the write failed -- this means that the buffer
+			 * is still assigned and the blocks are not being
+			 * used.  this seems like the best error recovery
+			 * we can get ...
+			 */
+			goto failed;
+		}
+#else
+		flush_metapage(mp);
+#endif
+
+		cp += PSIZE;
+		nbytes -= nb;
+	}
+
+	ea->flag = DXD_EXTENT;
+	DXDsize(ea, le32_to_cpu(ealist->size));
+	DXDlength(ea, nblocks);
+	DXDaddress(ea, blkno);
+
+	/* Free up INLINE area */
+	if (ji->ea.flag & DXD_INLINE)
+		ji->mode2 |= INLINEEA;
+
+	return 0;
+
+      failed:
+	dbFree(ip, blkno, nblocks);
+	return rc;
+}
+
+/*
+ * NAME: ea_read_inline
+ *                                                                    
+ * FUNCTION: Read an inlined EA into user's buffer
+ *                                                                    
+ * PARAMETERS:
+ *	ip	- Inode pointer
+ *	ealist	- Pointer to buffer to fill in with EA
+ *
+ * RETURNS: 0
+ */
+static int ea_read_inline(struct inode *ip, struct jfs_ea_list *ealist)
+{
+	struct jfs_inode_info *ji = JFS_IP(ip);
+	int ea_size = sizeDXD(&ji->ea);
+
+	if (ea_size == 0) {
+		ealist->size = 0;
+		return 0;
+	}
+
+	/* Sanity Check */
+	if ((sizeDXD(&ji->ea) > sizeof (ji->i_inline_ea)))
+		return -EIO;
+	if (le32_to_cpu(((struct jfs_ea_list *) &ji->i_inline_ea)->size)
+	    != ea_size)
+		return -EIO;
+
+	memcpy(ealist, ji->i_inline_ea, ea_size);
+	return 0;
+}
+
+/*
+ * NAME: ea_read
+ *                                                                    
+ * FUNCTION: copy EA data into user's buffer
+ *                                                                    
+ * PARAMETERS:
+ *	ip	- Inode pointer
+ *	ealist	- Pointer to buffer to fill in with EA
+ *
+ * NOTES:  If EA is inline calls ea_read_inline() to copy EA.
+ *
+ * RETURNS: 0 for success; other indicates failure
+ */
+static int ea_read(struct inode *ip, struct jfs_ea_list *ealist)
+{
+	struct super_block *sb = ip->i_sb;
+	struct jfs_inode_info *ji = JFS_IP(ip);
+	struct jfs_sb_info *sbi = JFS_SBI(sb);
+	int nblocks;
+	s64 blkno;
+	char *cp = (char *) ealist;
+	int i;
+	int nbytes, nb;
+	s32 bytes_to_read;
+	struct metapage *mp;
+
+	/* quick check for in-line EA */
+	if (ji->ea.flag & DXD_INLINE)
+		return ea_read_inline(ip, ealist);
+
+	nbytes = sizeDXD(&ji->ea);
+	assert(nbytes);
+
+	/* 
+	 * Figure out how many blocks were allocated when this EA list was
+	 * originally written to disk.
+	 */
+	nblocks = lengthDXD(&ji->ea) << sbi->l2nbperpage;
+	blkno = addressDXD(&ji->ea) << sbi->l2nbperpage;
+
+	/*
+	 * I have found the disk blocks which were originally used to store
+	 * the FEALIST.  now i loop over each contiguous block copying the
+	 * data into the buffer.
+	 */
+	for (i = 0; i < nblocks; i += sbi->nbperpage) {
+		/*
+		 * Determine how many bytes for this request, and round up to
+		 * the nearest aggregate block size
+		 */
+		nb = min(PSIZE, nbytes);
+		bytes_to_read =
+		    ((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
+		    << sb->s_blocksize_bits;
+
+		if (!(mp = read_metapage(ip, blkno + i, bytes_to_read, 1)))
+			return -EIO;
+
+		memcpy(cp, mp->data, nb);
+		release_metapage(mp);
+
+		cp += PSIZE;
+		nbytes -= nb;
+	}
+
+	return 0;
+}
+
+/*
+ * NAME: ea_get
+ *                                                                    
+ * FUNCTION: Returns buffer containing existing extended attributes.
+ *	     The size of the buffer will be the larger of the existing
+ *	     attributes size, or min_size.
+ *
+ *	     The buffer, which may be inlined in the inode or in the
+ * 	     page cache must be release by calling ea_release or ea_put
+ *                                                                    
+ * PARAMETERS:
+ *	inode	- Inode pointer
+ *	ea_buf	- Structure to be populated with ealist and its metadata
+ *	min_size- minimum size of buffer to be returned
+ *
+ * RETURNS: 0 for success; Other indicates failure
+ */
+static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
+{
+	struct jfs_inode_info *ji = JFS_IP(inode);
+	struct super_block *sb = inode->i_sb;
+	int size;
+	int ea_size = sizeDXD(&ji->ea);
+	int blocks_needed, current_blocks;
+	s64 blkno;
+	int rc;
+
+	/* When fsck.jfs clears a bad ea, it doesn't clear the size */
+	if (ji->ea.flag == 0)
+		ea_size = 0;
+
+	if (ea_size == 0) {
+		if (min_size == 0) {
+			ea_buf->flag = 0;
+			ea_buf->max_size = 0;
+			ea_buf->xattr = NULL;
+			return 0;
+		}
+		if ((min_size <= sizeof (ji->i_inline_ea)) &&
+		    (ji->mode2 & INLINEEA)) {
+			ea_buf->flag = EA_INLINE | EA_NEW;
+			ea_buf->max_size = sizeof (ji->i_inline_ea);
+			ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
+			DXDlength(&ea_buf->new_ea, 0);
+			DXDaddress(&ea_buf->new_ea, 0);
+			ea_buf->new_ea.flag = DXD_INLINE;
+			DXDsize(&ea_buf->new_ea, min_size);
+			return 0;
+		}
+		current_blocks = 0;
+	} else if (ji->ea.flag & DXD_INLINE) {
+		if (min_size <= sizeof (ji->i_inline_ea)) {
+			ea_buf->flag = EA_INLINE;
+			ea_buf->max_size = sizeof (ji->i_inline_ea);
+			ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
+			goto size_check;
+		}
+		current_blocks = 0;
+	} else {
+		assert(ji->ea.flag & DXD_EXTENT);
+		current_blocks = (ea_size + sb->s_blocksize - 1) >>
+		    sb->s_blocksize_bits;
+	}
+	size = max(min_size, ea_size);
+
+	if (size > PSIZE) {
+		/*
+		 * To keep the rest of the code simple.  Allocate a
+		 * contiguous buffer to work with
+		 */
+		ea_buf->xattr = kmalloc(size, GFP_KERNEL);
+		if (ea_buf->xattr == NULL)
+			return -ENOMEM;
+
+		ea_buf->flag |= EA_MALLOC;
+		ea_buf->max_size = (size + sb->s_blocksize - 1) &
+		    ~(sb->s_blocksize - 1);
+
+		if (ea_size == 0)
+			return 0;
+
+		if ((rc = ea_read(inode, ea_buf->xattr))) {
+			kfree(ea_buf->xattr);
+			ea_buf->xattr = NULL;
+			return rc;
+		}
+		goto size_check;
+	}
+	blocks_needed = (min_size + sb->s_blocksize - 1) >>
+	    sb->s_blocksize_bits;
+
+	if (blocks_needed > current_blocks) {
+		rc = dbAlloc(inode, INOHINT(inode), (s64) blocks_needed,
+			     &blkno);
+		if (rc)
+			return -rc;
+
+		DXDlength(&ea_buf->new_ea, blocks_needed);
+		DXDaddress(&ea_buf->new_ea, blkno);
+		ea_buf->new_ea.flag = DXD_EXTENT;
+		DXDsize(&ea_buf->new_ea, min_size);
+
+		ea_buf->flag = EA_EXTENT | EA_NEW;
+
+		ea_buf->mp = get_metapage(inode, blkno,
+					  blocks_needed << sb->s_blocksize_bits,
+					  1);
+		if (ea_buf->mp == NULL) {
+			dbFree(inode, blkno, (s64) blocks_needed);
+			return -EIO;
+		}
+		ea_buf->xattr = ea_buf->mp->data;
+		ea_buf->max_size = (min_size + sb->s_blocksize - 1) &
+		    ~(sb->s_blocksize - 1);
+		if (ea_size == 0)
+			return 0;
+		if ((rc = ea_read(inode, ea_buf->xattr))) {
+			discard_metapage(ea_buf->mp);
+			dbFree(inode, blkno, (s64) blocks_needed);
+			return rc;
+		}
+		goto size_check;
+	}
+	ea_buf->flag = EA_EXTENT;
+	ea_buf->mp = read_metapage(inode, addressDXD(&ji->ea),
+				   lengthDXD(&ji->ea), 1);
+	if (ea_buf->mp == NULL)
+		return -EIO;
+	ea_buf->xattr = ea_buf->mp->data;
+	ea_buf->max_size = (ea_size + sb->s_blocksize - 1) &
+	    ~(sb->s_blocksize - 1);
+
+      size_check:
+	if (EALIST_SIZE(ea_buf->xattr) != ea_size) {
+		printk(KERN_ERR "ea_get: invalid extended attribute\n");
+		dump_mem("xattr", ea_buf->xattr, ea_size);
+		ea_release(inode, ea_buf);
+		return -EIO;
+	}
+
+	return ea_size;
+}
+
+static void ea_release(struct inode *inode, struct ea_buffer *ea_buf)
+{
+	if (ea_buf->flag & EA_MALLOC)
+		kfree(ea_buf->xattr);
+	else if (ea_buf->flag & EA_EXTENT) {
+		assert(ea_buf->mp);
+		release_metapage(ea_buf->mp);
+
+		if (ea_buf->flag & EA_NEW)
+			dbFree(inode, addressDXD(&ea_buf->new_ea),
+			       lengthDXD(&ea_buf->new_ea));
+	}
+}
+
+static int ea_put(struct inode *inode, struct ea_buffer *ea_buf, int new_size)
+{
+	struct jfs_inode_info *ji = JFS_IP(inode);
+	unsigned long old_blocks, new_blocks;
+	int rc = 0;
+	tid_t tid;
+
+	if (new_size == 0) {
+		ea_release(inode, ea_buf);
+		ea_buf = 0;
+	} else if (ea_buf->flag & EA_INLINE) {
+		assert(new_size <= sizeof (ji->i_inline_ea));
+		ji->mode2 &= ~INLINEEA;
+		ea_buf->new_ea.flag = DXD_INLINE;
+		DXDsize(&ea_buf->new_ea, new_size);
+		DXDaddress(&ea_buf->new_ea, 0);
+		DXDlength(&ea_buf->new_ea, 0);
+	} else if (ea_buf->flag & EA_MALLOC) {
+		rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
+		kfree(ea_buf->xattr);
+	} else if (ea_buf->flag & EA_NEW) {
+		/* We have already allocated a new dxd */
+		flush_metapage(ea_buf->mp);
+	} else {
+		/* ->xattr must point to original ea's metapage */
+		rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
+		discard_metapage(ea_buf->mp);
+	}
+	if (rc)
+		return rc;
+
+	tid = txBegin(inode->i_sb, 0);
+	down(&ji->commit_sem);
+
+	old_blocks = new_blocks = 0;
+
+	if (ji->ea.flag & DXD_EXTENT) {
+		invalidate_dxd_metapages(inode, ji->ea);
+		old_blocks = lengthDXD(&ji->ea);
+	}
+
+	if (ea_buf) {
+		txEA(tid, inode, &ji->ea, &ea_buf->new_ea);
+		if (ea_buf->new_ea.flag & DXD_EXTENT) {
+			new_blocks = lengthDXD(&ea_buf->new_ea);
+			if (ji->ea.flag & DXD_INLINE)
+				ji->mode2 |= INLINEEA;
+		}
+		ji->ea = ea_buf->new_ea;
+	} else {
+		txEA(tid, inode, &ji->ea, 0);
+		if (ji->ea.flag & DXD_INLINE)
+			ji->mode2 |= INLINEEA;
+		ji->ea.flag = 0;
+		ji->ea.size = 0;
+	}
+
+	inode->i_blocks += LBLK2PBLK(inode->i_sb, new_blocks - old_blocks);
+	rc = txCommit(tid, 1, &inode, 0);
+	txEnd(tid);
+	up(&ji->commit_sem);
+
+	return rc;
+}
+
+static int can_set_xattr(struct inode *inode, const char *name,
+			 void *value, size_t value_len)
+{
+	if (IS_RDONLY(inode))
+		return -EROFS;
+
+	if (IS_IMMUTABLE(inode) || IS_APPEND(inode) || S_ISLNK(inode->i_mode))
+		return -EPERM;
+
+	if((strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) != 0) &&
+	   (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) != 0))
+		return -EOPNOTSUPP;
+
+	if (!S_ISREG(inode->i_mode) &&
+	    (!S_ISDIR(inode->i_mode) || inode->i_mode &S_ISVTX))
+		return -EPERM;
+
+	return permission(inode, MAY_WRITE);
+}
+
+int __jfs_setxattr(struct inode *inode, const char *name, void *value,
+		   size_t value_len, int flags)
+{
+	struct jfs_ea_list *ealist;
+	struct jfs_ea *ea, *old_ea = NULL, *next_ea = NULL;
+	struct ea_buffer ea_buf;
+	int old_ea_size = 0;
+	int xattr_size;
+	int new_size;
+	int namelen = strlen(name);
+	char *os2name = NULL;
+	int found = 0;
+	int rc;
+	int length;
+
+	if ((rc = can_set_xattr(inode, name, value, value_len)))
+		return rc;
+
+	if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
+		os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
+				  GFP_KERNEL);
+		if (!os2name)
+			return -ENOMEM;
+		strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
+		name = os2name;
+		namelen -= XATTR_OS2_PREFIX_LEN;
+	}
+
+	xattr_size = ea_get(inode, &ea_buf, 0);
+	if (xattr_size < 0) {
+		rc = xattr_size;
+		goto out;
+	}
+
+      again:
+	ealist = (struct jfs_ea_list *) ea_buf.xattr;
+	new_size = sizeof (struct jfs_ea_list);
+
+	if (xattr_size) {
+		for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist);
+		     ea = NEXT_EA(ea)) {
+			if ((namelen == ea->namelen) &&
+			    (memcmp(name, ea->name, namelen) == 0)) {
+				found = 1;
+				if (flags & XATTR_CREATE) {
+					rc = -EEXIST;
+					goto release;
+				}
+				old_ea = ea;
+				old_ea_size = EA_SIZE(ea);
+				next_ea = NEXT_EA(ea);
+			} else
+				new_size += EA_SIZE(ea);
+		}
+	}
+
+	if (!found) {
+		if (flags & XATTR_REPLACE) {
+			rc = -ENODATA;
+			goto release;
+		}
+		if (value == NULL) {
+			rc = 0;
+			goto release;
+		}
+	}
+	if (value)
+		new_size += sizeof (struct jfs_ea) + namelen + 1 + value_len;
+
+	if (new_size > ea_buf.max_size) {
+		/*
+		 * We need to allocate more space for merged ea list.
+		 * We should only have loop to again: once.
+		 */
+		ea_release(inode, &ea_buf);
+		xattr_size = ea_get(inode, &ea_buf, new_size);
+		if (xattr_size < 0) {
+			rc = xattr_size;
+			goto out;
+		}
+		goto again;
+	}
+
+	/* Remove old ea of the same name */
+	if (found) {
+		/* number of bytes following target EA */
+		length = (char *) END_EALIST(ealist) - (char *) next_ea;
+		if (length > 0)
+			memmove(old_ea, next_ea, length);
+		xattr_size -= old_ea_size;
+	}
+
+	/* Add new entry to the end */
+	if (value) {
+		if (xattr_size == 0)
+			/* Completely new ea list */
+			xattr_size = sizeof (struct jfs_ea_list);
+
+		ea = (struct jfs_ea *) ((char *) ealist + xattr_size);
+		ea->flag = 0;
+		ea->namelen = namelen;
+		ea->valuelen = (cpu_to_le16(value_len));
+		memcpy(ea->name, name, namelen);
+		ea->name[namelen] = 0;
+		if (value_len)
+			memcpy(&ea->name[namelen + 1], value, value_len);
+		xattr_size += EA_SIZE(ea);
+	}
+
+	/* DEBUG - If we did this right, these number match */
+	if (xattr_size != new_size) {
+		printk(KERN_ERR
+		       "jfs_xsetattr: xattr_size = %d, new_size = %d\n",
+		       xattr_size, new_size);
+
+		rc = -EINVAL;
+		goto release;
+	}
+
+	/*
+	 * If we're left with an empty list, there's no ea
+	 */
+	if (new_size == sizeof (struct jfs_ea_list))
+		new_size = 0;
+
+	ealist->size = cpu_to_le32(new_size);
+
+	rc = ea_put(inode, &ea_buf, new_size);
+
+	goto out;
+      release:
+	ea_release(inode, &ea_buf);
+      out:
+	if (os2name)
+		kfree(os2name);
+
+	return rc;
+}
+
+int jfs_setxattr(struct dentry *dentry, const char *name, void *value,
+		 size_t value_len, int flags)
+{
+	if (value == NULL) {	/* empty EA, do not remove */
+		value = "";
+		value_len = 0;
+	}
+
+	return __jfs_setxattr(dentry->d_inode, name, value, value_len, flags);
+}
+
+static inline int can_get_xattr(struct inode *inode, const char *name)
+{
+	return permission(inode, MAY_READ);
+}
+
+ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
+		       size_t buf_size)
+{
+	struct jfs_ea_list *ealist;
+	struct jfs_ea *ea;
+	struct ea_buffer ea_buf;
+	int xattr_size;
+	ssize_t size;
+	int namelen = strlen(name);
+	char *os2name = NULL;
+	int rc;
+	char *value;
+
+	if ((rc = can_get_xattr(inode, name)))
+		return rc;
+
+	if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
+		os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
+				  GFP_KERNEL);
+		if (!os2name)
+			return -ENOMEM;
+		strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
+		name = os2name;
+		namelen -= XATTR_OS2_PREFIX_LEN;
+	}
+
+	xattr_size = ea_get(inode, &ea_buf, 0);
+	if (xattr_size < 0) {
+		size = xattr_size;
+		goto out;
+	}
+
+	if (xattr_size == 0)
+		goto not_found;
+
+	ealist = (struct jfs_ea_list *) ea_buf.xattr;
+
+	/* Find the named attribute */
+	for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
+		if ((namelen == ea->namelen) &&
+		    memcmp(name, ea->name, namelen) == 0) {
+			/* Found it */
+			size = le16_to_cpu(ea->valuelen);
+			if (!data)
+				goto release;
+			else if (size > buf_size) {
+				size = -ERANGE;
+				goto release;
+			}
+			value = ((char *) &ea->name) + ea->namelen + 1;
+			memcpy(data, value, size);
+			goto release;
+		}
+      not_found:
+	size = -ENODATA;
+      release:
+	ea_release(inode, &ea_buf);
+      out:
+	if (os2name)
+		kfree(os2name);
+
+	return size;
+}
+
+ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
+		     size_t buf_size)
+{
+	return __jfs_getxattr(dentry->d_inode, name, data, buf_size);
+}
+
+ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
+{
+	struct inode *inode = dentry->d_inode;
+	char *buffer;
+	ssize_t size = 0;
+	int xattr_size;
+	struct jfs_ea_list *ealist;
+	struct jfs_ea *ea;
+	struct ea_buffer ea_buf;
+
+	xattr_size = ea_get(inode, &ea_buf, 0);
+	if (xattr_size < 0) {
+		size = xattr_size;
+		goto out;
+	}
+
+	if (xattr_size == 0)
+		goto release;
+
+	ealist = (struct jfs_ea_list *) ea_buf.xattr;
+
+	/* compute required size of list */
+	for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
+		size += name_size(ea) + 1;
+
+	if (!data)
+		goto release;
+
+	if (size > buf_size) {
+		size = -ERANGE;
+		goto release;
+	}
+
+	/* Copy attribute names to buffer */
+	buffer = data;
+	for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
+		int namelen = copy_name(buffer, ea);
+		buffer += namelen + 1;
+	}
+
+      release:
+	ea_release(inode, &ea_buf);
+      out:
+	return size;
+}
+
+int jfs_removexattr(struct dentry *dentry, const char *name)
+{
+	return __jfs_setxattr(dentry->d_inode, name, 0, 0, XATTR_REPLACE);
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)