xattr.c

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/*
 *   Copyright (C) International Business Machines  Corp., 2000-2004
 *   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/capability.h>
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/slab.h>
#include <linux/quotaops.h>
#include <linux/security.h>
#include "jfs_incore.h"
#include "jfs_superblock.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"
#include "jfs_acl.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


static int is_known_namespace(const char *name)
{
    if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
        strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
        strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
        strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
        return false;

    return true;
}

/*
 * 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 int is_os2_xattr(struct jfs_ea *ea)
{
    return !is_known_namespace(ea->name);
}

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 -EPERM;

        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;
    }

    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;

    /* Allocate new blocks to quota. */
    rc = dquot_alloc_block(ip, nblocks);
    if (rc)
        return rc;

    rc = dbAlloc(ip, INOHINT(ip), nblocks, &blkno);
    if (rc) {
        /*Rollback quota allocation. */
        dquot_free_block(ip, nblocks);
        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:
    /* Rollback quota allocation. */
    dquot_free_block(ip, nblocks);

    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);
    if (!nbytes) {
        jfs_error(sb, "ea_read: nbytes is 0");
        return -EIO;
    }

    /*
     * 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;
    int quota_allocation = 0;

    /* 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 {
        if (!(ji->ea.flag & DXD_EXTENT)) {
            jfs_error(sb, "ea_get: invalid ea.flag)");
            return -EIO;
        }
        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) {
        /* Allocate new blocks to quota. */
        rc = dquot_alloc_block(inode, blocks_needed);
        if (rc)
            return -EDQUOT;

        quota_allocation = blocks_needed;

        rc = dbAlloc(inode, INOHINT(inode), (s64) blocks_needed,
                 &blkno);
        if (rc)
            goto clean_up;

        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);
            rc = -EIO;
            goto clean_up;
        }
        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);
            goto clean_up;
        }
        goto size_check;
    }
    ea_buf->flag = EA_EXTENT;
    ea_buf->mp = read_metapage(inode, addressDXD(&ji->ea),
                   lengthDXD(&ji->ea) << sb->s_blocksize_bits,
                   1);
    if (ea_buf->mp == NULL) {
        rc = -EIO;
        goto clean_up;
    }
    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");
        print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1,
                     ea_buf->xattr, ea_size, 1);
        ea_release(inode, ea_buf);
        rc = -EIO;
        goto clean_up;
    }

    return ea_size;

      clean_up:
    /* Rollback quota allocation */
    if (quota_allocation)
        dquot_free_block(inode, quota_allocation);

    return (rc);
}

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(tid_t tid, 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;

    if (new_size == 0) {
        ea_release(inode, ea_buf);
        ea_buf = NULL;
    } 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;

    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, NULL);
        if (ji->ea.flag & DXD_INLINE)
            ji->mode2 |= INLINEEA;
        ji->ea.flag = 0;
        ji->ea.size = 0;
    }

    /* If old blocks exist, they must be removed from quota allocation. */
    if (old_blocks)
        dquot_free_block(inode, old_blocks);

    inode->i_ctime = CURRENT_TIME;

    return 0;
}

/*
 * can_set_system_xattr
 *
 * This code is specific to the system.* namespace.  It contains policy
 * which doesn't belong in the main xattr codepath.
 */
static int can_set_system_xattr(struct inode *inode, const char *name,
                const void *value, size_t value_len)
{
#ifdef CONFIG_JFS_POSIX_ACL
    struct posix_acl *acl;
    int rc;

    if (!inode_owner_or_capable(inode))
        return -EPERM;

    /*
     * POSIX_ACL_XATTR_ACCESS is tied to i_mode
     */
    if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
        acl = posix_acl_from_xattr(&init_user_ns, value, value_len);
        if (IS_ERR(acl)) {
            rc = PTR_ERR(acl);
            printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
                   rc);
            return rc;
        }
        if (acl) {
            rc = posix_acl_equiv_mode(acl, &inode->i_mode);
            posix_acl_release(acl);
            if (rc < 0) {
                printk(KERN_ERR
                       "posix_acl_equiv_mode returned %d\n",
                       rc);
                return rc;
            }
            mark_inode_dirty(inode);
        }
        /*
         * We're changing the ACL.  Get rid of the cached one
         */
        forget_cached_acl(inode, ACL_TYPE_ACCESS);

        return 0;
    } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
        acl = posix_acl_from_xattr(&init_user_ns, value, value_len);
        if (IS_ERR(acl)) {
            rc = PTR_ERR(acl);
            printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
                   rc);
            return rc;
        }
        posix_acl_release(acl);

        /*
         * We're changing the default ACL.  Get rid of the cached one
         */
        forget_cached_acl(inode, ACL_TYPE_DEFAULT);

        return 0;
    }
#endif          /* CONFIG_JFS_POSIX_ACL */
    return -EOPNOTSUPP;
}

/*
 * Most of the permission checking is done by xattr_permission in the vfs.
 * The local file system is responsible for handling the system.* namespace.
 * We also need to verify that this is a namespace that we recognize.
 */
static int can_set_xattr(struct inode *inode, const char *name,
             const void *value, size_t value_len)
{
    if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
        return can_set_system_xattr(inode, name, value, value_len);

    if (!strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) {
        /*
         * This makes sure that we aren't trying to set an
         * attribute in a different namespace by prefixing it
         * with "os2."
         */
        if (is_known_namespace(name + XATTR_OS2_PREFIX_LEN))
                return -EOPNOTSUPP;
        return 0;
    }

    /*
     * Don't allow setting an attribute in an unknown namespace.
     */
    if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
        strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
        strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
        return -EOPNOTSUPP;

    return 0;
}

int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
           const 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 (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;
    }

    down_write(&JFS_IP(inode)->xattr_sem);

    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(tid, inode, &ea_buf, new_size);

    goto out;
      release:
    ea_release(inode, &ea_buf);
      out:
    up_write(&JFS_IP(inode)->xattr_sem);

    kfree(os2name);

    return rc;
}

int jfs_setxattr(struct dentry *dentry, const char *name, const void *value,
         size_t value_len, int flags)
{
    struct inode *inode = dentry->d_inode;
    struct jfs_inode_info *ji = JFS_IP(inode);
    int rc;
    tid_t tid;

    if ((rc = can_set_xattr(inode, name, value, value_len)))
        return rc;

    if (value == NULL) {    /* empty EA, do not remove */
        value = "";
        value_len = 0;
    }

    tid = txBegin(inode->i_sb, 0);
    mutex_lock(&ji->commit_mutex);
    rc = __jfs_setxattr(tid, dentry->d_inode, name, value, value_len,
                flags);
    if (!rc)
        rc = txCommit(tid, 1, &inode, 0);
    txEnd(tid);
    mutex_unlock(&ji->commit_mutex);

    return rc;
}

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 *value;

    down_read(&JFS_IP(inode)->xattr_sem);

    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:
    up_read(&JFS_IP(inode)->xattr_sem);

    return size;
}

ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
             size_t buf_size)
{
    int err;

    if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
        /*
         * skip past "os2." prefix
         */
        name += XATTR_OS2_PREFIX_LEN;
        /*
         * Don't allow retrieving properly prefixed attributes
         * by prepending them with "os2."
         */
        if (is_known_namespace(name))
            return -EOPNOTSUPP;
    }

    err = __jfs_getxattr(dentry->d_inode, name, data, buf_size);

    return err;
}

/*
 * No special permissions are needed to list attributes except for trusted.*
 */
static inline int can_list(struct jfs_ea *ea)
{
    return (strncmp(ea->name, XATTR_TRUSTED_PREFIX,
                XATTR_TRUSTED_PREFIX_LEN) ||
        capable(CAP_SYS_ADMIN));
}

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;

    down_read(&JFS_IP(inode)->xattr_sem);

    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)) {
        if (can_list(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)) {
        if (can_list(ea)) {
            int namelen = copy_name(buffer, ea);
            buffer += namelen + 1;
        }
    }

      release:
    ea_release(inode, &ea_buf);
      out:
    up_read(&JFS_IP(inode)->xattr_sem);
    return size;
}

int jfs_removexattr(struct dentry *dentry, const char *name)
{
    struct inode *inode = dentry->d_inode;
    struct jfs_inode_info *ji = JFS_IP(inode);
    int rc;
    tid_t tid;

    if ((rc = can_set_xattr(inode, name, NULL, 0)))
        return rc;

    tid = txBegin(inode->i_sb, 0);
    mutex_lock(&ji->commit_mutex);
    rc = __jfs_setxattr(tid, dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
    if (!rc)
        rc = txCommit(tid, 1, &inode, 0);
    txEnd(tid);
    mutex_unlock(&ji->commit_mutex);

    return rc;
}

#ifdef CONFIG_JFS_SECURITY
int jfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
           void *fs_info)
{
    const struct xattr *xattr;
    tid_t *tid = fs_info;
    char *name;
    int err = 0;

    for (xattr = xattr_array; xattr->name != NULL; xattr++) {
        name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
                   strlen(xattr->name) + 1, GFP_NOFS);
        if (!name) {
            err = -ENOMEM;
            break;
        }
        strcpy(name, XATTR_SECURITY_PREFIX);
        strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);

        err = __jfs_setxattr(*tid, inode, name,
                     xattr->value, xattr->value_len, 0);
        kfree(name);
        if (err < 0)
            break;
    }
    return err;
}

int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir,
              const struct qstr *qstr)
{
    return security_inode_init_security(inode, dir, qstr,
                        &jfs_initxattrs, &tid);
}
#endif