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xattr.c

/*
 *   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/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


/*
 * 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;
      /*
       * Check for "security."
       */
      if ((ea->namelen >= XATTR_SECURITY_PREFIX_LEN) &&
          !strncmp(ea->name, XATTR_SECURITY_PREFIX,
                 XATTR_SECURITY_PREFIX_LEN))
            return false;
      /*
       * Check for "trusted."
       */
      if ((ea->namelen >= XATTR_TRUSTED_PREFIX_LEN) &&
          !strncmp(ea->name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_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 -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. */
      if (DQUOT_ALLOC_BLOCK(ip, nblocks)) {
            return -EDQUOT;
      }

      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. */
            if (DQUOT_ALLOC_BLOCK(inode, blocks_needed))
                  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 (!is_owner_or_cap(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(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) {
                  mode_t mode = inode->i_mode;
                  rc = posix_acl_equiv_mode(acl, &mode);
                  posix_acl_release(acl);
                  if (rc < 0) {
                        printk(KERN_ERR
                               "posix_acl_equiv_mode returned %d\n",
                               rc);
                        return rc;
                  }
                  inode->i_mode = mode;
                  mark_inode_dirty(inode);
            }
            /*
             * We're changing the ACL.  Get rid of the cached one
             */
            acl =JFS_IP(inode)->i_acl;
            if (acl != JFS_ACL_NOT_CACHED)
                  posix_acl_release(acl);
            JFS_IP(inode)->i_acl = JFS_ACL_NOT_CACHED;

            return 0;
      } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
            acl = posix_acl_from_xattr(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
             */
            acl =JFS_IP(inode)->i_default_acl;
            if (acl && (acl != JFS_ACL_NOT_CACHED))
                  posix_acl_release(acl);
            JFS_IP(inode)->i_default_acl = JFS_ACL_NOT_CACHED;

            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);

      /*
       * 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) &&
          strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_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 *os2name = NULL;
      char *value;

      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_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);

      kfree(os2name);

      return size;
}

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

      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_init_security(tid_t tid, struct inode *inode, struct inode *dir)
{
      int rc;
      size_t len;
      void *value;
      char *suffix;
      char *name;

      rc = security_inode_init_security(inode, dir, &suffix, &value, &len);
      if (rc) {
            if (rc == -EOPNOTSUPP)
                  return 0;
            return rc;
      }
      name = kmalloc(XATTR_SECURITY_PREFIX_LEN + 1 + strlen(suffix),
                   GFP_NOFS);
      if (!name) {
            rc = -ENOMEM;
            goto kmalloc_failed;
      }
      strcpy(name, XATTR_SECURITY_PREFIX);
      strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);

      rc = __jfs_setxattr(tid, inode, name, value, len, 0);

      kfree(name);
kmalloc_failed:
      kfree(suffix);
      kfree(value);

      return rc;
}
#endif

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