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/*

 *   Copyright (C) International Business Machines  Corp., 2000-2003

 *   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_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"

/*

 *      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 -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;

        }

        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);

        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;

        /* 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) {

                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;