Root/fs/jfs/xattr.c

1/*
2 * Copyright (C) International Business Machines Corp., 2000-2004
3 * Copyright (C) Christoph Hellwig, 2002
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/capability.h>
21#include <linux/fs.h>
22#include <linux/xattr.h>
23#include <linux/posix_acl_xattr.h>
24#include <linux/slab.h>
25#include <linux/quotaops.h>
26#include <linux/security.h>
27#include "jfs_incore.h"
28#include "jfs_superblock.h"
29#include "jfs_dmap.h"
30#include "jfs_debug.h"
31#include "jfs_dinode.h"
32#include "jfs_extent.h"
33#include "jfs_metapage.h"
34#include "jfs_xattr.h"
35#include "jfs_acl.h"
36
37/*
38 * jfs_xattr.c: extended attribute service
39 *
40 * Overall design --
41 *
42 * Format:
43 *
44 * Extended attribute lists (jfs_ea_list) consist of an overall size (32 bit
45 * value) and a variable (0 or more) number of extended attribute
46 * entries. Each extended attribute entry (jfs_ea) is a <name,value> double
47 * where <name> is constructed from a null-terminated ascii string
48 * (1 ... 255 bytes in the name) and <value> is arbitrary 8 bit data
49 * (1 ... 65535 bytes). The in-memory format is
50 *
51 * 0 1 2 4 4 + namelen + 1
52 * +-------+--------+--------+----------------+-------------------+
53 * | Flags | Name | Value | Name String \0 | Data . . . . |
54 * | | Length | Length | | |
55 * +-------+--------+--------+----------------+-------------------+
56 *
57 * A jfs_ea_list then is structured as
58 *
59 * 0 4 4 + EA_SIZE(ea1)
60 * +------------+-------------------+--------------------+-----
61 * | Overall EA | First FEA Element | Second FEA Element | .....
62 * | List Size | | |
63 * +------------+-------------------+--------------------+-----
64 *
65 * On-disk:
66 *
67 * FEALISTs are stored on disk using blocks allocated by dbAlloc() and
68 * written directly. An EA list may be in-lined in the inode if there is
69 * sufficient room available.
70 */
71
72struct ea_buffer {
73    int flag; /* Indicates what storage xattr points to */
74    int max_size; /* largest xattr that fits in current buffer */
75    dxd_t new_ea; /* dxd to replace ea when modifying xattr */
76    struct metapage *mp; /* metapage containing ea list */
77    struct jfs_ea_list *xattr; /* buffer containing ea list */
78};
79
80/*
81 * ea_buffer.flag values
82 */
83#define EA_INLINE 0x0001
84#define EA_EXTENT 0x0002
85#define EA_NEW 0x0004
86#define EA_MALLOC 0x0008
87
88
89static int is_known_namespace(const char *name)
90{
91    if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
92        strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
93        strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
94        strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
95        return false;
96
97    return true;
98}
99
100/*
101 * These three routines are used to recognize on-disk extended attributes
102 * that are in a recognized namespace. If the attribute is not recognized,
103 * "os2." is prepended to the name
104 */
105static int is_os2_xattr(struct jfs_ea *ea)
106{
107    return !is_known_namespace(ea->name);
108}
109
110static inline int name_size(struct jfs_ea *ea)
111{
112    if (is_os2_xattr(ea))
113        return ea->namelen + XATTR_OS2_PREFIX_LEN;
114    else
115        return ea->namelen;
116}
117
118static inline int copy_name(char *buffer, struct jfs_ea *ea)
119{
120    int len = ea->namelen;
121
122    if (is_os2_xattr(ea)) {
123        memcpy(buffer, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN);
124        buffer += XATTR_OS2_PREFIX_LEN;
125        len += XATTR_OS2_PREFIX_LEN;
126    }
127    memcpy(buffer, ea->name, ea->namelen);
128    buffer[ea->namelen] = 0;
129
130    return len;
131}
132
133/* Forward references */
134static void ea_release(struct inode *inode, struct ea_buffer *ea_buf);
135
136/*
137 * NAME: ea_write_inline
138 *
139 * FUNCTION: Attempt to write an EA inline if area is available
140 *
141 * PRE CONDITIONS:
142 * Already verified that the specified EA is small enough to fit inline
143 *
144 * PARAMETERS:
145 * ip - Inode pointer
146 * ealist - EA list pointer
147 * size - size of ealist in bytes
148 * ea - dxd_t structure to be filled in with necessary EA information
149 * if we successfully copy the EA inline
150 *
151 * NOTES:
152 * Checks if the inode's inline area is available. If so, copies EA inline
153 * and sets <ea> fields appropriately. Otherwise, returns failure, EA will
154 * have to be put into an extent.
155 *
156 * RETURNS: 0 for successful copy to inline area; -1 if area not available
157 */
158static int ea_write_inline(struct inode *ip, struct jfs_ea_list *ealist,
159               int size, dxd_t * ea)
160{
161    struct jfs_inode_info *ji = JFS_IP(ip);
162
163    /*
164     * Make sure we have an EA -- the NULL EA list is valid, but you
165     * can't copy it!
166     */
167    if (ealist && size > sizeof (struct jfs_ea_list)) {
168        assert(size <= sizeof (ji->i_inline_ea));
169
170        /*
171         * See if the space is available or if it is already being
172         * used for an inline EA.
173         */
174        if (!(ji->mode2 & INLINEEA) && !(ji->ea.flag & DXD_INLINE))
175            return -EPERM;
176
177        DXDsize(ea, size);
178        DXDlength(ea, 0);
179        DXDaddress(ea, 0);
180        memcpy(ji->i_inline_ea, ealist, size);
181        ea->flag = DXD_INLINE;
182        ji->mode2 &= ~INLINEEA;
183    } else {
184        ea->flag = 0;
185        DXDsize(ea, 0);
186        DXDlength(ea, 0);
187        DXDaddress(ea, 0);
188
189        /* Free up INLINE area */
190        if (ji->ea.flag & DXD_INLINE)
191            ji->mode2 |= INLINEEA;
192    }
193
194    return 0;
195}
196
197/*
198 * NAME: ea_write
199 *
200 * FUNCTION: Write an EA for an inode
201 *
202 * PRE CONDITIONS: EA has been verified
203 *
204 * PARAMETERS:
205 * ip - Inode pointer
206 * ealist - EA list pointer
207 * size - size of ealist in bytes
208 * ea - dxd_t structure to be filled in appropriately with where the
209 * EA was copied
210 *
211 * NOTES: Will write EA inline if able to, otherwise allocates blocks for an
212 * extent and synchronously writes it to those blocks.
213 *
214 * RETURNS: 0 for success; Anything else indicates failure
215 */
216static int ea_write(struct inode *ip, struct jfs_ea_list *ealist, int size,
217               dxd_t * ea)
218{
219    struct super_block *sb = ip->i_sb;
220    struct jfs_inode_info *ji = JFS_IP(ip);
221    struct jfs_sb_info *sbi = JFS_SBI(sb);
222    int nblocks;
223    s64 blkno;
224    int rc = 0, i;
225    char *cp;
226    s32 nbytes, nb;
227    s32 bytes_to_write;
228    struct metapage *mp;
229
230    /*
231     * Quick check to see if this is an in-linable EA. Short EAs
232     * and empty EAs are all in-linable, provided the space exists.
233     */
234    if (!ealist || size <= sizeof (ji->i_inline_ea)) {
235        if (!ea_write_inline(ip, ealist, size, ea))
236            return 0;
237    }
238
239    /* figure out how many blocks we need */
240    nblocks = (size + (sb->s_blocksize - 1)) >> sb->s_blocksize_bits;
241
242    /* Allocate new blocks to quota. */
243    rc = dquot_alloc_block(ip, nblocks);
244    if (rc)
245        return rc;
246
247    rc = dbAlloc(ip, INOHINT(ip), nblocks, &blkno);
248    if (rc) {
249        /*Rollback quota allocation. */
250        dquot_free_block(ip, nblocks);
251        return rc;
252    }
253
254    /*
255     * Now have nblocks worth of storage to stuff into the FEALIST.
256     * loop over the FEALIST copying data into the buffer one page at
257     * a time.
258     */
259    cp = (char *) ealist;
260    nbytes = size;
261    for (i = 0; i < nblocks; i += sbi->nbperpage) {
262        /*
263         * Determine how many bytes for this request, and round up to
264         * the nearest aggregate block size
265         */
266        nb = min(PSIZE, nbytes);
267        bytes_to_write =
268            ((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
269            << sb->s_blocksize_bits;
270
271        if (!(mp = get_metapage(ip, blkno + i, bytes_to_write, 1))) {
272            rc = -EIO;
273            goto failed;
274        }
275
276        memcpy(mp->data, cp, nb);
277
278        /*
279         * We really need a way to propagate errors for
280         * forced writes like this one. --hch
281         *
282         * (__write_metapage => release_metapage => flush_metapage)
283         */
284#ifdef _JFS_FIXME
285        if ((rc = flush_metapage(mp))) {
286            /*
287             * the write failed -- this means that the buffer
288             * is still assigned and the blocks are not being
289             * used. this seems like the best error recovery
290             * we can get ...
291             */
292            goto failed;
293        }
294#else
295        flush_metapage(mp);
296#endif
297
298        cp += PSIZE;
299        nbytes -= nb;
300    }
301
302    ea->flag = DXD_EXTENT;
303    DXDsize(ea, le32_to_cpu(ealist->size));
304    DXDlength(ea, nblocks);
305    DXDaddress(ea, blkno);
306
307    /* Free up INLINE area */
308    if (ji->ea.flag & DXD_INLINE)
309        ji->mode2 |= INLINEEA;
310
311    return 0;
312
313      failed:
314    /* Rollback quota allocation. */
315    dquot_free_block(ip, nblocks);
316
317    dbFree(ip, blkno, nblocks);
318    return rc;
319}
320
321/*
322 * NAME: ea_read_inline
323 *
324 * FUNCTION: Read an inlined EA into user's buffer
325 *
326 * PARAMETERS:
327 * ip - Inode pointer
328 * ealist - Pointer to buffer to fill in with EA
329 *
330 * RETURNS: 0
331 */
332static int ea_read_inline(struct inode *ip, struct jfs_ea_list *ealist)
333{
334    struct jfs_inode_info *ji = JFS_IP(ip);
335    int ea_size = sizeDXD(&ji->ea);
336
337    if (ea_size == 0) {
338        ealist->size = 0;
339        return 0;
340    }
341
342    /* Sanity Check */
343    if ((sizeDXD(&ji->ea) > sizeof (ji->i_inline_ea)))
344        return -EIO;
345    if (le32_to_cpu(((struct jfs_ea_list *) &ji->i_inline_ea)->size)
346        != ea_size)
347        return -EIO;
348
349    memcpy(ealist, ji->i_inline_ea, ea_size);
350    return 0;
351}
352
353/*
354 * NAME: ea_read
355 *
356 * FUNCTION: copy EA data into user's buffer
357 *
358 * PARAMETERS:
359 * ip - Inode pointer
360 * ealist - Pointer to buffer to fill in with EA
361 *
362 * NOTES: If EA is inline calls ea_read_inline() to copy EA.
363 *
364 * RETURNS: 0 for success; other indicates failure
365 */
366static int ea_read(struct inode *ip, struct jfs_ea_list *ealist)
367{
368    struct super_block *sb = ip->i_sb;
369    struct jfs_inode_info *ji = JFS_IP(ip);
370    struct jfs_sb_info *sbi = JFS_SBI(sb);
371    int nblocks;
372    s64 blkno;
373    char *cp = (char *) ealist;
374    int i;
375    int nbytes, nb;
376    s32 bytes_to_read;
377    struct metapage *mp;
378
379    /* quick check for in-line EA */
380    if (ji->ea.flag & DXD_INLINE)
381        return ea_read_inline(ip, ealist);
382
383    nbytes = sizeDXD(&ji->ea);
384    if (!nbytes) {
385        jfs_error(sb, "ea_read: nbytes is 0");
386        return -EIO;
387    }
388
389    /*
390     * Figure out how many blocks were allocated when this EA list was
391     * originally written to disk.
392     */
393    nblocks = lengthDXD(&ji->ea) << sbi->l2nbperpage;
394    blkno = addressDXD(&ji->ea) << sbi->l2nbperpage;
395
396    /*
397     * I have found the disk blocks which were originally used to store
398     * the FEALIST. now i loop over each contiguous block copying the
399     * data into the buffer.
400     */
401    for (i = 0; i < nblocks; i += sbi->nbperpage) {
402        /*
403         * Determine how many bytes for this request, and round up to
404         * the nearest aggregate block size
405         */
406        nb = min(PSIZE, nbytes);
407        bytes_to_read =
408            ((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
409            << sb->s_blocksize_bits;
410
411        if (!(mp = read_metapage(ip, blkno + i, bytes_to_read, 1)))
412            return -EIO;
413
414        memcpy(cp, mp->data, nb);
415        release_metapage(mp);
416
417        cp += PSIZE;
418        nbytes -= nb;
419    }
420
421    return 0;
422}
423
424/*
425 * NAME: ea_get
426 *
427 * FUNCTION: Returns buffer containing existing extended attributes.
428 * The size of the buffer will be the larger of the existing
429 * attributes size, or min_size.
430 *
431 * The buffer, which may be inlined in the inode or in the
432 * page cache must be release by calling ea_release or ea_put
433 *
434 * PARAMETERS:
435 * inode - Inode pointer
436 * ea_buf - Structure to be populated with ealist and its metadata
437 * min_size- minimum size of buffer to be returned
438 *
439 * RETURNS: 0 for success; Other indicates failure
440 */
441static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
442{
443    struct jfs_inode_info *ji = JFS_IP(inode);
444    struct super_block *sb = inode->i_sb;
445    int size;
446    int ea_size = sizeDXD(&ji->ea);
447    int blocks_needed, current_blocks;
448    s64 blkno;
449    int rc;
450    int quota_allocation = 0;
451
452    /* When fsck.jfs clears a bad ea, it doesn't clear the size */
453    if (ji->ea.flag == 0)
454        ea_size = 0;
455
456    if (ea_size == 0) {
457        if (min_size == 0) {
458            ea_buf->flag = 0;
459            ea_buf->max_size = 0;
460            ea_buf->xattr = NULL;
461            return 0;
462        }
463        if ((min_size <= sizeof (ji->i_inline_ea)) &&
464            (ji->mode2 & INLINEEA)) {
465            ea_buf->flag = EA_INLINE | EA_NEW;
466            ea_buf->max_size = sizeof (ji->i_inline_ea);
467            ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
468            DXDlength(&ea_buf->new_ea, 0);
469            DXDaddress(&ea_buf->new_ea, 0);
470            ea_buf->new_ea.flag = DXD_INLINE;
471            DXDsize(&ea_buf->new_ea, min_size);
472            return 0;
473        }
474        current_blocks = 0;
475    } else if (ji->ea.flag & DXD_INLINE) {
476        if (min_size <= sizeof (ji->i_inline_ea)) {
477            ea_buf->flag = EA_INLINE;
478            ea_buf->max_size = sizeof (ji->i_inline_ea);
479            ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
480            goto size_check;
481        }
482        current_blocks = 0;
483    } else {
484        if (!(ji->ea.flag & DXD_EXTENT)) {
485            jfs_error(sb, "ea_get: invalid ea.flag)");
486            return -EIO;
487        }
488        current_blocks = (ea_size + sb->s_blocksize - 1) >>
489            sb->s_blocksize_bits;
490    }
491    size = max(min_size, ea_size);
492
493    if (size > PSIZE) {
494        /*
495         * To keep the rest of the code simple. Allocate a
496         * contiguous buffer to work with
497         */
498        ea_buf->xattr = kmalloc(size, GFP_KERNEL);
499        if (ea_buf->xattr == NULL)
500            return -ENOMEM;
501
502        ea_buf->flag = EA_MALLOC;
503        ea_buf->max_size = (size + sb->s_blocksize - 1) &
504            ~(sb->s_blocksize - 1);
505
506        if (ea_size == 0)
507            return 0;
508
509        if ((rc = ea_read(inode, ea_buf->xattr))) {
510            kfree(ea_buf->xattr);
511            ea_buf->xattr = NULL;
512            return rc;
513        }
514        goto size_check;
515    }
516    blocks_needed = (min_size + sb->s_blocksize - 1) >>
517        sb->s_blocksize_bits;
518
519    if (blocks_needed > current_blocks) {
520        /* Allocate new blocks to quota. */
521        rc = dquot_alloc_block(inode, blocks_needed);
522        if (rc)
523            return -EDQUOT;
524
525        quota_allocation = blocks_needed;
526
527        rc = dbAlloc(inode, INOHINT(inode), (s64) blocks_needed,
528                 &blkno);
529        if (rc)
530            goto clean_up;
531
532        DXDlength(&ea_buf->new_ea, blocks_needed);
533        DXDaddress(&ea_buf->new_ea, blkno);
534        ea_buf->new_ea.flag = DXD_EXTENT;
535        DXDsize(&ea_buf->new_ea, min_size);
536
537        ea_buf->flag = EA_EXTENT | EA_NEW;
538
539        ea_buf->mp = get_metapage(inode, blkno,
540                      blocks_needed << sb->s_blocksize_bits,
541                      1);
542        if (ea_buf->mp == NULL) {
543            dbFree(inode, blkno, (s64) blocks_needed);
544            rc = -EIO;
545            goto clean_up;
546        }
547        ea_buf->xattr = ea_buf->mp->data;
548        ea_buf->max_size = (min_size + sb->s_blocksize - 1) &
549            ~(sb->s_blocksize - 1);
550        if (ea_size == 0)
551            return 0;
552        if ((rc = ea_read(inode, ea_buf->xattr))) {
553            discard_metapage(ea_buf->mp);
554            dbFree(inode, blkno, (s64) blocks_needed);
555            goto clean_up;
556        }
557        goto size_check;
558    }
559    ea_buf->flag = EA_EXTENT;
560    ea_buf->mp = read_metapage(inode, addressDXD(&ji->ea),
561                   lengthDXD(&ji->ea) << sb->s_blocksize_bits,
562                   1);
563    if (ea_buf->mp == NULL) {
564        rc = -EIO;
565        goto clean_up;
566    }
567    ea_buf->xattr = ea_buf->mp->data;
568    ea_buf->max_size = (ea_size + sb->s_blocksize - 1) &
569        ~(sb->s_blocksize - 1);
570
571      size_check:
572    if (EALIST_SIZE(ea_buf->xattr) != ea_size) {
573        printk(KERN_ERR "ea_get: invalid extended attribute\n");
574        print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1,
575                     ea_buf->xattr, ea_size, 1);
576        ea_release(inode, ea_buf);
577        rc = -EIO;
578        goto clean_up;
579    }
580
581    return ea_size;
582
583      clean_up:
584    /* Rollback quota allocation */
585    if (quota_allocation)
586        dquot_free_block(inode, quota_allocation);
587
588    return (rc);
589}
590
591static void ea_release(struct inode *inode, struct ea_buffer *ea_buf)
592{
593    if (ea_buf->flag & EA_MALLOC)
594        kfree(ea_buf->xattr);
595    else if (ea_buf->flag & EA_EXTENT) {
596        assert(ea_buf->mp);
597        release_metapage(ea_buf->mp);
598
599        if (ea_buf->flag & EA_NEW)
600            dbFree(inode, addressDXD(&ea_buf->new_ea),
601                   lengthDXD(&ea_buf->new_ea));
602    }
603}
604
605static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
606          int new_size)
607{
608    struct jfs_inode_info *ji = JFS_IP(inode);
609    unsigned long old_blocks, new_blocks;
610    int rc = 0;
611
612    if (new_size == 0) {
613        ea_release(inode, ea_buf);
614        ea_buf = NULL;
615    } else if (ea_buf->flag & EA_INLINE) {
616        assert(new_size <= sizeof (ji->i_inline_ea));
617        ji->mode2 &= ~INLINEEA;
618        ea_buf->new_ea.flag = DXD_INLINE;
619        DXDsize(&ea_buf->new_ea, new_size);
620        DXDaddress(&ea_buf->new_ea, 0);
621        DXDlength(&ea_buf->new_ea, 0);
622    } else if (ea_buf->flag & EA_MALLOC) {
623        rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
624        kfree(ea_buf->xattr);
625    } else if (ea_buf->flag & EA_NEW) {
626        /* We have already allocated a new dxd */
627        flush_metapage(ea_buf->mp);
628    } else {
629        /* ->xattr must point to original ea's metapage */
630        rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
631        discard_metapage(ea_buf->mp);
632    }
633    if (rc)
634        return rc;
635
636    old_blocks = new_blocks = 0;
637
638    if (ji->ea.flag & DXD_EXTENT) {
639        invalidate_dxd_metapages(inode, ji->ea);
640        old_blocks = lengthDXD(&ji->ea);
641    }
642
643    if (ea_buf) {
644        txEA(tid, inode, &ji->ea, &ea_buf->new_ea);
645        if (ea_buf->new_ea.flag & DXD_EXTENT) {
646            new_blocks = lengthDXD(&ea_buf->new_ea);
647            if (ji->ea.flag & DXD_INLINE)
648                ji->mode2 |= INLINEEA;
649        }
650        ji->ea = ea_buf->new_ea;
651    } else {
652        txEA(tid, inode, &ji->ea, NULL);
653        if (ji->ea.flag & DXD_INLINE)
654            ji->mode2 |= INLINEEA;
655        ji->ea.flag = 0;
656        ji->ea.size = 0;
657    }
658
659    /* If old blocks exist, they must be removed from quota allocation. */
660    if (old_blocks)
661        dquot_free_block(inode, old_blocks);
662
663    inode->i_ctime = CURRENT_TIME;
664
665    return 0;
666}
667
668/*
669 * can_set_system_xattr
670 *
671 * This code is specific to the system.* namespace. It contains policy
672 * which doesn't belong in the main xattr codepath.
673 */
674static int can_set_system_xattr(struct inode *inode, const char *name,
675                const void *value, size_t value_len)
676{
677#ifdef CONFIG_JFS_POSIX_ACL
678    struct posix_acl *acl;
679    int rc;
680
681    if (!inode_owner_or_capable(inode))
682        return -EPERM;
683
684    /*
685     * POSIX_ACL_XATTR_ACCESS is tied to i_mode
686     */
687    if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
688        acl = posix_acl_from_xattr(value, value_len);
689        if (IS_ERR(acl)) {
690            rc = PTR_ERR(acl);
691            printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
692                   rc);
693            return rc;
694        }
695        if (acl) {
696            mode_t mode = inode->i_mode;
697            rc = posix_acl_equiv_mode(acl, &mode);
698            posix_acl_release(acl);
699            if (rc < 0) {
700                printk(KERN_ERR
701                       "posix_acl_equiv_mode returned %d\n",
702                       rc);
703                return rc;
704            }
705            inode->i_mode = mode;
706            mark_inode_dirty(inode);
707        }
708        /*
709         * We're changing the ACL. Get rid of the cached one
710         */
711        forget_cached_acl(inode, ACL_TYPE_ACCESS);
712
713        return 0;
714    } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
715        acl = posix_acl_from_xattr(value, value_len);
716        if (IS_ERR(acl)) {
717            rc = PTR_ERR(acl);
718            printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
719                   rc);
720            return rc;
721        }
722        posix_acl_release(acl);
723
724        /*
725         * We're changing the default ACL. Get rid of the cached one
726         */
727        forget_cached_acl(inode, ACL_TYPE_DEFAULT);
728
729        return 0;
730    }
731#endif /* CONFIG_JFS_POSIX_ACL */
732    return -EOPNOTSUPP;
733}
734
735/*
736 * Most of the permission checking is done by xattr_permission in the vfs.
737 * The local file system is responsible for handling the system.* namespace.
738 * We also need to verify that this is a namespace that we recognize.
739 */
740static int can_set_xattr(struct inode *inode, const char *name,
741             const void *value, size_t value_len)
742{
743    if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
744        return can_set_system_xattr(inode, name, value, value_len);
745
746    if (!strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) {
747        /*
748         * This makes sure that we aren't trying to set an
749         * attribute in a different namespace by prefixing it
750         * with "os2."
751         */
752        if (is_known_namespace(name + XATTR_OS2_PREFIX_LEN))
753                return -EOPNOTSUPP;
754        return 0;
755    }
756
757    /*
758     * Don't allow setting an attribute in an unknown namespace.
759     */
760    if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
761        strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
762        strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
763        return -EOPNOTSUPP;
764
765    return 0;
766}
767
768int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
769           const void *value, size_t value_len, int flags)
770{
771    struct jfs_ea_list *ealist;
772    struct jfs_ea *ea, *old_ea = NULL, *next_ea = NULL;
773    struct ea_buffer ea_buf;
774    int old_ea_size = 0;
775    int xattr_size;
776    int new_size;
777    int namelen = strlen(name);
778    char *os2name = NULL;
779    int found = 0;
780    int rc;
781    int length;
782
783    if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
784        os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
785                  GFP_KERNEL);
786        if (!os2name)
787            return -ENOMEM;
788        strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
789        name = os2name;
790        namelen -= XATTR_OS2_PREFIX_LEN;
791    }
792
793    down_write(&JFS_IP(inode)->xattr_sem);
794
795    xattr_size = ea_get(inode, &ea_buf, 0);
796    if (xattr_size < 0) {
797        rc = xattr_size;
798        goto out;
799    }
800
801      again:
802    ealist = (struct jfs_ea_list *) ea_buf.xattr;
803    new_size = sizeof (struct jfs_ea_list);
804
805    if (xattr_size) {
806        for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist);
807             ea = NEXT_EA(ea)) {
808            if ((namelen == ea->namelen) &&
809                (memcmp(name, ea->name, namelen) == 0)) {
810                found = 1;
811                if (flags & XATTR_CREATE) {
812                    rc = -EEXIST;
813                    goto release;
814                }
815                old_ea = ea;
816                old_ea_size = EA_SIZE(ea);
817                next_ea = NEXT_EA(ea);
818            } else
819                new_size += EA_SIZE(ea);
820        }
821    }
822
823    if (!found) {
824        if (flags & XATTR_REPLACE) {
825            rc = -ENODATA;
826            goto release;
827        }
828        if (value == NULL) {
829            rc = 0;
830            goto release;
831        }
832    }
833    if (value)
834        new_size += sizeof (struct jfs_ea) + namelen + 1 + value_len;
835
836    if (new_size > ea_buf.max_size) {
837        /*
838         * We need to allocate more space for merged ea list.
839         * We should only have loop to again: once.
840         */
841        ea_release(inode, &ea_buf);
842        xattr_size = ea_get(inode, &ea_buf, new_size);
843        if (xattr_size < 0) {
844            rc = xattr_size;
845            goto out;
846        }
847        goto again;
848    }
849
850    /* Remove old ea of the same name */
851    if (found) {
852        /* number of bytes following target EA */
853        length = (char *) END_EALIST(ealist) - (char *) next_ea;
854        if (length > 0)
855            memmove(old_ea, next_ea, length);
856        xattr_size -= old_ea_size;
857    }
858
859    /* Add new entry to the end */
860    if (value) {
861        if (xattr_size == 0)
862            /* Completely new ea list */
863            xattr_size = sizeof (struct jfs_ea_list);
864
865        ea = (struct jfs_ea *) ((char *) ealist + xattr_size);
866        ea->flag = 0;
867        ea->namelen = namelen;
868        ea->valuelen = (cpu_to_le16(value_len));
869        memcpy(ea->name, name, namelen);
870        ea->name[namelen] = 0;
871        if (value_len)
872            memcpy(&ea->name[namelen + 1], value, value_len);
873        xattr_size += EA_SIZE(ea);
874    }
875
876    /* DEBUG - If we did this right, these number match */
877    if (xattr_size != new_size) {
878        printk(KERN_ERR
879               "jfs_xsetattr: xattr_size = %d, new_size = %d\n",
880               xattr_size, new_size);
881
882        rc = -EINVAL;
883        goto release;
884    }
885
886    /*
887     * If we're left with an empty list, there's no ea
888     */
889    if (new_size == sizeof (struct jfs_ea_list))
890        new_size = 0;
891
892    ealist->size = cpu_to_le32(new_size);
893
894    rc = ea_put(tid, inode, &ea_buf, new_size);
895
896    goto out;
897      release:
898    ea_release(inode, &ea_buf);
899      out:
900    up_write(&JFS_IP(inode)->xattr_sem);
901
902    kfree(os2name);
903
904    return rc;
905}
906
907int jfs_setxattr(struct dentry *dentry, const char *name, const void *value,
908         size_t value_len, int flags)
909{
910    struct inode *inode = dentry->d_inode;
911    struct jfs_inode_info *ji = JFS_IP(inode);
912    int rc;
913    tid_t tid;
914
915    if ((rc = can_set_xattr(inode, name, value, value_len)))
916        return rc;
917
918    if (value == NULL) { /* empty EA, do not remove */
919        value = "";
920        value_len = 0;
921    }
922
923    tid = txBegin(inode->i_sb, 0);
924    mutex_lock(&ji->commit_mutex);
925    rc = __jfs_setxattr(tid, dentry->d_inode, name, value, value_len,
926                flags);
927    if (!rc)
928        rc = txCommit(tid, 1, &inode, 0);
929    txEnd(tid);
930    mutex_unlock(&ji->commit_mutex);
931
932    return rc;
933}
934
935ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
936               size_t buf_size)
937{
938    struct jfs_ea_list *ealist;
939    struct jfs_ea *ea;
940    struct ea_buffer ea_buf;
941    int xattr_size;
942    ssize_t size;
943    int namelen = strlen(name);
944    char *value;
945
946    down_read(&JFS_IP(inode)->xattr_sem);
947
948    xattr_size = ea_get(inode, &ea_buf, 0);
949
950    if (xattr_size < 0) {
951        size = xattr_size;
952        goto out;
953    }
954
955    if (xattr_size == 0)
956        goto not_found;
957
958    ealist = (struct jfs_ea_list *) ea_buf.xattr;
959
960    /* Find the named attribute */
961    for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
962        if ((namelen == ea->namelen) &&
963            memcmp(name, ea->name, namelen) == 0) {
964            /* Found it */
965            size = le16_to_cpu(ea->valuelen);
966            if (!data)
967                goto release;
968            else if (size > buf_size) {
969                size = -ERANGE;
970                goto release;
971            }
972            value = ((char *) &ea->name) + ea->namelen + 1;
973            memcpy(data, value, size);
974            goto release;
975        }
976      not_found:
977    size = -ENODATA;
978      release:
979    ea_release(inode, &ea_buf);
980      out:
981    up_read(&JFS_IP(inode)->xattr_sem);
982
983    return size;
984}
985
986ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
987             size_t buf_size)
988{
989    int err;
990
991    if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
992        /*
993         * skip past "os2." prefix
994         */
995        name += XATTR_OS2_PREFIX_LEN;
996        /*
997         * Don't allow retrieving properly prefixed attributes
998         * by prepending them with "os2."
999         */
1000        if (is_known_namespace(name))
1001            return -EOPNOTSUPP;
1002    }
1003
1004    err = __jfs_getxattr(dentry->d_inode, name, data, buf_size);
1005
1006    return err;
1007}
1008
1009/*
1010 * No special permissions are needed to list attributes except for trusted.*
1011 */
1012static inline int can_list(struct jfs_ea *ea)
1013{
1014    return (strncmp(ea->name, XATTR_TRUSTED_PREFIX,
1015                XATTR_TRUSTED_PREFIX_LEN) ||
1016        capable(CAP_SYS_ADMIN));
1017}
1018
1019ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
1020{
1021    struct inode *inode = dentry->d_inode;
1022    char *buffer;
1023    ssize_t size = 0;
1024    int xattr_size;
1025    struct jfs_ea_list *ealist;
1026    struct jfs_ea *ea;
1027    struct ea_buffer ea_buf;
1028
1029    down_read(&JFS_IP(inode)->xattr_sem);
1030
1031    xattr_size = ea_get(inode, &ea_buf, 0);
1032    if (xattr_size < 0) {
1033        size = xattr_size;
1034        goto out;
1035    }
1036
1037    if (xattr_size == 0)
1038        goto release;
1039
1040    ealist = (struct jfs_ea_list *) ea_buf.xattr;
1041
1042    /* compute required size of list */
1043    for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
1044        if (can_list(ea))
1045            size += name_size(ea) + 1;
1046    }
1047
1048    if (!data)
1049        goto release;
1050
1051    if (size > buf_size) {
1052        size = -ERANGE;
1053        goto release;
1054    }
1055
1056    /* Copy attribute names to buffer */
1057    buffer = data;
1058    for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
1059        if (can_list(ea)) {
1060            int namelen = copy_name(buffer, ea);
1061            buffer += namelen + 1;
1062        }
1063    }
1064
1065      release:
1066    ea_release(inode, &ea_buf);
1067      out:
1068    up_read(&JFS_IP(inode)->xattr_sem);
1069    return size;
1070}
1071
1072int jfs_removexattr(struct dentry *dentry, const char *name)
1073{
1074    struct inode *inode = dentry->d_inode;
1075    struct jfs_inode_info *ji = JFS_IP(inode);
1076    int rc;
1077    tid_t tid;
1078
1079    if ((rc = can_set_xattr(inode, name, NULL, 0)))
1080        return rc;
1081
1082    tid = txBegin(inode->i_sb, 0);
1083    mutex_lock(&ji->commit_mutex);
1084    rc = __jfs_setxattr(tid, dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
1085    if (!rc)
1086        rc = txCommit(tid, 1, &inode, 0);
1087    txEnd(tid);
1088    mutex_unlock(&ji->commit_mutex);
1089
1090    return rc;
1091}
1092
1093#ifdef CONFIG_JFS_SECURITY
1094int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir,
1095              const struct qstr *qstr)
1096{
1097    int rc;
1098    size_t len;
1099    void *value;
1100    char *suffix;
1101    char *name;
1102
1103    rc = security_inode_init_security(inode, dir, qstr, &suffix, &value,
1104                      &len);
1105    if (rc) {
1106        if (rc == -EOPNOTSUPP)
1107            return 0;
1108        return rc;
1109    }
1110    name = kmalloc(XATTR_SECURITY_PREFIX_LEN + 1 + strlen(suffix),
1111               GFP_NOFS);
1112    if (!name) {
1113        rc = -ENOMEM;
1114        goto kmalloc_failed;
1115    }
1116    strcpy(name, XATTR_SECURITY_PREFIX);
1117    strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
1118
1119    rc = __jfs_setxattr(tid, inode, name, value, len, 0);
1120
1121    kfree(name);
1122kmalloc_failed:
1123    kfree(suffix);
1124    kfree(value);
1125
1126    return rc;
1127}
1128#endif
1129

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