fs/btrfs/props.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
0004  */
0005
0006 #include <linux/hashtable.h>
0007 #include "props.h"
0008 #include "btrfs_inode.h"
0009 #include "transaction.h"
0010 #include "ctree.h"
0011 #include "xattr.h"
0012 #include "compression.h"
0013
0014 #define BTRFS_PROP_HANDLERS_HT_BITS 8
0015 static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
0016
0017 struct prop_handler {
0018     struct hlist_node node;
0019     const char *xattr_name;
0020     int (*validate)(const struct btrfs_inode *inode, const char *value,
0021             size_t len);
0022     int (*apply)(struct inode *inode, const char *value, size_t len);
0023     const char *(*extract)(struct inode *inode);
0024     bool (*ignore)(const struct btrfs_inode *inode);
0025     int inheritable;
0026 };
0027
0028 static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
0029 {
0030     struct hlist_head *h;
0031
0032     h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
0033     if (hlist_empty(h))
0034         return NULL;
0035
0036     return h;
0037 }
0038
0039 static const struct prop_handler *
0040 find_prop_handler(const char *name,
0041           const struct hlist_head *handlers)
0042 {
0043     struct prop_handler *h;
0044
0045     if (!handlers) {
0046         u64 hash = btrfs_name_hash(name, strlen(name));
0047
0048         handlers = find_prop_handlers_by_hash(hash);
0049         if (!handlers)
0050             return NULL;
0051     }
0052
0053     hlist_for_each_entry(h, handlers, node)
0054         if (!strcmp(h->xattr_name, name))
0055             return h;
0056
0057     return NULL;
0058 }
0059
0060 int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
0061             const char *value, size_t value_len)
0062 {
0063     const struct prop_handler *handler;
0064
0065     if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
0066         return -EINVAL;
0067
0068     handler = find_prop_handler(name, NULL);
0069     if (!handler)
0070         return -EINVAL;
0071
0072     if (value_len == 0)
0073         return 0;
0074
0075     return handler->validate(inode, value, value_len);
0076 }
0077
0078 /*
0079  * Check if a property should be ignored (not set) for an inode.
0080  *
0081  * @inode:     The target inode.
0082  * @name:      The property's name.
0083  *
0084  * The caller must be sure the given property name is valid, for example by
0085  * having previously called btrfs_validate_prop().
0086  *
0087  * Returns:    true if the property should be ignored for the given inode
0088  *             false if the property must not be ignored for the given inode
0089  */
0090 bool btrfs_ignore_prop(const struct btrfs_inode *inode, const char *name)
0091 {
0092     const struct prop_handler *handler;
0093
0094     handler = find_prop_handler(name, NULL);
0095     ASSERT(handler != NULL);
0096
0097     return handler->ignore(inode);
0098 }
0099
0100 int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
0101            const char *name, const char *value, size_t value_len,
0102            int flags)
0103 {
0104     const struct prop_handler *handler;
0105     int ret;
0106
0107     handler = find_prop_handler(name, NULL);
0108     if (!handler)
0109         return -EINVAL;
0110
0111     if (value_len == 0) {
0112         ret = btrfs_setxattr(trans, inode, handler->xattr_name,
0113                      NULL, 0, flags);
0114         if (ret)
0115             return ret;
0116
0117         ret = handler->apply(inode, NULL, 0);
0118         ASSERT(ret == 0);
0119
0120         return ret;
0121     }
0122
0123     ret = btrfs_setxattr(trans, inode, handler->xattr_name, value,
0124                  value_len, flags);
0125     if (ret)
0126         return ret;
0127     ret = handler->apply(inode, value, value_len);
0128     if (ret) {
0129         btrfs_setxattr(trans, inode, handler->xattr_name, NULL,
0130                    0, flags);
0131         return ret;
0132     }
0133
0134     set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
0135
0136     return 0;
0137 }
0138
0139 static int iterate_object_props(struct btrfs_root *root,
0140                 struct btrfs_path *path,
0141                 u64 objectid,
0142                 void (*iterator)(void *,
0143                          const struct prop_handler *,
0144                          const char *,
0145                          size_t),
0146                 void *ctx)
0147 {
0148     int ret;
0149     char *name_buf = NULL;
0150     char *value_buf = NULL;
0151     int name_buf_len = 0;
0152     int value_buf_len = 0;
0153
0154     while (1) {
0155         struct btrfs_key key;
0156         struct btrfs_dir_item *di;
0157         struct extent_buffer *leaf;
0158         u32 total_len, cur, this_len;
0159         int slot;
0160         const struct hlist_head *handlers;
0161
0162         slot = path->slots[0];
0163         leaf = path->nodes[0];
0164
0165         if (slot >= btrfs_header_nritems(leaf)) {
0166             ret = btrfs_next_leaf(root, path);
0167             if (ret < 0)
0168                 goto out;
0169             else if (ret > 0)
0170                 break;
0171             continue;
0172         }
0173
0174         btrfs_item_key_to_cpu(leaf, &key, slot);
0175         if (key.objectid != objectid)
0176             break;
0177         if (key.type != BTRFS_XATTR_ITEM_KEY)
0178             break;
0179
0180         handlers = find_prop_handlers_by_hash(key.offset);
0181         if (!handlers)
0182             goto next_slot;
0183
0184         di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
0185         cur = 0;
0186         total_len = btrfs_item_size(leaf, slot);
0187
0188         while (cur < total_len) {
0189             u32 name_len = btrfs_dir_name_len(leaf, di);
0190             u32 data_len = btrfs_dir_data_len(leaf, di);
0191             unsigned long name_ptr, data_ptr;
0192             const struct prop_handler *handler;
0193
0194             this_len = sizeof(*di) + name_len + data_len;
0195             name_ptr = (unsigned long)(di + 1);
0196             data_ptr = name_ptr + name_len;
0197
0198             if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
0199                 memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
0200                          name_ptr,
0201                          XATTR_BTRFS_PREFIX_LEN))
0202                 goto next_dir_item;
0203
0204             if (name_len >= name_buf_len) {
0205                 kfree(name_buf);
0206                 name_buf_len = name_len + 1;
0207                 name_buf = kmalloc(name_buf_len, GFP_NOFS);
0208                 if (!name_buf) {
0209                     ret = -ENOMEM;
0210                     goto out;
0211                 }
0212             }
0213             read_extent_buffer(leaf, name_buf, name_ptr, name_len);
0214             name_buf[name_len] = '\0';
0215
0216             handler = find_prop_handler(name_buf, handlers);
0217             if (!handler)
0218                 goto next_dir_item;
0219
0220             if (data_len > value_buf_len) {
0221                 kfree(value_buf);
0222                 value_buf_len = data_len;
0223                 value_buf = kmalloc(data_len, GFP_NOFS);
0224                 if (!value_buf) {
0225                     ret = -ENOMEM;
0226                     goto out;
0227                 }
0228             }
0229             read_extent_buffer(leaf, value_buf, data_ptr, data_len);
0230
0231             iterator(ctx, handler, value_buf, data_len);
0232 next_dir_item:
0233             cur += this_len;
0234             di = (struct btrfs_dir_item *)((char *) di + this_len);
0235         }
0236
0237 next_slot:
0238         path->slots[0]++;
0239     }
0240
0241     ret = 0;
0242 out:
0243     btrfs_release_path(path);
0244     kfree(name_buf);
0245     kfree(value_buf);
0246
0247     return ret;
0248 }
0249
0250 static void inode_prop_iterator(void *ctx,
0251                 const struct prop_handler *handler,
0252                 const char *value,
0253                 size_t len)
0254 {
0255     struct inode *inode = ctx;
0256     struct btrfs_root *root = BTRFS_I(inode)->root;
0257     int ret;
0258
0259     ret = handler->apply(inode, value, len);
0260     if (unlikely(ret))
0261         btrfs_warn(root->fs_info,
0262                "error applying prop %s to ino %llu (root %llu): %d",
0263                handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
0264                root->root_key.objectid, ret);
0265     else
0266         set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
0267 }
0268
0269 int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
0270 {
0271     struct btrfs_root *root = BTRFS_I(inode)->root;
0272     u64 ino = btrfs_ino(BTRFS_I(inode));
0273     int ret;
0274
0275     ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
0276
0277     return ret;
0278 }
0279
0280 static int prop_compression_validate(const struct btrfs_inode *inode,
0281                      const char *value, size_t len)
0282 {
0283     if (!btrfs_inode_can_compress(inode))
0284         return -EINVAL;
0285
0286     if (!value)
0287         return 0;
0288
0289     if (btrfs_compress_is_valid_type(value, len))
0290         return 0;
0291
0292     if ((len == 2 && strncmp("no", value, 2) == 0) ||
0293         (len == 4 && strncmp("none", value, 4) == 0))
0294         return 0;
0295
0296     return -EINVAL;
0297 }
0298
0299 static int prop_compression_apply(struct inode *inode, const char *value,
0300                   size_t len)
0301 {
0302     struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
0303     int type;
0304
0305     /* Reset to defaults */
0306     if (len == 0) {
0307         BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
0308         BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
0309         BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
0310         return 0;
0311     }
0312
0313     /* Set NOCOMPRESS flag */
0314     if ((len == 2 && strncmp("no", value, 2) == 0) ||
0315         (len == 4 && strncmp("none", value, 4) == 0)) {
0316         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
0317         BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
0318         BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
0319
0320         return 0;
0321     }
0322
0323     if (!strncmp("lzo", value, 3)) {
0324         type = BTRFS_COMPRESS_LZO;
0325         btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
0326     } else if (!strncmp("zlib", value, 4)) {
0327         type = BTRFS_COMPRESS_ZLIB;
0328     } else if (!strncmp("zstd", value, 4)) {
0329         type = BTRFS_COMPRESS_ZSTD;
0330         btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
0331     } else {
0332         return -EINVAL;
0333     }
0334
0335     BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
0336     BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
0337     BTRFS_I(inode)->prop_compress = type;
0338
0339     return 0;
0340 }
0341
0342 static bool prop_compression_ignore(const struct btrfs_inode *inode)
0343 {
0344     /*
0345      * Compression only has effect for regular files, and for directories
0346      * we set it just to propagate it to new files created inside them.
0347      * Everything else (symlinks, devices, sockets, fifos) is pointless as
0348      * it will do nothing, so don't waste metadata space on a compression
0349      * xattr for anything that is neither a file nor a directory.
0350      */
0351     if (!S_ISREG(inode->vfs_inode.i_mode) &&
0352         !S_ISDIR(inode->vfs_inode.i_mode))
0353         return true;
0354
0355     return false;
0356 }
0357
0358 static const char *prop_compression_extract(struct inode *inode)
0359 {
0360     switch (BTRFS_I(inode)->prop_compress) {
0361     case BTRFS_COMPRESS_ZLIB:
0362     case BTRFS_COMPRESS_LZO:
0363     case BTRFS_COMPRESS_ZSTD:
0364         return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
0365     default:
0366         break;
0367     }
0368
0369     return NULL;
0370 }
0371
0372 static struct prop_handler prop_handlers[] = {
0373     {
0374         .xattr_name = XATTR_BTRFS_PREFIX "compression",
0375         .validate = prop_compression_validate,
0376         .apply = prop_compression_apply,
0377         .extract = prop_compression_extract,
0378         .ignore = prop_compression_ignore,
0379         .inheritable = 1
0380     },
0381 };
0382
0383 int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
0384                   struct inode *inode, struct inode *parent)
0385 {
0386     struct btrfs_root *root = BTRFS_I(inode)->root;
0387     struct btrfs_fs_info *fs_info = root->fs_info;
0388     int ret;
0389     int i;
0390     bool need_reserve = false;
0391
0392     if (!test_bit(BTRFS_INODE_HAS_PROPS,
0393               &BTRFS_I(parent)->runtime_flags))
0394         return 0;
0395
0396     for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
0397         const struct prop_handler *h = &prop_handlers[i];
0398         const char *value;
0399         u64 num_bytes = 0;
0400
0401         if (!h->inheritable)
0402             continue;
0403
0404         if (h->ignore(BTRFS_I(inode)))
0405             continue;
0406
0407         value = h->extract(parent);
0408         if (!value)
0409             continue;
0410
0411         /*
0412          * This is not strictly necessary as the property should be
0413          * valid, but in case it isn't, don't propagate it further.
0414          */
0415         ret = h->validate(BTRFS_I(inode), value, strlen(value));
0416         if (ret)
0417             continue;
0418
0419         /*
0420          * Currently callers should be reserving 1 item for properties,
0421          * since we only have 1 property that we currently support.  If
0422          * we add more in the future we need to try and reserve more
0423          * space for them.  But we should also revisit how we do space
0424          * reservations if we do add more properties in the future.
0425          */
0426         if (need_reserve) {
0427             num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
0428             ret = btrfs_block_rsv_add(fs_info, trans->block_rsv,
0429                           num_bytes,
0430                           BTRFS_RESERVE_NO_FLUSH);
0431             if (ret)
0432                 return ret;
0433         }
0434
0435         ret = btrfs_setxattr(trans, inode, h->xattr_name, value,
0436                      strlen(value), 0);
0437         if (!ret) {
0438             ret = h->apply(inode, value, strlen(value));
0439             if (ret)
0440                 btrfs_setxattr(trans, inode, h->xattr_name,
0441                            NULL, 0, 0);
0442             else
0443                 set_bit(BTRFS_INODE_HAS_PROPS,
0444                     &BTRFS_I(inode)->runtime_flags);
0445         }
0446
0447         if (need_reserve) {
0448             btrfs_block_rsv_release(fs_info, trans->block_rsv,
0449                     num_bytes, NULL);
0450             if (ret)
0451                 return ret;
0452         }
0453         need_reserve = true;
0454     }
0455
0456     return 0;
0457 }
0458
0459 void __init btrfs_props_init(void)
0460 {
0461     int i;
0462
0463     for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
0464         struct prop_handler *p = &prop_handlers[i];
0465         u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
0466
0467         hash_add(prop_handlers_ht, &p->node, h);
0468     }
0469 }
0470