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fs/ext2/xattr.c
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/* * linux/fs/ext2/xattr.c * * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de> * * Fix by Harrison Xing <harrison@mountainviewdata.com>. * Extended attributes for symlinks and special files added per * suggestion of Luka Renko <luka.renko@hermes.si>. * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>, * Red Hat Inc. * */ /* * Extended attributes are stored on disk blocks allocated outside of * any inode. The i_file_acl field is then made to point to this allocated * block. If all extended attributes of an inode are identical, these * inodes may share the same extended attribute block. Such situations * are automatically detected by keeping a cache of recent attribute block * numbers and hashes over the block's contents in memory. * * * Extended attribute block layout: * * +------------------+ * | header | * | entry 1 | | * | entry 2 | | growing downwards * | entry 3 | v * | four null bytes | * | . . . | * | value 1 | ^ * | value 3 | | growing upwards * | value 2 | | * +------------------+ * * The block header is followed by multiple entry descriptors. These entry |
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* descriptors are variable in size, and aligned to EXT2_XATTR_PAD |
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* byte boundaries. The entry descriptors are sorted by attribute name, * so that two extended attribute blocks can be compared efficiently. * * Attribute values are aligned to the end of the block, stored in * no specific order. They are also padded to EXT2_XATTR_PAD byte * boundaries. No additional gaps are left between them. * * Locking strategy * ---------------- * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem. * EA blocks are only changed if they are exclusive to an inode, so * holding xattr_sem also means that nothing but the EA block's reference * count will change. Multiple writers to an EA block are synchronized * by the bh lock. No more than a single bh lock is held at any time * to avoid deadlocks. */ #include <linux/buffer_head.h> |
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#include <linux/init.h> #include <linux/slab.h> |
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#include <linux/mbcache.h> |
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#include <linux/quotaops.h> #include <linux/rwsem.h> |
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#include <linux/security.h> |
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#include "ext2.h" #include "xattr.h" #include "acl.h" #define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data)) #define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr)) #define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1) #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) #ifdef EXT2_XATTR_DEBUG # define ea_idebug(inode, f...) do { \ printk(KERN_DEBUG "inode %s:%ld: ", \ inode->i_sb->s_id, inode->i_ino); \ printk(f); \ printk(" "); \ } while (0) # define ea_bdebug(bh, f...) do { \ |
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printk(KERN_DEBUG "block %pg:%lu: ", \ bh->b_bdev, (unsigned long) bh->b_blocknr); \ |
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printk(f); \ printk(" "); \ } while (0) #else # define ea_idebug(f...) # define ea_bdebug(f...) #endif static int ext2_xattr_set2(struct inode *, struct buffer_head *, struct ext2_xattr_header *); |
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static int ext2_xattr_cache_insert(struct mb_cache *, struct buffer_head *); |
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static struct buffer_head *ext2_xattr_cache_find(struct inode *, struct ext2_xattr_header *); static void ext2_xattr_rehash(struct ext2_xattr_header *, struct ext2_xattr_entry *); |
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static const struct xattr_handler *ext2_xattr_handler_map[] = { |
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[EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler, #ifdef CONFIG_EXT2_FS_POSIX_ACL |
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[EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler, [EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler, |
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#endif [EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler, #ifdef CONFIG_EXT2_FS_SECURITY [EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler, #endif }; |
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const struct xattr_handler *ext2_xattr_handlers[] = { |
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&ext2_xattr_user_handler, &ext2_xattr_trusted_handler, #ifdef CONFIG_EXT2_FS_POSIX_ACL |
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&posix_acl_access_xattr_handler, &posix_acl_default_xattr_handler, |
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#endif #ifdef CONFIG_EXT2_FS_SECURITY &ext2_xattr_security_handler, #endif NULL }; |
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static inline const struct xattr_handler * |
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ext2_xattr_handler(int name_index) { |
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const struct xattr_handler *handler = NULL; |
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if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map)) handler = ext2_xattr_handler_map[name_index]; return handler; } /* * ext2_xattr_get() * * Copy an extended attribute into the buffer * provided, or compute the buffer size required. * Buffer is NULL to compute the size of the buffer required. * * Returns a negative error number on failure, or the number of bytes * used / required on success. */ int ext2_xattr_get(struct inode *inode, int name_index, const char *name, void *buffer, size_t buffer_size) { struct buffer_head *bh = NULL; struct ext2_xattr_entry *entry; size_t name_len, size; char *end; int error; |
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struct mb_cache *ext2_mb_cache = EXT2_SB(inode->i_sb)->s_mb_cache; |
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ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", name_index, name, buffer, (long)buffer_size); if (name == NULL) return -EINVAL; |
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name_len = strlen(name); if (name_len > 255) return -ERANGE; |
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down_read(&EXT2_I(inode)->xattr_sem); error = -ENODATA; if (!EXT2_I(inode)->i_file_acl) goto cleanup; ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); error = -EIO; if (!bh) goto cleanup; ea_bdebug(bh, "b_count=%d, refcount=%d", atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); end = bh->b_data + bh->b_size; if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || HDR(bh)->h_blocks != cpu_to_le32(1)) { bad_block: ext2_error(inode->i_sb, "ext2_xattr_get", "inode %ld: bad block %d", inode->i_ino, EXT2_I(inode)->i_file_acl); error = -EIO; goto cleanup; } |
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/* find named attribute */ |
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entry = FIRST_ENTRY(bh); while (!IS_LAST_ENTRY(entry)) { struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry); if ((char *)next >= end) goto bad_block; if (name_index == entry->e_name_index && name_len == entry->e_name_len && memcmp(name, entry->e_name, name_len) == 0) goto found; entry = next; } |
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if (ext2_xattr_cache_insert(ext2_mb_cache, bh)) |
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ea_idebug(inode, "cache insert failed"); error = -ENODATA; goto cleanup; found: /* check the buffer size */ if (entry->e_value_block != 0) goto bad_block; size = le32_to_cpu(entry->e_value_size); if (size > inode->i_sb->s_blocksize || le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize) goto bad_block; |
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if (ext2_xattr_cache_insert(ext2_mb_cache, bh)) |
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ea_idebug(inode, "cache insert failed"); if (buffer) { error = -ERANGE; if (size > buffer_size) goto cleanup; /* return value of attribute */ memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), size); } error = size; cleanup: brelse(bh); up_read(&EXT2_I(inode)->xattr_sem); return error; } /* * ext2_xattr_list() * * Copy a list of attribute names into the buffer * provided, or compute the buffer size required. * Buffer is NULL to compute the size of the buffer required. * * Returns a negative error number on failure, or the number of bytes * used / required on success. */ static int |
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ext2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) |
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{ |
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struct inode *inode = d_inode(dentry); |
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struct buffer_head *bh = NULL; struct ext2_xattr_entry *entry; char *end; size_t rest = buffer_size; int error; |
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struct mb_cache *ext2_mb_cache = EXT2_SB(inode->i_sb)->s_mb_cache; |
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ea_idebug(inode, "buffer=%p, buffer_size=%ld", buffer, (long)buffer_size); down_read(&EXT2_I(inode)->xattr_sem); error = 0; if (!EXT2_I(inode)->i_file_acl) goto cleanup; ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); error = -EIO; if (!bh) goto cleanup; ea_bdebug(bh, "b_count=%d, refcount=%d", atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); end = bh->b_data + bh->b_size; if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || HDR(bh)->h_blocks != cpu_to_le32(1)) { bad_block: ext2_error(inode->i_sb, "ext2_xattr_list", "inode %ld: bad block %d", inode->i_ino, EXT2_I(inode)->i_file_acl); error = -EIO; goto cleanup; } /* check the on-disk data structure */ entry = FIRST_ENTRY(bh); while (!IS_LAST_ENTRY(entry)) { struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry); if ((char *)next >= end) goto bad_block; entry = next; } |
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if (ext2_xattr_cache_insert(ext2_mb_cache, bh)) |
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ea_idebug(inode, "cache insert failed"); /* list the attribute names */ for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry); entry = EXT2_XATTR_NEXT(entry)) { |
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const struct xattr_handler *handler = |
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ext2_xattr_handler(entry->e_name_index); |
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if (handler && (!handler->list || handler->list(dentry))) { const char *prefix = handler->prefix ?: handler->name; size_t prefix_len = strlen(prefix); size_t size = prefix_len + entry->e_name_len + 1; |
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if (buffer) { if (size > rest) { error = -ERANGE; goto cleanup; } |
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memcpy(buffer, prefix, prefix_len); buffer += prefix_len; memcpy(buffer, entry->e_name, entry->e_name_len); buffer += entry->e_name_len; *buffer++ = 0; |
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} rest -= size; } } error = buffer_size - rest; /* total size */ cleanup: brelse(bh); up_read(&EXT2_I(inode)->xattr_sem); return error; } /* * Inode operation listxattr() * |
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* d_inode(dentry)->i_mutex: don't care |
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*/ ssize_t ext2_listxattr(struct dentry *dentry, char *buffer, size_t size) { |
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return ext2_xattr_list(dentry, buffer, size); |
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} /* * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is * not set, set it. */ static void ext2_xattr_update_super_block(struct super_block *sb) { if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR)) return; |
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spin_lock(&EXT2_SB(sb)->s_lock); |
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EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR); |
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spin_unlock(&EXT2_SB(sb)->s_lock); |
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mark_buffer_dirty(EXT2_SB(sb)->s_sbh); |
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} /* * ext2_xattr_set() * |
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* Create, replace or remove an extended attribute for this inode. Value |
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* is NULL to remove an existing extended attribute, and non-NULL to * either replace an existing extended attribute, or create a new extended * attribute. The flags XATTR_REPLACE and XATTR_CREATE * specify that an extended attribute must exist and must not exist * previous to the call, respectively. * * Returns 0, or a negative error number on failure. */ int ext2_xattr_set(struct inode *inode, int name_index, const char *name, const void *value, size_t value_len, int flags) { struct super_block *sb = inode->i_sb; struct buffer_head *bh = NULL; struct ext2_xattr_header *header = NULL; struct ext2_xattr_entry *here, *last; size_t name_len, free, min_offs = sb->s_blocksize; int not_found = 1, error; char *end; /* * header -- Points either into bh, or to a temporarily * allocated buffer. * here -- The named entry found, or the place for inserting, within * the block pointed to by header. * last -- Points right after the last named entry within the block * pointed to by header. * min_offs -- The offset of the first value (values are aligned * towards the end of the block). * end -- Points right after the block pointed to by header. */ ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", name_index, name, value, (long)value_len); |
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if (value == NULL) value_len = 0; if (name == NULL) return -EINVAL; name_len = strlen(name); if (name_len > 255 || value_len > sb->s_blocksize) return -ERANGE; down_write(&EXT2_I(inode)->xattr_sem); if (EXT2_I(inode)->i_file_acl) { /* The inode already has an extended attribute block. */ bh = sb_bread(sb, EXT2_I(inode)->i_file_acl); error = -EIO; if (!bh) goto cleanup; ea_bdebug(bh, "b_count=%d, refcount=%d", atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); header = HDR(bh); end = bh->b_data + bh->b_size; if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || header->h_blocks != cpu_to_le32(1)) { bad_block: ext2_error(sb, "ext2_xattr_set", "inode %ld: bad block %d", inode->i_ino, EXT2_I(inode)->i_file_acl); error = -EIO; goto cleanup; } /* Find the named attribute. */ here = FIRST_ENTRY(bh); while (!IS_LAST_ENTRY(here)) { struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here); if ((char *)next >= end) goto bad_block; if (!here->e_value_block && here->e_value_size) { size_t offs = le16_to_cpu(here->e_value_offs); if (offs < min_offs) min_offs = offs; } not_found = name_index - here->e_name_index; if (!not_found) not_found = name_len - here->e_name_len; if (!not_found) not_found = memcmp(name, here->e_name,name_len); if (not_found <= 0) break; here = next; } last = here; /* We still need to compute min_offs and last. */ while (!IS_LAST_ENTRY(last)) { struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last); if ((char *)next >= end) goto bad_block; if (!last->e_value_block && last->e_value_size) { size_t offs = le16_to_cpu(last->e_value_offs); if (offs < min_offs) min_offs = offs; } last = next; } /* Check whether we have enough space left. */ free = min_offs - ((char*)last - (char*)header) - sizeof(__u32); } else { /* We will use a new extended attribute block. */ free = sb->s_blocksize - sizeof(struct ext2_xattr_header) - sizeof(__u32); here = last = NULL; /* avoid gcc uninitialized warning. */ } if (not_found) { /* Request to remove a nonexistent attribute? */ error = -ENODATA; if (flags & XATTR_REPLACE) goto cleanup; error = 0; if (value == NULL) goto cleanup; } else { /* Request to create an existing attribute? */ error = -EEXIST; if (flags & XATTR_CREATE) goto cleanup; if (!here->e_value_block && here->e_value_size) { size_t size = le32_to_cpu(here->e_value_size); if (le16_to_cpu(here->e_value_offs) + size > sb->s_blocksize || size > sb->s_blocksize) goto bad_block; free += EXT2_XATTR_SIZE(size); } free += EXT2_XATTR_LEN(name_len); } error = -ENOSPC; if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len)) goto cleanup; /* Here we know that we can set the new attribute. */ if (header) { |
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/* assert(header == HDR(bh)); */ |
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lock_buffer(bh); if (header->h_refcount == cpu_to_le32(1)) { |
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__u32 hash = le32_to_cpu(header->h_hash); |
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ea_bdebug(bh, "modifying in-place"); |
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/* * This must happen under buffer lock for * ext2_xattr_set2() to reliably detect modified block */ |
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mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache, hash, bh->b_blocknr); |
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/* keep the buffer locked while modifying it. */ } else { int offset; |
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unlock_buffer(bh); ea_bdebug(bh, "cloning"); header = kmalloc(bh->b_size, GFP_KERNEL); error = -ENOMEM; if (header == NULL) goto cleanup; memcpy(header, HDR(bh), bh->b_size); header->h_refcount = cpu_to_le32(1); offset = (char *)here - bh->b_data; here = ENTRY((char *)header + offset); offset = (char *)last - bh->b_data; last = ENTRY((char *)header + offset); } } else { /* Allocate a buffer where we construct the new block. */ |
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header = kzalloc(sb->s_blocksize, GFP_KERNEL); |
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error = -ENOMEM; if (header == NULL) goto cleanup; |
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end = (char *)header + sb->s_blocksize; header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC); header->h_blocks = header->h_refcount = cpu_to_le32(1); last = here = ENTRY(header+1); } /* Iff we are modifying the block in-place, bh is locked here. */ if (not_found) { /* Insert the new name. */ size_t size = EXT2_XATTR_LEN(name_len); size_t rest = (char *)last - (char *)here; memmove((char *)here + size, here, rest); memset(here, 0, size); here->e_name_index = name_index; here->e_name_len = name_len; memcpy(here->e_name, name, name_len); } else { if (!here->e_value_block && here->e_value_size) { char *first_val = (char *)header + min_offs; size_t offs = le16_to_cpu(here->e_value_offs); char *val = (char *)header + offs; size_t size = EXT2_XATTR_SIZE( le32_to_cpu(here->e_value_size)); if (size == EXT2_XATTR_SIZE(value_len)) { /* The old and the new value have the same size. Just replace. */ here->e_value_size = cpu_to_le32(value_len); memset(val + size - EXT2_XATTR_PAD, 0, EXT2_XATTR_PAD); /* Clear pad bytes. */ memcpy(val, value, value_len); goto skip_replace; } /* Remove the old value. */ memmove(first_val + size, first_val, val - first_val); memset(first_val, 0, size); here->e_value_offs = 0; min_offs += size; /* Adjust all value offsets. */ last = ENTRY(header+1); while (!IS_LAST_ENTRY(last)) { size_t o = le16_to_cpu(last->e_value_offs); if (!last->e_value_block && o < offs) last->e_value_offs = cpu_to_le16(o + size); last = EXT2_XATTR_NEXT(last); } } if (value == NULL) { /* Remove the old name. */ size_t size = EXT2_XATTR_LEN(name_len); last = ENTRY((char *)last - size); memmove(here, (char*)here + size, (char*)last - (char*)here); memset(last, 0, size); } } if (value != NULL) { /* Insert the new value. */ here->e_value_size = cpu_to_le32(value_len); if (value_len) { size_t size = EXT2_XATTR_SIZE(value_len); char *val = (char *)header + min_offs - size; here->e_value_offs = cpu_to_le16((char *)val - (char *)header); memset(val + size - EXT2_XATTR_PAD, 0, EXT2_XATTR_PAD); /* Clear the pad bytes. */ memcpy(val, value, value_len); } } skip_replace: if (IS_LAST_ENTRY(ENTRY(header+1))) { /* This block is now empty. */ if (bh && header == HDR(bh)) unlock_buffer(bh); /* we were modifying in-place. */ error = ext2_xattr_set2(inode, bh, NULL); } else { ext2_xattr_rehash(header, here); if (bh && header == HDR(bh)) unlock_buffer(bh); /* we were modifying in-place. */ error = ext2_xattr_set2(inode, bh, header); } cleanup: brelse(bh); if (!(bh && header == HDR(bh))) kfree(header); up_write(&EXT2_I(inode)->xattr_sem); return error; } /* * Second half of ext2_xattr_set(): Update the file system. */ static int ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, struct ext2_xattr_header *header) { struct super_block *sb = inode->i_sb; struct buffer_head *new_bh = NULL; int error; |
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struct mb_cache *ext2_mb_cache = EXT2_SB(sb)->s_mb_cache; |
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if (header) { new_bh = ext2_xattr_cache_find(inode, header); if (new_bh) { /* We found an identical block in the cache. */ if (new_bh == old_bh) { ea_bdebug(new_bh, "keeping this block"); } else { /* The old block is released after updating the inode. */ ea_bdebug(new_bh, "reusing block"); |
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error = dquot_alloc_block(inode, 1); if (error) { |
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unlock_buffer(new_bh); goto cleanup; } |
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le32_add_cpu(&HDR(new_bh)->h_refcount, 1); |
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638 639 640 641 642 643 644 645 646 |
ea_bdebug(new_bh, "refcount now=%d", le32_to_cpu(HDR(new_bh)->h_refcount)); } unlock_buffer(new_bh); } else if (old_bh && header == HDR(old_bh)) { /* Keep this block. No need to lock the block as we don't need to change the reference count. */ new_bh = old_bh; get_bh(new_bh); |
be0726d33
|
647 |
ext2_xattr_cache_insert(ext2_mb_cache, new_bh); |
1da177e4c
|
648 649 |
} else { /* We need to allocate a new block */ |
24097d12e
|
650 651 |
ext2_fsblk_t goal = ext2_group_first_block_no(sb, EXT2_I(inode)->i_block_group); |
a686cd898
|
652 |
int block = ext2_new_block(inode, goal, &error); |
1da177e4c
|
653 654 655 656 657 |
if (error) goto cleanup; ea_idebug(inode, "creating block %d", block); new_bh = sb_getblk(sb, block); |
2b0542a4a
|
658 |
if (unlikely(!new_bh)) { |
1da177e4c
|
659 |
ext2_free_blocks(inode, block, 1); |
addacc7d6
|
660 |
mark_inode_dirty(inode); |
ab6a773db
|
661 |
error = -ENOMEM; |
1da177e4c
|
662 663 664 665 666 667 |
goto cleanup; } lock_buffer(new_bh); memcpy(new_bh->b_data, header, new_bh->b_size); set_buffer_uptodate(new_bh); unlock_buffer(new_bh); |
be0726d33
|
668 |
ext2_xattr_cache_insert(ext2_mb_cache, new_bh); |
1da177e4c
|
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 |
ext2_xattr_update_super_block(sb); } mark_buffer_dirty(new_bh); if (IS_SYNC(inode)) { sync_dirty_buffer(new_bh); error = -EIO; if (buffer_req(new_bh) && !buffer_uptodate(new_bh)) goto cleanup; } } /* Update the inode. */ EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; inode->i_ctime = CURRENT_TIME_SEC; if (IS_SYNC(inode)) { |
c37650161
|
685 |
error = sync_inode_metadata(inode, 1); |
1da177e4c
|
686 687 688 689 |
/* In case sync failed due to ENOSPC the inode was actually * written (only some dirty data were not) so we just proceed * as if nothing happened and cleanup the unused block */ if (error && error != -ENOSPC) { |
3889717d2
|
690 691 692 693 |
if (new_bh && new_bh != old_bh) { dquot_free_block_nodirty(inode, 1); mark_inode_dirty(inode); } |
1da177e4c
|
694 695 696 697 698 699 700 |
goto cleanup; } } else mark_inode_dirty(inode); error = 0; if (old_bh && old_bh != new_bh) { |
1da177e4c
|
701 702 703 704 |
/* * If there was an old block and we are no longer using it, * release the old block. */ |
1da177e4c
|
705 706 |
lock_buffer(old_bh); if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) { |
be0726d33
|
707 708 709 710 711 712 |
__u32 hash = le32_to_cpu(HDR(old_bh)->h_hash); /* * This must happen under buffer lock for * ext2_xattr_set2() to reliably detect freed block */ |
7a2508e1b
|
713 714 |
mb_cache_entry_delete_block(ext2_mb_cache, hash, old_bh->b_blocknr); |
1da177e4c
|
715 |
/* Free the old block. */ |
1da177e4c
|
716 717 |
ea_bdebug(old_bh, "freeing"); ext2_free_blocks(inode, old_bh->b_blocknr, 1); |
addacc7d6
|
718 |
mark_inode_dirty(inode); |
1da177e4c
|
719 720 721 722 723 724 |
/* We let our caller release old_bh, so we * need to duplicate the buffer before. */ get_bh(old_bh); bforget(old_bh); } else { /* Decrement the refcount only. */ |
fba4d3997
|
725 |
le32_add_cpu(&HDR(old_bh)->h_refcount, -1); |
3889717d2
|
726 727 |
dquot_free_block_nodirty(inode, 1); mark_inode_dirty(inode); |
1da177e4c
|
728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 |
mark_buffer_dirty(old_bh); ea_bdebug(old_bh, "refcount now=%d", le32_to_cpu(HDR(old_bh)->h_refcount)); } unlock_buffer(old_bh); } cleanup: brelse(new_bh); return error; } /* * ext2_xattr_delete_inode() * * Free extended attribute resources associated with this inode. This * is called immediately before an inode is freed. */ void ext2_xattr_delete_inode(struct inode *inode) { struct buffer_head *bh = NULL; |
1da177e4c
|
751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 |
down_write(&EXT2_I(inode)->xattr_sem); if (!EXT2_I(inode)->i_file_acl) goto cleanup; bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); if (!bh) { ext2_error(inode->i_sb, "ext2_xattr_delete_inode", "inode %ld: block %d read error", inode->i_ino, EXT2_I(inode)->i_file_acl); goto cleanup; } ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || HDR(bh)->h_blocks != cpu_to_le32(1)) { ext2_error(inode->i_sb, "ext2_xattr_delete_inode", "inode %ld: bad block %d", inode->i_ino, EXT2_I(inode)->i_file_acl); goto cleanup; } |
1da177e4c
|
770 771 |
lock_buffer(bh); if (HDR(bh)->h_refcount == cpu_to_le32(1)) { |
be0726d33
|
772 773 774 775 776 777 |
__u32 hash = le32_to_cpu(HDR(bh)->h_hash); /* * This must happen under buffer lock for ext2_xattr_set2() to * reliably detect freed block */ |
7a2508e1b
|
778 779 |
mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache, hash, bh->b_blocknr); |
1da177e4c
|
780 781 782 |
ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1); get_bh(bh); bforget(bh); |
b2f49033d
|
783 |
unlock_buffer(bh); |
1da177e4c
|
784 |
} else { |
fba4d3997
|
785 |
le32_add_cpu(&HDR(bh)->h_refcount, -1); |
b2f49033d
|
786 787 788 |
ea_bdebug(bh, "refcount now=%d", le32_to_cpu(HDR(bh)->h_refcount)); unlock_buffer(bh); |
1da177e4c
|
789 790 791 |
mark_buffer_dirty(bh); if (IS_SYNC(inode)) sync_dirty_buffer(bh); |
3889717d2
|
792 |
dquot_free_block_nodirty(inode, 1); |
1da177e4c
|
793 |
} |
1da177e4c
|
794 795 796 797 798 799 800 801 |
EXT2_I(inode)->i_file_acl = 0; cleanup: brelse(bh); up_write(&EXT2_I(inode)->xattr_sem); } /* |
1da177e4c
|
802 803 804 805 806 807 808 809 |
* ext2_xattr_cache_insert() * * Create a new entry in the extended attribute cache, and insert * it unless such an entry is already in the cache. * * Returns 0, or a negative error number on failure. */ static int |
7a2508e1b
|
810 |
ext2_xattr_cache_insert(struct mb_cache *cache, struct buffer_head *bh) |
1da177e4c
|
811 812 |
{ __u32 hash = le32_to_cpu(HDR(bh)->h_hash); |
1da177e4c
|
813 |
int error; |
6048c64b2
|
814 |
error = mb_cache_entry_create(cache, GFP_NOFS, hash, bh->b_blocknr, 1); |
1da177e4c
|
815 |
if (error) { |
1da177e4c
|
816 817 818 819 820 |
if (error == -EBUSY) { ea_bdebug(bh, "already in cache (%d cache entries)", atomic_read(&ext2_xattr_cache->c_entry_count)); error = 0; } |
be0726d33
|
821 822 |
} else ea_bdebug(bh, "inserting [%x]", (int)hash); |
1da177e4c
|
823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 |
return error; } /* * ext2_xattr_cmp() * * Compare two extended attribute blocks for equality. * * Returns 0 if the blocks are equal, 1 if they differ, and * a negative error number on errors. */ static int ext2_xattr_cmp(struct ext2_xattr_header *header1, struct ext2_xattr_header *header2) { struct ext2_xattr_entry *entry1, *entry2; entry1 = ENTRY(header1+1); entry2 = ENTRY(header2+1); while (!IS_LAST_ENTRY(entry1)) { if (IS_LAST_ENTRY(entry2)) return 1; if (entry1->e_hash != entry2->e_hash || entry1->e_name_index != entry2->e_name_index || entry1->e_name_len != entry2->e_name_len || entry1->e_value_size != entry2->e_value_size || memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) return 1; if (entry1->e_value_block != 0 || entry2->e_value_block != 0) return -EIO; if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), (char *)header2 + le16_to_cpu(entry2->e_value_offs), le32_to_cpu(entry1->e_value_size))) return 1; entry1 = EXT2_XATTR_NEXT(entry1); entry2 = EXT2_XATTR_NEXT(entry2); } if (!IS_LAST_ENTRY(entry2)) return 1; return 0; } /* * ext2_xattr_cache_find() * * Find an identical extended attribute block. * * Returns a locked buffer head to the block found, or NULL if such * a block was not found or an error occurred. */ static struct buffer_head * ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) { __u32 hash = le32_to_cpu(header->h_hash); |
7a2508e1b
|
878 879 |
struct mb_cache_entry *ce; struct mb_cache *ext2_mb_cache = EXT2_SB(inode->i_sb)->s_mb_cache; |
1da177e4c
|
880 881 882 883 884 |
if (!header->h_hash) return NULL; /* never share */ ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); again: |
7a2508e1b
|
885 |
ce = mb_cache_entry_find_first(ext2_mb_cache, hash); |
1da177e4c
|
886 887 |
while (ce) { struct buffer_head *bh; |
1da177e4c
|
888 889 890 891 892 893 894 |
bh = sb_bread(inode->i_sb, ce->e_block); if (!bh) { ext2_error(inode->i_sb, "ext2_xattr_cache_find", "inode %ld: block %ld read error", inode->i_ino, (unsigned long) ce->e_block); } else { lock_buffer(bh); |
be0726d33
|
895 896 897 898 899 900 901 902 903 904 |
/* * We have to be careful about races with freeing or * rehashing of xattr block. Once we hold buffer lock * xattr block's state is stable so we can check * whether the block got freed / rehashed or not. * Since we unhash mbcache entry under buffer lock when * freeing / rehashing xattr block, checking whether * entry is still hashed is reliable. */ if (hlist_bl_unhashed(&ce->e_hash_list)) { |
7a2508e1b
|
905 |
mb_cache_entry_put(ext2_mb_cache, ce); |
be0726d33
|
906 907 908 909 |
unlock_buffer(bh); brelse(bh); goto again; } else if (le32_to_cpu(HDR(bh)->h_refcount) > |
1da177e4c
|
910 911 912 913 914 915 916 917 |
EXT2_XATTR_REFCOUNT_MAX) { ea_idebug(inode, "block %ld refcount %d>%d", (unsigned long) ce->e_block, le32_to_cpu(HDR(bh)->h_refcount), EXT2_XATTR_REFCOUNT_MAX); } else if (!ext2_xattr_cmp(header, HDR(bh))) { ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); |
7a2508e1b
|
918 919 |
mb_cache_entry_touch(ext2_mb_cache, ce); mb_cache_entry_put(ext2_mb_cache, ce); |
1da177e4c
|
920 921 922 923 924 |
return bh; } unlock_buffer(bh); brelse(bh); } |
7a2508e1b
|
925 |
ce = mb_cache_entry_find_next(ext2_mb_cache, ce); |
1da177e4c
|
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 |
} return NULL; } #define NAME_HASH_SHIFT 5 #define VALUE_HASH_SHIFT 16 /* * ext2_xattr_hash_entry() * * Compute the hash of an extended attribute. */ static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header, struct ext2_xattr_entry *entry) { __u32 hash = 0; char *name = entry->e_name; int n; for (n=0; n < entry->e_name_len; n++) { hash = (hash << NAME_HASH_SHIFT) ^ (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++; } if (entry->e_value_block == 0 && entry->e_value_size != 0) { __le32 *value = (__le32 *)((char *)header + le16_to_cpu(entry->e_value_offs)); for (n = (le32_to_cpu(entry->e_value_size) + EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) { hash = (hash << VALUE_HASH_SHIFT) ^ (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ le32_to_cpu(*value++); } } entry->e_hash = cpu_to_le32(hash); } #undef NAME_HASH_SHIFT #undef VALUE_HASH_SHIFT #define BLOCK_HASH_SHIFT 16 /* * ext2_xattr_rehash() * * Re-compute the extended attribute hash value after an entry has changed. */ static void ext2_xattr_rehash(struct ext2_xattr_header *header, struct ext2_xattr_entry *entry) { struct ext2_xattr_entry *here; __u32 hash = 0; ext2_xattr_hash_entry(header, entry); here = ENTRY(header+1); while (!IS_LAST_ENTRY(here)) { if (!here->e_hash) { /* Block is not shared if an entry's hash value == 0 */ hash = 0; break; } hash = (hash << BLOCK_HASH_SHIFT) ^ (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ le32_to_cpu(here->e_hash); here = EXT2_XATTR_NEXT(here); } header->h_hash = cpu_to_le32(hash); } #undef BLOCK_HASH_SHIFT |
be0726d33
|
997 |
#define HASH_BUCKET_BITS 10 |
7a2508e1b
|
998 |
struct mb_cache *ext2_xattr_create_cache(void) |
1da177e4c
|
999 |
{ |
7a2508e1b
|
1000 |
return mb_cache_create(HASH_BUCKET_BITS); |
1da177e4c
|
1001 |
} |
7a2508e1b
|
1002 |
void ext2_xattr_destroy_cache(struct mb_cache *cache) |
1da177e4c
|
1003 |
{ |
be0726d33
|
1004 |
if (cache) |
7a2508e1b
|
1005 |
mb_cache_destroy(cache); |
1da177e4c
|
1006 |
} |