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![Jan Kara](/assets/img/avatar_default.png)
Places which modify superblock feature / state fields mark the superblock buffer dirty so it is written out by flusher thread. Thus there's no need to set s_dirt there. The only other fields changing in the superblock are the numbers of free blocks, free inodes and s_wtime. There's no real need to write (or even compute) these periodically. Free blocks / inodes counters are recomputed on every mount from group counters anyway and value of s_wtime is only informational and imprecise anyway. So it should be enough to write these opportunistically on mount, remount, umount, and sync_fs times. Signed-off-by: Jan Kara <jack@suse.cz>
1029 lines
28 KiB
C
1029 lines
28 KiB
C
/*
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* linux/fs/ext2/xattr.c
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*
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* Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
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*
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* Fix by Harrison Xing <harrison@mountainviewdata.com>.
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* Extended attributes for symlinks and special files added per
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* suggestion of Luka Renko <luka.renko@hermes.si>.
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* xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
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* Red Hat Inc.
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*
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*/
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/*
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* Extended attributes are stored on disk blocks allocated outside of
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* any inode. The i_file_acl field is then made to point to this allocated
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* block. If all extended attributes of an inode are identical, these
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* inodes may share the same extended attribute block. Such situations
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* are automatically detected by keeping a cache of recent attribute block
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* numbers and hashes over the block's contents in memory.
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*
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*
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* Extended attribute block layout:
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*
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* +------------------+
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* | header |
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* | entry 1 | |
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* | entry 2 | | growing downwards
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* | entry 3 | v
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* | four null bytes |
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* | . . . |
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* | value 1 | ^
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* | value 3 | | growing upwards
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* | value 2 | |
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* +------------------+
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*
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* 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,
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* so that two extended attribute blocks can be compared efficiently.
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*
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* Attribute values are aligned to the end of the block, stored in
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* no specific order. They are also padded to EXT2_XATTR_PAD byte
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* boundaries. No additional gaps are left between them.
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*
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* Locking strategy
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* ----------------
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* EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem.
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* EA blocks are only changed if they are exclusive to an inode, so
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* holding xattr_sem also means that nothing but the EA block's reference
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* count will change. Multiple writers to an EA block are synchronized
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* by the bh lock. No more than a single bh lock is held at any time
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* to avoid deadlocks.
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*/
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#include <linux/buffer_head.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/mbcache.h>
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#include <linux/quotaops.h>
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#include <linux/rwsem.h>
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#include <linux/security.h>
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#include "ext2.h"
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#include "xattr.h"
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#include "acl.h"
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#define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data))
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#define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr))
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#define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1)
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#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
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#ifdef EXT2_XATTR_DEBUG
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# define ea_idebug(inode, f...) do { \
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printk(KERN_DEBUG "inode %s:%ld: ", \
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inode->i_sb->s_id, inode->i_ino); \
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printk(f); \
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printk("\n"); \
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} while (0)
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# define ea_bdebug(bh, f...) do { \
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char b[BDEVNAME_SIZE]; \
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printk(KERN_DEBUG "block %s:%lu: ", \
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bdevname(bh->b_bdev, b), \
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(unsigned long) bh->b_blocknr); \
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printk(f); \
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printk("\n"); \
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} while (0)
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#else
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# define ea_idebug(f...)
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# define ea_bdebug(f...)
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#endif
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static int ext2_xattr_set2(struct inode *, struct buffer_head *,
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struct ext2_xattr_header *);
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static int ext2_xattr_cache_insert(struct buffer_head *);
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static struct buffer_head *ext2_xattr_cache_find(struct inode *,
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struct ext2_xattr_header *);
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static void ext2_xattr_rehash(struct ext2_xattr_header *,
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struct ext2_xattr_entry *);
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static struct mb_cache *ext2_xattr_cache;
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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,
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#ifdef CONFIG_EXT2_FS_POSIX_ACL
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[EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext2_xattr_acl_access_handler,
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[EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext2_xattr_acl_default_handler,
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#endif
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[EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler,
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#ifdef CONFIG_EXT2_FS_SECURITY
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[EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler,
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#endif
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};
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const struct xattr_handler *ext2_xattr_handlers[] = {
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&ext2_xattr_user_handler,
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&ext2_xattr_trusted_handler,
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#ifdef CONFIG_EXT2_FS_POSIX_ACL
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&ext2_xattr_acl_access_handler,
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&ext2_xattr_acl_default_handler,
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#endif
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#ifdef CONFIG_EXT2_FS_SECURITY
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&ext2_xattr_security_handler,
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#endif
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NULL
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};
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static inline const struct xattr_handler *
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ext2_xattr_handler(int name_index)
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{
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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))
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handler = ext2_xattr_handler_map[name_index];
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return handler;
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}
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/*
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* ext2_xattr_get()
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*
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* Copy an extended attribute into the buffer
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* provided, or compute the buffer size required.
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* Buffer is NULL to compute the size of the buffer required.
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*
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* Returns a negative error number on failure, or the number of bytes
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* used / required on success.
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*/
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int
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ext2_xattr_get(struct inode *inode, int name_index, const char *name,
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void *buffer, size_t buffer_size)
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{
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struct buffer_head *bh = NULL;
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struct ext2_xattr_entry *entry;
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size_t name_len, size;
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char *end;
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int error;
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ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
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name_index, name, buffer, (long)buffer_size);
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if (name == NULL)
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return -EINVAL;
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name_len = strlen(name);
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if (name_len > 255)
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return -ERANGE;
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down_read(&EXT2_I(inode)->xattr_sem);
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error = -ENODATA;
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if (!EXT2_I(inode)->i_file_acl)
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goto cleanup;
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ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
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bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
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error = -EIO;
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if (!bh)
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goto cleanup;
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ea_bdebug(bh, "b_count=%d, refcount=%d",
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atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
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end = bh->b_data + bh->b_size;
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if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
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HDR(bh)->h_blocks != cpu_to_le32(1)) {
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bad_block: ext2_error(inode->i_sb, "ext2_xattr_get",
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"inode %ld: bad block %d", inode->i_ino,
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EXT2_I(inode)->i_file_acl);
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error = -EIO;
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goto cleanup;
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}
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/* find named attribute */
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entry = FIRST_ENTRY(bh);
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while (!IS_LAST_ENTRY(entry)) {
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struct ext2_xattr_entry *next =
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EXT2_XATTR_NEXT(entry);
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if ((char *)next >= end)
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goto bad_block;
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if (name_index == entry->e_name_index &&
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name_len == entry->e_name_len &&
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memcmp(name, entry->e_name, name_len) == 0)
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goto found;
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entry = next;
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}
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if (ext2_xattr_cache_insert(bh))
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ea_idebug(inode, "cache insert failed");
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error = -ENODATA;
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goto cleanup;
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found:
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/* check the buffer size */
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if (entry->e_value_block != 0)
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goto bad_block;
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size = le32_to_cpu(entry->e_value_size);
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if (size > inode->i_sb->s_blocksize ||
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le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize)
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goto bad_block;
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if (ext2_xattr_cache_insert(bh))
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ea_idebug(inode, "cache insert failed");
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if (buffer) {
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error = -ERANGE;
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if (size > buffer_size)
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goto cleanup;
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/* return value of attribute */
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memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
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size);
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}
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error = size;
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cleanup:
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brelse(bh);
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up_read(&EXT2_I(inode)->xattr_sem);
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return error;
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}
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/*
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* ext2_xattr_list()
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*
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* Copy a list of attribute names into the buffer
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* provided, or compute the buffer size required.
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* Buffer is NULL to compute the size of the buffer required.
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*
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* Returns a negative error number on failure, or the number of bytes
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* used / required on success.
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*/
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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 = dentry->d_inode;
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struct buffer_head *bh = NULL;
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struct ext2_xattr_entry *entry;
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char *end;
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size_t rest = buffer_size;
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int error;
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ea_idebug(inode, "buffer=%p, buffer_size=%ld",
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buffer, (long)buffer_size);
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down_read(&EXT2_I(inode)->xattr_sem);
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error = 0;
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if (!EXT2_I(inode)->i_file_acl)
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goto cleanup;
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ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
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bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
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error = -EIO;
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if (!bh)
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goto cleanup;
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ea_bdebug(bh, "b_count=%d, refcount=%d",
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atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
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end = bh->b_data + bh->b_size;
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if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
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HDR(bh)->h_blocks != cpu_to_le32(1)) {
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bad_block: ext2_error(inode->i_sb, "ext2_xattr_list",
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"inode %ld: bad block %d", inode->i_ino,
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EXT2_I(inode)->i_file_acl);
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error = -EIO;
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goto cleanup;
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}
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/* check the on-disk data structure */
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entry = FIRST_ENTRY(bh);
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while (!IS_LAST_ENTRY(entry)) {
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struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry);
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if ((char *)next >= end)
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goto bad_block;
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entry = next;
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}
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if (ext2_xattr_cache_insert(bh))
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ea_idebug(inode, "cache insert failed");
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/* list the attribute names */
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for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry);
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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) {
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size_t size = handler->list(dentry, buffer, rest,
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entry->e_name,
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entry->e_name_len,
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handler->flags);
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if (buffer) {
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if (size > rest) {
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error = -ERANGE;
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goto cleanup;
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}
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buffer += size;
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}
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rest -= size;
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}
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}
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error = buffer_size - rest; /* total size */
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cleanup:
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brelse(bh);
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up_read(&EXT2_I(inode)->xattr_sem);
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return error;
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}
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|
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/*
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* Inode operation listxattr()
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*
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* dentry->d_inode->i_mutex: don't care
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*/
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ssize_t
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ext2_listxattr(struct dentry *dentry, char *buffer, size_t size)
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{
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return ext2_xattr_list(dentry, buffer, size);
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}
|
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|
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/*
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* If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is
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* not set, set it.
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*/
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static void ext2_xattr_update_super_block(struct super_block *sb)
|
|
{
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if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR))
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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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}
|
|
|
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/*
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* ext2_xattr_set()
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*
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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
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* either replace an existing extended attribute, or create a new extended
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* attribute. The flags XATTR_REPLACE and XATTR_CREATE
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* specify that an extended attribute must exist and must not exist
|
|
* previous to the call, respectively.
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*
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* Returns 0, or a negative error number on failure.
|
|
*/
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int
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ext2_xattr_set(struct inode *inode, int name_index, const char *name,
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const void *value, size_t value_len, int flags)
|
|
{
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struct super_block *sb = inode->i_sb;
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struct buffer_head *bh = NULL;
|
|
struct ext2_xattr_header *header = NULL;
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struct ext2_xattr_entry *here, *last;
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size_t name_len, free, min_offs = sb->s_blocksize;
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int not_found = 1, error;
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char *end;
|
|
|
|
/*
|
|
* header -- Points either into bh, or to a temporarily
|
|
* allocated buffer.
|
|
* here -- The named entry found, or the place for inserting, within
|
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* the block pointed to by header.
|
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* last -- Points right after the last named entry within the block
|
|
* pointed to by header.
|
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* 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.
|
|
*/
|
|
|
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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;
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|
name_len = strlen(name);
|
|
if (name_len > 255 || value_len > sb->s_blocksize)
|
|
return -ERANGE;
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|
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) {
|
|
struct mb_cache_entry *ce;
|
|
|
|
/* assert(header == HDR(bh)); */
|
|
ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev,
|
|
bh->b_blocknr);
|
|
lock_buffer(bh);
|
|
if (header->h_refcount == cpu_to_le32(1)) {
|
|
ea_bdebug(bh, "modifying in-place");
|
|
if (ce)
|
|
mb_cache_entry_free(ce);
|
|
/* keep the buffer locked while modifying it. */
|
|
} else {
|
|
int offset;
|
|
|
|
if (ce)
|
|
mb_cache_entry_release(ce);
|
|
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. */
|
|
header = kzalloc(sb->s_blocksize, GFP_KERNEL);
|
|
error = -ENOMEM;
|
|
if (header == NULL)
|
|
goto cleanup;
|
|
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;
|
|
|
|
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");
|
|
|
|
error = dquot_alloc_block(inode, 1);
|
|
if (error) {
|
|
unlock_buffer(new_bh);
|
|
goto cleanup;
|
|
}
|
|
le32_add_cpu(&HDR(new_bh)->h_refcount, 1);
|
|
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);
|
|
ext2_xattr_cache_insert(new_bh);
|
|
} else {
|
|
/* We need to allocate a new block */
|
|
ext2_fsblk_t goal = ext2_group_first_block_no(sb,
|
|
EXT2_I(inode)->i_block_group);
|
|
int block = ext2_new_block(inode, goal, &error);
|
|
if (error)
|
|
goto cleanup;
|
|
ea_idebug(inode, "creating block %d", block);
|
|
|
|
new_bh = sb_getblk(sb, block);
|
|
if (!new_bh) {
|
|
ext2_free_blocks(inode, block, 1);
|
|
mark_inode_dirty(inode);
|
|
error = -EIO;
|
|
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);
|
|
ext2_xattr_cache_insert(new_bh);
|
|
|
|
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)) {
|
|
error = sync_inode_metadata(inode, 1);
|
|
/* 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) {
|
|
if (new_bh && new_bh != old_bh) {
|
|
dquot_free_block_nodirty(inode, 1);
|
|
mark_inode_dirty(inode);
|
|
}
|
|
goto cleanup;
|
|
}
|
|
} else
|
|
mark_inode_dirty(inode);
|
|
|
|
error = 0;
|
|
if (old_bh && old_bh != new_bh) {
|
|
struct mb_cache_entry *ce;
|
|
|
|
/*
|
|
* If there was an old block and we are no longer using it,
|
|
* release the old block.
|
|
*/
|
|
ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev,
|
|
old_bh->b_blocknr);
|
|
lock_buffer(old_bh);
|
|
if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) {
|
|
/* Free the old block. */
|
|
if (ce)
|
|
mb_cache_entry_free(ce);
|
|
ea_bdebug(old_bh, "freeing");
|
|
ext2_free_blocks(inode, old_bh->b_blocknr, 1);
|
|
mark_inode_dirty(inode);
|
|
/* 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. */
|
|
le32_add_cpu(&HDR(old_bh)->h_refcount, -1);
|
|
if (ce)
|
|
mb_cache_entry_release(ce);
|
|
dquot_free_block_nodirty(inode, 1);
|
|
mark_inode_dirty(inode);
|
|
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;
|
|
struct mb_cache_entry *ce;
|
|
|
|
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;
|
|
}
|
|
ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr);
|
|
lock_buffer(bh);
|
|
if (HDR(bh)->h_refcount == cpu_to_le32(1)) {
|
|
if (ce)
|
|
mb_cache_entry_free(ce);
|
|
ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
|
|
get_bh(bh);
|
|
bforget(bh);
|
|
unlock_buffer(bh);
|
|
} else {
|
|
le32_add_cpu(&HDR(bh)->h_refcount, -1);
|
|
if (ce)
|
|
mb_cache_entry_release(ce);
|
|
ea_bdebug(bh, "refcount now=%d",
|
|
le32_to_cpu(HDR(bh)->h_refcount));
|
|
unlock_buffer(bh);
|
|
mark_buffer_dirty(bh);
|
|
if (IS_SYNC(inode))
|
|
sync_dirty_buffer(bh);
|
|
dquot_free_block_nodirty(inode, 1);
|
|
}
|
|
EXT2_I(inode)->i_file_acl = 0;
|
|
|
|
cleanup:
|
|
brelse(bh);
|
|
up_write(&EXT2_I(inode)->xattr_sem);
|
|
}
|
|
|
|
/*
|
|
* ext2_xattr_put_super()
|
|
*
|
|
* This is called when a file system is unmounted.
|
|
*/
|
|
void
|
|
ext2_xattr_put_super(struct super_block *sb)
|
|
{
|
|
mb_cache_shrink(sb->s_bdev);
|
|
}
|
|
|
|
|
|
/*
|
|
* 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
|
|
ext2_xattr_cache_insert(struct buffer_head *bh)
|
|
{
|
|
__u32 hash = le32_to_cpu(HDR(bh)->h_hash);
|
|
struct mb_cache_entry *ce;
|
|
int error;
|
|
|
|
ce = mb_cache_entry_alloc(ext2_xattr_cache, GFP_NOFS);
|
|
if (!ce)
|
|
return -ENOMEM;
|
|
error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
|
|
if (error) {
|
|
mb_cache_entry_free(ce);
|
|
if (error == -EBUSY) {
|
|
ea_bdebug(bh, "already in cache (%d cache entries)",
|
|
atomic_read(&ext2_xattr_cache->c_entry_count));
|
|
error = 0;
|
|
}
|
|
} else {
|
|
ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash,
|
|
atomic_read(&ext2_xattr_cache->c_entry_count));
|
|
mb_cache_entry_release(ce);
|
|
}
|
|
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);
|
|
struct mb_cache_entry *ce;
|
|
|
|
if (!header->h_hash)
|
|
return NULL; /* never share */
|
|
ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
|
|
again:
|
|
ce = mb_cache_entry_find_first(ext2_xattr_cache, inode->i_sb->s_bdev,
|
|
hash);
|
|
while (ce) {
|
|
struct buffer_head *bh;
|
|
|
|
if (IS_ERR(ce)) {
|
|
if (PTR_ERR(ce) == -EAGAIN)
|
|
goto again;
|
|
break;
|
|
}
|
|
|
|
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);
|
|
if (le32_to_cpu(HDR(bh)->h_refcount) >
|
|
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)));
|
|
mb_cache_entry_release(ce);
|
|
return bh;
|
|
}
|
|
unlock_buffer(bh);
|
|
brelse(bh);
|
|
}
|
|
ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
#define NAME_HASH_SHIFT 5
|
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#define VALUE_HASH_SHIFT 16
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/*
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* ext2_xattr_hash_entry()
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*
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* Compute the hash of an extended attribute.
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*/
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static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header,
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struct ext2_xattr_entry *entry)
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{
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__u32 hash = 0;
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char *name = entry->e_name;
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int n;
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|
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for (n=0; n < entry->e_name_len; n++) {
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hash = (hash << NAME_HASH_SHIFT) ^
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(hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
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*name++;
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}
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|
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if (entry->e_value_block == 0 && entry->e_value_size != 0) {
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__le32 *value = (__le32 *)((char *)header +
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le16_to_cpu(entry->e_value_offs));
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for (n = (le32_to_cpu(entry->e_value_size) +
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EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) {
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hash = (hash << VALUE_HASH_SHIFT) ^
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(hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
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le32_to_cpu(*value++);
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}
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}
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entry->e_hash = cpu_to_le32(hash);
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|
}
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|
|
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#undef NAME_HASH_SHIFT
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|
#undef VALUE_HASH_SHIFT
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|
|
|
#define BLOCK_HASH_SHIFT 16
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|
|
|
/*
|
|
* ext2_xattr_rehash()
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|
*
|
|
* Re-compute the extended attribute hash value after an entry has changed.
|
|
*/
|
|
static void ext2_xattr_rehash(struct ext2_xattr_header *header,
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|
struct ext2_xattr_entry *entry)
|
|
{
|
|
struct ext2_xattr_entry *here;
|
|
__u32 hash = 0;
|
|
|
|
ext2_xattr_hash_entry(header, entry);
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|
here = ENTRY(header+1);
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|
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);
|
|
}
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|
|
|
#undef BLOCK_HASH_SHIFT
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|
|
|
int __init
|
|
init_ext2_xattr(void)
|
|
{
|
|
ext2_xattr_cache = mb_cache_create("ext2_xattr", 6);
|
|
if (!ext2_xattr_cache)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
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|
|
|
void
|
|
exit_ext2_xattr(void)
|
|
{
|
|
mb_cache_destroy(ext2_xattr_cache);
|
|
}
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