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Message-Id: <1375436989-18948-4-git-send-email-wenqing.lz@taobao.com>
Date: Fri, 2 Aug 2013 17:49:30 +0800
From: Zheng Liu <gnehzuil.liu@...il.com>
To: linux-ext4@...r.kernel.org
Cc: Zheng Liu <wenqing.lz@...bao.com>, Theodore Ts'o <tytso@....edu>
Subject: [PATCH v1 03/22] libext2fs: add functions to operate on extended attribute
From: Zheng Liu <wenqing.lz@...bao.com>
We need to define some functions to operate extended attribute in order
to support inline data.
Signed-off-by: Zheng Liu <wenqing.lz@...bao.com>
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
lib/ext2fs/ext2_err.et.in | 3 +
lib/ext2fs/ext2_ext_attr.h | 31 ++++++++
lib/ext2fs/ext2fs.h | 9 +++
lib/ext2fs/ext_attr.c | 186 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 229 insertions(+)
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index d20c6b7..7e6d6e5 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -476,4 +476,7 @@ ec EXT2_ET_MMP_CSUM_INVALID,
ec EXT2_ET_FILE_EXISTS,
"Ext2 file already exists"
+ec EXT2_ET_EXT_ATTR_CURRUPTED,
+ "Extended attribute currupted"
+
end
diff --git a/lib/ext2fs/ext2_ext_attr.h b/lib/ext2fs/ext2_ext_attr.h
index bbb0aaa..99ad849 100644
--- a/lib/ext2fs/ext2_ext_attr.h
+++ b/lib/ext2fs/ext2_ext_attr.h
@@ -15,6 +15,10 @@
/* Maximum number of references to one attribute block */
#define EXT2_EXT_ATTR_REFCOUNT_MAX 1024
+/* Name indexes */
+#define EXT4_EXT_ATTR_INDEX_SYSTEM 7
+#define EXT4_EXT_ATTR_SYSTEM_DATA "data"
+
struct ext2_ext_attr_header {
__u32 h_magic; /* magic number for identification */
__u32 h_refcount; /* reference count */
@@ -25,6 +29,10 @@ struct ext2_ext_attr_header {
__u32 h_reserved[3]; /* zero right now */
};
+struct ext2_ext_attr_ibody_header {
+ __u32 h_magic;
+};
+
struct ext2_ext_attr_entry {
__u8 e_name_len; /* length of name */
__u8 e_name_index; /* attribute name index */
@@ -57,6 +65,29 @@ struct ext2_ext_attr_entry {
#define EXT2_XATTR_SIZE(size) \
(((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
+#define IHDR(inode) \
+ ((struct ext2_ext_attr_ibody_header *) \
+ ((char *)inode + \
+ EXT2_GOOD_OLD_INODE_SIZE + \
+ inode->i_extra_isize))
+#define IFIRST(hdr) ((struct ext2_ext_attr_entry *)((hdr)+1))
+#define EXT2_ZERO_EXT_ATTR_VALUE ((void *)-1)
+
+struct ext2_ext_attr_info {
+ int name_index;
+ const char *name;
+ const void *value;
+ size_t value_len;
+};
+
+struct ext2_ext_attr_search {
+ struct ext2_ext_attr_entry *first;
+ void *base;
+ void *end;
+ struct ext2_ext_attr_entry *here;
+ int not_found;
+};
+
#ifdef __KERNEL__
# ifdef CONFIG_EXT2_FS_EXT_ATTR
extern int ext2_get_ext_attr(struct inode *, const char *, char *, size_t, int);
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 3346c00..8c30197 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1136,6 +1136,15 @@ extern errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk,
char *block_buf,
int adjust, __u32 *newcount,
ext2_ino_t inum);
+extern errcode_t ext2fs_ext_attr_ibody_find(ext2_filsys fs,
+ struct ext2_inode_large *inode,
+ struct ext2_ext_attr_info *i,
+ struct ext2_ext_attr_search *s);
+extern errcode_t ext2fs_ext_attr_find_entry(struct ext2_ext_attr_entry **pentry,
+ int name_index, const char *name,
+ size_t size, int sorted);
+extern errcode_t ext2fs_ext_attr_set_entry(struct ext2_ext_attr_info *i,
+ struct ext2_ext_attr_search *s);
/* extent.c */
extern errcode_t ext2fs_extent_header_verify(void *ptr, int size);
diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
index 9649a14..6d55340 100644
--- a/lib/ext2fs/ext_attr.c
+++ b/lib/ext2fs/ext_attr.c
@@ -186,3 +186,189 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust,
newcount);
}
+
+static errcode_t
+ext2fs_ext_attr_check_names(struct ext2_ext_attr_entry *entry, void *end)
+{
+ while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
+ struct ext2_ext_attr_entry *next = EXT2_EXT_ATTR_NEXT(entry);
+ if ((void *)next >= end)
+ return EXT2_ET_EXT_ATTR_CURRUPTED;
+ entry = next;
+ }
+ return 0;
+}
+
+static inline errcode_t
+ext2fs_ext_attr_check_entry(struct ext2_ext_attr_entry *entry, size_t size)
+{
+ size_t value_size = entry->e_value_size;
+
+ if (entry->e_value_block != 0 || value_size > size ||
+ entry->e_value_offs + value_size > size)
+ return EXT2_ET_EXT_ATTR_CURRUPTED;
+ return 0;
+}
+
+errcode_t ext2fs_ext_attr_find_entry(struct ext2_ext_attr_entry **pentry,
+ int name_index, const char *name,
+ size_t size, int sorted)
+{
+ struct ext2_ext_attr_entry *entry;
+ size_t name_len;
+ int cmp = 1;
+
+ if (name == NULL)
+ return EXT2_ET_INVALID_ARGUMENT;
+ name_len = strlen(name);
+ for (entry = *pentry; !EXT2_EXT_IS_LAST_ENTRY(entry);
+ entry = EXT2_EXT_ATTR_NEXT(entry)) {
+ cmp = name_index - entry->e_name_index;
+ if (!cmp)
+ cmp = name_len - entry->e_name_len;
+ if (!cmp)
+ cmp = memcmp(name, EXT2_EXT_ATTR_NAME(entry),
+ name_len);
+ if (cmp <= 0 && (sorted || cmp == 0))
+ break;
+ }
+ *pentry = entry;
+ if (!cmp && ext2fs_ext_attr_check_entry(entry, size))
+ return EXT2_ET_EXT_ATTR_CURRUPTED;
+ return cmp ? ENODATA : 0;
+}
+
+errcode_t ext2fs_ext_attr_ibody_find(ext2_filsys fs,
+ struct ext2_inode_large *inode,
+ struct ext2_ext_attr_info *i,
+ struct ext2_ext_attr_search *s)
+{
+ struct ext2_ext_attr_ibody_header *header;
+ errcode_t error;
+
+ if (inode->i_extra_isize == 0)
+ return 0;
+ header = IHDR(inode);
+ s->base = s->first = IFIRST(header);
+ s->here = s->first;
+ s->end = (char *)inode + EXT2_INODE_SIZE(fs->super);
+
+ error = ext2fs_ext_attr_check_names(IFIRST(header), s->end);
+ if (error)
+ return error;
+ /* Find the named attribute. */
+ error = ext2fs_ext_attr_find_entry(&s->here, i->name_index,
+ i->name, (char *)s->end -
+ (char *)s->base, 0);
+ if (error && error != ENODATA)
+ return error;
+ s->not_found = error;
+ return 0;
+}
+
+errcode_t ext2fs_ext_attr_set_entry(struct ext2_ext_attr_info *i,
+ struct ext2_ext_attr_search *s)
+{
+ struct ext2_ext_attr_entry *last;
+ size_t freesize, min_offs = (char *)s->end - (char *)s->base;
+ size_t name_len = strlen(i->name);
+
+ /* Compute min_offs and last. */
+ last = s->first;
+ for (; !EXT2_EXT_IS_LAST_ENTRY(last); last = EXT2_EXT_ATTR_NEXT(last)) {
+ if (!last->e_value_block && last->e_value_size) {
+ size_t offs = last->e_value_offs;
+ if (offs < min_offs)
+ min_offs = offs;
+ }
+ }
+ freesize = min_offs - ((char *)last - (char *)s->base) - sizeof(__u32);
+ if (!s->not_found) {
+ if (!s->here->e_value_block && s->here->e_value_size) {
+ size_t size = s->here->e_value_size;
+ freesize += EXT2_EXT_ATTR_SIZE(size);
+ }
+ freesize += EXT2_EXT_ATTR_LEN(name_len);
+ }
+ if (i->value) {
+ if (freesize < EXT2_EXT_ATTR_SIZE(i->value_len) ||
+ freesize < EXT2_EXT_ATTR_LEN(name_len) +
+ EXT2_EXT_ATTR_SIZE(i->value_len))
+ return ENOSPC;
+ }
+
+ if (i->value && s->not_found) {
+ /* Insert the new name. */
+ size_t size = EXT2_EXT_ATTR_LEN(name_len);
+ size_t rest = (char *)last - (char *)s->here + sizeof(__u32);
+ memmove((char *)s->here + size, s->here, rest);
+ memset(s->here, 0, size);
+ s->here->e_name_index = i->name_index;
+ s->here->e_name_len = name_len;
+ memcpy(EXT2_EXT_ATTR_NAME(s->here), i->name, name_len);
+ } else {
+ if (!s->here->e_value_block && s->here->e_value_size) {
+ char *first_val = (char *) s->base + min_offs;
+ size_t offs = s->here->e_value_offs;
+ char *val = (char *)s->base + offs;
+ size_t size = EXT2_EXT_ATTR_SIZE(s->here->e_value_size);
+
+ if (i->value && size == EXT2_EXT_ATTR_SIZE(i->value_len)) {
+ /* The old and the new value have the same
+ * size. Just replace. */
+ s->here->e_value_size = i->value_len;
+ if (i->value == EXT2_ZERO_EXT_ATTR_VALUE) {
+ memset(val, 0, size);
+ } else {
+ memset(val + size - EXT2_EXT_ATTR_PAD, 0,
+ EXT2_EXT_ATTR_PAD);
+ memcpy(val, i->value, i->value_len);
+ }
+ return 0;
+ }
+
+ /* Remove the old value. */
+ memmove(first_val + size, first_val, val - first_val);
+ memset(first_val, 0, size);
+ s->here->e_value_size = 0;
+ s->here->e_value_offs = 0;
+ min_offs += size;
+
+ /* Adjust all value offsets. */
+ last = s->first;
+ while (!EXT2_EXT_IS_LAST_ENTRY(last)) {
+ size_t o = last->e_value_offs;
+ if (!last->e_value_block &&
+ last->e_value_size && o < offs)
+ last->e_value_offs = o + size;
+ last = EXT2_EXT_ATTR_NEXT(last);
+ }
+ }
+ if (!i->value) {
+ /* Remove the old name. */
+ size_t size = EXT2_EXT_ATTR_LEN(name_len);
+ last = (struct ext2_ext_attr_entry *)last - size;
+ memmove(s->here, (char *)s->here + size,
+ (char *)last - (char *)s->here + sizeof(__u32));
+ memset(last, 0, size);
+ }
+ }
+
+ if (i->value) {
+ /* Insert the new value. */
+ s->here->e_value_size = i->value_len;
+ if (i->value_len) {
+ size_t size = EXT2_EXT_ATTR_SIZE(i->value_len);
+ char *val = (char *)s->base + min_offs - size;
+ s->here->e_value_offs = min_offs - size;
+ if (i->value == EXT2_ZERO_EXT_ATTR_VALUE) {
+ memset(val, 0, size);
+ } else {
+ memset(val + size - EXT2_EXT_ATTR_PAD, 0,
+ EXT2_EXT_ATTR_PAD);
+ memcpy(val, i->value, i->value_len);
+ }
+ }
+ }
+ return 0;
+}
--
1.7.9.7
--
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