[PATCH 7/9] erofs-utils: lib: use separate xattr parsers for listxattr/getxattr
Gao Xiang
hsiangkao at linux.alibaba.com
Thu Dec 25 05:31:29 AEDT 2025
Source kernel commit: f02615eb6f5a1e732230784bf0e3b6543540e853
Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
lib/xattr.c | 346 +++++++++++++++++++---------------------------------
1 file changed, 125 insertions(+), 221 deletions(-)
diff --git a/lib/xattr.c b/lib/xattr.c
index 273da2cec91b..5624311fdbba 100644
--- a/lib/xattr.c
+++ b/lib/xattr.c
@@ -1176,262 +1176,152 @@ static int erofs_init_inode_xattrs(struct erofs_inode *vi)
return ret;
}
-/*
- * the general idea for these return values is
- * if 0 is returned, go on processing the current xattr;
- * 1 (> 0) is returned, skip this round to process the next xattr;
- * -err (< 0) is returned, an error (maybe ENOXATTR) occurred
- * and need to be handled
- */
-struct xattr_iter_handlers {
- int (*entry)(struct erofs_xattr_iter *it, struct erofs_xattr_entry *entry);
- int (*name)(struct erofs_xattr_iter *it, unsigned int processed, char *buf,
- unsigned int len);
- int (*alloc_buffer)(struct erofs_xattr_iter *it, unsigned int value_sz);
- void (*value)(struct erofs_xattr_iter *it, unsigned int processed, char *buf,
- unsigned int len);
-};
-
-/*
- * Regardless of success or failure, `xattr_foreach' will end up with
- * `pos' pointing to the next xattr item rather than an arbitrary position.
- */
-static int xattr_foreach(struct erofs_xattr_iter *it,
- const struct xattr_iter_handlers *op,
- unsigned int *tlimit)
+static int erofs_xattr_copy_to_buffer(struct erofs_xattr_iter *it,
+ unsigned int len)
{
+ unsigned int slice, processed;
struct erofs_sb_info *sbi = it->sbi;
int blkmask = erofs_blksiz(sbi) - 1;
- struct erofs_xattr_entry entry;
- unsigned int value_sz, processed, slice;
- int err;
-
- /* 0. fixup blkaddr, pos */
- it->kaddr = erofs_bread(&it->buf, it->pos & ~blkmask, true);
- if (IS_ERR(it->kaddr))
- return PTR_ERR(it->kaddr);
-
- /*
- * 1. read xattr entry to the memory,
- * since we do EROFS_XATTR_ALIGN
- * therefore entry should be in the page
- */
- entry = *(struct erofs_xattr_entry *)
- (it->kaddr + erofs_blkoff(sbi, it->pos));
- if (tlimit) {
- unsigned int entry_sz = erofs_xattr_entry_size(&entry);
-
- /* xattr on-disk corruption: xattr entry beyond xattr_isize */
- if (*tlimit < entry_sz) {
- DBG_BUGON(1);
- return -EFSCORRUPTED;
- }
- *tlimit -= entry_sz;
- }
-
- it->pos += sizeof(struct erofs_xattr_entry);
- value_sz = le16_to_cpu(entry.e_value_size);
-
- /* handle entry */
- err = op->entry(it, &entry);
- if (err) {
- it->pos += entry.e_name_len + value_sz;
- goto out;
- }
-
- /* 2. handle xattr name (pos will finally be at the end of name) */
- processed = 0;
-
- while (processed < entry.e_name_len) {
- it->kaddr = erofs_bread(&it->buf, it->pos & ~blkmask, true);
- if (IS_ERR(it->kaddr)) {
- err = PTR_ERR(it->kaddr);
- goto out;
- }
-
- slice = min_t(unsigned int,
- erofs_blksiz(sbi) - erofs_blkoff(sbi, it->pos),
- entry.e_name_len - processed);
-
- /* handle name */
- err = op->name(it, processed,
- it->kaddr + erofs_blkoff(sbi, it->pos), slice);
- if (err) {
- it->pos += entry.e_name_len - processed + value_sz;
- goto out;
- }
-
- it->pos += slice;
- processed += slice;
- }
-
- /* 3. handle xattr value */
- processed = 0;
-
- if (op->alloc_buffer) {
- err = op->alloc_buffer(it, value_sz);
- if (err) {
- it->pos += value_sz;
- goto out;
- }
- }
+ void *src;
- while (processed < value_sz) {
+ for (processed = 0; processed < len; processed += slice) {
it->kaddr = erofs_bread(&it->buf, it->pos & ~blkmask, true);
- if (IS_ERR(it->kaddr)) {
- err = PTR_ERR(it->kaddr);
- goto out;
- }
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
- slice = min_t(unsigned int,
- erofs_blksiz(sbi) - erofs_blkoff(sbi, it->pos),
- value_sz - processed);
- op->value(it, processed, it->kaddr + erofs_blkoff(sbi, it->pos),
- slice);
+ src = it->kaddr + erofs_blkoff(sbi, it->pos);
+ slice = min_t(unsigned int, erofs_blksiz(sbi) -
+ erofs_blkoff(sbi, it->pos), len - processed);
+ memcpy(it->buffer + it->buffer_ofs, src, slice);
+ it->buffer_ofs += slice;
it->pos += slice;
- processed += slice;
}
-
-out:
- /* xattrs should be 4-byte aligned (on-disk constraint) */
- it->pos = EROFS_XATTR_ALIGN(it->pos);
- return err < 0 ? err : 0;
-}
-
-static int erofs_xattr_long_entrymatch(struct erofs_xattr_iter *it,
- struct erofs_xattr_entry *entry)
-{
- struct erofs_sb_info *sbi = it->sbi;
- struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
- (entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
-
- if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
- return -ENOATTR;
-
- if (it->index != pf->prefix->base_index ||
- it->len != entry->e_name_len + pf->infix_len)
- return -ENOATTR;
-
- if (memcmp(it->name, pf->prefix->infix, pf->infix_len))
- return -ENOATTR;
-
- it->infix_len = pf->infix_len;
- return 0;
-}
-
-static int xattr_entrymatch(struct erofs_xattr_iter *it,
- struct erofs_xattr_entry *entry)
-{
- /* should also match the infix for long name prefixes */
- if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX)
- return erofs_xattr_long_entrymatch(it, entry);
-
- if (it->index != entry->e_name_index ||
- it->len != entry->e_name_len)
- return -ENOATTR;
- it->infix_len = 0;
- return 0;
-}
-
-static int xattr_namematch(struct erofs_xattr_iter *it,
- unsigned int processed, char *buf, unsigned int len)
-{
- if (memcmp(buf, it->name + it->infix_len + processed, len))
- return -ENOATTR;
return 0;
}
-static int xattr_checkbuffer(struct erofs_xattr_iter *it,
- unsigned int value_sz)
+static int erofs_listxattr_foreach(struct erofs_xattr_iter *it)
{
- int err = it->buffer_size < value_sz ? -ERANGE : 0;
-
- it->buffer_ofs = value_sz;
- return !it->buffer ? 1 : err;
-}
-
-static void xattr_copyvalue(struct erofs_xattr_iter *it,
- unsigned int processed,
- char *buf, unsigned int len)
-{
- memcpy(it->buffer + processed, buf, len);
-}
-
-static const struct xattr_iter_handlers find_xattr_handlers = {
- .entry = xattr_entrymatch,
- .name = xattr_namematch,
- .alloc_buffer = xattr_checkbuffer,
- .value = xattr_copyvalue
-};
-
-static int xattr_entrylist(struct erofs_xattr_iter *it,
- struct erofs_xattr_entry *entry)
-{
- unsigned int base_index = entry->e_name_index;
- unsigned int prefix_len, infix_len = 0;
+ struct erofs_xattr_entry entry;
+ unsigned int base_index, name_total, prefix_len, infix_len = 0;
const char *prefix, *infix = NULL;
+ int err;
- if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ /* 1. handle xattr entry */
+ entry = *(struct erofs_xattr_entry *)
+ (it->kaddr + erofs_blkoff(it->sbi, it->pos));
+ it->pos += sizeof(struct erofs_xattr_entry);
+
+ base_index = entry.e_name_index;
+ if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
struct erofs_sb_info *sbi = it->sbi;
struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
- (entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
+ (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
- return 1;
+ return 0;
infix = pf->prefix->infix;
infix_len = pf->infix_len;
base_index = pf->prefix->base_index;
}
if (!base_index || base_index >= ARRAY_SIZE(xattr_types))
- return 1;
+ return 0;
prefix = xattr_types[base_index].prefix;
prefix_len = xattr_types[base_index].prefix_len;
+ name_total = prefix_len + infix_len + entry.e_name_len + 1;
if (!it->buffer) {
- it->buffer_ofs += prefix_len + infix_len +
- entry->e_name_len + 1;
- return 1;
+ it->buffer_ofs += name_total;
+ return 0;
}
- if (it->buffer_ofs + prefix_len + infix_len
- + entry->e_name_len + 1 > it->buffer_size)
+ if (it->buffer_ofs + name_total > it->buffer_size)
return -ERANGE;
memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);
it->buffer_ofs += prefix_len + infix_len;
- return 0;
-}
-static int xattr_namelist(struct erofs_xattr_iter *it,
- unsigned int processed, char *buf, unsigned int len)
-{
- memcpy(it->buffer + it->buffer_ofs, buf, len);
- it->buffer_ofs += len;
+ /* 2. handle xattr name */
+ err = erofs_xattr_copy_to_buffer(it, entry.e_name_len);
+ if (err)
+ return err;
+
+ it->buffer[it->buffer_ofs++] = '\0';
return 0;
}
-static int xattr_skipvalue(struct erofs_xattr_iter *it,
- unsigned int value_sz)
+static int erofs_getxattr_foreach(struct erofs_xattr_iter *it)
{
- it->buffer[it->buffer_ofs++] = '\0';
- return 1;
-}
+ struct erofs_sb_info *sbi = it->sbi;
+ int blkmask = erofs_blksiz(sbi) - 1;
+ struct erofs_xattr_entry entry;
+ unsigned int slice, processed, value_sz;
-static const struct xattr_iter_handlers list_xattr_handlers = {
- .entry = xattr_entrylist,
- .name = xattr_namelist,
- .alloc_buffer = xattr_skipvalue,
- .value = NULL
-};
+ /* 1. handle xattr entry */
+ entry = *(struct erofs_xattr_entry *)
+ (it->kaddr + erofs_blkoff(sbi, it->pos));
+ it->pos += sizeof(struct erofs_xattr_entry);
+ value_sz = le16_to_cpu(entry.e_value_size);
+
+ /* should also match the infix for long name prefixes */
+ if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
+ (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
+
+ if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
+ return -ENOATTR;
+
+ if (it->index != pf->prefix->base_index ||
+ it->len != entry.e_name_len + pf->infix_len)
+ return -ENOATTR;
+
+ if (memcmp(it->name, pf->prefix->infix, pf->infix_len))
+ return -ENOATTR;
+
+ it->infix_len = pf->infix_len;
+ } else {
+ if (it->index != entry.e_name_index ||
+ it->len != entry.e_name_len)
+ return -ENOATTR;
+
+ it->infix_len = 0;
+ }
+
+ /* 2. handle xattr name */
+ for (processed = 0; processed < entry.e_name_len; processed += slice) {
+ it->kaddr = erofs_bread(&it->buf, it->pos & ~blkmask, true);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
+
+ slice = min_t(unsigned int,
+ erofs_blksiz(sbi) - erofs_blkoff(sbi, it->pos),
+ entry.e_name_len - processed);
+ if (memcmp(it->name + it->infix_len + processed,
+ it->kaddr + erofs_blkoff(sbi, it->pos), slice))
+ return -ENOATTR;
+ it->pos += slice;
+ }
+
+ /* 3. handle xattr value */
+ if (!it->buffer) {
+ it->buffer_ofs = value_sz;
+ return 0;
+ }
+
+ if (it->buffer_size < value_sz)
+ return -ERANGE;
+
+ return erofs_xattr_copy_to_buffer(it, value_sz);
+}
static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it,
struct erofs_inode *vi, bool getxattr)
{
struct erofs_sb_info *sbi = vi->sbi;
- const struct xattr_iter_handlers *op;
- unsigned int xattr_header_sz, remaining;
+ int blkmask = erofs_blksiz(sbi) - 1;
+ unsigned int xattr_header_sz, remaining, entry_sz;
+ erofs_off_t next_pos;
int ret;
xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +
@@ -1441,18 +1331,31 @@ static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it,
return -ENOATTR;
}
- it->pos = erofs_iloc(vi) + vi->inode_isize + xattr_header_sz;
- it->kaddr = erofs_bread(&it->buf, it->pos & ~(erofs_blksiz(sbi) - 1),
- true);
- if (IS_ERR(it->kaddr))
- return PTR_ERR(it->kaddr);
-
remaining = vi->xattr_isize - xattr_header_sz;
- op = getxattr ? &find_xattr_handlers : &list_xattr_handlers;
+ it->pos = erofs_iloc(vi) + vi->inode_isize + xattr_header_sz;
while (remaining) {
- ret = xattr_foreach(it, op, &remaining);
+ it->kaddr = erofs_bread(&it->buf, it->pos & ~blkmask, true);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
+
+ entry_sz = erofs_xattr_entry_size(it->kaddr +
+ erofs_blkoff(it->sbi, it->pos));
+ /* xattr on-disk corruption: xattr entry beyond xattr_isize */
+ if (remaining < entry_sz) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ remaining -= entry_sz;
+ next_pos = it->pos + entry_sz;
+
+ if (getxattr)
+ ret = erofs_getxattr_foreach(it);
+ else
+ ret = erofs_listxattr_foreach(it);
if ((getxattr && ret != -ENOATTR) || (!getxattr && ret))
break;
+
+ it->pos = next_pos;
}
return ret;
}
@@ -1462,10 +1365,8 @@ static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it,
{
struct erofs_sb_info *sbi = vi->sbi;
unsigned int i;
- const struct xattr_iter_handlers *op;
int ret = -ENOATTR;
- op = getxattr ? &find_xattr_handlers : &list_xattr_handlers;
for (i = 0; i < vi->xattr_shared_count; ++i) {
it->pos = erofs_pos(sbi, sbi->xattr_blkaddr) +
vi->xattr_shared_xattrs[i] * sizeof(__le32);
@@ -1474,7 +1375,10 @@ static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it,
if (IS_ERR(it->kaddr))
return PTR_ERR(it->kaddr);
- ret = xattr_foreach(it, op, NULL);
+ if (getxattr)
+ ret = erofs_getxattr_foreach(it);
+ else
+ ret = erofs_listxattr_foreach(it);
if ((getxattr && ret != -ENOATTR) || (!getxattr && ret))
break;
}
--
2.43.5
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