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Message-Id: <20230518024551.123990-6-jefflexu@linux.alibaba.com>
Date: Thu, 18 May 2023 10:45:51 +0800
From: Jingbo Xu <jefflexu@...ux.alibaba.com>
To: xiang@...nel.org, chao@...nel.org, huyue2@...lpad.com,
linux-erofs@...ts.ozlabs.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH v3 5/5] erofs: use separate xattr parsers for listxattr/getxattr
There's a callback styled xattr parser, i.e. xattr_foreach(), which is
shared among listxattr and getxattr. Convert it to two separate xattr
parsers for listxattr and getxattr.
Signed-off-by: Jingbo Xu <jefflexu@...ux.alibaba.com>
---
fs/erofs/xattr.c | 389 +++++++++++++++++++++--------------------------
1 file changed, 170 insertions(+), 219 deletions(-)
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 435146628eed..111735fb6fbc 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -12,7 +12,7 @@ struct erofs_xattr_iter {
struct erofs_buf buf;
void *kaddr;
erofs_blk_t blkaddr;
- unsigned int ofs;
+ unsigned int ofs, t_ofs;
char *buffer;
int buffer_size, buffer_ofs;
@@ -21,6 +21,7 @@ struct erofs_xattr_iter {
struct qstr name;
struct dentry *dentry;
struct inode *inode;
+ unsigned int remaining; /* size of inline xattrs to be iterated */
bool getxattr;
};
@@ -46,6 +47,28 @@ static inline int erofs_xattr_iter_fixup_aligned(struct erofs_xattr_iter *it)
return erofs_xattr_iter_fixup(it);
}
+static int erofs_xattr_iter_prep(struct erofs_xattr_iter *it)
+{
+ unsigned int entry_sz;
+ int err;
+
+ err = erofs_xattr_iter_fixup(it);
+ if (err)
+ return err;
+
+ entry_sz = erofs_xattr_entry_size(it->kaddr + it->ofs);
+ it->t_ofs = it->ofs + entry_sz;
+ if (it->remaining) {
+ /* xattr on-disk corruption: xattr entry beyond xattr_isize */
+ if (it->remaining < entry_sz) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ it->remaining -= entry_sz;
+ }
+ return 0;
+}
+
static int erofs_init_inode_xattrs(struct inode *inode)
{
struct erofs_inode *const vi = EROFS_I(inode);
@@ -144,183 +167,6 @@ static int erofs_init_inode_xattrs(struct inode *inode)
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
- * `ofs' 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)
-{
- struct erofs_xattr_entry entry;
- unsigned int value_sz, processed, slice;
- int err;
-
- /* 0. fixup blkaddr, ofs, ipage */
- err = erofs_xattr_iter_fixup(it);
- if (err)
- return err;
-
- /*
- * 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 + it->ofs);
- 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->ofs += sizeof(struct erofs_xattr_entry);
- value_sz = le16_to_cpu(entry.e_value_size);
-
- /* handle entry */
- err = op->entry(it, &entry);
- if (err) {
- it->ofs += entry.e_name_len + value_sz;
- goto out;
- }
-
- /* 2. handle xattr name (ofs will finally be at the end of name) */
- processed = 0;
-
- while (processed < entry.e_name_len) {
- err = erofs_xattr_iter_fixup_aligned(it);
- if (err)
- goto out;
-
- slice = min_t(unsigned int, it->sb->s_blocksize - it->ofs,
- entry.e_name_len - processed);
-
- /* handle name */
- err = op->name(it, processed, it->kaddr + it->ofs, slice);
- if (err) {
- it->ofs += entry.e_name_len - processed + value_sz;
- goto out;
- }
-
- it->ofs += slice;
- processed += slice;
- }
-
- /* 3. handle xattr value */
- processed = 0;
-
- if (op->alloc_buffer) {
- err = op->alloc_buffer(it, value_sz);
- if (err) {
- it->ofs += value_sz;
- goto out;
- }
- }
-
- while (processed < value_sz) {
- err = erofs_xattr_iter_fixup_aligned(it);
- if (err)
- goto out;
-
- slice = min_t(unsigned int, it->sb->s_blocksize - it->ofs,
- value_sz - processed);
- op->value(it, processed, it->kaddr + it->ofs, slice);
- it->ofs += slice;
- processed += slice;
- }
-
-out:
- /* xattrs should be 4-byte aligned (on-disk constraint) */
- it->ofs = EROFS_XATTR_ALIGN(it->ofs);
- 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 = EROFS_SB(it->sb);
- 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->name.len != entry->e_name_len + pf->infix_len)
- return -ENOATTR;
-
- if (memcmp(it->name.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->name.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.name + it->infix_len + processed, len))
- return -ENOATTR;
- return 0;
-}
-
-static int xattr_checkbuffer(struct erofs_xattr_iter *it,
- unsigned int value_sz)
-{
- 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 bool erofs_xattr_user_list(struct dentry *dentry)
{
return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);
@@ -373,20 +219,74 @@ const struct xattr_handler *erofs_xattr_handlers[] = {
NULL,
};
-static int xattr_entrylist(struct erofs_xattr_iter *it,
- struct erofs_xattr_entry *entry)
+typedef int (*erofs_xattr_body_handler)(struct erofs_xattr_iter *it,
+ unsigned int processed, char *buf, unsigned int len);
+
+static int erofs_xattr_namematch(struct erofs_xattr_iter *it,
+ unsigned int processed, char *buf, unsigned int len)
+{
+ if (memcmp(buf, it->name.name + it->infix_len + processed, len))
+ return -ENOATTR;
+ return 0;
+}
+
+static int erofs_xattr_copy(struct erofs_xattr_iter *it,
+ unsigned int unused, char *buf, unsigned int len)
+{
+ memcpy(it->buffer + it->buffer_ofs, buf, len);
+ it->buffer_ofs += len;
+ return 0;
+}
+
+static int erofs_xattr_body(struct erofs_xattr_iter *it, unsigned int len,
+ erofs_xattr_body_handler handler)
+{
+ unsigned int slice, processed = 0;
+
+ while (processed < len) {
+ int err = erofs_xattr_iter_fixup_aligned(it);
+ if (err)
+ return err;
+
+ slice = min_t(unsigned int, it->sb->s_blocksize - it->ofs,
+ len - processed);
+ err = handler(it, processed, it->kaddr + it->ofs, slice);
+ if (err)
+ return err;
+
+ it->ofs += slice;
+ processed += slice;
+ }
+ return 0;
+}
+
+/*
+ * Wen returning 0 or ENOATTR, erofs_[list|get]xattr_foreach() will end up
+ * with `ofs' pointing to the next xattr item rather than an arbitrary position.
+ */
+static int erofs_listxattr_foreach(struct erofs_xattr_iter *it)
{
- unsigned int base_index = entry->e_name_index;
- unsigned int prefix_len, infix_len = 0;
+ struct erofs_xattr_entry entry;
+ unsigned int base_index, prefix_len, infix_len = 0;
const char *prefix, *infix = NULL;
+ int err;
+
+ err = erofs_xattr_iter_prep(it);
+ if (err)
+ return err;
+
+ /* 1. handle xattr entry */
+ entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
+ it->ofs += sizeof(struct erofs_xattr_entry);
+ base_index = entry.e_name_index;
- if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
struct erofs_sb_info *sbi = EROFS_SB(it->sb);
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;
+ goto out;
infix = pf->prefix->infix;
infix_len = pf->infix_len;
base_index = pf->prefix->base_index;
@@ -394,52 +294,102 @@ static int xattr_entrylist(struct erofs_xattr_iter *it,
prefix = erofs_xattr_prefix(base_index, it->dentry);
if (!prefix)
- return 1;
+ goto out;
prefix_len = strlen(prefix);
if (!it->buffer) {
- it->buffer_ofs += prefix_len + infix_len +
- entry->e_name_len + 1;
- return 1;
+ it->buffer_ofs += prefix_len + infix_len + entry.e_name_len + 1;
+ goto out;
}
if (it->buffer_ofs + prefix_len + infix_len +
- + entry->e_name_len + 1 > it->buffer_size)
+ entry.e_name_len + 1 > 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 can't be ENOATTR) */
+ err = erofs_xattr_body(it, entry.e_name_len, erofs_xattr_copy);
+ if (err)
+ return err;
+
+ it->buffer[it->buffer_ofs++] = '\0';
+ it->ofs += le16_to_cpu(entry.e_value_size);
+ it->ofs = EROFS_XATTR_ALIGN(it->ofs);
+ return 0;
+out:
+ it->ofs = it->t_ofs;
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_xattr_entry entry;
+ unsigned int value_sz;
+ int err;
-static const struct xattr_iter_handlers list_xattr_handlers = {
- .entry = xattr_entrylist,
- .name = xattr_namelist,
- .alloc_buffer = xattr_skipvalue,
- .value = NULL
-};
+ err = erofs_xattr_iter_prep(it);
+ if (err)
+ return err;
+
+ /* 1. handle xattr entry */
+ entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
+ it->ofs += sizeof(struct erofs_xattr_entry);
+ value_sz = le16_to_cpu(entry.e_value_size);
+
+ err = -ENOATTR;
+ /* should also match the infix for long name prefixes */
+ if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ struct erofs_sb_info *sbi = EROFS_SB(it->sb);
+ 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)
+ goto out;
+
+ if (it->index != pf->prefix->base_index ||
+ it->name.len != entry.e_name_len + pf->infix_len)
+ goto out;
+
+ if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))
+ goto out;
+
+ it->infix_len = pf->infix_len;
+ } else {
+ if (it->index != entry.e_name_index ||
+ it->name.len != entry.e_name_len)
+ goto out;
+ it->infix_len = 0;
+ }
+
+ /* 2. handle xattr name */
+ err = erofs_xattr_body(it, entry.e_name_len, erofs_xattr_namematch);
+ if (err)
+ goto out;
+
+ /* 3. handle xattr value */
+ if (!it->buffer) {
+ it->buffer_ofs = value_sz;
+ goto out; /* err == 0 */
+ }
+ if (it->buffer_size < value_sz)
+ return -ERANGE;
+
+ /* no need normalizing ofs on error (err can't be ENOATTR) */
+ err = erofs_xattr_body(it, value_sz, erofs_xattr_copy);
+ it->ofs = EROFS_XATTR_ALIGN(it->ofs);
+ return err;
+out:
+ it->ofs = it->t_ofs;
+ return err;
+}
static int erofs_iter_inline_xattr(struct erofs_xattr_iter *it)
{
struct erofs_inode *const vi = EROFS_I(it->inode);
- const struct xattr_iter_handlers *op;
- unsigned int xattr_header_sz, remaining;
+ unsigned int xattr_header_sz;
erofs_off_t pos;
int ret;
@@ -457,11 +407,12 @@ static int erofs_iter_inline_xattr(struct erofs_xattr_iter *it)
if (IS_ERR(it->kaddr))
return PTR_ERR(it->kaddr);
- remaining = vi->xattr_isize - xattr_header_sz;
- op = it->getxattr ? &find_xattr_handlers : &list_xattr_handlers;
-
- while (remaining) {
- ret = xattr_foreach(it, op, &remaining);
+ it->remaining = vi->xattr_isize - xattr_header_sz;
+ while (it->remaining) {
+ if (it->getxattr)
+ ret = erofs_getxattr_foreach(it);
+ else
+ ret = erofs_listxattr_foreach(it);
if ((it->getxattr && ret != -ENOATTR) || (!it->getxattr && ret))
break;
}
@@ -472,12 +423,9 @@ static int erofs_iter_shared_xattr(struct erofs_xattr_iter *it)
{
struct erofs_inode *const vi = EROFS_I(it->inode);
struct super_block *const sb = it->sb;
- const struct xattr_iter_handlers *op;
unsigned int i, xsid;
int ret = -ENOATTR;
- op = it->getxattr ? &find_xattr_handlers : &list_xattr_handlers;
-
for (i = 0; i < vi->xattr_shared_count; ++i) {
xsid = vi->xattr_shared_xattrs[i];
it->blkaddr = EROFS_SB(sb)->xattr_blkaddr +
@@ -487,7 +435,10 @@ static int erofs_iter_shared_xattr(struct erofs_xattr_iter *it)
if (IS_ERR(it->kaddr))
return PTR_ERR(it->kaddr);
- ret = xattr_foreach(it, op, NULL);
+ if (it->getxattr)
+ ret = erofs_getxattr_foreach(it);
+ else
+ ret = erofs_listxattr_foreach(it);
if ((it->getxattr && ret != -ENOATTR) || (!it->getxattr && ret))
break;
}
--
2.19.1.6.gb485710b
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