kernel: backport and enable tmpfs xattr support for 2.6.39
SVN-Revision: 27691
This commit is contained in:
Felix Fietkau
parent
9c606eb4c5
commit
fee32761f3
@ -2631,6 +2631,7 @@ CONFIG_TINY_RCU=y
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# CONFIG_TLAN is not set
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# CONFIG_TMD_HERMES is not set
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CONFIG_TMPFS=y
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CONFIG_TMPFS_XATTR=y
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# CONFIG_TMPFS_POSIX_ACL is not set
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# CONFIG_TOUCHSCREEN_AD7877 is not set
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# CONFIG_TOUCHSCREEN_AD7879 is not set
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@ -0,0 +1,477 @@
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--- a/fs/Kconfig
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+++ b/fs/Kconfig
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@@ -121,9 +121,25 @@ config TMPFS
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See <file:Documentation/filesystems/tmpfs.txt> for details.
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+config TMPFS_XATTR
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+ bool "Tmpfs extended attributes"
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+ depends on TMPFS
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+ default n
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+ help
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+ Extended attributes are name:value pairs associated with inodes by
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+ the kernel or by users (see the attr(5) manual page, or visit
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+ <http://acl.bestbits.at/> for details).
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+
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+ Currently this enables support for the trusted.* and
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+ security.* namespaces.
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+
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+ If unsure, say N.
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+
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+ You need this for POSIX ACL support on tmpfs.
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+
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config TMPFS_POSIX_ACL
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bool "Tmpfs POSIX Access Control Lists"
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- depends on TMPFS
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+ depends on TMPFS_XATTR
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select GENERIC_ACL
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help
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POSIX Access Control Lists (ACLs) support permissions for users and
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--- a/include/linux/shmem_fs.h
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+++ b/include/linux/shmem_fs.h
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@@ -9,6 +9,8 @@
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#define SHMEM_NR_DIRECT 16
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+#define SHMEM_SYMLINK_INLINE_LEN (SHMEM_NR_DIRECT * sizeof(swp_entry_t))
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+
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struct shmem_inode_info {
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spinlock_t lock;
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unsigned long flags;
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@@ -17,8 +19,12 @@ struct shmem_inode_info {
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unsigned long next_index; /* highest alloced index + 1 */
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struct shared_policy policy; /* NUMA memory alloc policy */
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struct page *i_indirect; /* top indirect blocks page */
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- swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
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+ union {
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+ swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
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+ char inline_symlink[SHMEM_SYMLINK_INLINE_LEN];
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+ };
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struct list_head swaplist; /* chain of maybes on swap */
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+ struct list_head xattr_list; /* list of shmem_xattr */
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struct inode vfs_inode;
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};
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--- a/mm/shmem.c
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+++ b/mm/shmem.c
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@@ -99,6 +99,13 @@ static struct vfsmount *shm_mnt;
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/* Pretend that each entry is of this size in directory's i_size */
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#define BOGO_DIRENT_SIZE 20
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+struct shmem_xattr {
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+ struct list_head list; /* anchored by shmem_inode_info->xattr_list */
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+ char *name; /* xattr name */
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+ size_t size;
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+ char value[0];
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+};
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+
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/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
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enum sgp_type {
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SGP_READ, /* don't exceed i_size, don't allocate page */
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@@ -822,6 +829,7 @@ static int shmem_notify_change(struct de
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static void shmem_evict_inode(struct inode *inode)
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{
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struct shmem_inode_info *info = SHMEM_I(inode);
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+ struct shmem_xattr *xattr, *nxattr;
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if (inode->i_mapping->a_ops == &shmem_aops) {
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truncate_inode_pages(inode->i_mapping, 0);
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@@ -834,6 +842,11 @@ static void shmem_evict_inode(struct ino
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mutex_unlock(&shmem_swaplist_mutex);
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}
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}
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+
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+ list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) {
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+ kfree(xattr->name);
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+ kfree(xattr);
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+ }
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BUG_ON(inode->i_blocks);
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shmem_free_inode(inode->i_sb);
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end_writeback(inode);
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@@ -1615,6 +1628,7 @@ static struct inode *shmem_get_inode(str
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spin_lock_init(&info->lock);
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info->flags = flags & VM_NORESERVE;
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INIT_LIST_HEAD(&info->swaplist);
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+ INIT_LIST_HEAD(&info->xattr_list);
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cache_no_acl(inode);
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switch (mode & S_IFMT) {
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@@ -2014,9 +2028,9 @@ static int shmem_symlink(struct inode *d
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info = SHMEM_I(inode);
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inode->i_size = len-1;
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- if (len <= (char *)inode - (char *)info) {
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+ if (len <= SHMEM_SYMLINK_INLINE_LEN) {
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/* do it inline */
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- memcpy(info, symname, len);
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+ memcpy(info->inline_symlink, symname, len);
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inode->i_op = &shmem_symlink_inline_operations;
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} else {
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error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
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@@ -2042,7 +2056,7 @@ static int shmem_symlink(struct inode *d
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static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
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{
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- nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
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+ nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink);
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return NULL;
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}
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@@ -2066,63 +2080,253 @@ static void shmem_put_link(struct dentry
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}
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}
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-static const struct inode_operations shmem_symlink_inline_operations = {
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- .readlink = generic_readlink,
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- .follow_link = shmem_follow_link_inline,
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-};
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-
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-static const struct inode_operations shmem_symlink_inode_operations = {
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- .readlink = generic_readlink,
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- .follow_link = shmem_follow_link,
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- .put_link = shmem_put_link,
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-};
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-
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-#ifdef CONFIG_TMPFS_POSIX_ACL
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+#ifdef CONFIG_TMPFS_XATTR
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/*
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- * Superblocks without xattr inode operations will get security.* xattr
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- * support from the VFS "for free". As soon as we have any other xattrs
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+ * Superblocks without xattr inode operations may get some security.* xattr
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+ * support from the LSM "for free". As soon as we have any other xattrs
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* like ACLs, we also need to implement the security.* handlers at
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* filesystem level, though.
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*/
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-static size_t shmem_xattr_security_list(struct dentry *dentry, char *list,
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- size_t list_len, const char *name,
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- size_t name_len, int handler_flags)
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+static int shmem_xattr_get(struct dentry *dentry, const char *name,
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+ void *buffer, size_t size)
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{
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- return security_inode_listsecurity(dentry->d_inode, list, list_len);
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-}
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+ struct shmem_inode_info *info;
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+ struct shmem_xattr *xattr;
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+ int ret = -ENODATA;
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-static int shmem_xattr_security_get(struct dentry *dentry, const char *name,
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- void *buffer, size_t size, int handler_flags)
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-{
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- if (strcmp(name, "") == 0)
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- return -EINVAL;
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- return xattr_getsecurity(dentry->d_inode, name, buffer, size);
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+ info = SHMEM_I(dentry->d_inode);
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+
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+ spin_lock(&info->lock);
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+ list_for_each_entry(xattr, &info->xattr_list, list) {
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+ if (strcmp(name, xattr->name))
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+ continue;
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+
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+ ret = xattr->size;
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+ if (buffer) {
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+ if (size < xattr->size)
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+ ret = -ERANGE;
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+ else
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+ memcpy(buffer, xattr->value, xattr->size);
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+ }
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+ break;
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+ }
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+ spin_unlock(&info->lock);
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+ return ret;
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}
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-static int shmem_xattr_security_set(struct dentry *dentry, const char *name,
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- const void *value, size_t size, int flags, int handler_flags)
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+static int shmem_xattr_set(struct dentry *dentry, const char *name,
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+ const void *value, size_t size, int flags)
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{
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- if (strcmp(name, "") == 0)
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- return -EINVAL;
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- return security_inode_setsecurity(dentry->d_inode, name, value,
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- size, flags);
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+ struct inode *inode = dentry->d_inode;
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+ struct shmem_inode_info *info = SHMEM_I(inode);
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+ struct shmem_xattr *xattr;
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+ struct shmem_xattr *new_xattr = NULL;
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+ size_t len;
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+ int err = 0;
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+
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+ /* value == NULL means remove */
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+ if (value) {
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+ /* wrap around? */
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+ len = sizeof(*new_xattr) + size;
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+ if (len <= sizeof(*new_xattr))
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+ return -ENOMEM;
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+
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+ new_xattr = kmalloc(len, GFP_KERNEL);
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+ if (!new_xattr)
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+ return -ENOMEM;
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+
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+ new_xattr->name = kstrdup(name, GFP_KERNEL);
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+ if (!new_xattr->name) {
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+ kfree(new_xattr);
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+ return -ENOMEM;
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+ }
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+
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+ new_xattr->size = size;
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+ memcpy(new_xattr->value, value, size);
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+ }
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+
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+ spin_lock(&info->lock);
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+ list_for_each_entry(xattr, &info->xattr_list, list) {
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+ if (!strcmp(name, xattr->name)) {
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+ if (flags & XATTR_CREATE) {
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+ xattr = new_xattr;
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+ err = -EEXIST;
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+ } else if (new_xattr) {
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+ list_replace(&xattr->list, &new_xattr->list);
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+ } else {
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+ list_del(&xattr->list);
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+ }
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+ goto out;
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+ }
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+ }
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+ if (flags & XATTR_REPLACE) {
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+ xattr = new_xattr;
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+ err = -ENODATA;
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+ } else {
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+ list_add(&new_xattr->list, &info->xattr_list);
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+ xattr = NULL;
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+ }
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+out:
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+ spin_unlock(&info->lock);
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+ if (xattr)
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+ kfree(xattr->name);
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+ kfree(xattr);
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+ return err;
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}
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-static const struct xattr_handler shmem_xattr_security_handler = {
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- .prefix = XATTR_SECURITY_PREFIX,
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- .list = shmem_xattr_security_list,
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- .get = shmem_xattr_security_get,
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- .set = shmem_xattr_security_set,
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-};
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static const struct xattr_handler *shmem_xattr_handlers[] = {
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+#ifdef CONFIG_TMPFS_POSIX_ACL
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&generic_acl_access_handler,
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&generic_acl_default_handler,
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- &shmem_xattr_security_handler,
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+#endif
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NULL
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};
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+
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+static int shmem_xattr_validate(const char *name)
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+{
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+ struct { const char *prefix; size_t len; } arr[] = {
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+ { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN },
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+ { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN }
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+ };
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+ int i;
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+
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+ for (i = 0; i < ARRAY_SIZE(arr); i++) {
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+ size_t preflen = arr[i].len;
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+ if (strncmp(name, arr[i].prefix, preflen) == 0) {
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+ if (!name[preflen])
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+ return -EINVAL;
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+ return 0;
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+ }
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+ }
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+ return -EOPNOTSUPP;
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+}
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+
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+static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,
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+ void *buffer, size_t size)
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+{
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+ int err;
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+
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+ /*
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+ * If this is a request for a synthetic attribute in the system.*
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+ * namespace use the generic infrastructure to resolve a handler
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+ * for it via sb->s_xattr.
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+ */
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+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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+ return generic_getxattr(dentry, name, buffer, size);
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+
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+ err = shmem_xattr_validate(name);
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+ if (err)
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+ return err;
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+
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+ return shmem_xattr_get(dentry, name, buffer, size);
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+}
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+
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+static int shmem_setxattr(struct dentry *dentry, const char *name,
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+ const void *value, size_t size, int flags)
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+{
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+ int err;
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+
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+ /*
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+ * If this is a request for a synthetic attribute in the system.*
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+ * namespace use the generic infrastructure to resolve a handler
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+ * for it via sb->s_xattr.
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+ */
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+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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+ return generic_setxattr(dentry, name, value, size, flags);
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+
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+ err = shmem_xattr_validate(name);
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+ if (err)
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+ return err;
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+
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+ if (size == 0)
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+ value = ""; /* empty EA, do not remove */
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+
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+ return shmem_xattr_set(dentry, name, value, size, flags);
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+
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+}
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+
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+static int shmem_removexattr(struct dentry *dentry, const char *name)
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+{
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+ int err;
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+
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+ /*
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+ * If this is a request for a synthetic attribute in the system.*
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+ * namespace use the generic infrastructure to resolve a handler
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+ * for it via sb->s_xattr.
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+ */
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+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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+ return generic_removexattr(dentry, name);
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+
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+ err = shmem_xattr_validate(name);
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+ if (err)
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+ return err;
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+
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+ return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE);
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+}
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+
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+static bool xattr_is_trusted(const char *name)
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+{
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+ return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
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+}
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+
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+static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
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+{
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+ bool trusted = capable(CAP_SYS_ADMIN);
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+ struct shmem_xattr *xattr;
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+ struct shmem_inode_info *info;
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+ size_t used = 0;
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+
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+ info = SHMEM_I(dentry->d_inode);
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+
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+ spin_lock(&info->lock);
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+ list_for_each_entry(xattr, &info->xattr_list, list) {
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+ size_t len;
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+
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+ /* skip "trusted." attributes for unprivileged callers */
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+ if (!trusted && xattr_is_trusted(xattr->name))
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+ continue;
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+
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+ len = strlen(xattr->name) + 1;
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+ used += len;
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+ if (buffer) {
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+ if (size < used) {
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+ used = -ERANGE;
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+ break;
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+ }
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+ memcpy(buffer, xattr->name, len);
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+ buffer += len;
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+ }
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+ }
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+ spin_unlock(&info->lock);
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+
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+ return used;
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+}
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+#endif /* CONFIG_TMPFS_XATTR */
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+
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+static const struct inode_operations shmem_symlink_inline_operations = {
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+ .readlink = generic_readlink,
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+ .follow_link = shmem_follow_link_inline,
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+#ifdef CONFIG_TMPFS_XATTR
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+ .setxattr = shmem_setxattr,
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+ .getxattr = shmem_getxattr,
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+ .listxattr = shmem_listxattr,
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+ .removexattr = shmem_removexattr,
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+#endif
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+};
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+
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+static const struct inode_operations shmem_symlink_inode_operations = {
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+ .readlink = generic_readlink,
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+ .follow_link = shmem_follow_link,
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+ .put_link = shmem_put_link,
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+#ifdef CONFIG_TMPFS_XATTR
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+ .setxattr = shmem_setxattr,
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+ .getxattr = shmem_getxattr,
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+ .listxattr = shmem_listxattr,
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+ .removexattr = shmem_removexattr,
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#endif
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+};
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static struct dentry *shmem_get_parent(struct dentry *child)
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{
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@@ -2402,8 +2606,10 @@ int shmem_fill_super(struct super_block
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sb->s_magic = TMPFS_MAGIC;
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sb->s_op = &shmem_ops;
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sb->s_time_gran = 1;
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-#ifdef CONFIG_TMPFS_POSIX_ACL
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+#ifdef CONFIG_TMPFS_XATTR
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sb->s_xattr = shmem_xattr_handlers;
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+#endif
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+#ifdef CONFIG_TMPFS_POSIX_ACL
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sb->s_flags |= MS_POSIXACL;
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#endif
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@@ -2501,11 +2707,13 @@ static const struct file_operations shme
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static const struct inode_operations shmem_inode_operations = {
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.setattr = shmem_notify_change,
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.truncate_range = shmem_truncate_range,
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+#ifdef CONFIG_TMPFS_XATTR
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+ .setxattr = shmem_setxattr,
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+ .getxattr = shmem_getxattr,
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+ .listxattr = shmem_listxattr,
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+ .removexattr = shmem_removexattr,
|
||||
+#endif
|
||||
#ifdef CONFIG_TMPFS_POSIX_ACL
|
||||
- .setxattr = generic_setxattr,
|
||||
- .getxattr = generic_getxattr,
|
||||
- .listxattr = generic_listxattr,
|
||||
- .removexattr = generic_removexattr,
|
||||
.check_acl = generic_check_acl,
|
||||
#endif
|
||||
|
||||
@@ -2523,23 +2731,27 @@ static const struct inode_operations shm
|
||||
.mknod = shmem_mknod,
|
||||
.rename = shmem_rename,
|
||||
#endif
|
||||
+#ifdef CONFIG_TMPFS_XATTR
|
||||
+ .setxattr = shmem_setxattr,
|
||||
+ .getxattr = shmem_getxattr,
|
||||
+ .listxattr = shmem_listxattr,
|
||||
+ .removexattr = shmem_removexattr,
|
||||
+#endif
|
||||
#ifdef CONFIG_TMPFS_POSIX_ACL
|
||||
.setattr = shmem_notify_change,
|
||||
- .setxattr = generic_setxattr,
|
||||
- .getxattr = generic_getxattr,
|
||||
- .listxattr = generic_listxattr,
|
||||
- .removexattr = generic_removexattr,
|
||||
.check_acl = generic_check_acl,
|
||||
#endif
|
||||
};
|
||||
|
||||
static const struct inode_operations shmem_special_inode_operations = {
|
||||
+#ifdef CONFIG_TMPFS_XATTR
|
||||
+ .setxattr = shmem_setxattr,
|
||||
+ .getxattr = shmem_getxattr,
|
||||
+ .listxattr = shmem_listxattr,
|
||||
+ .removexattr = shmem_removexattr,
|
||||
+#endif
|
||||
#ifdef CONFIG_TMPFS_POSIX_ACL
|
||||
.setattr = shmem_notify_change,
|
||||
- .setxattr = generic_setxattr,
|
||||
- .getxattr = generic_getxattr,
|
||||
- .listxattr = generic_listxattr,
|
||||
- .removexattr = generic_removexattr,
|
||||
.check_acl = generic_check_acl,
|
||||
#endif
|
||||
};
|
||||
@ -1,6 +1,6 @@
|
||||
--- a/mm/shmem.c
|
||||
+++ b/mm/shmem.c
|
||||
@@ -2731,6 +2731,16 @@ out:
|
||||
@@ -2943,6 +2943,16 @@ out:
|
||||
|
||||
/* common code */
|
||||
|
||||
@ -17,7 +17,7 @@
|
||||
/**
|
||||
* shmem_file_setup - get an unlinked file living in tmpfs
|
||||
* @name: name for dentry (to be seen in /proc/<pid>/maps
|
||||
@@ -2808,10 +2818,7 @@ int shmem_zero_setup(struct vm_area_stru
|
||||
@@ -3020,10 +3030,7 @@ int shmem_zero_setup(struct vm_area_stru
|
||||
if (IS_ERR(file))
|
||||
return PTR_ERR(file);
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user