Message ID | AM5PR0802MB25789D14841EF4E821D90578E1770@AM5PR0802MB2578.eurprd08.prod.outlook.com |
---|---|
State | New |
Series | "cgroup: add export_operations to cgroup super block" |
Headers | show |
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 9fdba79..a06c809 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -62,6 +62,7 @@ #include <linux/kthread.h> #include <linux/ve.h> #include <linux/stacktrace.h> +#include <linux/exportfs.h> #include <linux/atomic.h> @@ -1390,9 +1391,112 @@ out: } #endif +/* + * hashtable for inodes that have exported fhandles. + * When we export fhandle, we add it's inode into + * hashtable so we can find it fast + */ + +#define CGROUP_INODE_HASH_BITS 10 +static DEFINE_HASHTABLE(cgroup_inode_table, CGROUP_INODE_HASH_BITS); +static DEFINE_SPINLOCK(cgroup_inode_table_lock); + +struct cgroup_inode_hash_item { + struct inode* inode; + struct hlist_node hlist; +}; + +static inline unsigned long cgroup_inode_get_hash(unsigned int i_ino) +{ + return hash_32(i_ino, CGROUP_INODE_HASH_BITS); +} + +static struct cgroup_inode_hash_item* cgroup_inode_hash_find(unsigned int i_ino) +{ + struct cgroup_inode_hash_item *i; + struct hlist_head *head = cgroup_inode_table + cgroup_inode_get_hash(i_ino); + struct cgroup_inode_hash_item* found = 0; + + spin_lock(&cgroup_inode_table_lock); + hlist_for_each_entry(i, head, hlist) { + if(i->inode->i_ino == i_ino) { + found = i; + break; + } + } + spin_unlock(&cgroup_inode_table_lock); + + return found; +} + +static struct dentry *cgroup_fh_to_dentry(struct super_block *sb, + struct fid *fid, int fh_len, int fh_type) +{ + struct cgroup_inode_hash_item *item; + struct dentry *dentry = ERR_PTR(-ENOENT); + + if (fh_len < 1) + return NULL; + + item = cgroup_inode_hash_find(fid->raw[0]); + if (item) + dentry = d_find_alias(item->inode); + + return dentry; +} + +static int cgroup_encode_fh(struct inode *inode, __u32 *fh, int *len, + struct inode *parent) +{ + struct hlist_head *head = cgroup_inode_table + cgroup_inode_get_hash(inode->i_ino); + struct cgroup_inode_hash_item *item; + + if (*len < 1) { + *len = 1; + return FILEID_INVALID; + } + + if(cgroup_inode_hash_find(inode->i_ino) == 0) { + item = kmalloc(sizeof(struct cgroup_inode_hash_item), GFP_KERNEL); + /* + * encode_fh is expected to return 255 (FILEID_INVALID) in case of + * failure. We can't return ENOMEM, so return FILEID_INVALID at least + */ + if(!item) + return FILEID_INVALID; + item->inode = inode; + + spin_lock(&cgroup_inode_table_lock); + hlist_add_head(&item->hlist, head); + spin_unlock(&cgroup_inode_table_lock); + } + + fh[0] = inode->i_ino; + *len = 1; + return 1; +} + +static const struct export_operations cgroup_export_ops = { + .encode_fh = cgroup_encode_fh, + .fh_to_dentry = cgroup_fh_to_dentry, +}; + +static int cgroup_delete_inode(struct inode *inode){ + struct cgroup_inode_hash_item *item = cgroup_inode_hash_find(inode->i_ino); + if(item) { + spin_lock(&cgroup_inode_table_lock); + hlist_del(&item->hlist); + spin_unlock(&cgroup_inode_table_lock); + + kfree(item); + } + + return generic_delete_inode(inode); +} + static const struct super_operations cgroup_ops = { .statfs = simple_statfs, - .drop_inode = generic_delete_inode, + .drop_inode = cgroup_delete_inode, .show_options = cgroup_show_options, #ifdef CONFIG_VE .show_path = cgroup_show_path, @@ -1539,6 +1643,7 @@ static int cgroup_set_super(struct super_block *sb, void *data) sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = CGROUP_SUPER_MAGIC; sb->s_op = &cgroup_ops; + sb->s_export_op = &cgroup_export_ops; return 0; }
Pavel, it looks correct for me, though could you please review it too? thank you, Vasily Averin On 7/24/20 6:19 PM, Andrey Zhadchenko wrote: > criu uses fhandle from fdinfo to dump inotify objects. cgroup super block has > no export operations, but .encode_fh and .fh_to_dentry are needed for > inotify_fdinfo function and open_by_handle_at syscall in order to correctly > open files located on cgroupfs by fhandle. > Add hash table as a storage for inodes with exported fhandle. > > https://jira.sw.ru/browse/PSBM-105889 > Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com> > --- > kernel/cgroup.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 106 insertions(+), 1 deletion(-) > > diff --git a/kernel/cgroup.c b/kernel/cgroup.c > index 9fdba79..a06c809 100644 > --- a/kernel/cgroup.c > +++ b/kernel/cgroup.c > @@ -62,6 +62,7 @@ > #include <linux/kthread.h> > #include <linux/ve.h> > #include <linux/stacktrace.h> > +#include <linux/exportfs.h> > > #include <linux/atomic.h> > > @@ -1390,9 +1391,112 @@ out: > } > #endif > > +/* > + * hashtable for inodes that have exported fhandles. > + * When we export fhandle, we add it's inode into > + * hashtable so we can find it fast > + */ > + > +#define CGROUP_INODE_HASH_BITS 10 > +static DEFINE_HASHTABLE(cgroup_inode_table, CGROUP_INODE_HASH_BITS); > +static DEFINE_SPINLOCK(cgroup_inode_table_lock); > + > +struct cgroup_inode_hash_item { > + struct inode* inode; > + struct hlist_node hlist; > +}; > + > +static inline unsigned long cgroup_inode_get_hash(unsigned int i_ino) > +{ > + return hash_32(i_ino, CGROUP_INODE_HASH_BITS); > +} > + > +static struct cgroup_inode_hash_item* cgroup_inode_hash_find(unsigned int i_ino) > +{ > + struct cgroup_inode_hash_item *i; > + struct hlist_head *head = cgroup_inode_table + cgroup_inode_get_hash(i_ino); > + struct cgroup_inode_hash_item* found = 0; > + > + spin_lock(&cgroup_inode_table_lock); > + hlist_for_each_entry(i, head, hlist) { > + if(i->inode->i_ino == i_ino) { > + found = i; > + break; > + } > + } > + spin_unlock(&cgroup_inode_table_lock); > + > + return found; > +} > + > +static struct dentry *cgroup_fh_to_dentry(struct super_block *sb, > + struct fid *fid, int fh_len, int fh_type) > +{ > + struct cgroup_inode_hash_item *item; > + struct dentry *dentry = ERR_PTR(-ENOENT); > + > + if (fh_len < 1) > + return NULL; > + > + item = cgroup_inode_hash_find(fid->raw[0]); > + if (item) > + dentry = d_find_alias(item->inode); > + > + return dentry; > +} > + > +static int cgroup_encode_fh(struct inode *inode, __u32 *fh, int *len, > + struct inode *parent) > +{ > + struct hlist_head *head = cgroup_inode_table + cgroup_inode_get_hash(inode->i_ino); > + struct cgroup_inode_hash_item *item; > + > + if (*len < 1) { > + *len = 1; > + return FILEID_INVALID; > + } > + > + if(cgroup_inode_hash_find(inode->i_ino) == 0) { > + item = kmalloc(sizeof(struct cgroup_inode_hash_item), GFP_KERNEL); > + /* > + * encode_fh is expected to return 255 (FILEID_INVALID) in case of > + * failure. We can't return ENOMEM, so return FILEID_INVALID at least > + */ > + if(!item) > + return FILEID_INVALID; > + item->inode = inode; > + > + spin_lock(&cgroup_inode_table_lock); > + hlist_add_head(&item->hlist, head); > + spin_unlock(&cgroup_inode_table_lock); > + } > + > + fh[0] = inode->i_ino; > + *len = 1; > + return 1; > +} > + > +static const struct export_operations cgroup_export_ops = { > + .encode_fh = cgroup_encode_fh, > + .fh_to_dentry = cgroup_fh_to_dentry, > +}; > + > +static int cgroup_delete_inode(struct inode *inode){ > + struct cgroup_inode_hash_item *item = cgroup_inode_hash_find(inode->i_ino); > + if(item) { > + spin_lock(&cgroup_inode_table_lock); > + hlist_del(&item->hlist); > + spin_unlock(&cgroup_inode_table_lock); > + > + kfree(item); > + } > + > + return generic_delete_inode(inode); > +} > + > static const struct super_operations cgroup_ops = { > .statfs = simple_statfs, > - .drop_inode = generic_delete_inode, > + .drop_inode = cgroup_delete_inode, > .show_options = cgroup_show_options, > #ifdef CONFIG_VE > .show_path = cgroup_show_path, > @@ -1539,6 +1643,7 @@ static int cgroup_set_super(struct super_block *sb, void *data) > sb->s_blocksize_bits = PAGE_CACHE_SHIFT; > sb->s_magic = CGROUP_SUPER_MAGIC; > sb->s_op = &cgroup_ops; > + sb->s_export_op = &cgroup_export_ops; > > return 0; > } > -- > 1.8.3.1 > > > _______________________________________________ > Devel mailing list > Devel@openvz.org > https://lists.openvz.org/mailman/listinfo/devel >
criu uses fhandle from fdinfo to dump inotify objects. cgroup super block has no export operations, but .encode_fh and .fh_to_dentry are needed for inotify_fdinfo function and open_by_handle_at syscall in order to correctly open files located on cgroupfs by fhandle. Add hash table as a storage for inodes with exported fhandle. https://jira.sw.ru/browse/PSBM-105889 Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com> --- kernel/cgroup.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 106 insertions(+), 1 deletion(-) -- 1.8.3.1