diff options
| -rw-r--r-- | fs/inode.c | 85 | ||||
| -rw-r--r-- | include/linux/fs.h | 61 |
2 files changed, 92 insertions, 54 deletions
diff --git a/fs/inode.c b/fs/inode.c index 961355d00e3..87535753ab0 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -26,6 +26,7 @@ #include <linux/ima.h> #include <linux/cred.h> #include <linux/buffer_head.h> /* for inode_has_buffers */ +#include <linux/ratelimit.h> #include "internal.h" /* @@ -242,6 +243,11 @@ void __destroy_inode(struct inode *inode) BUG_ON(inode_has_buffers(inode)); security_inode_free(inode); fsnotify_inode_delete(inode); + if (!inode->i_nlink) { + WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); + atomic_long_dec(&inode->i_sb->s_remove_count); + } + #ifdef CONFIG_FS_POSIX_ACL if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) posix_acl_release(inode->i_acl); @@ -268,6 +274,85 @@ static void destroy_inode(struct inode *inode) call_rcu(&inode->i_rcu, i_callback); } +/** + * drop_nlink - directly drop an inode's link count + * @inode: inode + * + * This is a low-level filesystem helper to replace any + * direct filesystem manipulation of i_nlink. In cases + * where we are attempting to track writes to the + * filesystem, a decrement to zero means an imminent + * write when the file is truncated and actually unlinked + * on the filesystem. + */ +void drop_nlink(struct inode *inode) +{ + WARN_ON(inode->i_nlink == 0); + inode->__i_nlink--; + if (!inode->i_nlink) + atomic_long_inc(&inode->i_sb->s_remove_count); +} +EXPORT_SYMBOL(drop_nlink); + +/** + * clear_nlink - directly zero an inode's link count + * @inode: inode + * + * This is a low-level filesystem helper to replace any + * direct filesystem manipulation of i_nlink. See + * drop_nlink() for why we care about i_nlink hitting zero. + */ +void clear_nlink(struct inode *inode) +{ + if (inode->i_nlink) { + inode->__i_nlink = 0; + atomic_long_inc(&inode->i_sb->s_remove_count); + } +} +EXPORT_SYMBOL(clear_nlink); + +/** + * set_nlink - directly set an inode's link count + * @inode: inode + * @nlink: new nlink (should be non-zero) + * + * This is a low-level filesystem helper to replace any + * direct filesystem manipulation of i_nlink. + */ +void set_nlink(struct inode *inode, unsigned int nlink) +{ + if (!nlink) { + printk_ratelimited(KERN_INFO + "set_nlink() clearing i_nlink on %s inode %li\n", + inode->i_sb->s_type->name, inode->i_ino); + clear_nlink(inode); + } else { + /* Yes, some filesystems do change nlink from zero to one */ + if (inode->i_nlink == 0) + atomic_long_dec(&inode->i_sb->s_remove_count); + + inode->__i_nlink = nlink; + } +} +EXPORT_SYMBOL(set_nlink); + +/** + * inc_nlink - directly increment an inode's link count + * @inode: inode + * + * This is a low-level filesystem helper to replace any + * direct filesystem manipulation of i_nlink. Currently, + * it is only here for parity with dec_nlink(). + */ +void inc_nlink(struct inode *inode) +{ + if (WARN_ON(inode->i_nlink == 0)) + atomic_long_dec(&inode->i_sb->s_remove_count); + + inode->__i_nlink++; +} +EXPORT_SYMBOL(inc_nlink); + void address_space_init_once(struct address_space *mapping) { memset(mapping, 0, sizeof(*mapping)); diff --git a/include/linux/fs.h b/include/linux/fs.h index 7b8a681b1ef..8ac40921f5a 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1483,6 +1483,9 @@ struct super_block { struct shrinker s_shrink; /* per-sb shrinker handle */ + /* Number of inodes with nlink == 0 but still referenced */ + atomic_long_t s_remove_count; + /* Being remounted read-only */ int s_readonly_remount; }; @@ -1768,31 +1771,10 @@ static inline void mark_inode_dirty_sync(struct inode *inode) __mark_inode_dirty(inode, I_DIRTY_SYNC); } -/** - * set_nlink - directly set an inode's link count - * @inode: inode - * @nlink: new nlink (should be non-zero) - * - * This is a low-level filesystem helper to replace any - * direct filesystem manipulation of i_nlink. - */ -static inline void set_nlink(struct inode *inode, unsigned int nlink) -{ - inode->__i_nlink = nlink; -} - -/** - * inc_nlink - directly increment an inode's link count - * @inode: inode - * - * This is a low-level filesystem helper to replace any - * direct filesystem manipulation of i_nlink. Currently, - * it is only here for parity with dec_nlink(). - */ -static inline void inc_nlink(struct inode *inode) -{ - inode->__i_nlink++; -} +extern void inc_nlink(struct inode *inode); +extern void drop_nlink(struct inode *inode); +extern void clear_nlink(struct inode *inode); +extern void set_nlink(struct inode *inode, unsigned int nlink); static inline void inode_inc_link_count(struct inode *inode) { @@ -1800,35 +1782,6 @@ static inline void inode_inc_link_count(struct inode *inode) mark_inode_dirty(inode); } -/** - * drop_nlink - directly drop an inode's link count - * @inode: inode - * - * This is a low-level filesystem helper to replace any - * direct filesystem manipulation of i_nlink. In cases - * where we are attempting to track writes to the - * filesystem, a decrement to zero means an imminent - * write when the file is truncated and actually unlinked - * on the filesystem. - */ -static inline void drop_nlink(struct inode *inode) -{ - inode->__i_nlink--; -} - -/** - * clear_nlink - directly zero an inode's link count - * @inode: inode - * - * This is a low-level filesystem helper to replace any - * direct filesystem manipulation of i_nlink. See - * drop_nlink() for why we care about i_nlink hitting zero. - */ -static inline void clear_nlink(struct inode *inode) -{ - inode->__i_nlink = 0; -} - static inline void inode_dec_link_count(struct inode *inode) { drop_nlink(inode); |