From 2c567af418e3f9380c2051aada58b4e5a4b5c2ad Mon Sep 17 00:00:00 2001 From: Ira Weiny Date: Thu, 30 Apr 2020 07:41:37 -0700 Subject: [PATCH] fs: Introduce DCACHE_DONTCACHE DCACHE_DONTCACHE indicates a dentry should not be cached on final dput(). Also add a helper function to mark DCACHE_DONTCACHE on all dentries pointing to a specific inode when that inode is being set I_DONTCACHE. This facilitates dropping dentry references to inodes sooner which require eviction to swap S_DAX mode. Cc: Al Viro Signed-off-by: Ira Weiny Reviewed-by: Jan Kara Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/dcache.c | 19 +++++++++++++++++++ fs/xfs/xfs_icache.c | 2 +- include/linux/dcache.h | 2 ++ include/linux/fs.h | 1 + 4 files changed, 23 insertions(+), 1 deletion(-) diff --git a/fs/dcache.c b/fs/dcache.c index b280e07e162b..0d07fb335b78 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -647,6 +647,10 @@ static inline bool retain_dentry(struct dentry *dentry) if (dentry->d_op->d_delete(dentry)) return false; } + + if (unlikely(dentry->d_flags & DCACHE_DONTCACHE)) + return false; + /* retain; LRU fodder */ dentry->d_lockref.count--; if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST))) @@ -656,6 +660,21 @@ static inline bool retain_dentry(struct dentry *dentry) return true; } +void d_mark_dontcache(struct inode *inode) +{ + struct dentry *de; + + spin_lock(&inode->i_lock); + hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) { + spin_lock(&de->d_lock); + de->d_flags |= DCACHE_DONTCACHE; + spin_unlock(&de->d_lock); + } + inode->i_state |= I_DONTCACHE; + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL(d_mark_dontcache); + /* * Finish off a dentry we've decided to kill. * dentry->d_lock must be held, returns with it unlocked. diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index fa8554b3308d..d7deab608e2c 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -561,7 +561,7 @@ xfs_iget_cache_miss( */ iflags = XFS_INEW; if (flags & XFS_IGET_DONTCACHE) - VFS_I(ip)->i_state |= I_DONTCACHE; + d_mark_dontcache(VFS_I(ip)); ip->i_udquot = NULL; ip->i_gdquot = NULL; ip->i_pdquot = NULL; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c1488cc84fd9..a81f0c3cf352 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -177,6 +177,8 @@ struct dentry_operations { #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ +#define DCACHE_DONTCACHE 0x00000080 /* Purge from memory on final dput() */ + #define DCACHE_CANT_MOUNT 0x00000100 #define DCACHE_GENOCIDE 0x00000200 #define DCACHE_SHRINK_LIST 0x00000400 diff --git a/include/linux/fs.h b/include/linux/fs.h index 44bd45af760f..7c3e8c0306e0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3055,6 +3055,7 @@ static inline int generic_drop_inode(struct inode *inode) return !inode->i_nlink || inode_unhashed(inode) || (inode->i_state & I_DONTCACHE); } +extern void d_mark_dontcache(struct inode *inode); extern struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, int (*test)(struct inode *, void *),