From 5e993e2534e29b62790f9a2908b551b7fb3a63f0 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 24 Dec 2014 21:41:47 -0500 Subject: [PATCH] ncpfs: get rid of d_validate() nonsense What we want is to have non-counting references to children in pagecache of parent directory, and avoid picking them after a child has been freed. Fine, so let's just have ->d_prune() clear parent's inode "has directory contents in page cache" flag. That way we don't need ->d_fsdata for storing offsets, so we can use it as a quick and dirty "is it referenced from page cache" flag. Signed-off-by: Al Viro --- fs/ncpfs/dir.c | 98 +++++++++++++++++++++------------------- fs/ncpfs/ncp_fs_i.h | 1 + fs/ncpfs/ncplib_kernel.h | 30 ------------ 3 files changed, 52 insertions(+), 77 deletions(-) diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c index 008960101520..e7ca827d7694 100644 --- a/fs/ncpfs/dir.c +++ b/fs/ncpfs/dir.c @@ -77,6 +77,7 @@ static int ncp_hash_dentry(const struct dentry *, struct qstr *); static int ncp_compare_dentry(const struct dentry *, const struct dentry *, unsigned int, const char *, const struct qstr *); static int ncp_delete_dentry(const struct dentry *); +static void ncp_d_prune(struct dentry *dentry); const struct dentry_operations ncp_dentry_operations = { @@ -84,6 +85,7 @@ const struct dentry_operations ncp_dentry_operations = .d_hash = ncp_hash_dentry, .d_compare = ncp_compare_dentry, .d_delete = ncp_delete_dentry, + .d_prune = ncp_d_prune, }; #define ncp_namespace(i) (NCP_SERVER(i)->name_space[NCP_FINFO(i)->volNumber]) @@ -384,42 +386,6 @@ finished: return val; } -static struct dentry * -ncp_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos) -{ - struct dentry *dent = dentry; - - if (d_validate(dent, parent)) { - if (dent->d_name.len <= NCP_MAXPATHLEN && - (unsigned long)dent->d_fsdata == fpos) { - if (!dent->d_inode) { - dput(dent); - dent = NULL; - } - return dent; - } - dput(dent); - } - - /* If a pointer is invalid, we search the dentry. */ - spin_lock(&parent->d_lock); - list_for_each_entry(dent, &parent->d_subdirs, d_child) { - if ((unsigned long)dent->d_fsdata == fpos) { - if (dent->d_inode) - dget(dent); - else - dent = NULL; - spin_unlock(&parent->d_lock); - goto out; - } - } - spin_unlock(&parent->d_lock); - return NULL; - -out: - return dent; -} - static time_t ncp_obtain_mtime(struct dentry *dentry) { struct inode *inode = dentry->d_inode; @@ -435,6 +401,20 @@ static time_t ncp_obtain_mtime(struct dentry *dentry) return ncp_date_dos2unix(i.modifyTime, i.modifyDate); } +static inline void +ncp_invalidate_dircache_entries(struct dentry *parent) +{ + struct ncp_server *server = NCP_SERVER(parent->d_inode); + struct dentry *dentry; + + spin_lock(&parent->d_lock); + list_for_each_entry(dentry, &parent->d_subdirs, d_child) { + dentry->d_fsdata = NULL; + ncp_age_dentry(server, dentry); + } + spin_unlock(&parent->d_lock); +} + static int ncp_readdir(struct file *file, struct dir_context *ctx) { struct dentry *dentry = file->f_path.dentry; @@ -500,10 +480,21 @@ static int ncp_readdir(struct file *file, struct dir_context *ctx) struct dentry *dent; bool over; - dent = ncp_dget_fpos(ctl.cache->dentry[ctl.idx], - dentry, ctx->pos); - if (!dent) + spin_lock(&dentry->d_lock); + if (!(NCP_FINFO(inode)->flags & NCPI_DIR_CACHE)) { + spin_unlock(&dentry->d_lock); + goto invalid_cache; + } + dent = ctl.cache->dentry[ctl.idx]; + if (unlikely(!lockref_get_not_dead(&dent->d_lockref))) { + spin_unlock(&dentry->d_lock); + goto invalid_cache; + } + spin_unlock(&dentry->d_lock); + if (!dent->d_inode) { + dput(dent); goto invalid_cache; + } over = !dir_emit(ctx, dent->d_name.name, dent->d_name.len, dent->d_inode->i_ino, DT_UNKNOWN); @@ -548,6 +539,9 @@ init_cache: ctl.filled = 0; ctl.valid = 1; read_really: + spin_lock(&dentry->d_lock); + NCP_FINFO(inode)->flags |= NCPI_DIR_CACHE; + spin_unlock(&dentry->d_lock); if (ncp_is_server_root(inode)) { ncp_read_volume_list(file, ctx, &ctl); } else { @@ -573,6 +567,13 @@ out: return result; } +static void ncp_d_prune(struct dentry *dentry) +{ + if (!dentry->d_fsdata) /* not referenced from page cache */ + return; + NCP_FINFO(dentry->d_parent->d_inode)->flags &= ~NCPI_DIR_CACHE; +} + static int ncp_fill_cache(struct file *file, struct dir_context *ctx, struct ncp_cache_control *ctrl, struct ncp_entry_info *entry, @@ -630,6 +631,10 @@ ncp_fill_cache(struct file *file, struct dir_context *ctx, d_instantiate(newdent, inode); if (!hashed) d_rehash(newdent); + } else { + spin_lock(&dentry->d_lock); + NCP_FINFO(inode)->flags &= ~NCPI_DIR_CACHE; + spin_unlock(&dentry->d_lock); } } else { struct inode *inode = newdent->d_inode; @@ -639,12 +644,6 @@ ncp_fill_cache(struct file *file, struct dir_context *ctx, mutex_unlock(&inode->i_mutex); } - if (newdent->d_inode) { - ino = newdent->d_inode->i_ino; - newdent->d_fsdata = (void *) ctl.fpos; - ncp_new_dentry(newdent); - } - if (ctl.idx >= NCP_DIRCACHE_SIZE) { if (ctl.page) { kunmap(ctl.page); @@ -660,8 +659,13 @@ ncp_fill_cache(struct file *file, struct dir_context *ctx, ctl.cache = kmap(ctl.page); } if (ctl.cache) { - ctl.cache->dentry[ctl.idx] = newdent; - valid = 1; + if (newdent->d_inode) { + newdent->d_fsdata = newdent; + ctl.cache->dentry[ctl.idx] = newdent; + ino = newdent->d_inode->i_ino; + ncp_new_dentry(newdent); + } + valid = 1; } dput(newdent); end_advance: diff --git a/fs/ncpfs/ncp_fs_i.h b/fs/ncpfs/ncp_fs_i.h index 4b0bec477846..c4794504f843 100644 --- a/fs/ncpfs/ncp_fs_i.h +++ b/fs/ncpfs/ncp_fs_i.h @@ -22,6 +22,7 @@ struct ncp_inode_info { int access; int flags; #define NCPI_KLUDGE_SYMLINK 0x0001 +#define NCPI_DIR_CACHE 0x0002 __u8 file_handle[6]; struct inode vfs_inode; }; diff --git a/fs/ncpfs/ncplib_kernel.h b/fs/ncpfs/ncplib_kernel.h index b785f74bfe3c..250e443a07f3 100644 --- a/fs/ncpfs/ncplib_kernel.h +++ b/fs/ncpfs/ncplib_kernel.h @@ -184,36 +184,6 @@ ncp_new_dentry(struct dentry* dentry) dentry->d_time = jiffies; } -static inline void -ncp_renew_dentries(struct dentry *parent) -{ - struct ncp_server *server = NCP_SERVER(parent->d_inode); - struct dentry *dentry; - - spin_lock(&parent->d_lock); - list_for_each_entry(dentry, &parent->d_subdirs, d_child) { - if (dentry->d_fsdata == NULL) - ncp_age_dentry(server, dentry); - else - ncp_new_dentry(dentry); - } - spin_unlock(&parent->d_lock); -} - -static inline void -ncp_invalidate_dircache_entries(struct dentry *parent) -{ - struct ncp_server *server = NCP_SERVER(parent->d_inode); - struct dentry *dentry; - - spin_lock(&parent->d_lock); - list_for_each_entry(dentry, &parent->d_subdirs, d_child) { - dentry->d_fsdata = NULL; - ncp_age_dentry(server, dentry); - } - spin_unlock(&parent->d_lock); -} - struct ncp_cache_head { time_t mtime; unsigned long time; /* cache age */ -- 2.20.1