From 17457c5d0fa0b98cef9d2236a1518b1ded25fa5d Mon Sep 17 00:00:00 2001 From: Bharath SM Date: Wed, 11 Jun 2025 16:59:02 +0530 Subject: smb: improve directory cache reuse for readdir operations Currently, cached directory contents were not reused across subsequent 'ls' operations because the cache validity check relied on comparing the ctx pointer, which changes with each readdir invocation. As a result, the cached dir entries was not marked as valid and the cache was not utilized for subsequent 'ls' operations. This change uses the file pointer, which remains consistent across all readdir calls for a given directory instance, to associate and validate the cache. As a result, cached directory contents can now be correctly reused, improving performance for repeated directory listings. Performance gains with local windows SMB server: Without the patch and default actimeo=1: 1000 directory enumeration operations on dir with 10k files took 135.0s With this patch and actimeo=0: 1000 directory enumeration operations on dir with 10k files took just 5.1s Signed-off-by: Bharath SM Reviewed-by: Shyam Prasad N Cc: stable@vger.kernel.org Signed-off-by: Steve French --- fs/smb/client/cached_dir.h | 8 ++++---- fs/smb/client/readdir.c | 28 +++++++++++++++------------- 2 files changed, 19 insertions(+), 17 deletions(-) --- a/fs/smb/client/cached_dir.h +++ b/fs/smb/client/cached_dir.h @@ -21,10 +21,10 @@ struct cached_dirent { struct cached_dirents { bool is_valid:1; bool is_failed:1; - struct dir_context *ctx; /* - * Only used to make sure we only take entries - * from a single context. Never dereferenced. - */ + struct file *file; /* + * Used to associate the cache with a single + * open file instance. + */ struct mutex de_mutex; int pos; /* Expected ctx->pos */ struct list_head entries; --- a/fs/smb/client/readdir.c +++ b/fs/smb/client/readdir.c @@ -850,9 +850,9 @@ static bool emit_cached_dirents(struct c } static void update_cached_dirents_count(struct cached_dirents *cde, - struct dir_context *ctx) + struct file *file) { - if (cde->ctx != ctx) + if (cde->file != file) return; if (cde->is_valid || cde->is_failed) return; @@ -861,9 +861,9 @@ static void update_cached_dirents_count( } static void finished_cached_dirents_count(struct cached_dirents *cde, - struct dir_context *ctx) + struct dir_context *ctx, struct file *file) { - if (cde->ctx != ctx) + if (cde->file != file) return; if (cde->is_valid || cde->is_failed) return; @@ -876,11 +876,12 @@ static void finished_cached_dirents_coun static void add_cached_dirent(struct cached_dirents *cde, struct dir_context *ctx, const char *name, int namelen, - struct cifs_fattr *fattr) + struct cifs_fattr *fattr, + struct file *file) { struct cached_dirent *de; - if (cde->ctx != ctx) + if (cde->file != file) return; if (cde->is_valid || cde->is_failed) return; @@ -910,7 +911,8 @@ static void add_cached_dirent(struct cac static bool cifs_dir_emit(struct dir_context *ctx, const char *name, int namelen, struct cifs_fattr *fattr, - struct cached_fid *cfid) + struct cached_fid *cfid, + struct file *file) { bool rc; ino_t ino = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid); @@ -922,7 +924,7 @@ static bool cifs_dir_emit(struct dir_con if (cfid) { mutex_lock(&cfid->dirents.de_mutex); add_cached_dirent(&cfid->dirents, ctx, name, namelen, - fattr); + fattr, file); mutex_unlock(&cfid->dirents.de_mutex); } @@ -1022,7 +1024,7 @@ static int cifs_filldir(char *find_entry cifs_prime_dcache(file_dentry(file), &name, &fattr); return !cifs_dir_emit(ctx, name.name, name.len, - &fattr, cfid); + &fattr, cfid, file); } @@ -1073,8 +1075,8 @@ int cifs_readdir(struct file *file, stru * we need to initialize scanning and storing the * directory content. */ - if (ctx->pos == 0 && cfid->dirents.ctx == NULL) { - cfid->dirents.ctx = ctx; + if (ctx->pos == 0 && cfid->dirents.file == NULL) { + cfid->dirents.file = file; cfid->dirents.pos = 2; } /* @@ -1142,7 +1144,7 @@ int cifs_readdir(struct file *file, stru } else { if (cfid) { mutex_lock(&cfid->dirents.de_mutex); - finished_cached_dirents_count(&cfid->dirents, ctx); + finished_cached_dirents_count(&cfid->dirents, ctx, file); mutex_unlock(&cfid->dirents.de_mutex); } cifs_dbg(FYI, "Could not find entry\n"); @@ -1183,7 +1185,7 @@ int cifs_readdir(struct file *file, stru ctx->pos++; if (cfid) { mutex_lock(&cfid->dirents.de_mutex); - update_cached_dirents_count(&cfid->dirents, ctx); + update_cached_dirents_count(&cfid->dirents, file); mutex_unlock(&cfid->dirents.de_mutex); }