diff options
| -rw-r--r-- | Documentation/filesystems/porting | 18 | ||||
| -rw-r--r-- | fs/coda/dir.c | 18 | ||||
| -rw-r--r-- | fs/exportfs/expfs.c | 2 | ||||
| -rw-r--r-- | fs/readdir.c | 20 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 |
5 files changed, 48 insertions, 11 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 1567a53857bd..12c57abdaac9 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -557,3 +557,21 @@ in your dentry operations instead. will not happen in parallel ("same" in the sense of your ->d_compare()). Lookups on different names in the same directory can and do happen in parallel now. +-- +[recommended] + ->iterate_shared() is added; it's a parallel variant of ->iterate(). + Exclusion on struct file level is still provided (as well as that + between it and lseek on the same struct file), but if your directory + has been opened several times, you can get these called in parallel. + Exclusion between that method and all directory-modifying ones is + still provided, of course. + + Often enough ->iterate() can serve as ->iterate_shared() without any + changes - it is a read-only operation, after all. If you have any + per-inode or per-dentry in-core data structures modified by ->iterate(), + you might need something to serialize the access to them. If you + do dcache pre-seeding, you'll need to switch to d_alloc_parallel() for + that; look for in-tree examples. + + Old method is only used if the new one is absent; eventually it will + be removed. Switch while you still can; the old one won't stay. diff --git a/fs/coda/dir.c b/fs/coda/dir.c index 42e731b8c80a..6fb8672c0892 100644 --- a/fs/coda/dir.c +++ b/fs/coda/dir.c @@ -424,16 +424,22 @@ static int coda_readdir(struct file *coda_file, struct dir_context *ctx) BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); host_file = cfi->cfi_container; - if (host_file->f_op->iterate) { + if (host_file->f_op->iterate || host_file->f_op->iterate_shared) { struct inode *host_inode = file_inode(host_file); - - inode_lock(host_inode); ret = -ENOENT; if (!IS_DEADDIR(host_inode)) { - ret = host_file->f_op->iterate(host_file, ctx); - file_accessed(host_file); + if (host_file->f_op->iterate_shared) { + inode_lock_shared(host_inode); + ret = host_file->f_op->iterate_shared(host_file, ctx); + file_accessed(host_file); + inode_unlock_shared(host_inode); + } else { + inode_lock(host_inode); + ret = host_file->f_op->iterate(host_file, ctx); + file_accessed(host_file); + inode_unlock(host_inode); + } } - inode_unlock(host_inode); return ret; } /* Venus: we must read Venus dirents from a file */ diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 402c5caab5ca..207ba8d627ca 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -312,7 +312,7 @@ static int get_name(const struct path *path, char *name, struct dentry *child) goto out; error = -EINVAL; - if (!file->f_op->iterate) + if (!file->f_op->iterate && !file->f_op->iterate_shared) goto out_close; buffer.sequence = 0; diff --git a/fs/readdir.c b/fs/readdir.c index d7308b8f6cf7..a86c6c04b9bc 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -24,15 +24,21 @@ int iterate_dir(struct file *file, struct dir_context *ctx) { struct inode *inode = file_inode(file); + bool shared = false; int res = -ENOTDIR; - if (!file->f_op->iterate) + if (file->f_op->iterate_shared) + shared = true; + else if (!file->f_op->iterate) goto out; res = security_file_permission(file, MAY_READ); if (res) goto out; - inode_lock(inode); + if (shared) + inode_lock_shared(inode); + else + inode_lock(inode); // res = mutex_lock_killable(&inode->i_mutex); // if (res) // goto out; @@ -40,12 +46,18 @@ int iterate_dir(struct file *file, struct dir_context *ctx) res = -ENOENT; if (!IS_DEADDIR(inode)) { ctx->pos = file->f_pos; - res = file->f_op->iterate(file, ctx); + if (shared) + res = file->f_op->iterate_shared(file, ctx); + else + res = file->f_op->iterate(file, ctx); file->f_pos = ctx->pos; fsnotify_access(file); file_accessed(file); } - inode_unlock(inode); + if (shared) + inode_unlock_shared(inode); + else + inode_unlock(inode); out: return res; } diff --git a/include/linux/fs.h b/include/linux/fs.h index 3018f31f7aa0..3dc0258a2b64 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1674,6 +1674,7 @@ struct file_operations { ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); int (*iterate) (struct file *, struct dir_context *); + int (*iterate_shared) (struct file *, struct dir_context *); unsigned int (*poll) (struct file *, struct poll_table_struct *); long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); long (*compat_ioctl) (struct file *, unsigned int, unsigned long); |