[ck] Re: [ANCK-4.19 PATCH 8/9] fuse: use iversion for readdir cache verification

From: Miklos Szeredi <mszeredi(a)redhat.com> commit 261aaba72fdba17b74a3a434d9f925b43d90e958 upstream Use the internal iversion counter to make sure modifications of the directory through this filesystem are not missed by the mtime check (due to mtime granularity). Signed-off-by: Miklos Szeredi <mszeredi(a)redhat.com> Signed-off-by: Jeffle Xu <jefflexu(a)linux.alibaba.com>

--- fs/fuse/dir.c | 21 ++++++++++++++------- fs/fuse/fuse_i.h | 3 +++ fs/fuse/readdir.c | 5 ++++- 3 files changed, 21 insertions(+), 8 deletions(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 7d76b615ee11..27814ce8b52a 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -14,6 +14,7 @@ #include <linux/namei.h> #include <linux/slab.h> #include <linux/xattr.h> +#include <linux/iversion.h> #include <linux/posix_acl.h> static void fuse_advise_use_readdirplus(struct inode *dir) @@ -105,6 +106,12 @@ void fuse_invalidate_attr(struct inode *inode) get_fuse_inode(inode)->i_time = 0; } +static void fuse_dir_changed(struct inode *dir) +{ + fuse_invalidate_attr(dir); + inode_maybe_inc_iversion(dir, false); +} + /** * Mark the attributes as stale due to an atime change. Avoid the invalidate if * atime is not used. @@ -463,7 +470,7 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, kfree(forget); d_instantiate(entry, inode); fuse_change_entry_timeout(entry, &outentry); - fuse_invalidate_attr(dir); + fuse_dir_changed(dir); err = finish_open(file, entry, generic_file_open); if (err) { fi = get_fuse_inode(inode); @@ -578,7 +585,7 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args, } else { fuse_change_entry_timeout(entry, &outarg); } - fuse_invalidate_attr(dir); + fuse_dir_changed(dir); return 0; out_put_forget_req: @@ -688,7 +695,7 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry) drop_nlink(inode); spin_unlock(&fi->lock); fuse_invalidate_attr(inode); - fuse_invalidate_attr(dir); + fuse_dir_changed(dir); fuse_invalidate_entry_cache(entry); fuse_update_ctime(inode); } else if (err == -EINTR) @@ -710,7 +717,7 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry) err = fuse_simple_request(fc, &args); if (!err) { clear_nlink(d_inode(entry)); - fuse_invalidate_attr(dir); + fuse_dir_changed(dir); fuse_invalidate_entry_cache(entry); } else if (err == -EINTR) fuse_invalidate_entry(entry); @@ -749,9 +756,9 @@ static int fuse_rename_common(struct inode *olddir, struct dentry *oldent, fuse_update_ctime(d_inode(newent)); } - fuse_invalidate_attr(olddir); + fuse_dir_changed(olddir); if (olddir != newdir) - fuse_invalidate_attr(newdir); + fuse_dir_changed(newdir); /* newent will end up negative */ if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) { @@ -986,7 +993,7 @@ int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, if (!entry) goto unlock; - fuse_invalidate_attr(parent); + fuse_dir_changed(parent); fuse_invalidate_entry(entry); if (child_nodeid != 0 && d_really_is_positive(entry)) { diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 6f1e69a9d0ce..086b0c4c4a59 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -158,6 +158,9 @@ struct fuse_inode { /* modification time of directory when cache was started */ struct timespec64 mtime; + /* iversion of directory when cache was started */ + u64 iversion; + /* protects above fields */ spinlock_t lock; } rdc; diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c index 6e86bea9c4bf..656afd035e21 100644 --- a/fs/fuse/readdir.c +++ b/fs/fuse/readdir.c @@ -8,6 +8,7 @@ #include "fuse_i.h" +#include <linux/iversion.h> #include <linux/posix_acl.h> #include <linux/pagemap.h> #include <linux/highmem.h> @@ -449,6 +450,7 @@ static int fuse_readdir_cached(struct file *file, struct dir_context *ctx) /* Starting cache? Set cache mtime. */ if (!ctx->pos && !fi->rdc.size) { fi->rdc.mtime = inode->i_mtime; + fi->rdc.iversion = inode_query_iversion(inode); } spin_unlock(&fi->rdc.lock); return UNCACHED; @@ -459,7 +461,8 @@ static int fuse_readdir_cached(struct file *file, struct dir_context *ctx) * changed, and reset the cache if so. */ if (!ctx->pos) { - if (!timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) { + if (inode_peek_iversion(inode) != fi->rdc.iversion || + !timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) { fuse_rdc_reset(inode); goto retry_locked; }