From 4f05ee2f82b470c20f7ff260bb0d866425b09d05 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 30 Aug 2024 15:04:52 +0200 Subject: ext4: store cookie in private data Store the cookie to detect concurrent seeks on directories in file->private_data. Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-11-6d3e4816aa7b@kernel.org Acked-by: Theodore Ts'o Reviewed-by: Jan Kara Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner --- fs/ext4/dir.c | 50 ++++++++++++++++++++++++++++---------------------- fs/ext4/ext4.h | 2 ++ fs/ext4/inline.c | 7 ++++--- 3 files changed, 34 insertions(+), 25 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index ff4514e4626b..13196afe55ce 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -133,6 +133,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) struct super_block *sb = inode->i_sb; struct buffer_head *bh = NULL; struct fscrypt_str fstr = FSTR_INIT(NULL, 0); + struct dir_private_info *info = file->private_data; err = fscrypt_prepare_readdir(inode); if (err) @@ -229,7 +230,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) * readdir(2), then we might be pointing to an invalid * dirent right now. Scan from the start of the block * to make sure. */ - if (!inode_eq_iversion(inode, file->f_version)) { + if (!inode_eq_iversion(inode, info->cookie)) { for (i = 0; i < sb->s_blocksize && i < offset; ) { de = (struct ext4_dir_entry_2 *) (bh->b_data + i); @@ -249,7 +250,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) offset = i; ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset; - file->f_version = inode_query_iversion(inode); + info->cookie = inode_query_iversion(inode); } while (ctx->pos < inode->i_size @@ -384,6 +385,7 @@ static inline loff_t ext4_get_htree_eof(struct file *filp) static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence) { struct inode *inode = file->f_mapping->host; + struct dir_private_info *info = file->private_data; int dx_dir = is_dx_dir(inode); loff_t ret, htree_max = ext4_get_htree_eof(file); @@ -392,7 +394,7 @@ static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence) htree_max, htree_max); else ret = ext4_llseek(file, offset, whence); - file->f_version = inode_peek_iversion(inode) - 1; + info->cookie = inode_peek_iversion(inode) - 1; return ret; } @@ -429,18 +431,15 @@ static void free_rb_tree_fname(struct rb_root *root) *root = RB_ROOT; } - -static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp, - loff_t pos) +static void ext4_htree_init_dir_info(struct file *filp, loff_t pos) { - struct dir_private_info *p; - - p = kzalloc(sizeof(*p), GFP_KERNEL); - if (!p) - return NULL; - p->curr_hash = pos2maj_hash(filp, pos); - p->curr_minor_hash = pos2min_hash(filp, pos); - return p; + struct dir_private_info *p = filp->private_data; + + if (is_dx_dir(file_inode(filp)) && !p->initialized) { + p->curr_hash = pos2maj_hash(filp, pos); + p->curr_minor_hash = pos2min_hash(filp, pos); + p->initialized = true; + } } void ext4_htree_free_dir_info(struct dir_private_info *p) @@ -552,12 +551,7 @@ static int ext4_dx_readdir(struct file *file, struct dir_context *ctx) struct fname *fname; int ret = 0; - if (!info) { - info = ext4_htree_create_dir_info(file, ctx->pos); - if (!info) - return -ENOMEM; - file->private_data = info; - } + ext4_htree_init_dir_info(file, ctx->pos); if (ctx->pos == ext4_get_htree_eof(file)) return 0; /* EOF */ @@ -590,10 +584,10 @@ static int ext4_dx_readdir(struct file *file, struct dir_context *ctx) * cached entries. */ if ((!info->curr_node) || - !inode_eq_iversion(inode, file->f_version)) { + !inode_eq_iversion(inode, info->cookie)) { info->curr_node = NULL; free_rb_tree_fname(&info->root); - file->f_version = inode_query_iversion(inode); + info->cookie = inode_query_iversion(inode); ret = ext4_htree_fill_tree(file, info->curr_hash, info->curr_minor_hash, &info->next_hash); @@ -664,7 +658,19 @@ int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf, return 0; } +static int ext4_dir_open(struct inode *inode, struct file *file) +{ + struct dir_private_info *info; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + file->private_data = info; + return 0; +} + const struct file_operations ext4_dir_operations = { + .open = ext4_dir_open, .llseek = ext4_dir_llseek, .read = generic_read_dir, .iterate_shared = ext4_readdir, diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 08acd152261e..d62a4b9b26ce 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2553,6 +2553,8 @@ struct dir_private_info { __u32 curr_hash; __u32 curr_minor_hash; __u32 next_hash; + u64 cookie; + bool initialized; }; /* calculate the first block number of the group */ diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c index e7a09a99837b..4282e12dc405 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -1460,6 +1460,7 @@ int ext4_read_inline_dir(struct file *file, struct ext4_iloc iloc; void *dir_buf = NULL; int dotdot_offset, dotdot_size, extra_offset, extra_size; + struct dir_private_info *info = file->private_data; ret = ext4_get_inode_loc(inode, &iloc); if (ret) @@ -1503,12 +1504,12 @@ int ext4_read_inline_dir(struct file *file, extra_size = extra_offset + inline_size; /* - * If the version has changed since the last call to + * If the cookie has changed since the last call to * readdir(2), then we might be pointing to an invalid * dirent right now. Scan from the start of the inline * dir to make sure. */ - if (!inode_eq_iversion(inode, file->f_version)) { + if (!inode_eq_iversion(inode, info->cookie)) { for (i = 0; i < extra_size && i < offset;) { /* * "." is with offset 0 and @@ -1540,7 +1541,7 @@ int ext4_read_inline_dir(struct file *file, } offset = i; ctx->pos = offset; - file->f_version = inode_query_iversion(inode); + info->cookie = inode_query_iversion(inode); } while (ctx->pos < extra_size) { -- cgit v1.2.3