From d688d65a847ff910146eff51e70f4b7049895eb5 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 30 Aug 2024 15:04:49 +0200 Subject: fs: add generic_llseek_cookie() This is similar to generic_file_llseek() but allows the caller to specify a cookie that will be updated to indicate that a seek happened. Caller's requiring that information in their readdir implementations can use that. Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-8-6d3e4816aa7b@kernel.org Reviewed-by: Jan Kara Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner --- include/linux/fs.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index 58c91a52cad1..3e6b3c1afb31 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3202,6 +3202,8 @@ extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize); extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence); extern loff_t generic_file_llseek_size(struct file *file, loff_t offset, int whence, loff_t maxsize, loff_t eof); +loff_t generic_llseek_cookie(struct file *file, loff_t offset, int whence, + u64 *cookie); extern loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size); extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t); -- cgit v1.2.3 From 5e9b50dea970ae6d3e1309d4254157099734a2af Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 30 Aug 2024 15:04:59 +0200 Subject: fs: add f_pipe Only regular files with FMODE_ATOMIC_POS and directories need f_pos_lock. Place a new f_pipe member in a union with f_pos_lock that they can use and make them stop abusing f_version in follow-up patches. Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-18-6d3e4816aa7b@kernel.org Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner --- fs/file_table.c | 7 +++++++ include/linux/fs.h | 8 +++++++- 2 files changed, 14 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/fs/file_table.c b/fs/file_table.c index 3ef558f27a1c..7ce4d5dac080 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -156,6 +156,13 @@ static int init_file(struct file *f, int flags, const struct cred *cred) } spin_lock_init(&f->f_lock); + /* + * Note that f_pos_lock is only used for files raising + * FMODE_ATOMIC_POS and directories. Other files such as pipes + * don't need it and since f_pos_lock is in a union may reuse + * the space for other purposes. They are expected to initialize + * the respective member when opening the file. + */ mutex_init(&f->f_pos_lock); f->f_flags = flags; f->f_mode = OPEN_FMODE(flags); diff --git a/include/linux/fs.h b/include/linux/fs.h index 3e6b3c1afb31..ca4925008244 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1001,6 +1001,7 @@ static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index) * @f_cred: stashed credentials of creator/opener * @f_path: path of the file * @f_pos_lock: lock protecting file position + * @f_pipe: specific to pipes * @f_pos: file position * @f_version: file version * @f_security: LSM security context of this file @@ -1026,7 +1027,12 @@ struct file { const struct cred *f_cred; /* --- cacheline 1 boundary (64 bytes) --- */ struct path f_path; - struct mutex f_pos_lock; + union { + /* regular files (with FMODE_ATOMIC_POS) and directories */ + struct mutex f_pos_lock; + /* pipes */ + u64 f_pipe; + }; loff_t f_pos; u64 f_version; /* --- cacheline 2 boundary (128 bytes) --- */ -- cgit v1.2.3 From 11068e0b64cbb540b96e577fcca0926242ecaf58 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 30 Aug 2024 15:05:01 +0200 Subject: fs: remove f_version Now that detecting concurrent seeks is done by the filesystems that require it we can remove f_version and free up 8 bytes for future extensions. Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-20-6d3e4816aa7b@kernel.org Reviewed-by: Jan Kara Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner --- fs/read_write.c | 9 ++++----- include/linux/fs.h | 4 +--- 2 files changed, 5 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/fs/read_write.c b/fs/read_write.c index fb519e55c8e8..b19cce8e55b9 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -62,7 +62,8 @@ static loff_t vfs_setpos_cookie(struct file *file, loff_t offset, if (offset != file->f_pos) { file->f_pos = offset; - *cookie = 0; + if (cookie) + *cookie = 0; } return offset; } @@ -81,7 +82,7 @@ static loff_t vfs_setpos_cookie(struct file *file, loff_t offset, */ loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize) { - return vfs_setpos_cookie(file, offset, maxsize, &file->f_version); + return vfs_setpos_cookie(file, offset, maxsize, NULL); } EXPORT_SYMBOL(vfs_setpos); @@ -364,10 +365,8 @@ loff_t default_llseek(struct file *file, loff_t offset, int whence) } retval = -EINVAL; if (offset >= 0 || unsigned_offsets(file)) { - if (offset != file->f_pos) { + if (offset != file->f_pos) file->f_pos = offset; - file->f_version = 0; - } retval = offset; } out: diff --git a/include/linux/fs.h b/include/linux/fs.h index ca4925008244..7e11ce172140 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1003,7 +1003,6 @@ static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index) * @f_pos_lock: lock protecting file position * @f_pipe: specific to pipes * @f_pos: file position - * @f_version: file version * @f_security: LSM security context of this file * @f_owner: file owner * @f_wb_err: writeback error @@ -1034,11 +1033,10 @@ struct file { u64 f_pipe; }; loff_t f_pos; - u64 f_version; - /* --- cacheline 2 boundary (128 bytes) --- */ #ifdef CONFIG_SECURITY void *f_security; #endif + /* --- cacheline 2 boundary (128 bytes) --- */ struct fown_struct *f_owner; errseq_t f_wb_err; errseq_t f_sb_err; -- cgit v1.2.3