| Message ID | 20240830-vfs-file-f_version-v1-6-6d3e4816aa7b@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | file: remove f_version | expand |
On Fri 30-08-24 15:04:47, Christian Brauner wrote: > Add a new must_set_pos() helper. We will use it in follow-up patches. > Temporarily mark it as unused. This is only done to keep the diff small > and reviewable. > > Signed-off-by: Christian Brauner <brauner@kernel.org> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/read_write.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/fs/read_write.c b/fs/read_write.c > index 66ff52860496..acee26989d95 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -85,6 +85,58 @@ loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize) > } > EXPORT_SYMBOL(vfs_setpos); > > +/** > + * must_set_pos - check whether f_pos has to be updated > + * @offset: offset to use > + * @whence: type of seek operation > + * @eof: end of file > + * > + * Check whether f_pos needs to be updated and update @offset according > + * to @whence. > + * > + * Return: 0 if f_pos doesn't need to be updated, 1 if f_pos has to be > + * updated, and negative error code on failure. > + */ > +static __maybe_unused int must_set_pos(struct file *file, loff_t *offset, int whence, loff_t eof) > +{ > + switch (whence) { > + case SEEK_END: > + *offset += eof; > + break; > + case SEEK_CUR: > + /* > + * Here we special-case the lseek(fd, 0, SEEK_CUR) > + * position-querying operation. Avoid rewriting the "same" > + * f_pos value back to the file because a concurrent read(), > + * write() or lseek() might have altered it > + */ > + if (*offset == 0) { > + *offset = file->f_pos; > + return 0; > + } > + break; > + case SEEK_DATA: > + /* > + * In the generic case the entire file is data, so as long as > + * offset isn't at the end of the file then the offset is data. > + */ > + if ((unsigned long long)*offset >= eof) > + return -ENXIO; > + break; > + case SEEK_HOLE: > + /* > + * There is a virtual hole at the end of the file, so as long as > + * offset isn't i_size or larger, return i_size. > + */ > + if ((unsigned long long)*offset >= eof) > + return -ENXIO; > + *offset = eof; > + break; > + } > + > + return 1; > +} > + > /** > * generic_file_llseek_size - generic llseek implementation for regular files > * @file: file structure to seek on > > -- > 2.45.2 >
diff --git a/fs/read_write.c b/fs/read_write.c index 66ff52860496..acee26989d95 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -85,6 +85,58 @@ loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize) } EXPORT_SYMBOL(vfs_setpos); +/** + * must_set_pos - check whether f_pos has to be updated + * @offset: offset to use + * @whence: type of seek operation + * @eof: end of file + * + * Check whether f_pos needs to be updated and update @offset according + * to @whence. + * + * Return: 0 if f_pos doesn't need to be updated, 1 if f_pos has to be + * updated, and negative error code on failure. + */ +static __maybe_unused int must_set_pos(struct file *file, loff_t *offset, int whence, loff_t eof) +{ + switch (whence) { + case SEEK_END: + *offset += eof; + break; + case SEEK_CUR: + /* + * Here we special-case the lseek(fd, 0, SEEK_CUR) + * position-querying operation. Avoid rewriting the "same" + * f_pos value back to the file because a concurrent read(), + * write() or lseek() might have altered it + */ + if (*offset == 0) { + *offset = file->f_pos; + return 0; + } + break; + case SEEK_DATA: + /* + * In the generic case the entire file is data, so as long as + * offset isn't at the end of the file then the offset is data. + */ + if ((unsigned long long)*offset >= eof) + return -ENXIO; + break; + case SEEK_HOLE: + /* + * There is a virtual hole at the end of the file, so as long as + * offset isn't i_size or larger, return i_size. + */ + if ((unsigned long long)*offset >= eof) + return -ENXIO; + *offset = eof; + break; + } + + return 1; +} + /** * generic_file_llseek_size - generic llseek implementation for regular files * @file: file structure to seek on
Add a new must_set_pos() helper. We will use it in follow-up patches. Temporarily mark it as unused. This is only done to keep the diff small and reviewable. Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/read_write.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+)