Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <linux/fs_stack.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) /* does _NOT_ require i_mutex to be held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)  * This function cannot be inlined since i_size_{read,write} is rather
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)  * heavy-weight on 32-bit systems
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) void fsstack_copy_inode_size(struct inode *dst, struct inode *src)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 	loff_t i_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 	blkcnt_t i_blocks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 	 * i_size_read() includes its own seqlocking and protection from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 	 * preemption (see include/linux/fs.h): we need nothing extra for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 	 * that here, and prefer to avoid nesting locks than attempt to keep
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 	 * i_size and i_blocks in sync together.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 	i_size = i_size_read(src);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	 * But on 32-bit, we ought to make an effort to keep the two halves of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	 * i_blocks in sync despite SMP or PREEMPTION - though stat's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	 * generic_fillattr() doesn't bother, and we won't be applying quotas
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	 * (where i_blocks does become important) at the upper level.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	 * We don't actually know what locking is used at the lower level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 	 * but if it's a filesystem that supports quotas, it will be using
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	 * i_lock as in inode_add_bytes().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	if (sizeof(i_blocks) > sizeof(long))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 		spin_lock(&src->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	i_blocks = src->i_blocks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	if (sizeof(i_blocks) > sizeof(long))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 		spin_unlock(&src->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 	 * If CONFIG_SMP or CONFIG_PREEMPTION on 32-bit, it's vital for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 	 * fsstack_copy_inode_size() to hold some lock around
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 	 * i_size_write(), otherwise i_size_read() may spin forever (see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 	 * include/linux/fs.h).  We don't necessarily hold i_mutex when this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 	 * is called, so take i_lock for that case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 	 * And if on 32-bit, continue our effort to keep the two halves of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	 * i_blocks in sync despite SMP or PREEMPTION: use i_lock for that case
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 	 * too, and do both at once by combining the tests.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 	 * There is none of this locking overhead in the 64-bit case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 	if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 		spin_lock(&dst->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 	i_size_write(dst, i_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 	dst->i_blocks = i_blocks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 	if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 		spin_unlock(&dst->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) EXPORT_SYMBOL_GPL(fsstack_copy_inode_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) /* copy all attributes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) void fsstack_copy_attr_all(struct inode *dest, const struct inode *src)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 	dest->i_mode = src->i_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 	dest->i_uid = src->i_uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) 	dest->i_gid = src->i_gid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) 	dest->i_rdev = src->i_rdev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 	dest->i_atime = src->i_atime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 	dest->i_mtime = src->i_mtime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 	dest->i_ctime = src->i_ctime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 	dest->i_blkbits = src->i_blkbits;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 	dest->i_flags = src->i_flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) 	set_nlink(dest, src->i_nlink);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) EXPORT_SYMBOL_GPL(fsstack_copy_attr_all);