^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) #include "reiserfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #include <linux/mutex.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * The previous reiserfs locking scheme was heavily based on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * the tricky properties of the Bkl:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * - it was acquired recursively by a same task
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * - the performances relied on the release-while-schedule() property
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * Now that we replace it by a mutex, we still want to keep the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * recursive property to avoid big changes in the code structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * We use our own lock_owner here because the owner field on a mutex
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * is only available in SMP or mutex debugging, also we only need this field
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) * for this mutex, no need for a system wide mutex facility.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * Also this lock is often released before a call that could block because
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * reiserfs performances were partially based on the release while schedule()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * property of the Bkl.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) void reiserfs_write_lock(struct super_block *s)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) if (sb_i->lock_owner != current) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) mutex_lock(&sb_i->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) sb_i->lock_owner = current;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) /* No need to protect it, only the current task touches it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) sb_i->lock_depth++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) void reiserfs_write_unlock(struct super_block *s)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * Are we unlocking without even holding the lock?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * Such a situation must raise a BUG() if we don't want
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * to corrupt the data.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) BUG_ON(sb_i->lock_owner != current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) if (--sb_i->lock_depth == -1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) sb_i->lock_owner = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) mutex_unlock(&sb_i->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) int __must_check reiserfs_write_unlock_nested(struct super_block *s)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) int depth;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) /* this can happen when the lock isn't always held */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) if (sb_i->lock_owner != current)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) depth = sb_i->lock_depth;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) sb_i->lock_depth = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) sb_i->lock_owner = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) mutex_unlock(&sb_i->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) return depth;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) void reiserfs_write_lock_nested(struct super_block *s, int depth)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) /* this can happen when the lock isn't always held */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) if (depth == -1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) mutex_lock(&sb_i->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) sb_i->lock_owner = current;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) sb_i->lock_depth = depth;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) * Utility function to force a BUG if it is called without the superblock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) * write lock held. caller is the string printed just before calling BUG()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) void reiserfs_check_lock_depth(struct super_block *sb, char *caller)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) struct reiserfs_sb_info *sb_i = REISERFS_SB(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) WARN_ON(sb_i->lock_depth < 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) #ifdef CONFIG_REISERFS_CHECK
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) void reiserfs_lock_check_recursive(struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) struct reiserfs_sb_info *sb_i = REISERFS_SB(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) WARN_ONCE((sb_i->lock_depth > 0), "Unwanted recursive reiserfs lock!\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) #endif
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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