mirror of
https://github.com/AetherDroid/android_kernel_samsung_on5xelte.git
synced 2025-09-09 01:28:05 -04:00
Fixed MTP to work with TWRP
This commit is contained in:
awab228
commit
f6dfaef42e
50820 changed files with 20846062 additions and 0 deletions
393
fs/ext4/mmp.c
Normal file
393
fs/ext4/mmp.c
Normal file
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@ -0,0 +1,393 @@
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#include <linux/fs.h>
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#include <linux/random.h>
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#include <linux/buffer_head.h>
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#include <linux/utsname.h>
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#include <linux/kthread.h>
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#include "ext4.h"
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/* Checksumming functions */
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static __le32 ext4_mmp_csum(struct super_block *sb, struct mmp_struct *mmp)
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{
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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int offset = offsetof(struct mmp_struct, mmp_checksum);
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__u32 csum;
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csum = ext4_chksum(sbi, sbi->s_csum_seed, (char *)mmp, offset);
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return cpu_to_le32(csum);
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}
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static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *mmp)
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{
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if (!ext4_has_metadata_csum(sb))
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return 1;
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return mmp->mmp_checksum == ext4_mmp_csum(sb, mmp);
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}
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static void ext4_mmp_csum_set(struct super_block *sb, struct mmp_struct *mmp)
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{
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if (!ext4_has_metadata_csum(sb))
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return;
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mmp->mmp_checksum = ext4_mmp_csum(sb, mmp);
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}
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/*
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* Write the MMP block using WRITE_SYNC to try to get the block on-disk
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* faster.
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*/
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static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
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{
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struct mmp_struct *mmp = (struct mmp_struct *)(bh->b_data);
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/*
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* We protect against freezing so that we don't create dirty buffers
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* on frozen filesystem.
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*/
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sb_start_write(sb);
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ext4_mmp_csum_set(sb, mmp);
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mark_buffer_dirty(bh);
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lock_buffer(bh);
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bh->b_end_io = end_buffer_write_sync;
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get_bh(bh);
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submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
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wait_on_buffer(bh);
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sb_end_write(sb);
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if (unlikely(!buffer_uptodate(bh)))
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return 1;
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return 0;
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}
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/*
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* Read the MMP block. It _must_ be read from disk and hence we clear the
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* uptodate flag on the buffer.
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*/
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static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
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ext4_fsblk_t mmp_block)
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{
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struct mmp_struct *mmp;
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if (*bh)
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clear_buffer_uptodate(*bh);
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/* This would be sb_bread(sb, mmp_block), except we need to be sure
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* that the MD RAID device cache has been bypassed, and that the read
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* is not blocked in the elevator. */
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if (!*bh)
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*bh = sb_getblk(sb, mmp_block);
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if (!*bh)
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return -ENOMEM;
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if (*bh) {
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get_bh(*bh);
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lock_buffer(*bh);
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(*bh)->b_end_io = end_buffer_read_sync;
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submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
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wait_on_buffer(*bh);
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if (!buffer_uptodate(*bh)) {
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brelse(*bh);
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*bh = NULL;
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}
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}
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if (unlikely(!*bh)) {
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ext4_warning(sb, "Error while reading MMP block %llu",
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mmp_block);
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return -EIO;
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}
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mmp = (struct mmp_struct *)((*bh)->b_data);
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if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC ||
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!ext4_mmp_csum_verify(sb, mmp))
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return -EINVAL;
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return 0;
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}
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/*
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* Dump as much information as possible to help the admin.
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*/
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void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
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const char *function, unsigned int line, const char *msg)
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{
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__ext4_warning(sb, function, line, msg);
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__ext4_warning(sb, function, line,
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"MMP failure info: last update time: %llu, last update "
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"node: %s, last update device: %s\n",
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(long long unsigned int) le64_to_cpu(mmp->mmp_time),
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mmp->mmp_nodename, mmp->mmp_bdevname);
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}
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/*
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* kmmpd will update the MMP sequence every s_mmp_update_interval seconds
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*/
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static int kmmpd(void *data)
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{
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struct super_block *sb = ((struct mmpd_data *) data)->sb;
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struct buffer_head *bh = ((struct mmpd_data *) data)->bh;
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struct ext4_super_block *es = EXT4_SB(sb)->s_es;
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struct mmp_struct *mmp;
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ext4_fsblk_t mmp_block;
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u32 seq = 0;
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unsigned long failed_writes = 0;
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int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
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unsigned mmp_check_interval;
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unsigned long last_update_time;
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unsigned long diff;
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int retval;
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mmp_block = le64_to_cpu(es->s_mmp_block);
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mmp = (struct mmp_struct *)(bh->b_data);
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mmp->mmp_time = cpu_to_le64(get_seconds());
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/*
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* Start with the higher mmp_check_interval and reduce it if
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* the MMP block is being updated on time.
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*/
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mmp_check_interval = max(EXT4_MMP_CHECK_MULT * mmp_update_interval,
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EXT4_MMP_MIN_CHECK_INTERVAL);
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mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
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bdevname(bh->b_bdev, mmp->mmp_bdevname);
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memcpy(mmp->mmp_nodename, init_utsname()->nodename,
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sizeof(mmp->mmp_nodename));
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while (!kthread_should_stop()) {
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if (++seq > EXT4_MMP_SEQ_MAX)
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seq = 1;
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mmp->mmp_seq = cpu_to_le32(seq);
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mmp->mmp_time = cpu_to_le64(get_seconds());
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last_update_time = jiffies;
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retval = write_mmp_block(sb, bh);
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/*
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* Don't spew too many error messages. Print one every
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* (s_mmp_update_interval * 60) seconds.
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*/
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if (retval) {
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if ((failed_writes % 60) == 0)
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ext4_error(sb, "Error writing to MMP block");
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failed_writes++;
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}
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if (!(le32_to_cpu(es->s_feature_incompat) &
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EXT4_FEATURE_INCOMPAT_MMP)) {
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ext4_warning(sb, "kmmpd being stopped since MMP feature"
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" has been disabled.");
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EXT4_SB(sb)->s_mmp_tsk = NULL;
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goto failed;
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}
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if (sb->s_flags & MS_RDONLY) {
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ext4_warning(sb, "kmmpd being stopped since filesystem "
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"has been remounted as readonly.");
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EXT4_SB(sb)->s_mmp_tsk = NULL;
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goto failed;
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}
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diff = jiffies - last_update_time;
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if (diff < mmp_update_interval * HZ)
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schedule_timeout_interruptible(mmp_update_interval *
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HZ - diff);
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/*
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* We need to make sure that more than mmp_check_interval
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* seconds have not passed since writing. If that has happened
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* we need to check if the MMP block is as we left it.
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*/
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diff = jiffies - last_update_time;
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if (diff > mmp_check_interval * HZ) {
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struct buffer_head *bh_check = NULL;
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struct mmp_struct *mmp_check;
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retval = read_mmp_block(sb, &bh_check, mmp_block);
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if (retval) {
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ext4_error(sb, "error reading MMP data: %d",
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retval);
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EXT4_SB(sb)->s_mmp_tsk = NULL;
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goto failed;
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}
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mmp_check = (struct mmp_struct *)(bh_check->b_data);
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if (mmp->mmp_seq != mmp_check->mmp_seq ||
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memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
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sizeof(mmp->mmp_nodename))) {
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dump_mmp_msg(sb, mmp_check,
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"Error while updating MMP info. "
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"The filesystem seems to have been"
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" multiply mounted.");
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ext4_error(sb, "abort");
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goto failed;
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}
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put_bh(bh_check);
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}
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/*
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* Adjust the mmp_check_interval depending on how much time
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* it took for the MMP block to be written.
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*/
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mmp_check_interval = max(min(EXT4_MMP_CHECK_MULT * diff / HZ,
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EXT4_MMP_MAX_CHECK_INTERVAL),
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EXT4_MMP_MIN_CHECK_INTERVAL);
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mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
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}
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/*
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* Unmount seems to be clean.
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*/
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mmp->mmp_seq = cpu_to_le32(EXT4_MMP_SEQ_CLEAN);
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mmp->mmp_time = cpu_to_le64(get_seconds());
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retval = write_mmp_block(sb, bh);
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failed:
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kfree(data);
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brelse(bh);
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return retval;
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}
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/*
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* Get a random new sequence number but make sure it is not greater than
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* EXT4_MMP_SEQ_MAX.
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*/
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static unsigned int mmp_new_seq(void)
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{
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u32 new_seq;
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do {
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new_seq = prandom_u32();
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} while (new_seq > EXT4_MMP_SEQ_MAX);
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return new_seq;
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}
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/*
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* Protect the filesystem from being mounted more than once.
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*/
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int ext4_multi_mount_protect(struct super_block *sb,
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ext4_fsblk_t mmp_block)
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{
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struct ext4_super_block *es = EXT4_SB(sb)->s_es;
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struct buffer_head *bh = NULL;
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struct mmp_struct *mmp = NULL;
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struct mmpd_data *mmpd_data;
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u32 seq;
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unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
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unsigned int wait_time = 0;
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int retval;
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if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
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mmp_block >= ext4_blocks_count(es)) {
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ext4_warning(sb, "Invalid MMP block in superblock");
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goto failed;
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}
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retval = read_mmp_block(sb, &bh, mmp_block);
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if (retval)
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goto failed;
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mmp = (struct mmp_struct *)(bh->b_data);
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if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
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mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
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/*
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* If check_interval in MMP block is larger, use that instead of
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* update_interval from the superblock.
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*/
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if (le16_to_cpu(mmp->mmp_check_interval) > mmp_check_interval)
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mmp_check_interval = le16_to_cpu(mmp->mmp_check_interval);
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seq = le32_to_cpu(mmp->mmp_seq);
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if (seq == EXT4_MMP_SEQ_CLEAN)
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goto skip;
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if (seq == EXT4_MMP_SEQ_FSCK) {
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dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
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goto failed;
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}
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wait_time = min(mmp_check_interval * 2 + 1,
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mmp_check_interval + 60);
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/* Print MMP interval if more than 20 secs. */
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if (wait_time > EXT4_MMP_MIN_CHECK_INTERVAL * 4)
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ext4_warning(sb, "MMP interval %u higher than expected, please"
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" wait.\n", wait_time * 2);
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if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
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ext4_warning(sb, "MMP startup interrupted, failing mount\n");
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goto failed;
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}
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retval = read_mmp_block(sb, &bh, mmp_block);
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if (retval)
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goto failed;
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mmp = (struct mmp_struct *)(bh->b_data);
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if (seq != le32_to_cpu(mmp->mmp_seq)) {
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dump_mmp_msg(sb, mmp,
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"Device is already active on another node.");
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goto failed;
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}
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skip:
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/*
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* write a new random sequence number.
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*/
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seq = mmp_new_seq();
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mmp->mmp_seq = cpu_to_le32(seq);
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retval = write_mmp_block(sb, bh);
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if (retval)
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goto failed;
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/*
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* wait for MMP interval and check mmp_seq.
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*/
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if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
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ext4_warning(sb, "MMP startup interrupted, failing mount\n");
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goto failed;
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}
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retval = read_mmp_block(sb, &bh, mmp_block);
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if (retval)
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goto failed;
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mmp = (struct mmp_struct *)(bh->b_data);
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if (seq != le32_to_cpu(mmp->mmp_seq)) {
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dump_mmp_msg(sb, mmp,
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"Device is already active on another node.");
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goto failed;
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}
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mmpd_data = kmalloc(sizeof(struct mmpd_data), GFP_KERNEL);
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if (!mmpd_data) {
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ext4_warning(sb, "not enough memory for mmpd_data");
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goto failed;
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}
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mmpd_data->sb = sb;
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mmpd_data->bh = bh;
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/*
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* Start a kernel thread to update the MMP block periodically.
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*/
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EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, mmpd_data, "kmmpd-%s",
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bdevname(bh->b_bdev,
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mmp->mmp_bdevname));
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if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
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EXT4_SB(sb)->s_mmp_tsk = NULL;
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kfree(mmpd_data);
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ext4_warning(sb, "Unable to create kmmpd thread for %s.",
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sb->s_id);
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goto failed;
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}
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return 0;
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failed:
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brelse(bh);
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return 1;
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}
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