fs/ntfs3: Alternative boot if primary boot is corrupted

Some code refactoring added also.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 5158dd3..ecf899d 100644 (file)
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -724,6 +724,8 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
        struct MFT_REC *rec;
        u16 fn, ao;
        u8 cluster_bits;
+       u32 boot_off = 0;
+       const char *hint = "Primary boot";
 
        sbi->volume.blocks = dev_size >> PAGE_SHIFT;
 
@@ -731,11 +733,12 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
        if (!bh)
                return -EIO;
 
+check_boot:
        err = -EINVAL;
-       boot = (struct NTFS_BOOT *)bh->b_data;
+       boot = (struct NTFS_BOOT *)Add2Ptr(bh->b_data, boot_off);
 
        if (memcmp(boot->system_id, "NTFS    ", sizeof("NTFS    ") - 1)) {
-               ntfs_err(sb, "Boot's signature is not NTFS.");
+               ntfs_err(sb, "%s signature is not NTFS.", hint);
                goto out;
        }
 
@@ -748,14 +751,16 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
                           boot->bytes_per_sector[0];
        if (boot_sector_size < SECTOR_SIZE ||
            !is_power_of_2(boot_sector_size)) {
-               ntfs_err(sb, "Invalid bytes per sector %u.", boot_sector_size);
+               ntfs_err(sb, "%s: invalid bytes per sector %u.", hint,
+                        boot_sector_size);
                goto out;
        }
 
        /* cluster size: 512, 1K, 2K, 4K, ... 2M */
        sct_per_clst = true_sectors_per_clst(boot);
        if ((int)sct_per_clst < 0 || !is_power_of_2(sct_per_clst)) {
-               ntfs_err(sb, "Invalid sectors per cluster %u.", sct_per_clst);
+               ntfs_err(sb, "%s: invalid sectors per cluster %u.", hint,
+                        sct_per_clst);
                goto out;
        }
 
@@ -771,8 +776,8 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
        if (mlcn * sct_per_clst >= sectors || mlcn2 * sct_per_clst >= sectors) {
                ntfs_err(
                        sb,
-                       "Start of MFT 0x%llx (0x%llx) is out of volume 0x%llx.",
-                       mlcn, mlcn2, sectors);
+                       "%s: start of MFT 0x%llx (0x%llx) is out of volume 0x%llx.",
+                       hint, mlcn, mlcn2, sectors);
                goto out;
        }
 
@@ -784,7 +789,7 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 
        /* Check MFT record size. */
        if (record_size < SECTOR_SIZE || !is_power_of_2(record_size)) {
-               ntfs_err(sb, "Invalid bytes per MFT record %u (%d).",
+               ntfs_err(sb, "%s: invalid bytes per MFT record %u (%d).", hint,
                         record_size, boot->record_size);
                goto out;
        }
@@ -801,13 +806,13 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 
        /* Check index record size. */
        if (sbi->index_size < SECTOR_SIZE || !is_power_of_2(sbi->index_size)) {
-               ntfs_err(sb, "Invalid bytes per index %u(%d).", sbi->index_size,
-                        boot->index_size);
+               ntfs_err(sb, "%s: invalid bytes per index %u(%d).", hint,
+                        sbi->index_size, boot->index_size);
                goto out;
        }
 
        if (sbi->index_size > MAXIMUM_BYTES_PER_INDEX) {
-               ntfs_err(sb, "Unsupported bytes per index %u.",
+               ntfs_err(sb, "%s: unsupported bytes per index %u.", hint,
                         sbi->index_size);
                goto out;
        }
@@ -834,7 +839,7 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 
        /* Compare boot's cluster and sector. */
        if (sbi->cluster_size < boot_sector_size) {
-               ntfs_err(sb, "Invalid bytes per cluster (%u).",
+               ntfs_err(sb, "%s: invalid bytes per cluster (%u).", hint,
                         sbi->cluster_size);
                goto out;
        }
@@ -930,7 +935,46 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 
        err = 0;
 
+       if (bh->b_blocknr && !sb_rdonly(sb)) {
+               /*
+                * Alternative boot is ok but primary is not ok.
+                * Update primary boot.
+                */
+               struct buffer_head *bh0 = sb_getblk(sb, 0);
+               if (bh0) {
+                       if (buffer_locked(bh0))
+                               __wait_on_buffer(bh0);
+
+                       lock_buffer(bh0);
+                       memcpy(bh0->b_data, boot, sizeof(*boot));
+                       set_buffer_uptodate(bh0);
+                       mark_buffer_dirty(bh0);
+                       unlock_buffer(bh0);
+                       if (!sync_dirty_buffer(bh0))
+                               ntfs_warn(sb, "primary boot is updated");
+                       put_bh(bh0);
+               }
+       }
+
 out:
+       if (err == -EINVAL && !bh->b_blocknr && dev_size > PAGE_SHIFT) {
+               u32 block_size = min_t(u32, sector_size, PAGE_SIZE);
+               u64 lbo = dev_size - sizeof(*boot);
+
+               /*
+                * Try alternative boot (last sector)
+                */
+               brelse(bh);
+
+               sb_set_blocksize(sb, block_size);
+               bh = ntfs_bread(sb, lbo >> blksize_bits(block_size));
+               if (!bh)
+                       return -EINVAL;
+
+               boot_off = lbo & (block_size - 1);
+               hint = "Alternative boot";
+               goto check_boot;
+       }
        brelse(bh);
 
        return err;
@@ -955,6 +999,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
        struct ATTR_DEF_ENTRY *t;
        u16 *shared;
        struct MFT_REF ref;
+       bool ro = sb_rdonly(sb);
 
        ref.high = 0;
 
@@ -1035,6 +1080,10 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
        sbi->volume.minor_ver = info->minor_ver;
        sbi->volume.flags = info->flags;
        sbi->volume.ni = ni;
+       if (info->flags & VOLUME_FLAG_DIRTY) {
+               sbi->volume.real_dirty = true;
+               ntfs_info(sb, "It is recommened to use chkdsk.");
+       }
 
        /* Load $MFTMirr to estimate recs_mirr. */
        ref.low = cpu_to_le32(MFT_REC_MIRR);
@@ -1069,21 +1118,16 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 
        iput(inode);
 
-       if (sbi->flags & NTFS_FLAGS_NEED_REPLAY) {
-               if (!sb_rdonly(sb)) {
-                       ntfs_warn(sb,
-                                 "failed to replay log file. Can't mount rw!");
-                       err = -EINVAL;
-                       goto out;
-               }
-       } else if (sbi->volume.flags & VOLUME_FLAG_DIRTY) {
-               if (!sb_rdonly(sb) && !options->force) {
-                       ntfs_warn(
-                               sb,
-                               "volume is dirty and \"force\" flag is not set!");
-                       err = -EINVAL;
-                       goto out;
-               }
+       if ((sbi->flags & NTFS_FLAGS_NEED_REPLAY) && !ro) {
+               ntfs_warn(sb, "failed to replay log file. Can't mount rw!");
+               err = -EINVAL;
+               goto out;
+       }
+
+       if ((sbi->volume.flags & VOLUME_FLAG_DIRTY) && !ro && !options->force) {
+               ntfs_warn(sb, "volume is dirty and \"force\" flag is not set!");
+               err = -EINVAL;
+               goto out;
        }
 
        /* Load $MFT. */
@@ -1173,7 +1217,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 
                bad_len += len;
                bad_frags += 1;
-               if (sb_rdonly(sb))
+               if (ro)
                        continue;
 
                if (wnd_set_used_safe(&sbi->used.bitmap, lcn, len, &tt) || tt) {